Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2018	Mar. 11, 2019	Jun. 29, 2018
Document And Entity Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Trading Symbol	CSTR
Entity Registrant Name	CAPSTAR FINANCIAL HOLDINGS, INC.
Entity Central Index Key	0001676479
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Public Float			$ 221,083,857
Voting
Document And Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		17,719,816
Nonvoting
Document And Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		132,561

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets
Cash and due from banks	$ 17,967	$ 9,506
Interest-bearing deposits in financial institutions	76,714	68,572
Federal funds sold	10,762	4,719
Total cash and cash equivalents	105,443	82,797
Securities available-for-sale, at fair value	243,808	192,621
Securities held-to-maturity, fair value of $3,785, and $3,848 at December 31, 2018 and 2017, respectively	3,734	3,759
Loans held for sale	57,618	74,093
Loans, net of unearned income	1,429,794	947,537
Less allowance for loan losses	(12,113)	(13,721)
Loans, net	1,417,681	933,816
Premises and equipment, net	18,821	5,884
Restricted equity securities	12,038	8,806
Accrued interest receivable	5,964	4,084
Goodwill	37,510	6,219
Core deposit intangible, net	8,538	23
Other real estate owned, net	988	0
Other assets	51,740	32,327
Total assets	1,963,883	1,344,429
Deposits:
Non-interest-bearing	289,552	301,742
Interest-bearing	434,921	274,681
Savings and money market accounts	497,108	367,246
Time	348,427	176,197
Total deposits	1,570,008	1,119,866
Federal Home Loan Bank advances	125,000	70,000
Other liabilities	14,496	7,617
Total liabilities	1,709,504	1,197,483
Shareholders’ equity:
Series A convertible preferred stock, $1 par value; 5,000,000 shares authorized; 878,049 shares issued and outstanding at December 31, 2018 and 2017	878	878
Additional paid-in capital	211,789	118,120
Retained earnings	27,303	18,892
Accumulated other comprehensive loss, net of income tax	(3,316)	(2,527)
Total shareholders’ equity	254,379	146,946
Total liabilities and shareholders’ equity	1,963,883	1,344,429
Nonvoting
Shareholders’ equity:
Common stock	133	133
Voting
Shareholders’ equity:
Common stock	$ 17,592	$ 11,450

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Securities held to maturity, fair value	$ 3,785	$ 3,848
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	878,049	878,049
Preferred stock, shares outstanding	878,049	878,049
Voting
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	20,000,000	20,000,000
Common stock, shares issued	17,592,160	17,592,160
Common stock, shares outstanding	11,449,465	11,449,465
Nonvoting
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	5,000,000	5,000,000
Common stock, shares issued	132,561	132,561
Common stock, shares outstanding	132,561	132,561

Consolidated Statements of Income - USD ($)	12 Months Ended
Consolidated Statements of Income - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest income:
Loans, including fees	$ 60,751,000	$ 45,601,000	$ 40,213,000
Securities:
Taxable	4,184,000	3,696,000	3,448,000
Tax-exempt	1,201,000	1,230,000	1,158,000
Federal funds sold	63,000	41,000	19,000
Restricted equity securities	571,000	396,000	281,000
Interest-bearing deposits in financial institutions	1,011,000	551,000	276,000
Total interest income	67,781,000	51,515,000	45,395,000
Interest expense:
Interest-bearing deposits	4,164,000	2,447,000	1,489,000
Savings and money market accounts	5,446,000	3,188,000	2,859,000
Time deposits	3,940,000	2,445,000	2,085,000
Federal funds purchased	3,000	13,000	22,000
Securities sold under agreements to repurchase	3,000		1,000
Federal Home Loan Bank advances	2,533,000	1,559,000	475,000
Total interest expense	16,089,000	9,652,000	6,931,000
Net interest income	51,692,000	41,863,000	38,464,000
Provision for loan losses	2,842,000	12,870,000	2,829,000
Net interest income after provision for loan losses	48,850,000	28,993,000	35,635,000
Noninterest income:
Noninterest income	5,653,000	6,238,000	7,375,000
Net gain (loss) on sale of securities	3,000	(66,000)	121,000
Tri-Net fees	1,503,000	1,002,000	125,000
Bank owned life insurance income	2,660,000	578,000	601,000
Other noninterest income	3,490,000	1,640,000	1,754,000
Total noninterest income	15,459,000	10,908,000	11,084,000
Noninterest expense:
Salaries and employee benefits	28,586,000	20,400,000	20,461,000
Data processing and software	3,835,000	2,786,000	2,373,000
Professional fees	1,608,000	1,522,000	1,554,000
Occupancy	2,336,000	2,025,000	1,498,000
Equipment	2,471,000	2,071,000	1,743,000
Regulatory fees	1,028,000	1,111,000	1,091,000
Merger related expenses	9,803,000
Amortization of intangibles	465,000	48,000	54,000
Other operating	3,355,000	3,802,000	4,355,000
Total noninterest expense	53,487,000	33,765,000	33,129,000
Income before income taxes	10,822,000	6,136,000	13,590,000
Income tax expense	1,167,000	4,635,000	4,493,000
Net income	$ 9,655,000	$ 1,501,000	$ 9,097,000
Per share information:
Basic net income per share of common stock	$ 0.73	$ 0.13	$ 0.98
Diluted net income per share of common stock	$ 0.67	$ 0.12	$ 0.81
Weighted average shares outstanding:
Basic	13,277,614	11,280,580	9,328,236
Diluted	14,480,347	12,803,511	11,212,026
Treasury Management And Other Deposit Service Charges
Noninterest income:
Noninterest income	$ 2,150,000	$ 1,516,000	$ 1,108,000
Mortgage Banking Income
Noninterest income:
Noninterest income	$ 5,653,000	$ 6,238,000	$ 7,375,000

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 9,655	$ 1,501	$ 9,097
Unrealized gains (losses) on securities available-for-sale:
Unrealized holding gains (losses) arising during the period	(2,491)	4,855	(1,181)
Reclassification adjustment for (gains) losses included in net income	(3)	66	(121)
Tax effect	652	(1,884)	499
Net of tax	(1,842)	3,037	(803)
Unrealized losses on securities transferred to held-to-maturity:
Reclassification adjustment for losses included in net income	14	190	167
Tax effect	(4)	(73)	(64)
Net of tax	10	117	103
Unrealized gains (losses) on cash flow hedges:
Unrealized holding gains (losses) arising during the period	263	(72)	(330)
Reclassification adjustment for losses included in net income	920	863	416
Tax effect	(140)	(62)	(623)
Net of tax	1,043	729	(537)
Other comprehensive income (loss)	(789)	3,883	(1,237)
Comprehensive income	$ 8,866	$ 5,384	$ 7,860

Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock, Voting	Common Stock, Nonvoting	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning balance at Dec. 31, 2015	$ 108,586	$ 1,610	$ 8,577		$ 95,278	$ 8,035	$ (4,914)
Beginning balance, shares at Dec. 31, 2015			8,577,051
Issuance of restricted common stock, net of forfeitures and withholdings to satisfy employee tax obligations	(33)		$ 100		(133)
Issuance of restricted common stock, net of forfeitures and withholdings to satisfy employee tax obligations, shares			99,560
Stock-based compensation expense	842				842
Excess tax benefit from stock compensation	61				61
Exercise of common stock options, net of withholdings to satisfy employee tax obligations	96		$ 8		88
Exercise of common stock options, net of withholdings to satisfy employee tax obligations, shares			8,125
Issuance of common stock	21,563		$ 1,688		19,875
Issuance of common stock, shares			1,688,049
Conversion of preferred stock		(732)	$ 732
Conversion of preferred stock, shares			731,707
Exercise of common stock warrants	232		$ 100		132
Exercise of common stock warrants, shares			100,023
Net income	9,097					9,097
Other Comprehensive income (loss)	(1,237)						(1,237)
Ending balance at Dec. 31, 2016	139,207	878	$ 11,205		116,143	17,132	(6,151)
Ending balance, shares at Dec. 31, 2016			11,204,515
Issuance of restricted common stock, net of forfeitures and withholdings to satisfy employee tax obligations	(244)		$ 36		(280)
Issuance of restricted common stock, net of forfeitures and withholdings to satisfy employee tax obligations, shares			35,714
Stock-based compensation expense	1,061				1,061
Exercise of common stock options, net of withholdings to satisfy employee tax obligations	1,011		$ 154		857
Exercise of common stock options, net of withholdings to satisfy employee tax obligations, shares			154,050
Exercise of common stock warrants	527		$ 55	$ 133	339
Exercise of common stock warrants, shares			55,186	132,561
Reclassification of accumulated other comprehensive income due to tax rate change						259	(259)
Net income	1,501					1,501
Other Comprehensive income (loss)	3,883						3,883
Ending balance at Dec. 31, 2017	146,946	878	$ 11,450	$ 133	118,120	18,892	(2,527)
Ending balance, shares at Dec. 31, 2017			11,449,465	132,561
Beginning balance at Dec. 31, 2017	146,946	878	$ 11,450	$ 133	118,120	18,892	(2,527)
Beginning balance, shares at Dec. 31, 2017			11,449,465	132,561
Issuance of restricted common stock, net of forfeitures and withholdings to satisfy employee tax obligations	(445)		$ 107		(552)
Issuance of restricted common stock, net of forfeitures and withholdings to satisfy employee tax obligations, shares			107,640
Stock-based compensation expense	2,079				2,079
Exercise of common stock options, net of withholdings to satisfy employee tax obligations	3,653		$ 667		2,986
Exercise of common stock options, net of withholdings to satisfy employee tax obligations, shares			666,964
Exercise of common stock warrants	1,606		$ 186		1,420
Exercise of common stock warrants, shares			186,175
Issuance of common stock in conjunction with Athens acquisition, net of issuance costs	92,918		$ 5,182		87,736
Issuance of common stock in conjunction with Athens acquisition, net of issuance costs			5,181,916
Common and preferred stock dividends declared ($0.04 per share)	(1,244)					(1,244)
Net income	9,655					9,655
Other Comprehensive income (loss)	(789)						(789)
Ending balance at Dec. 31, 2018	254,379	878	$ 17,592	$ 133	211,789	27,303	(3,316)
Ending balance, shares at Dec. 31, 2018			17,592,160	132,561
Net income	(708)
Ending balance at Dec. 31, 2018	$ 254,379	$ 878	$ 17,592	$ 133	$ 211,789	$ 27,303	$ (3,316)
Ending balance, shares at Dec. 31, 2018			17,592,160	132,561

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
Consolidated Statements of Cash Flows - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 9,655,000	$ 1,501,000	$ 9,097,000
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Provision for loan losses	2,842,000	12,870,000	2,829,000
Accretion of discounts on acquired loans and deferred fees	(2,978,000)	(1,533,000)	(1,677,000)
Depreciation and amortization	1,028,000	450,000	422,000
Net amortization of premiums on investment securities	1,007,000	1,259,000	1,527,000
Securities (gains) losses, net	(3,000)	66,000	(121,000)
Mortgage banking income	$ (5,653,000)	$ (6,238,000)	$ (7,375,000)
Type of Revenue [Extensible List]	us-gaap:MortgageBankingMember	us-gaap:MortgageBankingMember	us-gaap:MortgageBankingMember
Tri-Net fees	$ (1,503,000)	$ (1,002,000)	$ (125,000)
Net (gain) loss on sale of loans	(248,000)	(113,000)
Net (gain) loss on disposal of premises and equipment		137,000
Net (gain) loss on sale of other real estate owned	0	0	(157,000)
Stock-based compensation	2,079,000	1,061,000	842,000
Excess tax benefit from stock compensation			(61,000)
Deferred income tax (benefit) expense	1,175,000	4,385,000	(295,000)
Origination of loans held for sale	(516,341,000)	(565,372,000)	(522,038,000)
Proceeds from loans held for sale	540,448,000	540,123,000	523,156,000
Net (increase) decrease in accrued interest receivable and other assets	1,395,000	(1,760,000)	(1,537,000)
Net increase (decrease) in accrued interest payable and other liabilities	461,000	(2,448,000)	1,814,000
Net cash provided by (used in) operating activities	33,364,000	(16,614,000)	6,301,000
Activities in securities available-for-sale:
Purchases	(44,787,000)	(30,525,000)	(81,946,000)
Sales	38,322,000	46,762,000	46,700,000
Maturities, prepayments and calls	19,245,000	18,828,000	23,644,000
Activities in securities held-to-maturity:
Purchases			(5,337,000)
Maturities, prepayments and calls		1,560,000	1,656,000
Purchase of restricted equity securities	(12,000)	(2,774,000)	(618,000)
Net increase in loans	(139,124,000)	(20,916,000)	(126,505,000)
Purchase of premises and equipment	(4,244,000)	(1,075,000)	(814,000)
Proceeds from the sale of premises and equipment		3,000
Proceeds from BOLI death benefit	3,416,000
Cash received from acquisitions, net	12,053,000
Proceeds from sale of other real estate			373,000
Net cash provided by (used in) investing activities	(115,131,000)	11,863,000	(142,847,000)
Cash flows from financing activities:
Net increase (decrease) in deposits	45,622,000	(8,857,000)	90,262,000
Proceeds from Federal Home Loan Bank advances	125,000,000	135,000,000	55,000,000
Payments on Federal Home Loan Bank advances	(70,000,000)	(120,000,000)	(45,000,000)
Proceeds from issuance of common stock			21,563,000
Exercise of common stock options and warrants, net of repurchase of restricted shares	4,814,000	1,294,000	295,000
Excess tax benefit from stock compensation			61,000
Termination of interest rate swap agreement			(1,954,000)
Common and preferred stock dividends paid	(1,244,000)
Net increase (decrease) in repurchase agreements	221,000		(3,755,000)
Net cash provided by financing activities	104,413,000	7,437,000	116,472,000
Net increase (decrease) in cash and cash equivalents	22,646,000	2,686,000	(20,074,000)
Cash and cash equivalents at beginning of period	82,797,000	80,111,000	100,185,000
Cash and cash equivalents at end of period	105,443,000	82,797,000	80,111,000
Supplemental disclosures of cash paid:
Interest paid	15,378,000	9,540,000	6,897,000
Income taxes	1,716,000	1,047,000	4,114,000
Supplemental disclosures of noncash transactions:
Loans charged off to the allowance for loan and lease losses	$ 4,954,000	12,769,000	$ 1,452,000
Securities transferred from held-to-maturity to available-for-sale		41,665,000
Loans transferred from held-for-sale to held-for-investment		$ 507,000

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

NOTE 1 – SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Basis of Presentation

The consolidated financial statements as of December 31, 2018 and 2017 and for each of the three years in the period ended December 31, 2018 include CapStar Financial Holdings, Inc. and it’s wholly owned subsidiary, CapStar Bank (the “Bank”, together referred to as the “Company”). Significant intercompany transactions and accounts are eliminated in consolidation. On February 5, 2016, CapStar Financial Holdings, Inc. acquired all of the Bank’s issued and outstanding shares of common stock, preferred stock, common stock options and warrants, and the Bank became the wholly owned subsidiary of CapStar Financial Holdings, Inc. (the “Share Exchange”).

The consolidated financial statements of the Company have been prepared in conformity with U.S. generally accepted accounting principles (“GAAP”) and conform to general practices within the banking industry.

Business Combinations

The Company accounts for business combinations using the acquisition method of accounting. The accounts of an acquired entity are included as of the date of acquisition, and any excess of purchase price over the fair value of the net assets acquired is capitalized as goodwill. Under this method, all identifiable assets acquired, including purchased loans, and liabilities assumed are recorded at fair value.

The Company typically issues common stock and/or pays cash for an acquisition, depending on the terms of the acquisition agreement. The value of shares of common stock issued is determined based on the market price of the stock as of the closing of the acquisition.

Nature of Operations

Through the Bank, the Company provides full banking services to consumer and corporate customers located primarily in Tennessee. The Bank operates under a state bank charter and is a member of the Federal Reserve System. As a state member bank, the Bank is subject to regulations of the Tennessee Department of Financial Institutions, the Board of Governors of the Federal Reserve System (the “Federal Reserve”), and the Federal Deposit Insurance Corporation.

Initial Public Offering

On September 21, 2016, the Securities and Exchange Commission (“SEC”) declared effective our registration statement on Form S-1 registering shares of our common stock. On September 27, 2016, we completed the initial public offering of 2,972,750 shares of our common stock. Of the 2,972,750 shares sold, 1,688,049 shares were sold by us and 1,284,701 shares were sold by certain selling shareholders. Of the 1,284,701 shares sold by certain selling shareholders, 731,707 were from shares of preferred stock converted to shares of common stock and 79,166 from the cashless exercise of 250,000 common stock warrants. We received net proceeds of approximately $21.6 million from the offering, after deducting the underwriting discounts and offering expenses. We did not receive any proceeds from the sale of shares by the selling shareholders.

Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Material estimates that are particularly susceptible to significant change relate to the determination of the allowance for loan losses, determination of impairment of intangible assets, including goodwill, the valuation of our investment portfolio and deferred tax assets.

Cash and Cash Equivalents

For purposes of reporting cash flows, cash and cash equivalents include cash on hand, amounts due from banks, interest-bearing deposits in financial institutions and federal funds sold. Generally, federal funds sold are purchased and sold for one-day periods. The Company maintains deposits in excess of the federal insurance amounts with other financial institutions. Management makes deposits only with financial institutions it considers to be financially sound.

Securities

The Bank accounts for securities under the provisions of Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 320, Investments – Debt and Equity Securities. Under the provisions of FASB ASC 320, securities are to be classified in three categories and accounted for as follows:

Securities Held to Maturity - Debt securities are classified as held to maturity securities when the Bank has the positive intent and ability to hold the securities to maturity. Securities held to maturity are carried at amortized cost.

Trading Securities - Debt and equity securities that are bought and held principally for the purpose of selling them in the near term are classified as trading securities and reported at fair value, with unrealized gains and losses included in earnings. No securities have been classified as trading securities.

Securities Available for Sale - Debt and equity securities not classified as either held to maturity securities or trading securities are classified as available for sale securities. Securities available for sale are carried at estimated fair value with unrealized gains and losses excluded from earnings and reported as a separate component of shareholders’ equity in other comprehensive income (loss).

Interest income includes amortization of purchase premiums or discounts. Premiums and discounts on securities are amortized on the level-yield method without anticipating prepayments, except for mortgage-backed securities where prepayments are anticipated. Realized gains and losses from the sales of securities are recorded on the trade date and determined using the specific-identification method.

Management evaluates securities for other-than-temporary impairment (“OTTI”) on at least a quarterly basis, and more frequently when economic or market conditions warrant such an evaluation. For securities in an unrealized loss position, management considers the extent and duration of the unrealized loss, the financial condition and near-term prospects of the issuer and any collateral underlying the relevant security. Management also assesses whether it intends to sell, or it is more likely than not that it will be required to sell, a security in an unrealized loss position before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the entire difference between amortized cost and fair value is recognized as impairment through earnings. For debt securities that do not meet the aforementioned criteria, the amount of impairment is split into two components as follows: (1) OTTI related to credit loss, which must be recognized in the income statement and (2) OTTI related to other factors, which is recognized in other comprehensive income (loss). The credit loss is defined as the difference between the present value of the cash flows expected to be collected and the amortized cost basis. For equity securities, the entire amount of impairment is recognized through earnings.

Loans Held for Sale

Mortgage loans originated and intended for sale in the secondary market are carried at the lower of aggregate cost or fair value, as determined by outstanding commitments from investors. Net unrealized losses, if any, are recorded as a valuation allowance and charged to earnings. Realized gains and losses are recognized when legal title of the loan has transferred to the investor and sales proceeds have been received and are reflected in the accompanying statement of income in gain on sale of loans, net of related costs such as commission expenses. The Company does not securitize mortgage loans. If the Company sells loans with servicing rights retained, the carrying value of the mortgage loan sold is reduced by the amount allocated to the servicing right.

Tri-Net Fees

Tri-Net fees represent a line of business, implemented in the fourth quarter of 2016, which originates, with the intent to sell, commercial real estate loans to third-party investors. All of these loan sales transfer servicing rights to the buyer. Realized gains and losses are recognized when legal title of the loan has transferred to the investor and sales proceeds have been received and are reflected in the accompanying statements of income in Tri-Net fees, net of related costs such as commission expenses. Loans that have not been sold at period end are classified as held for sale on the balance sheet and recorded at the lower of aggregate cost or fair value. Net unrealized losses, if any, are recorded as a valuation allowance and charged to earnings.

Loans

The Company has six classes of loans for financial reporting purposes: commercial real estate, consumer real estate, construction and land development, commercial and industrial, consumer and other. The appropriate classification is determined based on the underlying collateral utilized to secure each loan.

Commercial real estate loans are categorized as such based on investor exposures where repayment is largely dependent upon the operation, refinance, or sale of the underlying real estate. Commercial real estate also includes owner occupied commercial real estate.

Consumer real estate consists primarily of 1-4 family residential properties including home equity lines of credit.

Construction and land development loans include loans where the repayment is dependent on the successful completion and operation and/or sale of the related real estate project. Construction and land development loans include 1-4 family construction projects and commercial construction endeavors such as warehouses, apartments, office and retail space and land acquisition and development.

Commercial and industrial loans include loans to business enterprises issued for commercial, industrial and/or other professional purposes.

Consumer loans include all loans issued to individuals not included in the consumer real estate class.

Other loans include all loans not included in the classes of loans above and leases.

Loans that management has the intent and ability to hold for the foreseeable future or until maturity or payoff are reported at the principal balance outstanding, net of purchase premiums and discounts, deferred loan fees and costs, and an allowance for loan losses. Interest income is accrued on the unpaid principal balance. Loan origination fees, net of certain direct origination costs, are deferred and recognized in interest income using the level-yield method without anticipating prepayments.

The accrual of interest on loans is discontinued at the time the loan is 90 days past due unless the credit is well secured and in process of collection. Consumer loans and any accrued interest is typically charged off no later than 180 days past due. Past due status is based on contractual terms of the loan. In all cases, loans are placed on nonaccrual or charged off at an earlier date if collection of principal or interest is considered doubtful and collection is highly questionable. Amortization of deferred loan fees is discontinued when a loan is placed on nonaccrual status.

All interest accrued but not received for loans placed on nonaccrual is reversed against interest income. Interest received on such loans is accounted for on the cash-basis or cost-recovery method, until qualifying for return to accrual status. Under the cost-recovery method, interest income is not recognized until the loan balance is reduced to zero. Under the cash-basis method, interest income is recorded when the payment is received in cash. Loans are returned to accrual status when all the principal and interest amounts contractually due are brought current and future payments are reasonably assured. Loans can also be returned to accrual status when they become well secured and in the process of collection.

Acquired Loans

Acquired loans are accounted for under the acquisition method of accounting. The acquired loans are recorded at their estimated fair values as of the acquisition date. Fair value of acquired loans is determined using a discounted cash flow model based on assumptions regarding the amount and timing of principal and interest payments, estimated prepayments, estimated default rates, estimated loss severity in the event of defaults, and current market rates. Estimated credit losses are included in the determination of fair value; therefore, an allowance for loan losses is not recorded on the acquisition date.

An acquired loan is considered purchased credit impaired when there is evidence of credit deterioration since origination and it is probable at the date of acquisition that the Bank will be unable to collect all contractually required payments.

Purchased credit impaired loans are accounted for individually or aggregated into pools of loans based on common risk characteristics such as loan type and risk rating. The Company estimates the amount and timing of expected cash flows for each loan or pool, and the expected cash flows in excess of amount paid (fair value) is recorded as interest income over the remaining life of the loan or pool (accretable yield). The excess of the loan’s or pool’s contractual principal and interest over expected cash flows is not recorded (nonaccretable difference). Over the life of the loan or pool, expected cash flows continue to be estimated. If the present value of expected cash flows is less than the carrying amount, a loss is recorded as a provision for loan losses. If the present value of expected cash flows is greater than the carrying amount, it is recognized as part of future interest income.

Acquired non-impaired loans are recorded at their initial fair value and adjusted for subsequent advances, pay downs, amortization or accretion of any premium or discount on purchase, charge-offs and additional provisioning that may be required.

Allowance for Loan losses

The allowance for loan losses (“ALL”) is maintained at a level that management believes to be adequate to absorb expected loan losses inherent in the loan portfolio as of the balance sheet date. The allowance for loan losses is a valuation allowance for estimated credit losses inherent in the loan and lease portfolio, increased by the provision for loan losses and decreased by charge-offs, net of recoveries. Quarterly, the Company estimates the allowance required using peer group loss experience, the nature and volume of the portfolio, information about specific borrower situations and estimated collateral values, economic conditions, and other factors. The Company’s historical loss experience is based on the actual loss history by class of loan for comparable peer institutions due to the Company’s limited loss history. Allocations of the allowance may be made for specific loans, but the entire allowance is available for any loan that, in management’s judgment, should be charged off. Loan losses are charged against the allowance when management believes the uncollectibility of a loan balance is confirmed. Subsequent recoveries are credited to the allowance for loan losses.

The Company also considers the results of the external independent loan review when assessing the adequacy of the allowance and incorporates relevant loan review results in the loan impairment and overall adequacy of allowance determinations. Furthermore, regulatory agencies periodically review the Company’s allowance for loan losses and may require the Company to record adjustments to the allowance based on their judgment of information available to them at the time of their examinations.

Additional considerations are included in the determination of the adequacy of the allowance based on the continuous review conducted by relationship managers and credit department personnel. The Company’s loan policy requires that each customer relationship wherein total exposure exceeds $1.5 million be subject to a formal credit review at least annually. Should these reviews identify potential collection concerns, appropriate adjustments to the allowance may be made.

The allowance consists of specific and general components as discussed below. While the allowance consists of separate components, these terms are primarily used to describe a process. Both portions of the allowance are available to provide for inherent losses in the entire portfolio.

Specific Component

The specific component relates to loans that are individually determined to be impaired when, based on current information and events, it is probable that the Company will be unable to collect all amounts due according to the contractual terms of the loan agreement. Loans for which the terms have been modified resulting in a concession, and for which the borrower is experiencing financial difficulties, are considered troubled debt restructurings (“TDRs”) and classified as impaired.

Factors considered by management in determining impairment include payment status, collateral value, and the probability of collecting scheduled principal and interest payments when due. Loans that experience insignificant payment delays and payment shortfalls generally are not classified as impaired. Management determines the significance of payment delays and payment shortfalls on a case-by-case basis, taking into consideration all of the circumstances surrounding the loan and the borrower, including the length of the delay, the reasons for the delay, the borrower’s prior payment record, and the amount of the shortfall in relation to the principal and interest owed.

Loans meeting any of the following criteria are individually evaluated for impairment: risk rated substandard (as defined in Note 4), on non-accrual status or past due greater than 90 days. If a loan is impaired, a portion of the allowance is allocated based on the present value of estimated future cash flows using the loan’s existing rate or at the fair value of collateral less costs to sell if repayment is expected solely from the collateral. Changes to the valuation allowance are recorded as a component of the provision for loan losses.

TDRs are individually evaluated for impairment and included in the separately identified impairment disclosures. TDRs are measured at the present value of estimated future cash flows using the loan’s effective rate at inception. If a TDR is considered to be a collateral dependent loan, the loan is reported, net, at the fair value of the collateral less costs to sell.

General Component

The general component of the allowance for loan losses covers loans that are collectively evaluated for impairment. Large groups of homogeneous loans are collectively evaluated for impairment, and accordingly, they are not included in the separately identified impairment disclosures. The general allowance component also includes loans that are individually identified for impairment evaluation but are not considered impaired. The general component is based on historical loss experience adjusted for current factors. Due to the Company’s limited loss history, the historical loss experience is based on the actual loss history by class of loan for comparable peer institutions.

The Company utilized a 28 quarter look-back period as of December 31, 2016 and a 33 quarter look-back period as of December 31, 2017. Subsequently, the Company increased its look-back period for a total of 37 quarters as of December 31, 2018. In the current economic environment, management believes the extension of the look-back period was necessary in order to capture sufficient loss observations to develop a reliable loss estimate of credit losses. This extension of the historical look-back period to capture the historical loss experience of peer banks was applied to all classes and segments of our loan portfolio.

The actual loss experience is supplemented with other environmental factors that capture changes in trends, conditions, and other relevant factors that may cause estimated credit losses as of the evaluation date to differ from historical loss experience. The allocation for environmental factors is by nature subjective. These amounts represent estimated probable inherent credit losses, which exist but have not been captured in the historical loss experience. The environmental factors include consideration of the following: changes in lending policies and procedures, economic conditions, nature and volume of the portfolio, experience of lending management, volume and severity of past due loans, quality of the loan review system, value of underlying collateral for collateral dependent loans, concentrations, and other external factors.

Servicing Rights

When mortgage loans are sold with servicing retained, servicing rights are initially recorded at fair value with the income statement effect recorded in other noninterest income. Fair value is based on market prices for comparable mortgage servicing contracts, when available or alternatively, is based on a valuation model that calculates the present value of estimated future net servicing income. All classes of servicing assets are subsequently measured using the amortization method which requires servicing rights to be amortized into non-interest income in proportion to, and over the period of, the estimated future net servicing income of the underlying loans.

Servicing rights are evaluated for impairment based upon the fair value of the rights as compared to carrying amount. Impairment is determined by stratifying rights into groupings based on predominant risk characteristics, such as interest rate, loan type and investor type. Impairment is recognized through a valuation allowance for an individual grouping, to the extent that fair value is less than the carrying amount. If the Company later determines that all or a portion of the impairment no longer exists for a particular grouping, a reduction of the allowance may be recorded as an increase to income. Changes in valuation allowances are reported with other noninterest income on the income statement. The fair values of servicing rights are subject to significant fluctuations as a result of changes in estimated and actual prepayment speeds and default rates and losses.

Servicing fee income, which is reported on the income statement within other noninterest income, is recorded for fees earned for servicing loans. The fees are based on a contractual percentage of the outstanding principal; or a fixed amount per loan and are recorded as income when earned. The amortization of mortgage servicing rights is netted against loan servicing fee income. Net servicing fees totaled $102,000 for the year ended December 31, 2018. There were no servicing fees for the years ended December 31, 2017 or 2016. Late fees and ancillary fees related to loan servicing are not material.

Transfers of Financial Assets

Transfers of financial assets are accounted for as sales, when control over the assets has been relinquished. Control over transferred assets is deemed to be surrendered when the assets have been isolated from the Bank, the transferee obtains the right (free of conditions that constrain it from taking advantage of that right) to pledge or exchange the transferred assets, and the Company does not maintain effective control over the transferred assets through an agreement to repurchase them before their maturity.

Premises and Equipment

Premises and equipment are stated at cost less accumulated depreciation and amortization. Depreciation is computed principally by the straight-line method over the estimated useful lives of the assets. Leasehold improvements are amortized by the straight-line method based on the shorter of the asset lives or the expected lease terms. Useful lives for premises and equipment range from three to thirty-nine years.

These assets are reviewed for impairment when events indicate their carrying amount may not be recoverable from future undiscounted cash flows. If impaired, the assets are recorded at fair value.

The Company is the lessee with respect to several office locations. All such leases are accounted for as operating leases within the accompanying financial statements. These leases include rent escalation clauses. The Company expenses the costs associated with these escalating payments over the life of the expected lease term using the straight-line method. As of December 31, 2018, the deferred liability associated with these escalating rentals was approximately $639,000 and is included in other liabilities in the accompanying balance sheets.

Bank Owned Life Insurance

The Bank has purchased life insurance policies on certain key executives. Bank owned life insurance is recorded at the amount that can be realized under the insurance contract at the balance sheet date, which is the cash surrender value adjusted for other charges or other amounts due that are probable at settlement.

Securities Sold under Agreements to Repurchase

The Bank enters into sales of securities under agreements to repurchase at a specified future date. Such repurchase agreements are considered financing arrangements and, accordingly, the obligation to repurchase assets sold is reflected as a liability in the balance sheets of the Bank. Repurchase agreements are collateralized by debt securities which are owned and under the control of the Bank.

Goodwill and Other Intangible Assets

Goodwill resulting from business combinations is generally determined as the excess of the fair value of the consideration transferred, plus the fair value of any noncontrolling interests in the acquiree, over the fair value of the net assets acquired and liabilities assumed as of the acquisition date. Goodwill and intangible assets acquired in a purchase business combination and determined to have an indefinite useful life are not amortized, but tested for impairment at least annually or more frequently if events and circumstances exists that indicate that a goodwill impairment test should be performed. The Company has selected October 31st as the date to perform the annual impairment test. Intangible assets with definite useful lives are amortized over their estimated useful lives to their estimated residual values. Goodwill is the only intangible asset with an indefinite life on the balance sheet.

Other intangible assets consist of core deposit intangible assets arising from whole bank acquisitions and are amortized on an accelerated method over their estimated useful lives, which range from six to ten years.

Other Real Estate Owned

Other real estate owned (“OREO”) includes assets that have been acquired in satisfaction of debt through foreclosure and are recorded at estimated fair value less the estimated cost of disposition. Fair value is based on independent appraisals and other relevant factors. Valuation adjustments required at foreclosure are charged to the allowance for loan losses. Subsequent to foreclosure, additional losses resulting from the periodic revaluation of the property are charged to other real estate expense. Costs of operating and maintaining the properties and any gains or losses recognized on disposition are also included in other real estate expense. Improvements made to properties are capitalized if the expenditures are expected to be recovered upon the sale of the properties.

Restricted Equity Securities

The Bank is a member of the FHLB system. Members are required to own a certain amount of stock based on the level of borrowings and other factors, and may invest additional amounts. FHLB stock is carried at cost, classified as a restricted equity security, and periodically evaluated for impairment based on an assessment of the ultimate recovery of par value. Both cash and stock dividends are reported as income.

The Bank is also a member of the Federal Reserve System, and as such, holds stock of the Federal Reserve Bank of Atlanta (“Federal Reserve Bank”). Federal Reserve Bank stock is carried at cost, classified as a restricted equity security, and periodically evaluated for impairment based on ultimate recovery of par value. Both cash and stock dividends are reported as income.

Income Taxes

Income tax expense is the total of the current year income tax due or refundable and the change in deferred tax assets and liabilities. Deferred tax assets and liabilities are the expected future tax amounts for the temporary differences between carrying amounts and tax bases of assets and liabilities, computed using enacted tax rates. A valuation allowance, if needed, reduces deferred tax assets to the amount expected to be realized.

A tax position is recognized as a benefit only if it is “more likely than not” that the tax position would be sustained in a tax examination, with a tax examination being presumed to occur. The amount recognized is the largest amount of tax benefit that is greater than 50% likely of being realized on examination. For tax positions not meeting the “more likely than not” test, no tax benefit is recorded. The Company’s tax returns remain open to audit under the statute of limitations by the IRS and various states for the years ended December 31, 2015 through 2018. It is the Company’s policy to recognize interest and/or penalties related to income tax matters in income tax expense.

Stock-Based Compensation

Stock-based compensation expense is recognized based on the fair value of the portion of stock-based payment awards that are ultimately expected to vest, reduced for estimated forfeitures. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods, if actual forfeitures differ from those estimates. A Black-Scholes model is utilized to estimate the fair value of stock options, while the market price of the Company’s common stock at the date of grant is used for restricted stock awards. Compensation expense is recognized over the required service period, generally defined as the vesting period. For awards with graded vesting, compensation expense is recognized on a straight-line basis over the requisite service period for the entire award. For awards with performance vesting criteria, anticipated performance is projected to determine the number of awards expected to vest, and the corresponding aggregate expense is adjusted to reflect the elapsed portion of the performance period.

Advertising Costs

Advertising costs are expensed as incurred. Advertising expense was approximately $383,000, $310,000 and $252,000 for the years ended December 31, 2018, 2017 and 2016, respectively.

Off-Balance Sheet Financial Instruments

In the ordinary course of business, the Bank has entered into off-balance-sheet financial instruments consisting of commitments to extend credit and standby letters of credit. Such financial instruments are recorded in the financial statements when they are funded or related fees are incurred or received.

Derivative Instruments

Derivative instruments are recorded on the balance sheet at their respective fair values. The accounting for changes in fair value (i.e., gains or losses) of a derivative instrument depends on whether it has been designated and qualifies as part of a hedging relationship. If the derivative instrument is not designated as a hedge, the gain or loss on the derivative instrument is recognized in earnings in the period of change.

The Bank enters into interest rate swaps (“swaps”) to facilitate customer transactions and meet their financing needs. Upon entering into these arrangements to meet customer needs, the Bank enters into offsetting positions with large U.S. financial institutions in order to minimize risk to the Bank. These swaps are derivatives, but are not designated as hedging instruments.

The Bank also has forward starting cash flow hedges to manage its future interest rate exposure. These derivative contracts have been designated as hedges and, as such, changes in the fair value of these derivative instruments are recorded in other comprehensive income (loss). The Bank prepares written hedge documentation for all derivatives which are designated as hedges. The written hedge documentation includes identification of, among other items, the risk management objective, hedging instrument, hedged item and methodologies for assessing and measuring hedge effectiveness and ineffectiveness, along with support for management’s assertion that the hedge will be highly effective.

The effective portion of the changes in the fair value of a derivative that is highly effective and that has been designated and qualifies as a cash flow hedge are initially recorded in accumulated other comprehensive income (loss) and subsequently reclassified into earnings in the same period during which the hedged item affects earnings. The ineffective portion, if any, would be recognized in current period earnings.

The Bank discontinues hedge accounting when it determines that the derivative is no longer effective in offsetting changes in the cash flows of the hedged item, the derivative is settled or terminates, or treatment of the derivative as a hedge is no longer appropriate or intended. When hedge accounting is discontinued, subsequent changes in fair value of the derivative are recorded as non-interest income. When a cash flow hedge is discontinued but the hedged cash flows or forecasted transactions are still expected to occur, gains or losses that were accumulated in other comprehensive income (loss) are amortized into earnings over the same periods which the hedged transactions will affect earnings.

Cash flows resulting from the derivative financial instruments that are accounted for as hedges are classified in the cash flow statement in the same category as the cash flows of the items being hedged.

Comprehensive Income

Comprehensive income consists of net income and other comprehensive income (loss). Other comprehensive income includes unrealized gains and losses on securities available for sale, unrealized gains and losses on securities transferred to held to maturity and unrealized gains and losses on cash flow hedges which are also recognized as separate components of equity. The Bank’s policy is to release the income tax effects of items in accumulated other comprehensive income (loss) when the item is realized.

Fair Value Measurements

Fair values of financial instruments are estimated using relevant market information and other assumptions, as more fully disclosed in a separate note. Fair value estimates involve uncertainties and matters of significant judgment regarding interest rates, credit risk, prepayments, and other factors, especially in the absence of broad markets for particular items. Changes in assumptions or in market conditions could significantly affect these estimates.

Restriction on Cash Balances

Regulation D of the Federal Reserve Act requires that banks maintain reserve balances with their applicable Federal Reserve Bank based principally on the type and amount of their deposits. The Bank was required to have a reserve balance of $63,890,000, $43,940,000, and $40,902,000 at December 31, 2018, 2017 and 2016, respectively. The reserve balance that the Bank must maintain at the Federal Reserve Bank of Atlanta is included in interest-bearing deposits in financial institutions as of December 31, 2018, 2017 and 2016.

Subsequent Events

The Company has evaluated subsequent events for recognition and disclosure through March 15, 2019, which is the date the financial statements were available to be issued.

Income Per Common Share

Basic net income per share available to common stockholders (“EPS”) is computed by dividing net income available to common stockholders by the weighted average shares of common stock outstanding for the period. Diluted EPS reflects the dilution that could occur if securities or other contracts to issue common stock were exercised or converted. The difference between basic and diluted weighted average shares outstanding is attributable to convertible preferred stock, common stock options and warrants. The dilutive effect of outstanding convertible preferred stock, common stock options and warrants is reflected in diluted EPS by application of the treasury stock method.

No antidilutive stock options were excluded from calculation for the years ended December 31, 2018, 2017 or December 31, 2016.

The following is a summary of the basic and diluted earnings per share calculation for each of the following years (in thousands except share data):

	Year Ended December 31,
	2018		2017		2016
Basic net income per share calculation:
Numerator – Net income	$	9,655	$	1,501	$	9,097
Denominator – Average common shares outstanding		13,277,614		11,280,580		9,328,236
Basic net income per share	$	0.73	$	0.13	$	0.98
Diluted net income per share calculation:
Numerator – Net income	$	9,655	$	1,501	$	9,097
Denominator – Average common shares outstanding		13,277,614		11,280,580		9,328,236
Dilutive shares contingently issuable		1,202,733		1,522,931		1,883,790
Average diluted common shares outstanding		14,480,347		12,803,511		11,212,026
Diluted net income per share	$	0.67	$	0.12	$	0.81

Recently Issued Accounting Pronouncements

ASU 2014-09, Revenue from Contracts with Customers

In May 2014, the FASB issued guidance to change the recognition of revenue from contracts with customers. The core principle of the new guidance is that an entity should recognize revenue to reflect the transfer of goods and services to customers in an amount equal to the consideration the entity receives or expects to receive. The guidance was effective for the Company for reporting periods beginning after December 15, 2017.

The Company applied the guidance using a modified retrospective approach. The Company's revenue is comprised of net interest income and noninterest income. The scope of the guidance explicitly excludes net interest income as well as many other revenues for financial assets and liabilities including loans, leases, securities, and derivatives. Accordingly, the majority of our revenues will not be affected. The Company has performed an assessment of our revenue contracts related to revenue streams that are within the scope of the standard. Our accounting policies will not change materially since the principles of revenue recognition from the ASU are largely consistent with existing guidance and current practices applied by our businesses. We did not identify material changes to the timing or amount of revenue recognition.

The Company records revenue from contracts with customers in accordance with Accounting Standards Codification Topic 606, “Revenue from Contracts with Customers” (“Topic 606”). Under Topic 606, the Company must identify the contract with a customer, identify the performance obligations in the contract, determine the transaction price, allocate the transaction price to the performance obligations in the contract, and recognize revenue when (or as) the Company satisfies a performance obligation. Significant revenue has not been recognized in the current reporting period that results from performance obligations satisfied in previous periods.

The Company’s primary sources of revenue are derived from interest and dividends earned on loans, investment securities, and other financial instruments that are not within the scope of Topic 606. The Company has evaluated the nature of its contracts with customers and determined that further disaggregation of revenue from contracts with customers into more granular categories beyond what is presented in the Consolidated Statements of Income was not necessary. The Company generally fully satisfies its performance obligations on its contracts with customers as services are rendered and the transaction prices are typically fixed; charged either on a periodic basis or based on activity. Our accounting policies will not change materially since the principles of revenue recognition form the Accounting Standards Update are largely consistent with existing guidance and current practices applied by our business.

A description of the Company’s revenue streams accounted for under Topic 606 follows:

Treasury management and other deposit service charges: The Company earns fees from its deposit customers for transaction based, account maintenance, and overdraft services. Transaction based fees are recognized at the time the transaction is executed as that is the point in time the Company fulfills the customer’s request. Account maintenance fees are earned over the course of a month, representing the period over which the Company satisfies its performance obligation. Overdraft fees are recognized at the point in time that the overdraft occurs. Service charges on deposits are withdrawn from the customer’s account balance.

Interchange income: Included in other noninterest income are interchange fees, which the Company earns from debit cardholder transactions conducted through various payment networks. Interchange fees from cardholder transactions represent a percentage of the underlying transaction value and are recognized daily, concurrently with the transaction processing series provided to the cardholder.

Gains/Losses on Sales of OREO: The Company records a gain or loss from the sale of OREO when control of the property transfers to the buyer, which generally occurs at the time of an executed deed. When the Company finances the sale of OREO to the buyer, the Company assesses whether the buyer is committed to perform their obligation under the contract and whether collectability of the transaction price is probable. Once these criteria are met, the OREO asset is derecognized and the gain or loss on sale is recorded upon the transfer of control of the property to the buyer. In determining the gain or loss on the sale, the Company adjusts the transaction price and related gain (loss) on sale if a significant financing component is present.

ASU 2016-02, Leases

In February 2016, the FASB amended the Leases topic of the Accounting Standards Codification to revise certain aspects of recognition, measurement, presentation, and disclosure of leasing transactions. The amendments will be effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted.

The Company adopted the guidance using the modified retrospective method and practical expedients for transition. The practical expedients allow the Company to largely account for our existing leases consistent with current guidance except for the incremental balance sheet recognition for lessees. The Company evaluated the new guidance and its impact on the Company’s financial statements. Based on leases outstanding at December 31, 2018, the impact of adoption on January 1, 2019 was recording a lease liability of approximately $13.4 million, a right-of-use asset of approximately $12.8 million, and elimination of deferred rent of approximately $0.6 million.

ASU 2016-13, Financial Instruments – Credit Losses

In June 2016, the FASB issued guidance to change the accounting for credit losses and modify the impairment model for certain debt securities. The amendments will be effective for the Company for reporting periods beginning after December 15, 2019. Early adoption is permitted for all organizations for periods beginning after December 15, 2018.

The Company will apply the amendments to the ASU through a cumulative-effect adjustment to retained earnings as of the beginning of the year of adoption. While early adoption is permitted beginning in first quarter 2019, we do not expect to elect that option. We are evaluating the impact of the ASU on our consolidated financial statements. In addition to our allowance for loan losses, we will also record an allowance for credit losses on debt securities instead of applying the impairment model currently utilized. The amount of the adjustments will be impacted by each portfolio's composition and credit quality at the adoption date as well as economic conditions and forecasts at that time.

ASU 2017-04, Simplifying the Test of Goodwill Impairment

In January 2017, the FASB amended the Goodwill and Other Topic of the Accounting Standards Codification to simplify the accounting for goodwill impairment for public business entities and other entities that have goodwill reported in their financial statements and have not elected the private company alternative for the subsequent measurement of goodwill. The amendment removes Step 2 of the goodwill impairment test. A goodwill impairment will now be the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. The effective date and transition requirements for the technical corrections will be effective for the Company for reporting periods beginning after December 15, 2019. The Company does not expect these amendments to have a material effect on its financial statements.

ASU 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities

In August 2017, the FASB amended the requirements of the Derivatives and Hedging Topic of the Accounting Standards Codification to improve the financial reporting of hedging relationships to better portray the economic results of an entity’s risk management activities in its financial statements. The amendments will be effective for the Company for interim and annual periods beginning after December 15, 2018. Early adoption is permitted. The Company adopted this standard December 1, 2017. However, there was no material effect on the financial statements.

ASU 2018-02, Income Statement: Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income

In February 2018, the FASB Issued (2018-02), Income Statement (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income, which allows Companies to reclassify the stranded effects in other comprehensive income to retained earnings as a result of the change in the tax rates under the Tax Reform Act. The Company has opted to early adopt this pronouncement by retrospective application to each period in which the effect of the change in the tax rate under the Tax Cuts and Jobs Act is recognized. The Company made an election to reclassify income tax effects of the Tax Reform Act, amounting to approximately $259,000, from accumulated other comprehensive income to retained earnings. The impact of the reclassification from other comprehensive income to retained earnings is included in the Statement of Changes in Shareholders’ Equity.

ASU 2018-07, Compensation – Stock Compensation

In June 2018, the FASB amended the Compensation—Stock Compensation Topic of the Accounting Standards Codification. The amendments expand the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. The amendments are effective for years beginning after December 15, 2018, including interim periods within that year. Early adoption is permitted, but no earlier than an entity’s adoption date of Topic 606. The Company does not expect these amendments to have a material effect on its financial statements.

Acquisition

12 Months Ended

Dec. 31, 2018

Business Combinations [Abstract]

Acquisition

NOTE 2 – ACQUISITIONS

On October 1, 2018, the Company acquired 100% of the outstanding common shares of Athens Bancshares Company (“Athens”), the bank holding company for Athens Federal Community Bank, National Association (“Athens Federal”). Under the terms of the acquisition, Athens common shareholders received 2.864 shares of the Company’s common stock in exchange for each share of Athens common stock. With the acquisition, the Company further expanded its franchise into the East Tennessee market. Athens’ results of operations were included in the Company’s results beginning October 1, 2018. Acquisition related costs of $9,803,000 are included in the Company’s income statement for the year ended December 31, 2018. The fair value of the common shares issued as part of the consideration paid for Athens was determined by the closing price of the Company’s common shares immediately preceding the acquisition date.

Goodwill of $31,291,000 arising from the acquisition consisted largely of synergies and the cost savings resulting from the combining of the operations of the companies. Goodwill associated with Athens acquisition is not amortizable for book or tax purposes. The following table summarizes the consideration paid for Athens and the amounts of the assets acquired and liabilities assumed recognized at the acquisition date (in thousands):

	As recorded by Athens Bancshares			Initial fair value adjustments				Measurement period adjustments		As recorded by CapStar Financial Holdings
Assets:
Cash and cash equivalents	$	12,053		$	—			$	—	$	12,053
Securities		67,342			84		(a)		—		67,426
Loans, gross		349,597			(4,764	)	(b)		—		344,833
Allowance for loan losses		(4,039	)		4,039		(c)		—		—
Premises and equipment, net		7,637			1,571		(d)		—		9,208
Core deposit intangible		2,758			6,222		(e)		—		8,980
Other		29,566			944		(f)		—		30,510
Total	$	464,914		$	8,096			$	—	$	473,010
Liabilities:
Deposits	$	404,027		$	493		(g)	$	—	$	404,520
Other		5,363			1,500		(h)		—		6,863
Total	$	409,390		$	1,993			$	—	$	411,383

Net identifiable assets acquired										$	61,627

Total cost of acquisition:
Value of stock issued				$	86,538
Value of rolled stock options					6,380
Total cost of acquisition				$	92,918					$	92,918

Goodwill recorded related to acquisition										$	31,291

________________________________________________________

(a)	The amount represents the fair value adjustment of securities that were subsequently sold.

(b)	The amount represents the adjustment of the net book value of Athens’ loans to their estimated fair value based on interest rates and expected cash flows at the date of acquisition.

(c)	The amount represents the removal of Athens’ existing allowance for loan losses.

(d)	The amount represents the adjustment of the net book value of Athens’ premises and equipment to their estimated fair value.

(e)	The amount represents the net adjustment of removing Athens’ existing core deposit intangible from prior acquisitions and recording the fair value of the core deposit intangible representing the intangible value of the deposit base acquired and the fair value of the customer relationship.

(f)	The amount represents the net adjustment of the fair value of mortgage servicing rights acquired and the deferred tax asset recognized on the fair value adjustments on Athens acquired assets and assumed liabilities.

(g)	The amount represents the adjustment necessary because the weighted average interest rate of Athens’ time deposits exceeded the cost of similar funding at the time of acquisition. The fair value adjustment will be amortized to reduce future interest expense over the life of the portfolio.

(h)	The amount represents the liability assumed in connection with the merger agreement whereby the Company will make a $1,500,000 charitable contribution to the Athens Foundation over a three year period.

The following unaudited pro forma financial information presents the combined results of the Company and Athens as if the acquisition had occurred as of January 1, 2017, after giving effect to certain adjustments, including amortization of the core deposit intangible, and related income tax effects. The pro forma financial information does not necessarily reflect the results of operations that would have occurred had the Company and Athens constituted a single entity during such periods (in thousands, except share data):

	Pro forma combined twelve months ended December 31, 2018		Pro forma combined twelve months ended December 31, 2017
Net interest income	$	66,935	$	59,148
Noninterest income		20,692		17,540
Total revenue		87,627		76,688

Net income		21,167		5,851

Per share information:
Basic net income per share of common stock	$	1.24	$	0.36
Diluted net income per share of common stock	$	1.14	$	0.32

Investment Securities

12 Months Ended

Dec. 31, 2018

Investments Debt And Equity Securities [Abstract]

Investment Securities

NOTE 3 – INVESTMENT SECURITIES

Investment securities have been classified in the balance sheet according to management’s intent. The Company’s classification of securities at December 31, 2018 and 2017 was as follows (in thousands):

	December 31, 2018									December 31, 2017
	Amortized Cost		Gross unrealized gains		Gross unrealized (losses)			Estimated fair value		Amortized Cost		Gross unrealized gains		Gross unrealized (losses)			Estimated fair value
Securities available-for-sale:
U. S. government agency securities	$	11,053	$	—	$	(347	)	$	10,706	$	11,433	$	12	$	(168	)	$	11,277
State and municipal securities		62,142		765		(981	)		61,926		51,790		1,430		(222	)		52,998
Mortgage-backed securities		146,547		776		(3,165	)		144,158		108,236		40		(1,714	)		106,562
Asset-backed securities		15,437		4		(157	)		15,284		16,575		—		(198	)		16,377
Other debt securities		11,863		71		(200	)		11,734		5,326		81		—			5,407
Total	$	247,042	$	1,616	$	(4,850	)	$	243,808	$	193,360	$	1,563	$	(2,302	)	$	192,621
Securities held-to-maturity:
State and municipal securities	$	3,734	$	54	$	(3	)	$	3,785	$	3,759	$	89	$	—		$	3,848
Total	$	3,734	$	54	$	(3	)	$	3,785	$	3,759	$	89	$	—		$	3,848

During the third quarter of 2013, approximately $36,789,000 of available for sale securities were transferred to the held to maturity category. The transfers of the securities into the held to maturity category from the available for sale category were made at fair value at the date of transfer. The unrealized holding loss at the date of the transfer continues to be reported in a separate component of shareholders’ equity and is being amortized over the remaining life of the securities as an adjustment of yield in a manner consistent with the amortization of the premiums and discounts.

During the fourth quarter of 2017, approximately $41,665,000 of held to maturity securities were transferred to the available for sale category. The Company was able to make the transfer due to early adoption of ASU 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities. The transfers of the securities into the available for sale category from the held to maturity category were made at fair value at the date of transfer.

The amortized cost and fair value of debt and equity securities at December 31, 2018, by contractual maturity, are shown below (in thousands). Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Securities not due at a single maturity date are shown separately.

	Available-for-sale				Held-to-maturity
	Amortized cost		Estimated fair value		Amortized cost		Estimated fair value
Due in less than one year	$	3,561	$	3,573	$	395	$	396
Due one to five years		23,294		23,472		3,339		3,389
Due five to ten years		45,662		45,367		—		—
Due beyond ten years		12,541		11,954		—		—
Mortgage-backed securities		146,547		144,158		—		—
Asset-backed securities		15,437		15,284		—		—
	$	247,042	$	243,808	$	3,734	$	3,785

Results from sales of debt and equity securities were as follows (in thousands):

	Year ended December 31
	2018			2017			2016
Proceeds	$	38,322		$	46,762		$	46,700
Gross gains		116			121			216
Gross losses		(113	)		(190	)		(146	)

The table above does not include activity from maturities, prepayments or calls on debt or equity securities.

Securities with a market value of $171,542,000 and $111,970,000 at December 31, 2018 and 2017, respectively, were pledged to collateralize public deposits, derivative positions and Federal Home Loan Bank advances.

At December 31, 2018 and 2017 there were no holdings of securities of any one issuer, other than the U.S. Government and its agencies, in an amount greater than 10% of shareholders’ equity.

The following tables show the Company’s securities with unrealized losses, aggregated by major security type and length of time in a continuous unrealized loss position (in thousands):

	Less than 12 months					12 months or more					Total
December 31, 2018	Estimated fair value		Gross unrealized losses			Estimated fair value		Gross unrealized losses			Estimated fair value		Gross unrealized losses
U. S. government agency securities	$	—	$	—		$	10,706	$	(347	)	$	10,706	$	(347	)
State and municipal securities		13,455		(212	)		17,376		(772	)		30,831		(984	)
Mortgage-backed securities		7,075		(17	)		87,232		(3,148	)		94,307		(3,165	)
Asset-backed securities		8,262		(145	)		2,439		(12	)		10,701		(157	)
Other debt securities		5,362		(200	)		—		—			5,362		(200	)
Total temporarily impaired securities	$	34,154	$	(574	)	$	117,753	$	(4,279	)	$	151,907	$	(4,853	)
December 31, 2017
U. S. government agency securities	$	7,375	$	(90	)	$	1,912	$	(78	)	$	9,287	$	(168	)
State and municipal securities		7,490		(106	)		5,798		(116	)		13,288		(222	)
Mortgage-backed securities		29,832		(322	)		67,813		(1,392	)		97,645		(1,714	)
Asset-backed securities		—		—			16,377		(198	)		16,377		(198	)
Other debt securities		—		—			—		—			—		—
Total temporarily impaired securities	$	44,697	$	(518	)	$	91,900	$	(1,784	)	$	136,597	$	(2,302	)

Declines in the fair value of securities below their cost that are deemed to be other-than-temporary are reflected in earnings as realized losses to the extent the impairment is related to credit losses. The amount of the impairment of available for sale securities related to other factors is recognized in other comprehensive income (loss). In estimating other-than-temporary impairment losses, management considers, among other things, the length of time and the extent to which the fair value has been less than cost, the financial condition and near-term prospects of the issuer and the intent and ability of the Company to hold the security for a period of time sufficient to allow for any anticipated recovery in fair value. The unrealized losses shown above are primarily due to increases in market rates over the yields available at the time of purchase of the underlying securities and not credit quality. Because the Company does not intend to sell these securities and it is more likely than not that the Company will not be required to sell the securities before recovery of their amortized cost bases, which may be maturity, the Company does not consider these securities to be other than temporarily impaired at December 31, 2018. There were no other-than-temporary impairments for the years ended December 31, 2018 or 2017.

Loans and Allowance for Loan Losses

12 Months Ended

Dec. 31, 2018

Receivables [Abstract]

Loans and Allowance for Loan and Lease Losses

NOTE 4 – LOANS AND ALLOWANCE FOR LOAN LOSSES

Loans at December 31, 2018 and 2017 were as follows (in thousands):

	December 31, 2018			December 31, 2017
Commercial real estate	$	550,446		$	350,622
Consumer real estate		253,562			102,581
Construction and land development		174,670			82,586
Commercial and industrial		404,600			373,248
Consumer		25,615			6,862
Other		21,002			31,983
Total		1,429,895			947,882
Less net unearned income		(101	)		(345	)
Total loans		1,429,794			947,537
Allowance for loan losses		(12,113	)		(13,721	)
Total loans, net	$	1,417,681		$	933,816

At December 31, 2018, variable-rate and fixed-rate loans totaled $827,491,000 and $602,404,000, respectively. At December 31, 2017, variable-rate and fixed-rate loans totaled $608,128,000 and $339,754,000, respectively.

The Company categorizes loans into risk categories based on relevant information about the ability of borrowers to service their debt such as: current financial information, historical payment experience, credit documentation, public information, and current economic trends, among other factors. The Company analyzes all commercial loans, and consumer relationships with an outstanding balance greater than $500,000, individually and assigns each loan a risk rating. This analysis is performed on a continual basis by the relationship managers and credit department personnel. On at least an annual basis an independent party performs a formal credit risk review of a sample of the loan portfolio. Among other things, this review assesses the appropriateness of the loan’s risk rating. The Company uses the following definitions for risk ratings:

Special Mention – A special mention asset possesses deficiencies or potential weaknesses deserving of management’s attention. If uncorrected, such weaknesses or deficiencies may expose the Company to an increased risk of loss in the future.

Substandard – A substandard asset is inadequately protected by the current sound net worth and paying capacity of the obligor or of the collateral pledged, if any. Assets so classified must have a well-defined weakness or weaknesses that jeopardize the liquidation of the debt. They are characterized by the distinct possibility that the Company will sustain some loss if deficiencies are not corrected. Loss potential, while existing in the aggregate amount of substandard assets, does not have to exist in individual assets classified substandard.

Doubtful – A doubtful asset has all weaknesses inherent in one classified substandard, with the added characteristic that weaknesses make collection or liquidation in full, on the basis of existing facts, conditions, and values, highly questionable and improbable. The probability of loss is extremely high, but certain important and reasonable specific pending factors which may work to the advantage and strengthening of the asset exist, therefore, its classification as an estimated loss is deferred until a more exact status may be determined. Pending factors include proposed merger, acquisition or liquidation procedures, capital injection, perfecting liens on additional collateral, and refinancing plans.

Loans not falling into the criteria above are considered to be pass-rated loans. The Company utilizes six loan grades within the pass risk rating.

The following table provides the risk category of loans by applicable class of loans as of December 31, 2018 and 2017 (in thousands):

	Non-impaired Loans
December 31, 2018	Pass		Special Mention		Substandard		Total Non-impaired		Total Impaired Loans		Total
Commercial real estate	$	547,616	$	177	$	1,262	$	549,055	$	1,391	$	550,446
Consumer real estate		249,273		1,676		1,691		252,640		922		253,562
Construction and land development		174,591		52		19		174,662		8		174,670
Commercial and industrial		388,719		7,790		6,545		403,054		1,546		404,600
Consumer		25,556		1		27		25,584		31		25,615
Other		21,002		—		—		21,002		—		21,002
Total	$	1,406,757	$	9,696	$	9,544	$	1,425,997	$	3,898	$	1,429,895
December 31, 2017
Commercial real estate	$	349,415	$	—	$	—	$	349,415	$	1,207	$	350,622
Consumer real estate		102,571		—		10		102,581		—		102,581
Construction and land development		82,586		—		—		82,586		—		82,586
Commercial and industrial		349,494		11,193		11,073		371,760		1,488		373,248
Consumer		6,849		—		13		6,862		—		6,862
Other		31,983		—		—		31,983		—		31,983
Total	$	922,898	$	11,193	$	11,096	$	945,187	$	2,695	$	947,882

None of the Company’s loans had a risk rating of “Doubtful” as of December 31, 2018 or 2017.

The following tables detail the changes in the ALL for the years ending December 31, 2018, 2017 and 2016 by loan classification (in thousands):

	Commercial real estate			Consumer real estate			Construction and land development		Commercial and industrial			Consumer			Other			Total
Year ended December 31, 2018
Balance, beginning of period	$	3,324		$	1,063		$	1,628	$	7,209		$	91		$	406		$	13,721
Charged-off loans		—			—			—		(4,831	)		(84	)		(39	)		(4,954	)
Recoveries		22			4			—		395			75			8			504
Provision for loan losses		(37	)		(62	)		803		2,263			23			(148	)		2,842
Balance, end of period	$	3,309		$	1,005		$	2,431	$	5,036		$	105		$	227		$	12,113

Year ended December 31, 2017
Balance, beginning of period	$	2,655		$	1,013		$	1,574	$	5,618		$	76		$	698		$	11,634
Charged-off loans		—			—			—		(12,769	)		—			—			(12,769	)
Recoveries		9			—			—		1,865			112			—			1,986
Provision for loan losses		660			50			54		12,495			(97	)		(292	)		12,870
Balance, end of period	$	3,324		$	1,063		$	1,628	$	7,209		$	91		$	406		$	13,721

Year ended December 31, 2016
Balance, beginning of period	$	2,879		$	968		$	914	$	4,693		$	103		$	575		$	10,132
Charged-off loans		(350	)		—			—		(956	)		(146	)		—			(1,452	)
Recoveries		52			—			—		23			50			—			125
Provision for loan losses		74			45			660		1,858			69			123			2,829
Balance, end of period	$	2,655		$	1,013		$	1,574	$	5,618		$	76		$	698		$	11,634

A breakdown of the ALL and the loan portfolio by loan category at December 31, 2018 and 2017 follows (in thousands):

	Commercial real estate		Consumer real estate		Construction and land development		Commercial and industrial		Consumer		Other		Total
December 31, 2018
Allowance for Loan Losses:
Collectively evaluated for impairment	$	3,309	$	1,005	$	2,431	$	5,036	$	105	$	227	$	12,113
Individually evaluated for impairment		—		—		—		—		—		—		—
Balances, end of period	$	3,309	$	1,005	$	2,431	$	5,036	$	105	$	227	$	12,113
Loans:
Collectively evaluated for impairment	$	549,055	$	252,640	$	174,662	$	403,054	$	25,584	$	21,002	$	1,425,997
Individually evaluated for impairment		1,391		922		8		1,546		31		—		3,898
Balances, end of period	$	550,446	$	253,562	$	174,670	$	404,600	$	25,615	$	21,002	$	1,429,895

December 31, 2017
Allowance for Loan Losses:
Collectively evaluated for impairment	$	3,324	$	1,063	$	1,628	$	7,109	$	91	$	406	$	13,621
Individually evaluated for impairment		—		—		—		100		—		—		100
Balances, end of period	$	3,324	$	1,063	$	1,628	$	7,209	$	91	$	406	$	13,721
Loans:
Collectively evaluated for impairment	$	349,415	$	102,581	$	82,586	$	371,760	$	6,862	$	31,983	$	945,187
Individually evaluated for impairment		1,207		—		—		1,488		—		—		2,695
Balances, end of period	$	350,622	$	102,581	$	82,586	$	373,248	$	6,862	$	31,983	$	947,882

The following table presents the allocation of the ALL for each respective loan category with the corresponding percentage of loans in each category to total loans, net of deferred fees as of December 31, 2018 and 2017 (dollars in thousands):

	December 31, 2018					December 31, 2017
	Amount		Percent of total loans, net of deferred fees			Amount		Percent of total loans, net of deferred fees
Commercial real estate	$	3,309		0.23	%	$	3,324		0.35	%
Consumer real estate		1,005		0.07			1,063		0.11
Construction and land development		2,431		0.17			1,628		0.17
Commercial and industrial		5,036		0.35			7,209		0.76
Consumer		105		0.01			91		0.01
Other		227		0.02			406		0.04
Total allowance for loan and lease losses	$	12,113		0.85	%	$	13,721		1.45	%

The following table presents information related to impaired loans as of and for the years ended December 31, 2018 and 2017 (in thousands):


	December 31, 2018						December 31, 2017
	Recorded investment		Unpaid principal balance		Related allowance		Recorded investment		Unpaid principal balance		Related allowance
With no related allowance recorded:
Commercial real estate	$	1,391	$	1,775	$	—	$	1,207	$	1,645	$	—
Consumer real estate		922		1,204		—		—		—		—
Construction and land development		8		18		—		—		—		—
Commercial and industrial		1,546		6,350		—		—		—		—
Consumer		31		56		—		—		—		—
Other		—		—		—		—		—		—
Subtotal		3,898		9,403		—		1,207		1,645		—
With an allowance recorded:
Commercial real estate		—		—		—		—		—		—
Consumer real estate		—		—		—		—		—		—
Construction and land development		—		—		—		—		—		—
Commercial and industrial		—		—		—		1,488		2,770		100
Consumer		—		—		—		—		—		—
Other		—		—		—		—		—		—
Subtotal		—		—		—		1,488		2,770		100
Total	$	3,898	$	9,403	$	—	$	2,695	$	4,415	$	100

The recorded investment in loans excludes accrued interest receivable and loan origination fees, net due to immateriality. For purposes of this disclosure, the unpaid principal balance is not reduced for partial charge-offs.

The following table presents information related to the average recorded investment and interest income recognized on impaired loans for the years ended December 31, 2018, 2017 and 2016 (in thousands):

	Year Ended				Year Ended				Year Ended
	December 31, 2018				December 31, 2017				December 31, 2016
	Average recorded investment		Interest income recognized		Average recorded investment		Interest income recognized		Average recorded investment		Interest income recognized
With no related allowance recorded:
Commercial real estate	$	1,198	$	158	$	1,258	$	—	$	655	$	—
Consumer real estate		185		—		—		—		302		—
Construction and land development		94		2		—		—		—		—
Commercial and industrial		5,557		121		—		—		—		—
Consumer		7		—		—		—		63		—
Other		—		—		—		—		—		—
Subtotal		7,041		281		1,258		—		1,020		—
With an allowance recorded:
Commercial real estate		—		—		—		—		974		—
Consumer real estate		—		—		—		—		—		—
Construction and land development		—		—		—		—		—		—
Commercial and industrial		—		—		2,077		—		1,155		44
Consumer		—		—		—		—		—		—
Other		—		—		—		—		—		—
Subtotal		—		—		2,077		—		2,129		44
Total	$	7,041	$	281	$	3,335	$	—	$	3,149	$	44

There was no interest income recognized on a cash basis for impaired loans for the years ended December 31, 2018, 2017 or 2016.

Non-accrual loans and loans past due 90 days still on accrual include both smaller balance homogeneous loans that are collectively evaluated for impairment and individually classified impaired loans. Impaired loans include commercial loans that are individually evaluated for impairment and deemed impaired (i.e., individually classified impaired loans) as well as TDRs for all loan classifications.

The following table presents the aging of the recorded investment in past-due loans as of December 31, 2018 and 2017 by class of loans (in thousands):

	30 - 59		60 - 89		Greater Than
	Days		Days		89 Days		Total		Loans Not
December 31, 2018	Past Due		Past Due		Past Due		Past Due		Past Due		Total
Commercial real estate	$	300	$	227	$	—	$	527	$	549,919	$	550,446
Consumer real estate		69		75		775		919		252,643		253,562
Construction and land development		—		—		—		—		174,670		174,670
Commercial and industrial		54		—		—		54		404,546		404,600
Consumer		52		—		43		95		25,520		25,615
Other		—		—		—		—		21,002		21,002
Total	$	475	$	302	$	818	$	1,595	$	1,428,300	$	1,429,895
December 31, 2017
Commercial real estate	$	—	$	—	$	—	$	—	$	350,622	$	350,622
Consumer real estate		—		—		218		218		102,363		102,581
Construction and land development		—		—		—		—		82,586		82,586
Commercial and industrial		1,967		209		—		2,176		371,072		373,248
Consumer		—		—		13		13		6,849		6,862
Other		—		—		—		—		31,983		31,983
Total	$	1,967	$	209	$	231	$	2,407	$	945,475	$	947,882

The following table presents the recorded investment in non-accrual loans, past due loans over 89 days and accruing and troubled debt restructurings (“TDR”) by class of loans as of December 31, 2018 and 2017 (in thousands):

			Past Due Over 89		Troubled Debt
	Non-Accrual		Days and Accruing		Restructurings
December 31, 2018
Commercial real estate	$	—	$	—	$	1,391
Consumer real estate		1,187		214		—
Construction and land development		19		—		—
Commercial and industrial		817		—		—
Consumer		55		—		—
Other		—		—		—
Total	$	2,078	$	214	$	1,391

December 31, 2017
Commercial real estate	$	1,207	$	—	$	1,206
Consumer real estate		—		218		—
Construction and land development		—		—		—
Commercial and industrial		1,488		—		—
Consumer		—		13		—
Other		—		—		—
Total	$	2,695	$	231	$	1,206

As of December 31, 2018 and 2017 all loans classified as nonperforming were deemed to be impaired.

As of December 31, 2018 and 2017 the Company had recorded investments in TDR of $2.1 million and $1.2 million, respectively. The Company did not allocate a specific allowance for those loans at December 31, 2018 or 2017 and there were no commitments to lend additional amounts. Loans accounted for as TDR include modifications from original terms such as those due to bankruptcy proceedings, certain modifications of amortization periods or extended suspension of principal payments due to customer financial difficulties. In order to determine whether a borrower is experiencing financial difficulty, an evaluation is performed of the probability that the borrower will be in payment default on any of its debt in the foreseeable future without the modification. This evaluation is performed under the Company’s loan policy. Loans accounted for as TDR are individually evaluated for impairment.

The following table presents loans by class modified as TDR that occurred during the year ended December 31, 2016 (in thousands). There were no TDR identified during the years ended December 31, 2018 or 2017.

	Year Ended
	December 31, 2016
	Number of contracts		Pre modification outstanding recorded investment		Post modification outstanding recorded investment, net of related allowance

Commercial real estate		1	$	1,948	$	1,170
Consumer real estate		—		—		—
Construction and land development		—		—		—
Commercial and industrial		—		—		—
Consumer		—		—		—
Other		—		—		—
Total		1	$	1,948	$	1,170

The following table presents loans by class modified as TDR for which there was a payment default within twelve months following the modification during the year ended December 31, 2016 (in thousands). There were no TDR for which there was a payment default within the twelve months following the modification during the years ended December 31, 2018 or 2017.

	Year Ended
	December 31, 2016
	Number of contracts		Recorded investment

Commercial real estate		—	$	—
Consumer real estate		—		—
Construction and land development		—		—
Commercial and industrial		—		—
Consumer		1		124
Other		—		—
Total		1	$	124

The consumer loan TDR that subsequently defaulted during the year ended December 31, 2016 had no specific reserve in the ALL and resulted in a $0.1 million charge-off.

A loan is considered to be in payment default once it is 30 days contractually past due under the modified terms.

Acquired Loans

On October 1, 2018, the Company acquired Athens (see Note 2 for more information). As a result of the acquisition, the Company recorded loans with a fair value of $344.8 million. Of those loans, $1.7 million were considered to be purchased credit impaired (“PCI”) loans, which are loans for which it is probable at the acquisition date that all contractually required payments will not be collected. The remaining loans are considered to be purchased non-impaired loans and their related fair value discount or premium is recognized as an adjustment to yield over the remaining life of each loan.

The following table relates to acquired Athens PCI loans and summarizes the contractually required payments, which includes principal and interest, expected cash flows to be collected, and the fair value of acquired PCI loans at the acquisition date (in thousands):

	Athens Bancshares acquisition on October 1, 2018
Contractually required payments	$	3,151
Nonaccretable difference		(1,049	)
Cash flows expected to be collected at acquisition		2,102
Accretable yield		(436	)
Fair value of PCI loans at acquisition date	$	1,666

The following table relates to acquired Athens purchased non-impaired loans and provides the contractually required payments, fair value, and estimate of contractual cash flows not expected to be collected at the acquisition date (in thousands):

	Athens Bancshares acquisition on October 1, 2018
Contractually required payments	$	404,692
Fair value of acquired loans at acquisition date		343,167
Contractual cash flows not expected to be collected		1,807

The following table presents changes in the carrying value of PCI loans (in thousands):

	For the year ended December 31, 2018
Balance at beginning of period	$	—
Additions due to acquisition of Athens Bancshares		1,666
Change due to payments received and accretion		(46	)
Change due to loan charge-offs		—
Other		—
Balance at end of period	$	1,620

The following table presents changes in the accretable yield for PCI loans (in thousands):

	For the year ended December 31, 2018
Balance at beginning of period	$	—
Additions due to acquisition of Athens Bancshares		436
Accretion		(9	)
Reclassification from (to) nonaccretable difference		—
Other, net		13
Balance at end of period	$	440

PCI loans had no impact on the ALL for the years ended December 31, 2018, 2017 or 2016.

Leases

The Company has entered into various direct finance leases. The leases are reported as part of other loans. The lease terms vary from two to six years. The components of the direct financing leases as of December 31, 2018 and 2017 were as follows (in thousands):

	December 31, 2018			December 31, 2017
Total minimum lease payments receivable	$	379		$	714
Less:
Unearned income		(19	)		(49	)
Net leases	$	360		$	665

The future minimum lease payments receivable under the direct financing leases as of December 31, 2018 were as follows (in thousands):

Year ending December 31:
2019	$	178
2020		167
2021		34
2022		—
2023		—
	$	379

- Definition

The entire disclosure for claims held for amounts due a entity, excluding financing receivables. Examples include, but are not limited to, trade accounts receivables, notes receivables, loans receivables. Includes disclosure for allowance for credit losses.

+ References + Details

Loan Servicing

12 Months Ended

Dec. 31, 2018

Transfers And Servicing [Abstract]

Loan Servicing

NOTE 5 – LOAN SERVICING

Mortgage loans serviced for FHLMC are not reported as assets. The principal balance of these loans at December 31, 2018 was $170.1 million. These servicing rights were acquired in our acquisition of Athens. There were no mortgage loans serviced for others as of December 31, 2017. Custodial escrow balances maintained in connection with serviced loans was $462,000 at December 31, 2018.

Activity for loan servicing rights and the related valuation allowance are summarized as follows (in thousands):

	For the year ended December 31, 2018
Loan servicing rights:
Balance at beginning of period	$	—
Additions		1,809
Disposals		—
Amortized to offset other noninterest income		(73	)
Change in valuation allowance		—
Balance at end of period	$	1,736

Valuation allowance:
Balance at beginning of period	$	—
Additions expensed		—
Reductions credited to other noninterest income		—
Direct write-downs		—
Balance at end of period	$	—

Premises and Equipment

12 Months Ended

Dec. 31, 2017

Property Plant And Equipment [Abstract]

Premises and Equipment

NOTE 6 – PREMISES AND EQUIPMENT

Premises and equipment at December 31, 2018 and 2017 are summarized as follows (in thousands):

	Range of useful lives	December 31, 2018			December 31, 2017
Land	Not applicable	$	2,997		$	1,180
Buildings	39 years		9,965			3,586
Leasehold improvements	1 to 17 years		939			777
Furniture and equipment	1 to 7 years		3,730			2,659
Fixed assets in process	Not applicable		4,023			—
			21,654			8,202
Less accumulated depreciation and amortization			(2,833	)		(2,318	)
		$	18,821		$	5,884

Premises and equipment depreciation and amortization expense for the years ended December 31, 2018, 2017 and 2016 totaled $516,000, $401,000 and $360,000, respectively.

The Company leases certain properties under noncancelable lease arrangements. The leases have various terms, and maturity dates, including extensions through 2032. The leases have various other terms including payments for common area maintenance, escalation increases over the term of the lease and various renewal options. Rent expense related to these leases for 2018, 2017 and 2016 totaled $1,677,000, $1,521,000 and $1,016,000 respectively.

Future minimum payments under these operating leases as of December 31, 2018 are as follows (in thousands):

Year ending December 31:
2019	$	1,538
2020		1,539
2021		1,567
2022		1,453
2023		1,402
Thereafter		8,821
	$	16,320

Goodwill and Intangible Assets

12 Months Ended

Dec. 31, 2018

Goodwill And Intangible Assets Disclosure [Abstract]

Goodwill and Intangible Assets

NOTE 7 – GOODWILL AND INTANGIBLE ASSETS

Goodwill

The change in goodwill during the years ended December 31, 2018 and 2017 was as follows (in thousands):

	2018		2017
Beginning of year	$	6,219	$	6,219
Acquired goodwill		31,291		—
Impairment		—		—
End of year	$	37,510	$	6,219

Impairment exists when a reporting unit’s carrying value of goodwill exceeds its fair value. At October 31, 2018, the Company’s reporting unit had positive equity and the Company elected to perform a qualitative assessment to determine if it was more likely than not that the fair value of the reporting unit exceeded its carrying value, including goodwill. The qualitative assessment indicated that it was more likely than not that the fair value of the reporting unit exceeded its carrying value, resulting in no impairment.

Acquired Intangible Assets

Acquired intangible assets at December 31, 2018 and 2017 were as follows (in thousands):

	December 31, 2018					December 31, 2017
	Gross Carrying Amount		Accumulated Amortization			Gross Carrying Amount		Accumulated Amortization
Amortized intangible assets:
Core deposit intangibles	$	9,267	$	(729	)	$	287	$	(264	)

Aggregate amortization expense was $465,000 for 2018, $48,000 for 2017 and $54,000 for 2016.

Estimated amortization expense for each of the next five years is as follows (in thousands):

Year ending December 31:
2019	$	1,655
2020		1,477
2021		1,299
2022		1,121
2023		943
Thereafter		2,043
Total	$	8,538

Other Real Estate Owned

12 Months Ended

Dec. 31, 2018

Other Real Estate [Abstract]

Other Real Estate Owned

NOTE 8 – OTHER REAL ESTATE OWNED

Other real estate owned activity was as follows (in thousands):

	2018		2017		2016
Beginning balance	$	—	$	—	$	216
Additions due to acquisition of Athens Bancshares		988		—		—
Loans transferred to other real estate owned		—		—		—
Direct write-downs		—		—		—
Sales of other real estate owned		—		—		(216	)
End of year	$	988	$	—	$	—

Other real estate owned is presented net of the valuation allowance which is allocated to the specific properties held.

Activity in the valuation allowance was as follows during the years ended December 31, 2018, 2017 and 2016, respectively (in thousands):

	2018		2017		2016
Beginning balance	$	—	$	—	$	450
Additions/(recoveries) charged/(credited) to expense		—		—		—
Reductions from sales of other real estate owned		—		—		(450	)
Direct write-downs		—		—		—
End of year	$	—	$	—	$	—

Expenses related to other real estate owned during the years ended December 31, 2018, 2017 and 2016, respectively include (in thousands):

	2018		2017		2016
Net (gain) loss on sales	$	—	$	—	$	(157	)
Provision for unrealized losses		—		—		—
Operating expenses, net of rental income		—		—		14
Total	$	—	$	—	$	(143	)

- Definition

The entire disclosure for real estate owned (as defined). Generally, the largest component of real estate owned by lenders is assets taken in settlement of troubled loans through surrender or foreclosure. Real estate investments, real estate loans that qualify as investments in real estate, and premises that are no longer used in operations may also be included in real estate owned.

+ References + Details

Deposits

12 Months Ended

Dec. 31, 2018

Deposits [Abstract]

Deposits

NOTE 9 – DEPOSITS

Time deposits that exceed the FDIC deposit insurance limit of $250,000 at December 31, 2018 and 2017 were $98,086,000 and $54,460,000, respectively.

Scheduled maturities of time deposits for the next five years and thereafter are as follows (in thousands):

Maturity:
2019	$	254,839
2020		57,800
2021		15,167
2022		12,068
2023		8,294
Thereafter		259
	$	348,427

At December 31, 2018 and 2017, the Company had $193,000 and $19,000, respectively of deposit accounts in overdraft status that were reclassified to loans in the accompanying balance sheets.

Federal Home Loan Bank Advances

12 Months Ended

Dec. 31, 2018

Federal Home Loan Banks [Abstract]

Federal Home Loan Bank Advances

NOTE 10 – FEDERAL HOME LOAN BANK ADVANCES

The Company had outstanding borrowings totaling $125,000,000 and $70,000,000 at December 31, 2018 and 2017, respectively, via various advances. These advances are non-callable; interest payments are due monthly, with principal due at maturity.

The following is a summary of the contractual maturities and average effective rates of outstanding advances (dollars in thousands):

	December 31, 2018					December 31, 2017
Year	Amount		Interest Rates			Amount		Interest Rates
2017	$	—		—		$	—		—
2018		—		—			70,000		1.66	%
2019		125,000		2.48	%		—		—
2020		—		—			—		—
2021		—		—			—		—
2022		—		—			—		—
2023		—		—			—		—
Thereafter		—		—			—		—
Total	$	125,000		2.48	%	$	70,000		1.66	%

Advances from the FHLB are collateralized by investment securities with a market value of $3.9 million, FHLB stock and certain commercial and residential real estate mortgage loans totaling $665.7 million under a blanket mortgage collateral agreement. At December 31, 2018, the amount of available credit from the FHLB totaled $71.9 million.

Accumulated Other Comprehensive Income (Loss)

12 Months Ended

Dec. 31, 2018

Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]

Accumulated Other Comprehensive Income (Loss)

NOTE 11 – ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)

The following were changes in accumulated other comprehensive income (loss) by component, net of tax, for the years ended December 31, 2018 and 2017 (in thousands):

				Unrealized Gains			Unrealized
	Gains and			and Losses			Losses on
	Losses on			on Available			Securities
	Cash Flow			for Sale			Transferred to
Year Ended December 31, 2018	Hedges			Securities			Held to Maturity			Total
Beginning Balance	$	(3,679	)	$	1,162		$	(10	)	$	(2,527	)
Other comprehensive income (loss) before reclassification, net of tax		1,891			(1,844	)		20			67
Amounts reclassified from accumulated other comprehensive income (loss), net of tax		(848	)		2			(10	)		(856	)
Net current period other comprehensive income (loss)		1,043			(1,842	)		10			(789	)
Ending Balance	$	(2,636	)	$	(680	)	$	—		$	(3,316	)

Year Ended December 31, 2017
Beginning Balance	$	(4,241	)	$	(698	)	$	(1,212	)	$	(6,151	)
Other comprehensive income (loss) before reclassification, net of tax		1,499			3,077			235			4,811
Amounts reclassified for securities transferred from held-to-maturity to available-for-sale		—			(1,086	)		1,086			—
Amounts reclassified from accumulated other comprehensive income (loss), net of tax		(770	)		(41	)		(117	)		(928	)
Net current period other comprehensive income (loss)		729			1,950			1,204			3,883
Reclassification of accumulated other comprehensive income due to tax rate change		(167	)		(90	)		(2	)		(259	)
Ending Balance	$	(3,679	)	$	1,162		$	(10	)	$	(2,527	)

The following were significant amounts reclassified out of each component of accumulated other comprehensive income (loss) for the years ended December 31, 2018, 2017 and 2016 (in thousands):

										Affected Line Item
Details about Accumulated Other	Year Ended			Year Ended			Year Ended			in the Statement Where
Comprehensive Income Components	December 31, 2018			December 31, 2017			December 31, 2016			Net Income is Presented
Unrealized losses on cash flow hedges	$	(441	)	$	(430	)	$	(151	)	Interest expense - money market
		(479	)		(429	)		(265	)	Interest expense - Federal Home Loan Bank advances
		72			89			—		Income tax benefit
	$	(848	)	$	(770	)	$	(416	)	Net of tax
Unrealized gains and (losses) on available-for-sale securities	$	3		$	(66	)	$	121		Net gain (loss) on sale of securities
		(1	)		25			(46	)	Income tax (expense) benefit
	$	2		$	(41	)	$	75		Net of tax
Unrealized losses on securities transferred to held-to-maturity	$	(14	)	$	(190	)	$	(167	)	Interest income - securities
		4			73			64		Income tax benefit
	$	(10	)	$	(117	)	$	(103	)	Net of tax

Income Taxes

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Income Taxes

NOTE 12 – INCOME TAXES

The components of income tax expense are summarized as follows (in thousands):

	2018			2017		2016
Current:
Federal	$	15		$	214	$	4,029
State		(23	)		36		759
		(8	)		250		4,788
Deferred:
Federal		872			4,218		(395	)
State		303			167		100
		1,175			4,385		(295	)
Total	$	1,167		$	4,635	$	4,493

A reconciliation of actual income tax expense in the financial statements to the “expected” tax expense (computed by applying the statutory federal income tax rate of 21% to income before income taxes) for the years ended December 31, 2018, 2017 and 2016 is as follows (in thousands):

	2018			2017			2016
Computed "expected" tax expense	$	2,272		$	2,086		$	4,621
State income taxes, net of effect of federal income taxes		221			134			567
Tax-exempt interest income		(298	)		(418	)		(394	)
Earnings on bank owned life insurance contracts		(559	)		(197	)		(204	)
Disallowed expenses		93			86			60
Excess tax benefits related to stock compensation		(857	)		(632	)		—
Write-down of deferred tax assets due to tax reform		—			3,562			—
Nondeductible merger expenses		281			—			—
Other		14			14			(157	)
Total	$	1,167		$	4,635		$	4,493

As a result of the Tax Cuts and Jobs Act of 2017 that was signed into law December 2017, the Company revalued its net deferred tax asset position. This revaluation resulted in a $3.6 million decrease in net deferred tax assets and a corresponding increase to income tax expense for the year ended December 31, 2017.

Significant items that gave rise to deferred taxes at December 31, 2018 and 2017 were as follows (in thousands):

	December 31, 2018		December 31, 2017
Deferred tax assets:
Allowance for loan losses	$	2,795	$	3,227
Depreciation		—		—
Net operating loss carryforward		2,002		843
Organization and preopening costs		457		557
Stock-based compensation		835		672
Acquired loans		1,319		124
Acquired deposits		106		22
Nonaccrual interest		75		25
Accrued incentive compensation		97		—
Reserve for contingencies		143		496
Accrued contributions		207		169
Unrealized loss on securities available-for-sale		845		193
Unrealized loss on securities held-to-maturity		—		4
Cash flow hedge		219		359
Accrued vacation		45		45
Other		—		134
Deferred tax assets		9,145		6,870
Deferred tax liabilities:
Prepaid expenses		77		134
Depreciation		645		39
Goodwill		81		138
Amortization of core deposit intangible		1,398		6
Other		334		—
Deferred tax liabilities		2,535		317
Net deferred tax asset	$	6,610	$	6,553

At December 31, 2018, the Company had federal net operating loss carryforwards of approximately $8,561,000, which expire at various dates from 2030 to 2032. Approximately $4,548,000 of the net operating loss carryforwards can be carried forward indefinitely. Deferred tax assets are fully recognized because the benefits are more likely than not to be realized based on management’s estimation of future taxable earnings.

There were no significant unrecognized income tax benefits as of December 31, 2018 or 2017. As of December 31, 2018 and 2017, the Company had no accrued interest or penalties related to uncertain tax positions.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2018

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

NOTE 13 – COMMITMENTS AND CONTINGENCIES

In the normal course of business, the Company has outstanding commitments and contingent liabilities, such as commitments to extend credit and standby letters of credit, which are not included in the accompanying financial statements. The Company’s exposure to credit loss in the event of nonperformance by the other party to the financial instruments for commitments to extend credit and standby letters of credit is represented by the contractual or notional amount of those instruments. The Company uses the same credit policies in making such commitments as it does for instruments that are included in the balance sheet.

The following table sets forth outstanding financial instruments whose contract amounts represent credit risk as of December 31, 2018 and 2017 (in thousands):

	Contract or notional amount
	December 31, 2018		December 31, 2017
Financial instruments whose contract amounts represent credit risk:
Unused commitments to extend credit	$	707,675	$	584,494
Standby letters of credit		12,273		11,552
Total	$	719,948	$	596,046

The Company is party to litigation and claims arising in the normal course of business. Management believes that the liabilities, if any, arising from such litigation and claims as of December 31, 2018, will not have a material impact on the financial statements of the Company.

Regulatory Matters And Restrictions On Dividends

12 Months Ended

Dec. 31, 2018

Banking And Thrift [Abstract]

Regulatory Matters And Restrictions On Dividends

NOTE 15 – REGULATORY MATTERS AND RESTRICTIONS ON DIVIDENDS

The Company and the Bank are subject to regulatory capital requirements administered by the Federal Reserve and the Bank is also subject to the regulatory capital requirements of the Tennessee Department of Financial Institutions. Failure to meet capital requirements can initiate certain mandatory – and possibly additional discretionary – actions by regulators that could, in that event, have a material adverse effect on the institutions’ financial statements. The relevant regulations require the Company and the Bank to meet specific capital adequacy guidelines that involve quantitative measures of their assets, liabilities and certain off-balance-sheet items as calculated under regulatory accounting principles. The capital classifications of the Company and the Bank are also subject to qualitative judgments by their regulators about components, risk weightings, and other factors. Those qualitative judgments could also affect the capital status of the Company and the Bank and the amount of dividends the Company and the Bank may distribute. The final rules implementing the Basel Committee on Companying Supervision’s capital guidelines for U.S. Banks (Basel III rules) became effective for the Company on January 1, 2015 with full compliance with all of the requirements being phased in over a multi-year schedule, and fully phased in by January 1, 2019. The net unrealized gain or loss on available for sale securities is not included in computing regulatory capital. Management believes as of December 31, 2018, the Company and the Bank met all regulatory capital adequacy requirements to which they are subject.

The Federal Deposit Insurance Corporation Improvement Act of 1991 establishes a system of “prompt corrective action” to resolve the problems of undercapitalized insured depository institutions. Under this system, federal banking regulators have established five capital categories: well capitalized, adequately capitalized, undercapitalized, significantly undercapitalized, and critically undercapitalized, although these terms are not used to represent overall financial condition. Federal banking regulators are required to take various mandatory supervisory actions and are authorized to take other discretionary actions with respect to institutions in the three undercapitalized categories. The severity of the action depends upon the capital category in which the institution is placed. For example, institutions in all three undercapitalized categories are automatically restricted from paying distributions and management fees, whereas only an institution that is significantly undercapitalized or critically undercapitalized is restricted in its compensation paid to senior executive officers. Generally, subject to a narrow exception, the banking regulator must appoint a receiver or conservator for an institution that is critically undercapitalized.

At December 31, 2018 and 2017, the Company and the Bank were well capitalized under the regulatory framework for prompt corrective action. There have been no conditions or events since that notification that management believes have changed the Company’s or the Bank’s category.

The Company’s and the Bank’s capital amounts and ratios are presented in the following table (dollars in thousands):

	Actual					Minimum capital requirement (1)					Minimum to be well-capitalized (2)
	Amount		Ratio			Amount		Ratio			Amount		Ratio
At December 31, 2018:
Total capital to risk-weighted assets:
CapStar Financial Holdings, Inc.	$	222,030		12.8	%	$	138,336		8.0	%	$ N/A		N/A
CapStar Bank		201,972		11.7			138,294		8.0			172,868		10.0
Tier I capital to risk-weighted assets:
CapStar Financial Holdings, Inc.		209,738		12.1			103,752		6.0		N/A		N/A
CapStar Bank		189,680		11.0			103,721		6.0			138,294		8.0
Common equity Tier 1 capital to risk weighted assets:
CapStar Financial Holdings, Inc.		200,738		11.6			77,814		4.5		N/A		N/A
CapStar Bank		173,180		10.0			77,791		4.5			112,364		6.5
Tier I capital to average assets:
CapStar Financial Holdings, Inc.		209,738		11.1			75,867		4.0		N/A		N/A
CapStar Bank		189,680		10.0			75,828		4.0			94,785		5.0
At December 31, 2017:
Total capital to risk-weighted assets:
CapStar Financial Holdings, Inc.	$	156,176		12.5	%	$	99,932		8.0	%	$ N/A		N/A
CapStar Bank		142,138		11.4			99,928		8.0			124,909		10.0
Tier I capital to risk-weighted assets:
CapStar Financial Holdings, Inc.		142,276		11.4			74,949		6.0		N/A		N/A
CapStar Bank		128,238		10.3			74,946		6.0			99,928		8.0
Common equity Tier 1 capital to risk weighted assets:
CapStar Financial Holdings, Inc.		133,445		10.7			56,212		4.5		N/A		N/A
CapStar Bank		111,907		9.0			56,209		4.5			81,191		6.5
Tier I capital to average assets:
CapStar Financial Holdings, Inc.		142,276		10.7			53,218		4.0		N/A		N/A
CapStar Bank		128,238		9.6			53,215		4.0			66,519		5.0

(1)

For the calendar year 2018, the Company was required to maintain a capital conservation buffer of Tier 1 common equity capital in excess of minimum risk-based capital ratios by at least 1.875% to avoid limits on capital distributions and certain discretionary bonus payments to executive officers and similar employees.

(2)

For the Company to be well-capitalized, the Bank must be well-capitalized and the Company must not be subject to any written agreement, order, capital directive, or prompt corrective action directive issued by the Federal Reserve to meet and maintain a specific capital level for any capital measure.

Under Tennessee banking law, the Bank is subject to restrictions on the payment of dividends. Banking regulations limit the amount of dividends that may be paid without prior approval of the Tennessee Department of Financial Institutions. Under these regulations, the amount of dividends that may be paid in any calendar year without prior approval of the Tennessee Department of Financial Institutions is limited to the current year’s net income, combined with the retained net income of the preceding two years, subject to the capital requirements described above. The Bank’s payment of dividends may also be affected or limited by other factors, such as the requirement to maintain adequate capital above regulatory guidelines. The federal banking agencies have indicated that paying dividends that deplete a depository institution’s capital base to an inadequate level would be an unsafe and unsound banking practice. Under the Federal Deposit Insurance Corporation Improvement Act of 1991, a depository institution may not pay any dividends if payment would cause it to become undercapitalized or if it already is undercapitalized. Moreover, the federal agencies have issued policy statements that provide that Company holding companies and insured banks should generally only pay dividends out of current operating earnings.

Based on these regulations, the Bank was eligible to pay $22.2 million and $19.3 million of dividends as of December 31, 2018 and 2017, respectively. The Bank paid the Company $1.2 million of dividends during 2018 and this amount was paid out to shareholders by the Company during 2018.

- Definition

The entire disclosure for banks, savings institutions, and credit unions, for regulatory capital requirements imposed by the Federal Reserve System (FRB), the Federal Deposit Insurance Corporation (FDIC), the Office of Thrift Supervision (OTS) or for any state imposed capital requirements, as applicable. The disclosure may include (1) a description of regulatory capital requirements (a) for capital adequacy purposes and (b) established by the prompt corrective action provisions of Section 38 of the Federal Depository Insurance Act; (2) the actual or possible material effects of noncompliance with such requirements; (3) whether the entity is in compliance with the regulatory capital requirements including (a) required and actual ratios and amounts of Tier 1 leverage, Tier 1 risk-based, and total risk-based capital, tangible capital (for savings institutions), and Tier 3 capital for market risk (for certain banks and bank holding companies), (b) factors that may significantly affect capital adequacy; (4) the prompt corrective action category in which the entity was classified as of its most recent notification; (5) whether management believes any conditions or events since notification have changed the entity's category. Also may include additional information that might be disclosed in situations where substantial doubt about the entity's ability to continue as a going concern for a reasonable period of time.

+ References

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+ Details

Nonvoting and Series A Preferred Stock and Stock Warrants

12 Months Ended

Dec. 31, 2018

Equity [Abstract]

Nonvoting and Series A Preferred Stock and Stock Warrants

NOTE 16 – NONVOTING AND SERIES A PREFERRED STOCK AND STOCK WARRANTS

Nonvoting Common Stock

The Company has authorized 5,000,000 shares of its common stock as nonvoting common stock. The nonvoting common stock has the same rights and privileges as the common stock other than the nonvoting designation. Under certain conditions, as outlined in the Company’s charter, the nonvoting stock may be converted, on a one-to-one basis, to common stock. In conjunction with the Company’s initial public offering, 79,166 shares of nonvoting common stock were issued and simultaneously converted to common stock on a one-to-one basis as further described under “Warrants” below. At December 31, 2018 and 2017 there were 132,561 shares of nonvoting common stock outstanding.

Preferred Stock

In conjunction with its initial capital issuance in 2008, the Bank issued 1,609,756 shares of Series A Preferred Stock to certain shareholders. During 2016, coinciding with the Company’s initial public offering, 731,707 preferred shares were converted to common shares.

The Series A Preferred Stock contains a liquidation preference and certain antidilution provisions. Holders of Series A Preferred Stock also have certain consent rights with respect to changes to the Company’s charter or bylaws that would materially adversely affect the preferences, rights and powers of such stock and the right to receive certain financial reports. The Series A Preferred Stock is noncumulative, perpetual and, except as otherwise provided below or pursuant to Tennessee law, nonvoting. Holders of Series A Preferred Stock participate equally in dividends paid on the common stock on an as converted basis. In addition, the Series A Preferred Stock is convertible to nonvoting common stock upon the occurrence of certain underwritten public offerings and certain transfers or proposed transfers by the Company’s organizing shareholders.

Warrants

In conjunction with the issuance of the 1,609,756 shares of the Series A Preferred Stock, the holders of such stock were issued 500,000 warrants to purchase shares of the Company’s nonvoting common stock at a purchase price of $10.25 per share. The warrants were exercisable at any time and expired ten years from the date of grant of July 14, 2008. As of December 31, 2018, all of these warrants have been exercised and none of these warrants remain outstanding.

As part of the initial capital issuance in 2008, each organizer of the Company (“Organizers”) who became a director of the Company received a warrant to purchase, at the purchase price of $10.00 per share, 10,000 shares of the Company’s common stock. These warrants were issued in compliance with the FDIC’s policy on noncash compensation in recognition of the Organizers considerable contribution of time, expertise, and capital. The Company issued warrants to purchase 60,000 shares of common stock to these organizers. The warrants expired ten years from date of grant of July 14, 2008. As of December 31, 2018, all of these warrants have been exercised and no warrants remain outstanding.

In addition, each subscriber for shares who is a Tennessee resident or any entity controlled by a Tennessee resident and invested a minimum of $500,000 in the offering, received a warrant to purchase additional shares of common stock equal to 5% of accepted subscriptions at the purchase price of $10.00 per share. The Company issued warrants to purchase 238,319 shares of common stock to these subscribers. The warrants expired ten years from date of grant of July 14, 2008. As of December 31, 2018, all of these warrants have been exercised and no warrants remain outstanding.

Stock Options and Restricted Shares

12 Months Ended

Dec. 31, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock Options and Restricted Shares

NOTE 18 – STOCK OPTIONS AND RESTRICTED SHARES

During 2008, the board of directors of the Company approved the CapStar Bank 2008 Stock Incentive Plan. Following the formation of CapStar Financial Holdings, Inc. in 2016, and in connection with the Share Exchange, the outstanding awards of restricted stock and stock options under the CapStar Bank 2008 Stock Incentive Plan were exchanged for similar awards of restricted stock and stock options issued by CapStar Financial Holdings, Inc. under the Stock Incentive Plan (the “Plan”), which the board of directors adopted in 2016. The Plan provides for the grant of stock-based incentives, including stock options, restricted stock units, performance awards and restricted stock, to employees, directors and service providers that are subject to forfeiture until vesting conditions have been satisfied by the award recipient under the terms of the award. The Plan is intended to help align the interests of employees and our shareholders and reward our employees for improved Company performance. The Plan reserved 1,569,475 shares of stock for issuance of stock incentives. Stock incentives include both restricted stock and stock option grants. During 2018 the board of directors approved the addition of 400,000 shares of stock for issuance of stock incentives under the Plan. Total shares issuable under the plan are 422,900 at December 31, 2018.

The Company has recognized stock-based compensation expense, within salaries and employee benefits for employees, and within other non-interest expense for directors, in the consolidated statements of income as follows (in thousands):

	For the year ended December 31,
	2018			2017			2016
Stock-based compensation expense before income taxes	$	2,079		$	1,061		$	842
Less: deferred tax benefit		(543	)		(406	)		(322	)
Reduction of net income	$	1,536		$	655		$	520

Restricted Shares

Compensation expense is recognized over the vesting period of the awards based on the fair value of the stock at the issue date. The recipients have the right to vote and receive dividends but cannot sell, transfer, assign, pledge, hypothecate, or otherwise encumber the restricted stock until the shares have vested. Restricted shares fully vest on the third anniversary of the grant date. A summary of the changes in the Company’s nonvested restricted shares for 2018 follows:

				Weighted
				Average
	Restricted			Grant Date
Nonvested Shares	Shares			Fair Value
Nonvested at beginning of period		187,253		$	14.21
Granted		140,131			16.73
Vested		(161,604	)		13.54
Forfeited		(8,164	)		15.92
Nonvested at end of period		157,616		$	17.00

As of December 31, 2018, there was $1,814,000 of total unrecognized compensation cost related to nonvested shares granted under the Plan. The cost is expected to be recognized over a weighted-average period of 2.1 years. The total fair value of shares vested during the years ended December 31, 2018, 2017 and 2016 was $2,804,000, $1,174,000 and $513,000, respectively.

Stock Options

Option awards are generally granted with an exercise price equal to the fair value of the Company’s common stock at the date of grant. Option awards generally have a three year vesting period and a ten year contractual term.

The fair value of each option grant is estimated on the date of grant using the Black-Scholes option pricing model that uses the assumptions noted in the table below. Expected volatility is based on calculations performed by management using industry data. At the time of issuance, the Company’s expected dividend yield was 0.00% because the Company had no current plan to pay dividends and historically had not paid dividends. The expected term of options granted was calculated using the “simplified” method for plain vanilla options as permitted under authoritative literature. The risk-free rate for periods within the contractual life of the option is based on the U.S. Treasury yield curve in effect at the time of grant.

The fair value of options granted was determined using the following weighted average assumptions as of the grant date. There were no options granted during 2018 or 2017.

	2016
Dividend yield		—
Expected term (in years)		7.48
Expected stock price volatility		17.20	%
Risk-free interest rate		1.66	%
Pre-vest forfeiture rate		10.25	%

A summary of the activity in stock options for 2018 follows:

						Weighted
				Weighted		Average
				Average		Remaining
				Exercise		Contractual
	Shares			Price		Term (years)
Outstanding at beginning of period		756,050		$	10.50
Additions due to acquisition of Athens Bancshares		548,051		$	5.06
Granted		—			—
Exercised		(796,198	)		8.16
Forfeited or expired		—			—
Outstanding at end of period		507,903		$	8.66		4.0
Fully vested and expected to vest		506,783		$	8.66		4.1
Exercisable at end of period		480,403		$	8.46		4.0

Information related to stock options during 2018, 2017 and 2016 follows:

	2018		2017		2016
Intrinsic value of options exercised	$	7,654,738	$	2,010,536	$	53,756
Cash received from option exercises		6,897,845		2,013,840		96,306
Tax benefit realized from option exercises		846,725		774,056		20,583
Weighted average fair value of options granted		—		—		3.16

As of December 31, 2018, there was $32,000 of total unrecognized compensation cost related to nonvested stock options granted under the Plan. The cost is expected to be recognized over a weighted-average period of 0.9 years.

Employee Benefit Plans

12 Months Ended

Dec. 31, 2018

Compensation And Retirement Disclosure [Abstract]

Employee Benefit Plans

NOTE 20 – EMPLOYEE BENEFIT PLANS

The Company has a Retirement Savings 401(k) Plan in which employees may participate. The Company has elected a safe harbor 401(k) plan and as such is required to make an annual contribution of 3% of the employees’ salaries annually. An employee does not have to contribute to receive the employer contribution. In addition, the Company may make an additional discretionary contribution up to 6% of the employees’ salaries annually. For the years ended December 31, 2018, 2017 and 2016, the Company contributed $639,000, $550,000 and $536,000, respectively, to the 401(k) Plan.

The Company also has a Health Reimbursement Plan in place to offset the cost of healthcare deductibles for employees. At the end of the year, up to one-half of the unused balance in the employee’s account will be available for the following year up to a maximum of the deductible for that employee.

Derivative Instruments

12 Months Ended

Dec. 31, 2018

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Derivative Instruments

NOTE 21 – DERIVATIVE INSTRUMENTS

The Company utilizes interest rate swap agreements as part of its asset liability management strategy to help manage its interest rate risk position. The notional amount of the interest rate swaps does not represent amounts exchanged by the parties. The amount exchanged is determined by reference to the notional amount and the other terms of the individual interest rate swap agreements.

Interest Rate Swaps Designated as Cash Flow Hedges

Forward starting interest rate swaps with notional amounts totaling $20 million as of December 31, 2018 and 2017, were designated as cash flow hedges of certain liabilities and were determined to be fully effective during all periods presented. As such, no amount of ineffectiveness has been included in net income. Therefore, the aggregate fair value of the swaps is recorded in other assets (liabilities) with changes in fair value recorded in other comprehensive income (loss). The amount included in accumulated other comprehensive income (loss) would be reclassified to current earnings should the hedges no longer be considered effective. The Company expects the hedges to remain fully effective during the remaining terms of the swaps.

Summary information about the interest-rate swaps designated as cash flow hedges was as follows (dollars in thousands):

	December 31, 2018			December 31, 2017
Notional amounts	$	20,000		$	20,000
Weighted average pay rates		3.54	%		3.54	%
Weighted average receive rates	3 month LIBOR			3 month LIBOR
Weighted average maturity	4.5 years			5.5 years
Fair value	$	(836	)	$	(1,375	)
Amount of unrealized loss recognized in accumulated other comprehensive income, net of tax	$	(617	)	$	(849	)

Cash flows began on these forward starting interest rate swaps in 2017. As such, $275,000 and $233,000 of interest expense was recorded on these swap transactions during 2018 and 2017, respectively.

Pursuant to its interest rate swap agreements, the Company pledged collateral to the counterparties in the form of investment securities with a carrying value of $2,038,000 at December 31, 2018. There was no collateral posted from the counterparties to the Company as of December 31, 2018. It is possible that the Company may need to post additional collateral in the future or that the counterparties may be required to post collateral to the Company in the future.

Other Interest Rate Swaps

The Company also enters into swaps to facilitate customer transactions and meet their financing needs. Upon entering into these transactions the Company enters into offsetting positions with large U.S. financial institutions in order to minimize risk to the Company. A summary of the Company’s customer related interest rate swaps is as follows (in thousands):

	December 31, 2018					December 31, 2017
	Notional		Estimated			Notional		Estimated
	amount		fair value			amount		fair value
Interest rate swap agreements:
Pay fixed/receive variable swaps	$	29,126	$	24		$	41,863	$	55
Pay variable/receive fixed swaps		29,126		(24	)		41,863		(55	)
Total	$	58,252	$	—		$	83,726	$	—

Related Party

12 Months Ended

Dec. 31, 2018

Related Party

NOTE 22 – RELATED PARTY

The Company may enter into loan transactions with certain directors, executive officers, significant shareholders, and their affiliates. Such transactions were made in the ordinary course of business on substantially the same terms, including interest rates and collateral, as those prevailing at the same time for comparable transactions with persons not affiliated with the Company, and did not, in the opinion of management, involve more than normal credit risk or present other unfavorable features. None of these loans were impaired at December 31, 2018 or 2017. Activity within these loans during the years ended December 31, 2018 and 2017 was as follows (in thousands):

	Total commitment			Total funded commitment
Year ended December 31, 2018
Beginning of period	$	49,409		$	21,890
New commitments/draw downs		3,631			1,038
Repayments		(8,228	)		(7,483	)
End of period	$	44,812		$	15,445

Year ended December 31, 2017
Beginning of period	$	31,076		$	20,325
New commitments/draw downs		21,203			4,320
Repayments		(2,870	)		(2,755	)
End of period	$	49,409		$	21,890

Deposits from directors, executive officers, significant shareholders and their affiliates at December 31, 2018 and 2017 were $11.4 million and $10.8 million, respectively.

Fair Value

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Fair Value

NOTE 23 – FAIR VALUE

Fair value is the exchange price that would be received for an asset or paid to transfer a liability (exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. There are three levels of inputs that may be used to measure fair values:

Level 1:		Quoted prices (unadjusted) for identical assets or liabilities in active markets that the entity has the ability to access as of the measurement date.

Level 2:		Significant observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data.

Level 3:		Significant unobservable inputs that reflect a reporting entity’s own assumptions about the assumptions that market participants would use in pricing an asset or liability.

The Company used the following methods and significant assumptions to estimate fair value:

Investment Securities : The fair values for investment securities are determined by quoted market prices, if available (Level 1). For securities where quoted prices are not available, fair values are calculated based on market prices of similar securities (Level 2), using matrix pricing. Matrix pricing is a mathematical technique commonly used to price debt securities that are not actively traded and values debt securities by relying on quoted prices for the specific securities and the securities’ relationship to other benchmark quoted securities (Level 2 inputs). For securities where quoted prices or market prices of similar securities are not available, fair values are calculated using discounted cash flows or other market indicators (Level 3). See below for additional discussion of Level 3 valuation methodologies and significant inputs. The fair values of all securities are determined from third party pricing services without adjustment.

Derivatives-Interest Rate Swaps : The fair values of derivatives are based on valuation models using observable market data as of the measurement date (Level 2). The Company’s derivatives are traded in an over-the-counter market where quoted market prices are not always available. Therefore, the fair values of derivatives are determined using quantitative models that utilize multiple market inputs. The inputs will vary based on the type of derivative, but could include interest rates, prices and indices to generate continuous yield or pricing curves, prepayment rates, and volatility factors to value the position. The majority of market inputs are actively quoted and can be validated through external sources, including brokers, market transactions and third-party pricing services. The fair values of all interest rate swaps are determined from third party pricing services without adjustment.

Impaired Loans : The fair value of impaired loans with specific allocations of the allowance for loan losses is generally based on recent appraisals. These appraisals may utilize a single valuation approach or a combination of approaches including comparable sales and the income approach. Adjustments are routinely made in the appraisal process by the independent appraisers to adjust for differences between the comparable sales and income data available for similar loans and collateral underlying such loans. Such adjustments result in a Level 3 classification of the inputs for determining fair value. Collateral may be valued using an appraisal, net book value per the borrower’s financial statements, or aging reports, adjusted or discounted based on management’s historical knowledge, changes in market conditions from the time of the valuation, and management’s expertise and knowledge of the client and client’s business, resulting in a Level 3 fair value classification. Impaired loans are evaluated on at least a quarterly basis for additional impairment and adjusted in accordance with the loan policy.

Other Real Estate Owned : Assets acquired through or instead of loan foreclosure are initially recorded at fair value less costs to sell when acquired, establishing a new cost basis. These assets are subsequently accounted for at lower of cost or fair value less estimated costs to sell. Fair value is commonly based on recent real estate appraisals which are updated no less frequently than annually. These appraisals may utilize a single valuation approach or a combination of approaches including comparable sales and the income approach with data from comparable properties. Adjustments are routinely made in the appraisal process by the independent appraisers to adjust for differences between the comparable sales and income data available. Appraisals may be adjusted or discounted based on management’s historical knowledge, changes in market conditions from the time of the valuation, and/or management’s expertise and knowledge of the collateral. Such adjustments result in a Level 3 classification of the inputs for determining fair value. Real estate owned properties are evaluated on a quarterly basis for additional impairment and adjusted accordingly. The Company had no other real estate owned carried at fair value at December 31, 2018 or 2017.

Loans Held For Sale: Loans held for sale are carried at the lower of cost or fair value, which is evaluated on a pool-level basis. The fair value of loans held for sale is determined using quoted prices for similar assets, adjusted for specific attributes of that loan or other observable market data, such as outstanding commitments from third party investors (Level 2). There were no loans held for sale carried at fair value at December 31, 2018 or 2017.

Assets and liabilities measured at fair value on a recurring basis are summarized below (in thousands):

	Fair value measurements at December 31, 2018
				Quoted prices
				in active		Significant
				markets for		other			Significant
				identical		observable			unobservable
	Carrying			assets		inputs			inputs
	Value			(Level 1)		(Level 2)			(Level 3)
Assets:
Securities available-for-sale:
U.S. government-sponsored agencies	$	10,706		$	—	$	10,706		$	—
Obligations of states and political subdivisions		61,926			—		61,926			—
Mortage-backed securities-residential		144,158			—		144,158			—
Asset-backed securities		15,284			—		15,284			—
Other debt securities		11,734			—		11,734			—
Total securities available-for-sale	$	243,808		$	—	$	243,808		$	—
Derivatives:
Interest rate swaps - customer related	$	494		$	—	$	494		$	—
Liabilities:
Derivatives:
Interest rate swaps - customer related	$	(494	)	$	—	$	(494	)	$	—
Interest rate swaps - cash flow hedges		(836	)		—		(836	)		—
Total derivatives	$	(1,330	)	$	—	$	(1,330	)	$	—

	Fair value measurements at December 31, 2017
				Quoted prices
				in active		Significant
				markets for		other			Significant
				identical		observable			unobservable
	Carrying			assets		inputs			inputs
	Value			(Level 1)		(Level 2)			(Level 3)
Assets:
Securities available-for-sale:
U.S. government-sponsored agencies	$	11,277		$	—	$	11,277		$	—
Obligations of states and political subdivisions		52,998			—		52,998			—
Mortage-backed securities-residential		106,562			—		106,562			—
Asset-backed securities		16,377			—		16,377			—
Other debt securities		5,407			—		5,407			—
Total securities available-for-sale	$	192,621		$	—	$	192,621		$	—
Derivatives:
Interest rate swaps - customer related	$	184		$	—	$	184		$	—
Liabilities:
Derivatives:
Interest rate swaps - customer related	$	(184	)	$	—	$	(184	)	$	—
Interest rate swaps - cash flow hedges		(1,375	)		—		(1,375	)		—
Total derivatives	$	(1,559	)	$	—	$	(1,559	)	$	—

Assets measured at fair value on a nonrecurring basis are summarized below (in thousands). There were no assets measured at fair value on a nonrecurring basis at December 31, 2018:

Fair value measurements at December 31, 2017

Quoted prices

in active

Significant

markets for

other

Significant

identical

observable

unobservable

Carrying

assets

inputs

Value

(level 1)

(level 2)

(level 3)

Assets:

Impaired loans:

Commercial and industrial

1,388

—

1,388

The following table presents quantitative information about Level 3 fair value measurements for assets measured at fair value on a nonrecurring basis (dollars in thousands). There were no assets measured at fair value on a nonrecurring basis at December 31, 2018:

Range

Fair

Valuation

Unobservable

(Weighted-

December 31, 2017

Value

Technique(s)

Input(s)

Average)

Impaired loans:

Commercial and industrial

1,388

Sales comparison approach

Appraisal discounts

Fair Value of Financial Instruments

The carrying value and estimated fair values of the Company’s financial instruments at December 31, 2018, 2017 and 2016 were as follows (in thousands):

	December 31, 2018				December 31, 2017
	Carrying				Carrying				Fair value
	amount		Fair value		amount		Fair value		level of input
Financial assets:
Cash and due from banks, interest-bearing deposits in financial institutions	$	94,681	$	94,681	$	78,078	$	78,078	Level 1
Federal funds sold		10,762		10,762		4,719		4,719	Level 1
Securities available-for-sale		243,808		243,808		192,621		192,621	Level 2
Securities held-to-maturity		3,734		3,785		3,759		3,848	Level 2
Loans held for sale		57,618		58,596		74,093		75,549	Level 2
Restricted equity securities		12,038	N/A			8,806	N/A		N/A
Loans, net of unearned income		1,429,794		1,442,082		947,537		944,037	Level 3
Accrued interest receivable		5,964		5,964		4,084		4,084	Level 2
Other assets		34,489		34,489		22,663		22,663	Level 2
Financial liabilities:
Deposits		1,570,008		1,504,101		1,119,866		1,065,669	Level 3
Federal Home Loan Bank advances		125,000		126,548		70,000		69,980	Level 2
Other liabilities		2,753		2,753		3,672		3,672	Level 3

The methods and assumptions, not previously presented, used to estimate fair values are described as follows:

(a)	Cash and Due from Banks, Interest-Bearing Deposits in Financial Institutions

For these short-term instruments, the carrying amount is a reasonable estimate of fair value.

(b)	Federal Funds Sold

Federal funds sold clear on a daily basis. For this reason, the carrying amount is a reasonable estimate of fair value.

(c)	Restricted Equity Securities

It is not practical to determine the fair value of restricted securities due to restrictions placed on their transferability.

(d)	Loans, net

During the first quarter of 2018, the Company adopted ASU 2016-01, “Recognition and Measurement of Financial Assets and Liabilities.” The amendments included within this standard, which are applied prospectively, require the Company to disclose fair value of financial instruments measured at amortized cost on the balance sheet to measure that fair value using an exit price notion. Prior to adopting the amendments included in the standard, the Company was allowed to measure fair value under an entry price notion. The entry price notion previously applied by the Company used a discounted cash flows technique to calculate the present value of expected future cash flows for a financial instrument. The exit price notion uses the same approach, but also incorporates other factors, such as enhanced credit risk, illiquidity risk and market factors that sometimes exist in exit prices in dislocated markets.

As of December 31, 2018, the technique used by the Company to estimate the exit price of the loan portfolio consists of similar procedures to those used as of December 31, 2017 and 2016, but with added emphasis on both illiquidity risk and credit risk not captured by the previously applied entry price notion. The fair value of the Company’s loan portfolio has always included a credit risk assumption in the determination of the fair value of its loans. This credit risk assumption is intended to approximate the fair value that a market participant would realize in a hypothetical orderly transaction. The Company’s loan portfolio is initially fair valued using a segmented approach. The Company divides its loan portfolio into the following categories: variable rate loans, impaired loans and all other loans. The results are then adjusted to account for credit risk as described above. However, under the new guidance, the Company believes a further credit risk discount must be applied through the use of a discounted cash flow model to compensate for illiquidity risk, based on certain assumptions included within the discounted cash flow model, primarily the use of discount rates that better capture inherent credit risk over the lifetime of a loan. This consideration of enhanced credit risk provides an estimated exit price for the Company’s loan portfolio.

For variable-rate loans that reprice frequently and have no significant change in credit risk, fair values approximate carrying values. Fair values for impaired loans are estimated using discounted cash flow models or based on the fair value of the underlying collateral.

As of December 31, 2018, the fair value of the Company’s loan portfolio includes a credit risk assumption in the determination of the fair value of its loans. This credit risk assumption is intended to approximate the fair value that a market participant would realize in a hypothetical orderly transaction. The Company’s loan portfolio is initially fair valued using a segmented approach. The Company divides its loan portfolio into the following categories: variable rate loans, impaired loans and all other loans. The results are then adjusted to account for credit risk. For variable-rate loans that reprice frequently and have no significant change in credit risk, fair values approximate carrying values. Fair values for impaired loans are estimated using discounted cash flow models or based on the fair value of the underlying collateral. For other loans, fair values are estimated using discounted cash flow models, using current market interest rates offered for loans with similar terms to borrowers of similar credit quality. The values derived from the discounted cash flow approach for each of the above portfolios are then further discounted to incorporate credit risk. The methods utilized to estimate the fair value of loans do not necessarily represent an exit price as of December 31, 2017.

(e)	Accrued interest receivable

The carrying amount of accrued interest approximates fair value.

(f)	Other Assets

Included in other assets are bank owned life insurance, certain interest rate swap agreements and the cash flow hedge relationships. The fair values of interest rate swap agreements and the cash flow hedge relationships are based on independent pricing services that utilize pricing models with observable market inputs. For bank owned life insurance, the carrying amount is based on the cash surrender value and is a reasonable estimate of fair value.

(g)

Deposits

The fair value of demand deposits, savings accounts and certain money market deposits is the amount payable on demand at the reporting date. The fair value of certificates of deposit is estimated by discounted cash flow models, using current market interest rates offered on certificates with similar remaining maturities.

(h)	Federal Home Loan Bank Advances

The fair value of fixed rate Federal Home Loan Bank Advances is estimated using discounted cash flow models, using current market interest rates offered on certificates, advances and other borrowings with similar remaining maturities.

(i)

Other Liabilities

Included in other liabilities are accrued interest payable, certain interest rate swap agreements, the cash flow hedge relationships and contingent consideration. The fair values of interest rate swap agreements and the cash flow hedge relationships are based on independent pricing services that utilize pricing models with observable market inputs. The fair value of contingent consideration is estimated by a discounted cash flow model that utilizes various unobservable inputs. The carrying amounts of accrued interest approximate fair value.

(j)	Off-Balance Sheet Instruments

Fair values for off-balance sheet, credit-related financial instruments are based on fees currently charged to enter into similar agreements, taking into account the remaining terms of the agreements and the counterparties’ credit standing. The fair value of commitments is not material.

(k)	Limitations

Fair value estimates are made at a specific point in time, based on relevant market information and information about the financial instruments. These estimates do not reflect any premium or discount that could result from offering for sale at one time the Company’s entire holdings of a particular instrument. Because no market exists for a significant portion of the Company’s financial instruments, fair value estimates are based on judgments regarding future expected loss experience, current economic conditions, risk characteristics of various financial instruments, and other factors. These estimates are subjective in nature and involve uncertainties and matters of significant judgment and, therefore, cannot be determined with precision. Changes in assumptions could significantly affect the estimates.

Fair value estimates are based on estimating on and off-balance sheet financial instruments without attempting to estimate the value of anticipated future business and the value of assets and liabilities that are not considered financial instruments. For example, fixed assets are not considered financial instruments and their value has not been incorporated into the fair value estimates. In addition, the tax ramifications related to the realization of the unrealized gains and losses can have a significant effect on fair value estimates and have not been considered in the estimates.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Parent Company Only Financial Information

12 Months Ended

Dec. 31, 2018

Condensed Financial Information Of Parent Company Only Disclosure [Abstract]

Parent Company Only Financial Information

NOTE 24 – PARENT COMPANY ONLY FINANCIAL INFORMATION

The following information presents the condensed balance sheet, statement of income, and cash flows of CapStar Financial Holdings, Inc. as of and for the year ended December 31, 2018 and 2017 (in thousands).

Condensed Balance Sheets

	December 31, 2018		December 31, 2017
Assets
Cash and cash equivalents	$	19,918	$	14,108
Investment in consolidated subsidiary		234,263		132,909
Other assets		499		61
Total assets	$	254,680	$	147,078
Liabilities and Shareholders’ Equity
Other liabilities	$	301		132
Total shareholders’ equity		254,379		146,946
Total liabilities and shareholders’ equity	$	254,680	$	147,078

Condensed Income Statements

	Year Ended			Year Ended
	December 31, 2018			December 31, 2017
Income - dividends from subsidiary	$	1,225		$	—
Expenses		1,054			879
Income before income taxes and equity in undistributed net income of subsidiary		171			(879	)
Income tax benefit		(242	)		(256	)
Income (loss) before equity in undistributed net income of subsidiary		413			(623	)
Equity in undistributed net income of subsidiary		9,242			2,124
Net income	$	9,655		$	1,501

Condensed Statements of Cash Flows

	Year Ended			Year Ended
	December 31, 2018			December 31, 2017
Cash flows from operating activities:
Net income	$	9,655		$	1,501
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Increase in other assets		(221	)		(62	)
Increase in other liabilities		169			77
Equity in undistributed net income of subsidiary		(9,242	)		(2,124	)
Net cash provided by (used in) operating activities		361			(608	)
Cash flows from investing activities:
Investments in subsidiary		—			(10,000	)
Cash received from acquisitions, net		1,421			—
Net cash provided by (used in) investing activities		1,421			(10,000	)
Cash flows from financing activities:
Issuance of common stock		—			—
Exercise of common stock options and warrants, net of repurchase of restricted shares		5,260			1,764
Common and preferred stock dividends paid		(1,232	)
Net cash provided by financing activities		4,028			1,764
Net increase (decrease) in cash and cash equivalents		5,810			(8,844	)
Cash and cash equivalents at beginning of period		14,108			22,952
Cash and cash equivalents at end of period	$	19,918		$	14,108

Quarterly Financial Results (Unaudited)

12 Months Ended

Dec. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Results (Unaudited)

NOTE 25 – QUARTERLY FINANCIAL RESULTS (UNAUDITED)

The following is a summary of quarterly financial results (unaudited) for 2018, 2017 and 2016:

	First Quarter			Second Quarter			Third Quarter			Fourth Quarter
2018
Interest income	$	13,744		$	15,354		$	15,782		$	22,900
Interest expense		2,898			3,767			4,239			5,184
Net interest income		10,846			11,587			11,543			17,716
Provision for loan losses		678			169			481			1,514
Net interest income after provision for loan losses		10,168			11,418			11,062			16,202
Noninterest income		3,088			2,765			3,218			6,387
Noninterest expense		9,580			10,005			10,070			23,832
Net income (loss) before income tax expense		3,676			4,178			4,210			(1,243	)
Income tax expense (benefit)		483			665			554			(535	)
Net income (loss)	$	3,193		$	3,513		$	3,656		$	(708	)
Net income (loss) per share, basic	$	0.27		$	0.30		$	0.30		$	(0.04	)
Net income (loss) per share, diluted	$	0.25		$	0.27		$	0.28		$	(0.04	)
2017
Interest income	$	11,979		$	12,891		$	13,521		$	13,124
Interest expense		2,047			2,320			2,678			2,606
Net interest income		9,932			10,571			10,843			10,518
Provision for loan losses		3,405			9,690			(195	)		(30	)
Net interest income after provision for loan losses		6,527			881			11,038			10,548
Noninterest income		2,133			2,666			3,372			2,736
Noninterest expense		8,376			8,217			8,475			8,699
Net income (loss) before income tax expense		284			(4,670	)		5,935			4,585
Income tax expense (benefit)		(47	)		(1,328	)		1,516			4,494
Net income (loss)	$	331		$	(3,342	)	$	4,419		$	91
Net income (loss) per share, basic	$	0.03		$	(0.30	)	$	0.39		$	0.01
Net income (loss) per share, diluted	$	0.03		$	(0.26	)	$	0.35		$	0.01
2016
Interest income	$	10,598		$	10,915		$	11,875		$	12,007
Interest expense		1,642			1,714			1,749			1,827
Net interest income		8,956			9,201			10,126			10,180
Provision for loan losses		937			183			1,639			70
Net interest income after provision for loan losses		8,019			9,018			8,487			10,110
Noninterest income		2,371			2,568			3,191			2,954
Noninterest expense		8,010			7,951			8,527			8,642
Net income before income tax expense		2,380			3,635			3,151			4,422
Income tax expense		796			1,159			1,042			1,495
Net income	$	1,584		$	2,476		$	2,109		$	2,927
Net income per share, basic	$	0.18		$	0.29		$	0.24		$	0.26
Net income per share, diluted	$	0.15		$	0.23		$	0.20		$	0.23

Schedule I - Athens Bancshares Corporation & Subsidiary - Unaudited Financial Statements

12 Months Ended

Dec. 31, 2018

Athens Bancshares Corporation & Subsidiary

Restructuring Cost And Reserve [Line Items]

Unaudited Financial Statements

Athens Bancshares Corporation & Subsidiary

Unaudited Consolidated Balance Sheet

(Dollars in thousands, except share data)

September 30, 2018

Assets
Cash and due from banks	$	6,489
Interest-bearing deposits in financial institutions		4,495
Federal funds sold		1,069
Total cash and cash equivalents		12,053
Securities available-for-sale, at fair value		67,342
Loans held for sale		476
Loans		349,121
Less allowance for loan losses		(4,039	)
Loans, net		345,082
Premises and equipment, net		7,637
Restricted equity securities		3,220
Accrued interest receivable		1,410
Core deposit intangible, net		2,758
Other real estate owned, net		988
Other assets		23,948
Total assets	$	464,914
Liabilities and Shareholders’ Equity
Deposits:
Non-interest-bearing	$	58,523
Interest-bearing		114,988
Savings and money market accounts		115,327
Time		115,189
Total deposits		404,027
Other liabilities		5,363
Total liabilities		409,390
Shareholders’ equity:
Preferred stock, $.01 par value; 10,000,000 shares authorized; none issued		—
Common stock, voting, $.01 par value; 50,000,000 shares authorized; 1,809,358 shares issued and outstanding		18
Additional paid-in capital		21,788
Retained earnings		35,273
Accumulated other comprehensive loss, net of income tax		(1,555	)
Total shareholders’ equity		55,524
Total liabilities and shareholders’ equity	$	464,914

See accompanying notes to consolidated financial statements.

Athens Bancshares Corporation & Subsidiary

Unaudited Consolidated Statement of Income

(Dollars in thousands, except share data)

For the Nine Months Ended September 30, 2018

Interest income:
Loans, including fees	$	13,443
Securities:
Taxable		772
Tax-exempt		593
Federal funds sold		135
Restricted equity securities		339
Interest-bearing deposits in financial institutions		183
Total interest income		15,465
Interest expense:
Interest-bearing deposits		386
Savings and money market accounts		27
Time deposits		990
Note payable to bank		9
Total interest expense		1,412
Net interest income		14,053
Provision for loan losses		146
Net interest income after provision for loan losses		13,907
Noninterest income:
Treasury management and other deposit service charges		2,184
Mortgage banking income		842
Other noninterest income		2,207
Total noninterest income		5,233
Noninterest expense:
Salaries and employee benefits		7,065
Data processing and software		1,138
Professional fees		532
Occupancy		1,112
Equipment		568
Regulatory fees		269
Merger related expenses		4,731
Amortization of intangibles		273
Other operating		2,074
Total noninterest expense		17,762
Income before income taxes		1,378
Income tax expense		753
Net income	$	625
Per share information:
Basic net income per share of common stock	$	0.36
Diluted net income per share of common stock	$	0.35
Weighted average shares outstanding:
Basic		1,725,105
Diluted		1,802,595

See accompanying notes to consolidated financial statements.

Athens Bancshares Corporation & Subsidiary

Unaudited Consolidated Statement of Comprehensive Loss

(Dollars in thousands)

For the Nine Months Ended September 30, 2018

Net income	$	625
Other comprehensive loss:
Unrealized losses on securities available-for-sale:
Unrealized holding losses arising during the period		(1,912	)
Tax effect		500
Other comprehensive loss		(1,412	)
Comprehensive loss	$	(787	)

See accompanying notes to consolidated financial statements.

Athens Bancshares Corporation & Subsidiary

Unaudited Consolidated Statement of Changes in Shareholders’ Equity

(Dollars in thousands, except share data)

For the Nine Months Ended September 30, 2018

	Common stock, voting (shares)			Common stock, voting (amount)		Additional paid-in capital		Common stock acquired by benefit plans			Retained earnings			Accumulated other comprehensive loss			Total shareholders' equity
Balance December 31, 2017		1,806,084		$	18	$	18,800	$	(1,037	)	$	34,906		$	(143	)	$	52,544
Stock-based compensation expense		—			—		83		—			—			—			83
Exercise of common stock options, net of withholdings to satisfy employee tax obligations		25,663			—		295		—			—			—			295
Shares released by ESOP trust and termination of ESOP		(22,389	)		—		2,610		1,037			—			—			3,647
Common and preferred stock dividends declared		—			—		—		—			(258	)		—			(258	)
Net income		—			—		—		—			625			—			625
Other comprehensive loss		—			—		—		—			—			(1,412	)		(1,412	)
Balance September 30, 2018		1,809,358		$	18	$	21,788	$	—		$	35,273		$	(1,555	)	$	55,524

See accompanying notes to consolidated financial statements.

Athens Bancshares Corporation & Subsidiary

Unaudited Consolidated Statement of Cash Flows

(Dollars in thousands)

For the Nine Months Ended September 30, 2018

Cash flows from operating activities:
Net income	$	625
Adjustments to reconcile net income to net cash used in operating activities:
Provision for loan losses		146
Depreciation and amortization		591
Net amortization of premiums on investment securities		218
Mortgage banking income		(842	)
Net gain on sale of other real estate owned		(74	)
Stock-based compensation		83
Deferred income tax benefit		(630	)
Origination of loans held for sale		(13,333	)
Proceeds from loans held for sale		13,699
Net increase in accrued interest receivable and other assets		(7,721	)
Net decrease in accrued interest payable and other liabilities		(1,941	)
Net cash used in operating activities		(9,179	)
Cash flows from investing activities:
Activities in securities available-for-sale:
Maturities, prepayments and calls		7,336
Purchase of restricted equity securities		1,260
Net increase in loans		(25,999	)
Purchase of premises and equipment		(716	)
Net cash used in investing activities		(18,119	)
Cash flows from financing activities:
Net increase in deposits		1,004
Payments on note payable to bank		(1,383	)
Exercise of common stock options		295
Common and preferred stock dividends paid		(258	)
Termination of ESOP		3,647
Net decrease in repurchase agreements		(463	)
Net cash provided by financing activities		2,842
Net decrease in cash and cash equivalents		(24,456	)
Cash and cash equivalents at beginning of period		36,509
Cash and cash equivalents at end of period	$	12,053
Supplemental disclosures of cash paid:
Interest paid	$	1,445
Income taxes		1,645

See accompanying notes to consolidated financial statements.

Athens Bancshares Corporation & Subsidiary

Notes to Consolidated Financial Statements

NOTE 1 – SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Basis of Presentation

The accompanying unaudited consolidated financial statements as of and for the period ended September 30, 2018 include Athens Bancshares Corporation and its wholly owned subsidiary, Athens Federal Community Bank, NA (the “Bank”, together referred to as the “Company”). Significant intercompany transactions and accounts are eliminated in consolidation.

The accompanying unaudited consolidated financial statements have been prepared in accordance with Generally Accepted Accounting Principles (“GAAP”) for interim financial information and in accordance with the instructions to Form 10-Q and Article 8 of Regulation S-X as promulgated by the SEC. Accordingly, they do not include all the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments (consisting only of normal recurring accruals) considered necessary for a fair presentation of the financial condition and results of operations for the periods presented have been included. Operating results for the nine months ended September 30, 2018, are not necessarily indicative of the results that may be expected for the full year or in any other period.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Material estimates that are particularly susceptible to significant change relate to the determination of the allowance for loan losses (“ALL”), the valuation of our investment portfolio and deferred tax assets. There have been no significant changes to the Company’s critical accounting policies as disclosed in the Company’s Annual Report for the year ended December 31, 2017.

Subsequent Events

Accounting Standards Codification (“ASC”) 855, Subsequent Events, establishes general standards of accounting for and disclosure of events that occur after the balance sheet date but before financial statements are issued. The Company evaluated all events or transactions that occurred after September 30, 2018 through the date of the issued financial statements.

NOTE 2 – LOANS AND ALLOWANCE FOR LOAN LOSSES

A summary of the loan portfolio as of September 30, 2018 follows (dollars in thousands):


Commercial real estate	$	117,744
Consumer real estate		138,255
Construction and land development		51,872
Commercial and industrial		23,885
Consumer and other		18,548
Total		350,304
Less net unearned income		(1,183	)
Total loans		349,121
Allowance for loan losses		(4,039	)
Total loans, net	$	345,082

The following tables detail the changes in the ALL for the nine months ended September 30, 2018 (dollars in thousands):

	Commercial real estate			Consumer real estate		Construction and land development		Commercial and industrial			Consumer and other			Total

Balance, beginning of period	$	1,333		$	1,011	$	206	$	474		$	937		$	3,961
Charged-off loans		—			—		—		—			(181	)		(181	)
Recoveries		20			17		1		—			75			113
Provision for loan losses		(3	)		260		17		(76	)		(52	)		146
Balance, end of period	$	1,350		$	1,288	$	224	$	398		$	779		$	4,039

A breakdown of the ALL and the loan portfolio by loan category at September 30, 2018 follows (dollars in thousands):

	Commercial real estate		Consumer real estate		Construction and land development		Commercial and industrial		Consumer and other		Total

Allowance for Loan Losses:
Collectively evaluated for impairment	$	1,284	$	1,288	$	224	$	356	$	777	$	3,929
Individually evaluated for impairment		66		—		—		42		2		110
Balances, end of period	$	1,350	$	1,288	$	224	$	398	$	779	$	4,039
Loans:
Collectively evaluated for impairment	$	117,562	$	136,983	$	51,850	$	22,370	$	18,480	$	347,245
Individually evaluated for impairment		182		1,272		22		1,515		68		3,059
Balances, end of period	$	117,744	$	138,255	$	51,872	$	23,885	$	18,548	$	350,304

The following table presents the Company’s impaired loans that were evaluated for specific loss allowance as of September 30, 2018 (dollars in thousands):

	Recorded investment		Unpaid principal balance		Related allowance
With no related allowance recorded:
Commercial real estate	$	—	$	—	$	—
Consumer real estate		1,272		1,272		—
Construction and land development		22		22		—
Commercial and industrial		—		—		—
Consumer		—		—		—
Other		—		—		—
Subtotal		1,294		1,294		—
With an allowance recorded:
Commercial real estate		182		182		66
Consumer real estate		—		—		—
Construction and land development		—		—		—
Commercial and industrial		1,515		1,515		42
Consumer		68		68		2
Other		—		—		—
Subtotal		1,765		1,765		110
Total	$	3,059	$	3,059	$	110

The following table presents the recorded investment in non-accrual loans, past due loans over 89 days outstanding and accruing and troubled debt restructurings (“TDR”) by class of loans as of September 30, 2018 (dollars in thousands):

			Past Due Over 89		Troubled Debt
	Non-Accrual		Days and Accruing		Restructurings

Commercial real estate	$	—	$	—	$	182
Consumer real estate		987		—		783
Construction and land development		21		—		—
Commercial and industrial		—		—		1,510
Consumer and other		64		—		20
Total	$	1,072	$	—	$	2,495

NOTE 3 – STOCK OPTIONS


Stock-based compensation expense before income taxes	$	83
Less: deferred tax benefit		(22	)
Reduction of net income	$	61

A summary of the activity in stock options for the nine months ended September 30, 2018 follows:

						Weighted
				Weighted		Average
				Average		Remaining
				Exercise		Contractual
	Shares			Price		Term (years)
Outstanding at beginning of period		217,024		$	14.12
Granted		—			—
Exercised		(25,663	)		11.50
Forfeited or expired		—			—
Outstanding at end of period		191,361		$	14.48		3.1
Fully vested and expected to vest		191,361		$	14.48		3.1
Exercisable at end of period		191,361		$	14.48		3.1

Information related to stock options for the nine months ended September 30, 2018 follows:


Intrinsic value of options exercised	$	1,038,000
Cash received from option exercises		295,000
Tax benefit realized from option exercises		189,000
Weighted average fair value of options granted		—

NOTE 4 – EARNINGS PER SHARE

The following is a summary of the basic and diluted earnings per share calculation for the nine months ended September 30, 2018 (dollars in thousands, except share data):


Basic net income per share calculation:
Numerator – Net income	$	625
Denominator – Average common shares outstanding		1,725,105
Basic net income per share	$	0.36
Diluted net income per share calculation:
Numerator – Net income	$	625
Denominator – Average common shares outstanding		1,725,105
Dilutive shares contingently issuable		77,490
Average diluted common shares outstanding		1,802,595
Diluted net income per share	$	0.35

NOTE 5 – EMPLOYEE STOCK OWNERSIP PLAN

The Bank sponsored a leveraged ESOP that covered substantially all employees who met certain age and eligibility requirements. The ESOP purchased 222,180 shares with the proceeds of a 15 year loan from the Company which was payable in annual installments and bore interest at 3.25% per annum. ESOP shares are held by the plan trustee in a suspense account until allocated to participant accounts. Shares released from the suspense account are allocated to participants on the basis of their relative compensation in the year of allocation. Participants become vested in the allocated shares upon four years of employment with the Bank. Any forfeited shares are allocated to other participants in the same proportion as contributions. As ESOP shares are allocated to participants, the Bank recognizes compensation expense equal to the fair value of the earned ESOP shares. As of September 30, 2018 the Bank terminated the ESOP, allocated all unallocated shares to participants and paid of the loan to the Company. For the nine months ended September 30, 2018, the Bank recognized $3.6 million in compensation expense related to terminating the ESOP and allocating the remaining shares to participants.

NOTE 6 – SUBSEQUENT EVENT

On October 1, 2018, pursuant to the Agreement and Plan of Merger, dated as of June 11, 2018 (the “Merger Agreement”), by and between CapStar Financial Holdings, Inc., a Tennessee corporation (“CapStar”), and Athens Bancshares Corporation, a Tennessee corporation (“Athens”), Athens was merged with and into CapStar, with CapStar continuing as the surviving entity (the “Merger”). Immediately following the Merger, Athens Federal Community Bank, National Association, a wholly owned subsidiary of Athens, merged with and into CapStar Bank, a wholly owned subsidiary of CapStar (the “Bank Merger”), with CapStar Bank continuing as the surviving entity in the Bank Merger.

On the terms and subject to the conditions set forth in the Merger Agreement, at the effective time of the Merger (the “Effective Time”), each share of common stock, par value $0.01, of Athens (“Athens Common Stock”) issued and outstanding immediately prior to the completion of the merger (other than dissenting shares and shares of Athens common stock owned directly or indirectly by Athens, CapStar and their wholly owned subsidiaries (in each case, other than shares of Athens common stock held in a fiduciary capacity or in connection with debts previously contracted) was converted into the right to receive 2.864 shares (the “Exchange Ratio”) of voting common stock, par value $1.00 per share, of CapStar (“CapStar Common Stock”), with cash paid in lieu of fractional shares. This resulted in the issuance of 5,181,916 shares of CapStar common stock on October 1, 2018.

At the Effective Time, each outstanding and unexercised Athens stock option granted under the Athens Bancshares Corporation 2010 Equity Incentive Plan (the “Athens Equity Plan”) that was held by an employee or service provider of Athens who had terminated service prior to the Effective Time was cancelled and converted into the right to receive the cash value of the merger consideration (determined in accordance with the terms of the Merger Agreement), less the applicable option exercise price and less applicable withholding taxes. Except as described in the prior sentence, each outstanding and unexercised Athens stock option granted under the Athens Equity Plan was converted into an option to purchase shares of CapStar Common Stock, with the number of shares and exercise price adjusted to reflect the Exchange Ratio in accordance with the terms of the Merger Agreement. The converted options resulted in the right to purchase 548,051 shares of CapStar Common Stock at a weighted average exercise price of $5.06.

Total acquisition consideration resulting from the Merger amounted to approximately $92.9 million.

The foregoing description of the Merger Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Merger Agreement, a copy of which was attached as Exhibit 2.1 to CapStar’s Form 8-K filed with the U.S. Securities and Exchange Commission on June 14, 2018 and the terms of which are incorporated herein by reference.

Schedule II - Unaudited Pro Forma Combined Consolidated Financial Information of Capstar Financial Holdings, Inc. and Athens Bancshares Corporation

12 Months Ended

Dec. 31, 2018

Pro Forma Combined Consolidated Financial Information Disclosure [Abstract]

Schedule II - Unaudited Pro Forma Combined Consolidated Financial Information of Capstar Financial Holdings, Inc. and Athens Bancshares Corporation

SCHEDULE II—UNAUDITED PRO FORMA COMBINED CONSOLIDATED FINANCIAL INFORMATION OF CAPSTAR FINANCIAL HOLDINGS, INC. AND ATHENS BANCSHARES CORPORATION

The following unaudited pro forma combined consolidated financial information and accompanying notes showing the impact on the historical financial conditions and results of operations of CapStar and Athens have been prepared to illustrate the effects of the merger under the acquisition method of accounting. See “The Merger — Accounting Treatment.”

The unaudited pro forma combined consolidated income statement for the year ended December 31, 2018 is presented as if the merger had occurred on January 1, 2018. The historical consolidated financial information has been adjusted to reflect factually supportable items that are directly attributable to the merger and, with respect to the income statement only, expected to have a continuing impact on consolidated results of operations, as such, one-time merger costs are not included.

The unaudited pro forma combined consolidated financial statement is provided for informational purposes only. The unaudited pro forma combined consolidated financial statements is not necessarily, and should not be assumed to be, an indication of the results that would have been achieved had the merger been completed as of the dates indicated or that may be achieved in the future. The preparation of the unaudited pro forma combined consolidated financial statement and related adjustments required management to make certain assumptions and estimates. The unaudited pro forma combined consolidated financial statements should be read together with:

•

the accompanying notes to the unaudited pro forma combined consolidated financial statement;

•

CapStar’s audited consolidated financial statements and accompanying notes as of and for the twelve months ended December 31, 2018, included in CapStar’s Annual Report on Form 10-K for the year ended December 31, 2018;

•

CapStar’s Quarterly Report on Form 10-Q for the three months ended September 30, 2018, which is incorporated by reference into this joint proxy statement/prospectus;

•

Athens’ audited consolidated financial statements and accompanying notes as of and for the year ended December 31, 2017;

•

Athens’ unaudited consolidated financial statements and accompanying notes as of and for the nine months ended September 30, 2018;

•

other information pertaining to CapStar and Athens incorporated by reference into, or included in, this joint proxy statement/prospectus.

See “Selected Historical Consolidated Financial Data of CapStar,” “Selected Historical Consolidated Financial Data of Athens,” “Documents Incorporated by Reference” and “Index to Athens’s Consolidated Financial Statements.”

Unaudited Pro Forma Combined Consolidated Statement of Income

For the year ended December 31, 2018

(in thousands, except per share data)

	CapStar, as reported, For the Nine Months Ended September 30, 2018		Athens, as reported, for the Nine Months Ended September 30, 2018		CapStar, as reported, for the Three Months Ended December 31, 2018			Pro Forma Adjustments				Pro Forma Combined For the Year Ended December 31, 2018
Interest income:
Loans, including fees	$	40,197	$	13,443	$	20,554		$	1,003		b,f	$	75,197
Securities:
Taxable		2,775		772		1,411			—				4,958
Tax-exempt		784		593		416			—				1,793
Federal funds sold		56		135		8			—				199
Restricted equity securities		389		339		181			—				909
Interest-bearing deposits in financial institutions		679		183		330			—				1,192
Total interest income		44,880		15,465		22,900			1,003				84,248
Interest expense:
Deposits		9,088		1,403		4,462			(178	)	e		14,775
Federal funds purchased		3		—		—			—				3
Securities sold under agreements to repurchase		—		—		3							3
Federal Home Loan Bank advances		1,813		—		719			—				2,532
Note payable to bank		—		9		—			(9	)	b		—
Total interest expense		10,904		1,412		5,184			(187	)			17,313
Net interest income		33,976		14,053		17,716			1,190				66,935
Provision for loan losses		1,328		146		1,514			—				2,988
Net interest income after provision for loan losses		32,648		13,907		16,202			1,190				63,947
Noninterest income:
Treasury management and other deposit service charges		1,357		2,184		793			—				4,334
Net gain (loss) on sale of securities		2		—		1			—				3
Tri-Net fees		1,227		—		276			—				1,503
Mortgage banking income		4,329		842		1,324			—				6,495
Other noninterest income		2,157		2,207		3,993			—				8,357
Total noninterest income		9,072		5,233		6,387			—				20,692
Noninterest expense:
Salaries and employee benefits		19,111		7,065		9,475			—				35,651
Data processing and software		2,411		1,138		1,424			—				4,973
Professional fees		1,074		532		534			—				2,140
Occupancy		1,600		1,112		736			—				3,448
Equipment		1,661		568		810			—				3,039
Regulatory fees		664		269		364			—				1,297
Merger related expenses		875		4,731		8,929			(14,535	)	a		—
Other operating		2,259		2,347		1,560			985		c,d		7,151
Total noninterest expense		29,655		17,762		23,832			(13,550	)			57,699
Income before income taxes		12,065		1,378		(1,243	)		14,740				26,940
Income tax expense (benefit)		1,702		753		(535	)		3,853		g		5,773
Net income	$	10,363	$	625	$	(708	)	$	10,887			$	21,167
Per share information:
Basic net income per share of common stock	$	0.87	$	0.36	$	(0.04	)	$	—			$	1.24
Diluted net income per share of common stock	$	0.79	$	0.35	$	(0.04	)	$	—			$	1.14
Weighted average shares outstanding:
Basic		11,851,476		1,725,105		17,509,525			3,456,811				17,033,392
Diluted		13,052,758		1,802,595		18,716,562			3,761,316				18,616,669

See accompanying notes to Unaudited Pro Forma Combined Consolidated Financial Information

NOTES TO UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENT

(all amounts are in thousands, except per share data, unless otherwise indicated)

Note 1—Basis of Pro Forma Presentation

The unaudited pro forma combined income statement for the year ended December 31, 2018 is based on the historical financial statements of CapStar and Athens after giving effect to the completion of the mergers and the assumptions and adjustments described in the accompanying notes. Such financial statements do not reflect cost savings or operating synergies expected to result from the mergers, or the costs to achieve these cost savings or operating synergies, or any anticipated disposition of assets that may result from the integration of the operations of the three companies. Certain historical financial information has been reclassified to conform to the current presentation.

The transactions will be accounted for under the acquisition method of accounting in accordance with Accounting Standards Codification (“ASC”) Topic 805, Business Combinations (“ASC 805”). In business combination transactions in which the consideration given is not in the form of cash (that is, in the form of non-cash assets, liabilities incurred, or equity interests issued), measurement of the acquisition consideration is based on the fair value of the consideration given or the fair value of the asset (or net assets) acquired, whichever is more clearly evident and, thus, a more reliable measure.

Under ASC 805, all of the assets acquired and liabilities assumed in a business combination are recognized at their acquisition-date fair value, while transaction costs and restructuring costs associated with the business combination are expensed as incurred. The excess of the acquisition consideration over the fair value of assets acquired and liabilities assumed, if any, is allocated to goodwill. Changes in deferred tax asset valuation allowances and income tax uncertainties after the acquisition date generally affect income tax expense. Subsequent to the completion of the merger, CapStar and Athens will finalize an integration plan, which may affect how the assets acquired, including intangible assets, will be utilized by the combined company. For those assets in the combined company that will be phased out or will no longer be used, additional amortization, depreciation and possibly impairment charges will be recorded after management completes the integration plan.

The unaudited pro forma information is presented solely for informational purposes and is not necessarily indicative of the combined results of operations or financial position that might have been achieved for the periods or dates indicated, nor is it necessarily indicative of the future results of the combined company.

Note 2—Acquisition Consideration

Under the terms of the Athens Merger Agreement, Athens shareholders received 2.864 shares of CapStar common stock for each share of Athens common stock.

As of October 1, 2018, the acquisition consideration was as follows.

(dollars are in thousands, except per share data)
Total number of common shares as provided by Athens management		1,809,358
Total number of Athens common stock to exchange		1,809,358
Per share exchange ratio		2.864
Number of shares of CapStar common stock as exchanged		5,181,916
Multiplied by CapStar common stock price per share on September 30, 2018	$	16.70
Estimated fair value of CapStar common stock issued (“Stock Consideration”)	$	86,538

Total number of stock options outstanding as provided by Athens management to exchange		548,051
Intrinsic value per stock option outstanding	$	11.64
Estimated fair value of stock options rolled ("Rolled Stock Options Consideration")	$	6,380

Stock Consideration	$	86,538
Rolled Stock Options Consideration	$	6,380
Total Preliminary Estimated Acquisition Consideration	$	92,918

Note 3—Preliminary Estimated Acquisition Consideration Allocation

Under the acquisition method of accounting, the total acquisition consideration is allocated to the acquired tangible and intangible assets and assumed liabilities of Athens based on their estimated fair values as of the closing of the merger. The excess of the acquisition consideration over the fair value of assets acquired and liabilities assumed, if any, is allocated to goodwill.

The allocation of the estimated acquisition consideration with regard to Athens is preliminary because the proposed merger has not yet been completed. The preliminary allocation is based on estimates, assumptions, valuations, and other studies which have not progressed to a stage where there is sufficient information to make a definitive allocation. Accordingly, the acquisition consideration allocation unaudited pro forma adjustments will remain preliminary until CapStar management determines the final acquisition consideration and the fair values of assets acquired and liabilities assumed. The final determination of the acquisition consideration allocation is anticipated to be completed as soon as practicable after the completion of the merger and will be based on the value of the CapStar common stock at the closing of the merger. The final amounts allocated to assets acquired and liabilities assumed could differ significantly from the amounts presented in the unaudited pro forma combined consolidated financial statement.

The total preliminary estimated acquisition consideration as shown in the table above is allocated to Athens’s tangible and intangible assets and liabilities as of September 30, 2018 based on their preliminary estimated fair values as follows.

Cash and cash equivalents	$	12,053
Securities available-for-sale		67,426
Loans		344,833
Premises and equipment, net		9,208
Goodwill		31,291
Core deposit intangible		8,980
Other assets		30,510
Deposits		(404,520	)
Other liabilities		(6,863	)
Total acquisition consideration	$	92,918

Approximately $8,980 has been allocated to amortizable intangible assets acquired. The amortization related to the fair value of net amortizable intangible assets is reflected as a pro forma adjustment to the unaudited pro forma condensed combined financial statement.

Identifiable intangible assets. The fair values of intangible assets were determined based on the provisions of ASC 805, which defines fair value in accordance with ASC Topic 820, Fair Value Measurements and Disclosures (“ASC 820”). ASC 820 defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Intangible assets were identified that met either the separability criterion or the contractual-legal criterion described in ASC 805. The allocation to intangible assets is allocated to core deposit intangibles.

Goodwill. Goodwill represents the excess of the preliminary estimated acquisition consideration over the preliminary fair value of the underlying net tangible and intangible assets. Among the factors that contributed to a purchase price in excess of the fair value of the net tangible and intangible assets are the skill sets, operations, customer base and organizational cultures that can be leveraged to enable the combined company to build an enterprise greater than the sum of its parts. In accordance with ASC Topic 350, Intangibles—Goodwill and Other, goodwill will not be amortized, but instead will be tested for impairment at least annually and whenever events or circumstances have occurred that may indicate a possible impairment. In the event management determines that the value of goodwill has become impaired, the combined company will incur an accounting charge for the amount of the impairment during the period in which the determination is made.

Note 4—Preliminary Unaudited Pro Forma and Acquisition Accounting Adjustments

The unaudited pro forma financial information is not necessarily indicative of what the financial position actually would have been had the merger been completed at the date indicated. Such information includes adjustments which are preliminary and may be revised. Such revisions may result in material changes. The financial position shown herein is not necessarily indicative of what the past financial position of the combined companies would have been, nor necessarily indicative of the financial position of the post-merger periods. The unaudited pro forma financial information does not give consideration to the impact of possible cost savings, expense efficiencies, synergies, strategy modifications, asset dispositions or other actions that may result from the merger.

The following unaudited pro forma adjustments result from accounting for the merger, including the determination of fair value of the assets, liabilities, and commitments which CapStar, as the acquirer, will acquire from Athens. The descriptions related to these preliminary adjustments are as follows.

Income Statement – Pro Forma Adjustments

		Debit		Credit
a	Remove one-time merger related expenses			$	14,535
b	Elimination of intercompany income/expense		9		9
c	Remove amortization of existing CDI				273
d	Amortization of new CDI		1,258
e	Deposit premium amortization				178
f	Estimate of loan interest accretion				1,012
g	Income tax benefit of pro forma adjustments		3,853

a)	Remove one-time merger related expenses incurred to date.

b)	Elimination of intercompany income/expense related to Athens' deposits/loan held at CapStar.

c)	Remove amortization expense of Athens’ existing core deposit intangible ("CDI") asset.

d)	The estimate of CDI related to CapStar's acquisition of Athens is expected to approximate $8,980 and will be amortized over a ten year period on an accelerated basis which is expected to produce approximately $1.7 million of amortization expense during the first twelve months of operations.

e)	The amortization related to a time deposit premium recorded in connection with estimating the fair value of Athens’ time deposits.

Represents the estimate of the first twelve months interest income accretion related to the preliminary estimate of the fair value adjustment of the loans acquired pursuant to the merger. The total amount to be accreted in interest income over the estimated lives of the related loans is approximately $4.8 million.

g)	Adjustment to reflect the income tax provision of the Pro Forma Adjustments using 26.14% as the incremental effective tax rate.

Note 5—Earnings per Common Share

Unaudited pro forma earnings per common share for the year ended December 31, 2018 has been calculated using CapStar’s historic weighted average common shares outstanding plus the common shares assumed to be issued to Athens’ shareholders in the merger.

The following table sets forth the calculation of basic and diluted unaudited pro forma earnings per common share for the year ended December 31, 2018. In the table below, amounts are in thousands except for per share data.

	Basic		Diluted
Pro forma net income available to common shareholders	$	21,167	$	21,167
Weighted average common shares outstanding:
CapStar		11,851,476		13,052,758
Common shares issued to Athens		5,181,916		5,563,911
Pro forma		17,033,392		18,616,669
Pro forma net income per common share	$	1.24	$	1.14

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Basis of Presentation

Business Combinations

Nature of Operations

Initial Public Offering

Estimates

Cash and Cash Equivalents

Consumer real estate consists primarily of 1-4 family residential properties including home equity lines of credit.

Commercial and industrial loans include loans to business enterprises issued for commercial, industrial and/or other professional purposes.

Consumer loans include all loans issued to individuals not included in the consumer real estate class.

Other loans include all loans not included in the classes of loans above and leases.

Acquired Loans

Allowance for Loan Losses

Allowance for Loan losses

Specific Component

General Component

Transfers of Financial Assets

Servicing Rights

Transfers of Financial Assets

Premises and Equipment

These assets are reviewed for impairment when events indicate their carrying amount may not be recoverable from future undiscounted cash flows. If impaired, the assets are recorded at fair value.

Bank Owned Life Insurance

Securities Sold under Agreements to Repurchase

Goodwill and Other Intangible Assets

Other Real Estate Owned

Restricted Equity Securities

Income Taxes

Share-Based Compensation

Stock-Based Compensation

Advertising Costs

Advertising costs are expensed as incurred. Advertising expense was approximately $383,000, $310,000 and $252,000 for the years ended December 31, 2018, 2017 and 2016, respectively.

Off-Balance Sheet Financial Instruments

Derivative Instruments

Comprehensive Income

Fair Value Measurements

Restriction on Cash Balances

Subsequent Events

The Company has evaluated subsequent events for recognition and disclosure through March 15, 2019, which is the date the financial statements were available to be issued.

Income Per Common Share

No antidilutive stock options were excluded from calculation for the years ended December 31, 2018, 2017 or December 31, 2016.

The following is a summary of the basic and diluted earnings per share calculation for each of the following years (in thousands except share data):

	Year Ended December 31,
	2018		2017		2016
Basic net income per share calculation:
Numerator – Net income	$	9,655	$	1,501	$	9,097
Denominator – Average common shares outstanding		13,277,614		11,280,580		9,328,236
Basic net income per share	$	0.73	$	0.13	$	0.98
Diluted net income per share calculation:
Numerator – Net income	$	9,655	$	1,501	$	9,097
Denominator – Average common shares outstanding		13,277,614		11,280,580		9,328,236
Dilutive shares contingently issuable		1,202,733		1,522,931		1,883,790
Average diluted common shares outstanding		14,480,347		12,803,511		11,212,026
Diluted net income per share	$	0.67	$	0.12	$	0.81

Recently Issued Accounting Pronouncements

ASU 2014-09, Revenue from Contracts with Customers

A description of the Company’s revenue streams accounted for under Topic 606 follows:

ASU 2016-02, Leases

ASU 2016-13, Financial Instruments – Credit Losses

ASU 2017-04, Simplifying the Test of Goodwill Impairment

ASU 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities

ASU 2018-02, Income Statement: Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income

ASU 2018-07, Compensation – Stock Compensation

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Summary of the Basic and Diluted Earnings Per Share

The following is a summary of the basic and diluted earnings per share calculation for each of the following years (in thousands except share data):

	Year Ended December 31,
	2018		2017		2016
Basic net income per share calculation:
Numerator – Net income	$	9,655	$	1,501	$	9,097
Denominator – Average common shares outstanding		13,277,614		11,280,580		9,328,236
Basic net income per share	$	0.73	$	0.13	$	0.98
Diluted net income per share calculation:
Numerator – Net income	$	9,655	$	1,501	$	9,097
Denominator – Average common shares outstanding		13,277,614		11,280,580		9,328,236
Dilutive shares contingently issuable		1,202,733		1,522,931		1,883,790
Average diluted common shares outstanding		14,480,347		12,803,511		11,212,026
Diluted net income per share	$	0.67	$	0.12	$	0.81

Acquisition (Tables)

12 Months Ended

Dec. 31, 2018

Business Combinations [Abstract]

Schedule of Consideration Paid and Amounts of Assets Acquired and Liabilities Assumed

The following table summarizes the consideration paid for Athens and the amounts of the assets acquired and liabilities assumed recognized at the acquisition date (in thousands):

	As recorded by Athens Bancshares			Initial fair value adjustments				Measurement period adjustments		As recorded by CapStar Financial Holdings
Assets:
Cash and cash equivalents	$	12,053		$	—			$	—	$	12,053
Securities		67,342			84		(a)		—		67,426
Loans, gross		349,597			(4,764	)	(b)		—		344,833
Allowance for loan losses		(4,039	)		4,039		(c)		—		—
Premises and equipment, net		7,637			1,571		(d)		—		9,208
Core deposit intangible		2,758			6,222		(e)		—		8,980
Other		29,566			944		(f)		—		30,510
Total	$	464,914		$	8,096			$	—	$	473,010
Liabilities:
Deposits	$	404,027		$	493		(g)	$	—	$	404,520
Other		5,363			1,500		(h)		—		6,863
Total	$	409,390		$	1,993			$	—	$	411,383

Net identifiable assets acquired										$	61,627

Total cost of acquisition:
Value of stock issued				$	86,538
Value of rolled stock options					6,380
Total cost of acquisition				$	92,918					$	92,918

Goodwill recorded related to acquisition										$	31,291

________________________________________________________

(a)	The amount represents the fair value adjustment of securities that were subsequently sold.

(b)	The amount represents the adjustment of the net book value of Athens’ loans to their estimated fair value based on interest rates and expected cash flows at the date of acquisition.

(c)	The amount represents the removal of Athens’ existing allowance for loan losses.

(d)	The amount represents the adjustment of the net book value of Athens’ premises and equipment to their estimated fair value.

(e)	The amount represents the net adjustment of removing Athens’ existing core deposit intangible from prior acquisitions and recording the fair value of the core deposit intangible representing the intangible value of the deposit base acquired and the fair value of the customer relationship.

(f)	The amount represents the net adjustment of the fair value of mortgage servicing rights acquired and the deferred tax asset recognized on the fair value adjustments on Athens acquired assets and assumed liabilities.

(g)	The amount represents the adjustment necessary because the weighted average interest rate of Athens’ time deposits exceeded the cost of similar funding at the time of acquisition. The fair value adjustment will be amortized to reduce future interest expense over the life of the portfolio.

(h)	The amount represents the liability assumed in connection with the merger agreement whereby the Company will make a $1,500,000 charitable contribution to the Athens Foundation over a three year period.

Schedule of Unaudited Pro Forma Financial Information

	Pro forma combined twelve months ended December 31, 2018		Pro forma combined twelve months ended December 31, 2017
Net interest income	$	66,935	$	59,148
Noninterest income		20,692		17,540
Total revenue		87,627		76,688

Net income		21,167		5,851

Per share information:
Basic net income per share of common stock	$	1.24	$	0.36
Diluted net income per share of common stock	$	1.14	$	0.32

Investment Securities (Tables)

12 Months Ended

Dec. 31, 2018

Investments Debt And Equity Securities [Abstract]

Summary of Company's Classification of Securities

The Company’s classification of securities at December 31, 2018 and 2017 was as follows (in thousands):

	December 31, 2018									December 31, 2017
	Amortized Cost		Gross unrealized gains		Gross unrealized (losses)			Estimated fair value		Amortized Cost		Gross unrealized gains		Gross unrealized (losses)			Estimated fair value
Securities available-for-sale:
U. S. government agency securities	$	11,053	$	—	$	(347	)	$	10,706	$	11,433	$	12	$	(168	)	$	11,277
State and municipal securities		62,142		765		(981	)		61,926		51,790		1,430		(222	)		52,998
Mortgage-backed securities		146,547		776		(3,165	)		144,158		108,236		40		(1,714	)		106,562
Asset-backed securities		15,437		4		(157	)		15,284		16,575		—		(198	)		16,377
Other debt securities		11,863		71		(200	)		11,734		5,326		81		—			5,407
Total	$	247,042	$	1,616	$	(4,850	)	$	243,808	$	193,360	$	1,563	$	(2,302	)	$	192,621
Securities held-to-maturity:
State and municipal securities	$	3,734	$	54	$	(3	)	$	3,785	$	3,759	$	89	$	—		$	3,848
Total	$	3,734	$	54	$	(3	)	$	3,785	$	3,759	$	89	$	—		$	3,848

Summary of Amortized Cost and Fair Value of Debt Securities by Contractual Maturity

	Available-for-sale				Held-to-maturity
	Amortized cost		Estimated fair value		Amortized cost		Estimated fair value
Due in less than one year	$	3,561	$	3,573	$	395	$	396
Due one to five years		23,294		23,472		3,339		3,389
Due five to ten years		45,662		45,367		—		—
Due beyond ten years		12,541		11,954		—		—
Mortgage-backed securities		146,547		144,158		—		—
Asset-backed securities		15,437		15,284		—		—
	$	247,042	$	243,808	$	3,734	$	3,785

Summary of Sale of Debt and Equity Securities

Results from sales of debt and equity securities were as follows (in thousands):

	Year ended December 31
	2018			2017			2016
Proceeds	$	38,322		$	46,762		$	46,700
Gross gains		116			121			216
Gross losses		(113	)		(190	)		(146	)

Summary of Securities with Unrealized Losses Aggregated by Major Security Type and Length of Time Continuous Unrealized Loss Position

The following tables show the Company’s securities with unrealized losses, aggregated by major security type and length of time in a continuous unrealized loss position (in thousands):

	Less than 12 months					12 months or more					Total
December 31, 2018	Estimated fair value		Gross unrealized losses			Estimated fair value		Gross unrealized losses			Estimated fair value		Gross unrealized losses
U. S. government agency securities	$	—	$	—		$	10,706	$	(347	)	$	10,706	$	(347	)
State and municipal securities		13,455		(212	)		17,376		(772	)		30,831		(984	)
Mortgage-backed securities		7,075		(17	)		87,232		(3,148	)		94,307		(3,165	)
Asset-backed securities		8,262		(145	)		2,439		(12	)		10,701		(157	)
Other debt securities		5,362		(200	)		—		—			5,362		(200	)
Total temporarily impaired securities	$	34,154	$	(574	)	$	117,753	$	(4,279	)	$	151,907	$	(4,853	)
December 31, 2017
U. S. government agency securities	$	7,375	$	(90	)	$	1,912	$	(78	)	$	9,287	$	(168	)
State and municipal securities		7,490		(106	)		5,798		(116	)		13,288		(222	)
Mortgage-backed securities		29,832		(322	)		67,813		(1,392	)		97,645		(1,714	)
Asset-backed securities		—		—			16,377		(198	)		16,377		(198	)
Other debt securities		—		—			—		—			—		—
Total temporarily impaired securities	$	44,697	$	(518	)	$	91,900	$	(1,784	)	$	136,597	$	(2,302	)

Loans and Allowance for Loan Losses (Tables)

12 Months Ended

Dec. 31, 2018

Receivables [Abstract]

Summary of Loans

Loans at December 31, 2018 and 2017 were as follows (in thousands):

	December 31, 2018			December 31, 2017
Commercial real estate	$	550,446		$	350,622
Consumer real estate		253,562			102,581
Construction and land development		174,670			82,586
Commercial and industrial		404,600			373,248
Consumer		25,615			6,862
Other		21,002			31,983
Total		1,429,895			947,882
Less net unearned income		(101	)		(345	)
Total loans		1,429,794			947,537
Allowance for loan losses		(12,113	)		(13,721	)
Total loans, net	$	1,417,681		$	933,816

Summary of Risk Category of Loans by Applicable Class of Loans

The following table provides the risk category of loans by applicable class of loans as of December 31, 2018 and 2017 (in thousands):

	Non-impaired Loans
December 31, 2018	Pass		Special Mention		Substandard		Total Non-impaired		Total Impaired Loans		Total
Commercial real estate	$	547,616	$	177	$	1,262	$	549,055	$	1,391	$	550,446
Consumer real estate		249,273		1,676		1,691		252,640		922		253,562
Construction and land development		174,591		52		19		174,662		8		174,670
Commercial and industrial		388,719		7,790		6,545		403,054		1,546		404,600
Consumer		25,556		1		27		25,584		31		25,615
Other		21,002		—		—		21,002		—		21,002
Total	$	1,406,757	$	9,696	$	9,544	$	1,425,997	$	3,898	$	1,429,895
December 31, 2017
Commercial real estate	$	349,415	$	—	$	—	$	349,415	$	1,207	$	350,622
Consumer real estate		102,571		—		10		102,581		—		102,581
Construction and land development		82,586		—		—		82,586		—		82,586
Commercial and industrial		349,494		11,193		11,073		371,760		1,488		373,248
Consumer		6,849		—		13		6,862		—		6,862
Other		31,983		—		—		31,983		—		31,983
Total	$	922,898	$	11,193	$	11,096	$	945,187	$	2,695	$	947,882

Summary of Changes and Breakdown of Allowance for Loan Losses and Loan Portfolio by Loan Category

The following tables detail the changes in the ALL for the years ending December 31, 2018, 2017 and 2016 by loan classification (in thousands):

	Commercial real estate			Consumer real estate			Construction and land development		Commercial and industrial			Consumer			Other			Total
Year ended December 31, 2018
Balance, beginning of period	$	3,324		$	1,063		$	1,628	$	7,209		$	91		$	406		$	13,721
Charged-off loans		—			—			—		(4,831	)		(84	)		(39	)		(4,954	)
Recoveries		22			4			—		395			75			8			504
Provision for loan losses		(37	)		(62	)		803		2,263			23			(148	)		2,842
Balance, end of period	$	3,309		$	1,005		$	2,431	$	5,036		$	105		$	227		$	12,113

Year ended December 31, 2017
Balance, beginning of period	$	2,655		$	1,013		$	1,574	$	5,618		$	76		$	698		$	11,634
Charged-off loans		—			—			—		(12,769	)		—			—			(12,769	)
Recoveries		9			—			—		1,865			112			—			1,986
Provision for loan losses		660			50			54		12,495			(97	)		(292	)		12,870
Balance, end of period	$	3,324		$	1,063		$	1,628	$	7,209		$	91		$	406		$	13,721

Year ended December 31, 2016
Balance, beginning of period	$	2,879		$	968		$	914	$	4,693		$	103		$	575		$	10,132
Charged-off loans		(350	)		—			—		(956	)		(146	)		—			(1,452	)
Recoveries		52			—			—		23			50			—			125
Provision for loan losses		74			45			660		1,858			69			123			2,829
Balance, end of period	$	2,655		$	1,013		$	1,574	$	5,618		$	76		$	698		$	11,634

A breakdown of the ALL and the loan portfolio by loan category at December 31, 2018 and 2017 follows (in thousands):

	Commercial real estate		Consumer real estate		Construction and land development		Commercial and industrial		Consumer		Other		Total
December 31, 2018
Allowance for Loan Losses:
Collectively evaluated for impairment	$	3,309	$	1,005	$	2,431	$	5,036	$	105	$	227	$	12,113
Individually evaluated for impairment		—		—		—		—		—		—		—
Balances, end of period	$	3,309	$	1,005	$	2,431	$	5,036	$	105	$	227	$	12,113
Loans:
Collectively evaluated for impairment	$	549,055	$	252,640	$	174,662	$	403,054	$	25,584	$	21,002	$	1,425,997
Individually evaluated for impairment		1,391		922		8		1,546		31		—		3,898
Balances, end of period	$	550,446	$	253,562	$	174,670	$	404,600	$	25,615	$	21,002	$	1,429,895

December 31, 2017
Allowance for Loan Losses:
Collectively evaluated for impairment	$	3,324	$	1,063	$	1,628	$	7,109	$	91	$	406	$	13,621
Individually evaluated for impairment		—		—		—		100		—		—		100
Balances, end of period	$	3,324	$	1,063	$	1,628	$	7,209	$	91	$	406	$	13,721
Loans:
Collectively evaluated for impairment	$	349,415	$	102,581	$	82,586	$	371,760	$	6,862	$	31,983	$	945,187
Individually evaluated for impairment		1,207		—		—		1,488		—		—		2,695
Balances, end of period	$	350,622	$	102,581	$	82,586	$	373,248	$	6,862	$	31,983	$	947,882

Allocation of ALL with Corresponding Percentage of Loans in Each Category to Total Loans, Net of Deferred Fee

	December 31, 2018					December 31, 2017
	Amount		Percent of total loans, net of deferred fees			Amount		Percent of total loans, net of deferred fees
Commercial real estate	$	3,309		0.23	%	$	3,324		0.35	%
Consumer real estate		1,005		0.07			1,063		0.11
Construction and land development		2,431		0.17			1,628		0.17
Commercial and industrial		5,036		0.35			7,209		0.76
Consumer		105		0.01			91		0.01
Other		227		0.02			406		0.04
Total allowance for loan and lease losses	$	12,113		0.85	%	$	13,721		1.45	%

Summary of Information Related to Impaired Loans

The following table presents information related to impaired loans as of and for the years ended December 31, 2018 and 2017 (in thousands):


	December 31, 2018						December 31, 2017
	Recorded investment		Unpaid principal balance		Related allowance		Recorded investment		Unpaid principal balance		Related allowance
With no related allowance recorded:
Commercial real estate	$	1,391	$	1,775	$	—	$	1,207	$	1,645	$	—
Consumer real estate		922		1,204		—		—		—		—
Construction and land development		8		18		—		—		—		—
Commercial and industrial		1,546		6,350		—		—		—		—
Consumer		31		56		—		—		—		—
Other		—		—		—		—		—		—
Subtotal		3,898		9,403		—		1,207		1,645		—
With an allowance recorded:
Commercial real estate		—		—		—		—		—		—
Consumer real estate		—		—		—		—		—		—
Construction and land development		—		—		—		—		—		—
Commercial and industrial		—		—		—		1,488		2,770		100
Consumer		—		—		—		—		—		—
Other		—		—		—		—		—		—
Subtotal		—		—		—		1,488		2,770		100
Total	$	3,898	$	9,403	$	—	$	2,695	$	4,415	$	100

	Year Ended				Year Ended				Year Ended
	December 31, 2018				December 31, 2017				December 31, 2016
	Average recorded investment		Interest income recognized		Average recorded investment		Interest income recognized		Average recorded investment		Interest income recognized
With no related allowance recorded:
Commercial real estate	$	1,198	$	158	$	1,258	$	—	$	655	$	—
Consumer real estate		185		—		—		—		302		—
Construction and land development		94		2		—		—		—		—
Commercial and industrial		5,557		121		—		—		—		—
Consumer		7		—		—		—		63		—
Other		—		—		—		—		—		—
Subtotal		7,041		281		1,258		—		1,020		—
With an allowance recorded:
Commercial real estate		—		—		—		—		974		—
Consumer real estate		—		—		—		—		—		—
Construction and land development		—		—		—		—		—		—
Commercial and industrial		—		—		2,077		—		1,155		44
Consumer		—		—		—		—		—		—
Other		—		—		—		—		—		—
Subtotal		—		—		2,077		—		2,129		44
Total	$	7,041	$	281	$	3,335	$	—	$	3,149	$	44

Schedule of Aging of Recorded Investment in Past-due Loans, by Class of Loans

The following table presents the aging of the recorded investment in past-due loans as of December 31, 2018 and 2017 by class of loans (in thousands):

	30 - 59		60 - 89		Greater Than
	Days		Days		89 Days		Total		Loans Not
December 31, 2018	Past Due		Past Due		Past Due		Past Due		Past Due		Total
Commercial real estate	$	300	$	227	$	—	$	527	$	549,919	$	550,446
Consumer real estate		69		75		775		919		252,643		253,562
Construction and land development		—		—		—		—		174,670		174,670
Commercial and industrial		54		—		—		54		404,546		404,600
Consumer		52		—		43		95		25,520		25,615
Other		—		—		—		—		21,002		21,002
Total	$	475	$	302	$	818	$	1,595	$	1,428,300	$	1,429,895
December 31, 2017
Commercial real estate	$	—	$	—	$	—	$	—	$	350,622	$	350,622
Consumer real estate		—		—		218		218		102,363		102,581
Construction and land development		—		—		—		—		82,586		82,586
Commercial and industrial		1,967		209		—		2,176		371,072		373,248
Consumer		—		—		13		13		6,849		6,862
Other		—		—		—		—		31,983		31,983
Total	$	1,967	$	209	$	231	$	2,407	$	945,475	$	947,882

Schedule of Recorded In Non Accrual Loans, Past Due Loans over 89 Days and Accruing and Troubled Debt Restructurings

			Past Due Over 89		Troubled Debt
	Non-Accrual		Days and Accruing		Restructurings
December 31, 2018
Commercial real estate	$	—	$	—	$	1,391
Consumer real estate		1,187		214		—
Construction and land development		19		—		—
Commercial and industrial		817		—		—
Consumer		55		—		—
Other		—		—		—
Total	$	2,078	$	214	$	1,391

December 31, 2017
Commercial real estate	$	1,207	$	—	$	1,206
Consumer real estate		—		218		—
Construction and land development		—		—		—
Commercial and industrial		1,488		—		—
Consumer		—		13		—
Other		—		—		—
Total	$	2,695	$	231	$	1,206

Schedule of Loans by Class Modified as TDR

The following table presents loans by class modified as TDR that occurred during the year ended December 31, 2016 (in thousands).

	Year Ended
	December 31, 2016
	Number of contracts		Pre modification outstanding recorded investment		Post modification outstanding recorded investment, net of related allowance

Commercial real estate		1	$	1,948	$	1,170
Consumer real estate		—		—		—
Construction and land development		—		—		—
Commercial and industrial		—		—		—
Consumer		—		—		—
Other		—		—		—
Total		1	$	1,948	$	1,170

Schedule of Loans by Class Modified as TDR for the Payment Default Within Twelve Months

	Year Ended
	December 31, 2016
	Number of contracts		Recorded investment

Commercial real estate		—	$	—
Consumer real estate		—		—
Construction and land development		—		—
Commercial and industrial		—		—
Consumer		1		124
Other		—		—
Total		1	$	124

Summary of contractually required payments for Athens Bancshares expected at acquisition date

	Athens Bancshares acquisition on October 1, 2018
Contractually required payments	$	3,151
Nonaccretable difference		(1,049	)
Cash flows expected to be collected at acquisition		2,102
Accretable yield		(436	)
Fair value of PCI loans at acquisition date	$	1,666

Summary of contractually required payments for Athens Bancshares not expected at acquisition date

	Athens Bancshares acquisition on October 1, 2018
Contractually required payments	$	404,692
Fair value of acquired loans at acquisition date		343,167
Contractual cash flows not expected to be collected		1,807

Schedule of activity in purchased credit impaired loans

The following table presents changes in the carrying value of PCI loans (in thousands):

	For the year ended December 31, 2018
Balance at beginning of period	$	—
Additions due to acquisition of Athens Bancshares		1,666
Change due to payments received and accretion		(46	)
Change due to loan charge-offs		—
Other		—
Balance at end of period	$	1,620

The following table presents changes in the accretable yield for PCI loans (in thousands):

	For the year ended December 31, 2018
Balance at beginning of period	$	—
Additions due to acquisition of Athens Bancshares		436
Accretion		(9	)
Reclassification from (to) nonaccretable difference		—
Other, net		13
Balance at end of period	$	440

Schedule of Components of Direct Financing Leases

The components of the direct financing leases as of December 31, 2018 and 2017 were as follows (in thousands):

	December 31, 2018			December 31, 2017
Total minimum lease payments receivable	$	379		$	714
Less:
Unearned income		(19	)		(49	)
Net leases	$	360		$	665

Summary of Future Minimum Lease Payments Receivable under Direct Financing Leases

The future minimum lease payments receivable under the direct financing leases as of December 31, 2018 were as follows (in thousands):

Year ending December 31:
2019	$	178
2020		167
2021		34
2022		—
2023		—
	$	379

Loan Servicing (Tables)

12 Months Ended

Dec. 31, 2018

Transfers And Servicing [Abstract]

Schedule of Activity for Loan Servicing Rights and Related Valuation Allowance

Activity for loan servicing rights and the related valuation allowance are summarized as follows (in thousands):

	For the year ended December 31, 2018
Loan servicing rights:
Balance at beginning of period	$	—
Additions		1,809
Disposals		—
Amortized to offset other noninterest income		(73	)
Change in valuation allowance		—
Balance at end of period	$	1,736

Valuation allowance:
Balance at beginning of period	$	—
Additions expensed		—
Reductions credited to other noninterest income		—
Direct write-downs		—
Balance at end of period	$	—

Premises and Equipment (Tables)

12 Months Ended

Dec. 31, 2017

Property Plant And Equipment [Abstract]

Summary of Premises and Equipment

Premises and equipment at December 31, 2018 and 2017 are summarized as follows (in thousands):

	Range of useful lives	December 31, 2018			December 31, 2017
Land	Not applicable	$	2,997		$	1,180
Buildings	39 years		9,965			3,586
Leasehold improvements	1 to 17 years		939			777
Furniture and equipment	1 to 7 years		3,730			2,659
Fixed assets in process	Not applicable		4,023			—
			21,654			8,202
Less accumulated depreciation and amortization			(2,833	)		(2,318	)
		$	18,821		$	5,884

Summary of Future Minimum Payments under Operating Leases

Future minimum payments under these operating leases as of December 31, 2018 are as follows (in thousands):

Year ending December 31:
2019	$	1,538
2020		1,539
2021		1,567
2022		1,453
2023		1,402
Thereafter		8,821
	$	16,320

Goodwill and Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2018

Goodwill And Intangible Assets Disclosure [Abstract]

Schedule of Change in Goodwill

The change in goodwill during the years ended December 31, 2018 and 2017 was as follows (in thousands):

	2018		2017
Beginning of year	$	6,219	$	6,219
Acquired goodwill		31,291		—
Impairment		—		—
End of year	$	37,510	$	6,219

Summary of Acquired Intangible Assets

Acquired intangible assets at December 31, 2018 and 2017 were as follows (in thousands):

	December 31, 2018					December 31, 2017
	Gross Carrying Amount		Accumulated Amortization			Gross Carrying Amount		Accumulated Amortization
Amortized intangible assets:
Core deposit intangibles	$	9,267	$	(729	)	$	287	$	(264	)

Summary of Estimated Amortization Expense

Estimated amortization expense for each of the next five years is as follows (in thousands):

Year ending December 31:
2019	$	1,655
2020		1,477
2021		1,299
2022		1,121
2023		943
Thereafter		2,043
Total	$	8,538

Other Real Estate Owned (Tables)

12 Months Ended

Dec. 31, 2018

Other Real Estate [Abstract]

Summary of Other Real Estate Owned Activity

Other real estate owned activity was as follows (in thousands):

	2018		2017		2016
Beginning balance	$	—	$	—	$	216
Additions due to acquisition of Athens Bancshares		988		—		—
Loans transferred to other real estate owned		—		—		—
Direct write-downs		—		—		—
Sales of other real estate owned		—		—		(216	)
End of year	$	988	$	—	$	—

Summary of Valuation Allowance Activity in Other Real Estate Owned

Activity in the valuation allowance was as follows during the years ended December 31, 2018, 2017 and 2016, respectively (in thousands):

	2018		2017		2016
Beginning balance	$	—	$	—	$	450
Additions/(recoveries) charged/(credited) to expense		—		—		—
Reductions from sales of other real estate owned		—		—		(450	)
Direct write-downs		—		—		—
End of year	$	—	$	—	$	—

Summary of Expenses Related to Other Real Estate Owned

Expenses related to other real estate owned during the years ended December 31, 2018, 2017 and 2016, respectively include (in thousands):

	2018		2017		2016
Net (gain) loss on sales	$	—	$	—	$	(157	)
Provision for unrealized losses		—		—		—
Operating expenses, net of rental income		—		—		14
Total	$	—	$	—	$	(143	)

Deposits (Tables)

12 Months Ended

Dec. 31, 2018

Deposits [Abstract]

Scheduled Maturities of Time Deposits

Scheduled maturities of time deposits for the next five years and thereafter are as follows (in thousands):

Maturity:
2019	$	254,839
2020		57,800
2021		15,167
2022		12,068
2023		8,294
Thereafter		259
	$	348,427

Federal Home Loan Bank Advances (Tables)

12 Months Ended

Dec. 31, 2018

Federal Home Loan Banks [Abstract]

Summary of Contractual Maturities and Average Effective Rates of Outstanding Advances

The following is a summary of the contractual maturities and average effective rates of outstanding advances (dollars in thousands):

	December 31, 2018					December 31, 2017
Year	Amount		Interest Rates			Amount		Interest Rates
2017	$	—		—		$	—		—
2018		—		—			70,000		1.66	%
2019		125,000		2.48	%		—		—
2020		—		—			—		—
2021		—		—			—		—
2022		—		—			—		—
2023		—		—			—		—
Thereafter		—		—			—		—
Total	$	125,000		2.48	%	$	70,000		1.66	%

Accumulated Other Comprehensive Income (Loss) (Tables)

12 Months Ended

Dec. 31, 2018

Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]

Summary of Changes in Accumulated Other Comprehensive Income (Loss) by Component, Net of Tax

The following were changes in accumulated other comprehensive income (loss) by component, net of tax, for the years ended December 31, 2018 and 2017 (in thousands):

				Unrealized Gains			Unrealized
	Gains and			and Losses			Losses on
	Losses on			on Available			Securities
	Cash Flow			for Sale			Transferred to
Year Ended December 31, 2018	Hedges			Securities			Held to Maturity			Total
Beginning Balance	$	(3,679	)	$	1,162		$	(10	)	$	(2,527	)
Other comprehensive income (loss) before reclassification, net of tax		1,891			(1,844	)		20			67
Amounts reclassified from accumulated other comprehensive income (loss), net of tax		(848	)		2			(10	)		(856	)
Net current period other comprehensive income (loss)		1,043			(1,842	)		10			(789	)
Ending Balance	$	(2,636	)	$	(680	)	$	—		$	(3,316	)

Year Ended December 31, 2017
Beginning Balance	$	(4,241	)	$	(698	)	$	(1,212	)	$	(6,151	)
Other comprehensive income (loss) before reclassification, net of tax		1,499			3,077			235			4,811
Amounts reclassified for securities transferred from held-to-maturity to available-for-sale		—			(1,086	)		1,086			—
Amounts reclassified from accumulated other comprehensive income (loss), net of tax		(770	)		(41	)		(117	)		(928	)
Net current period other comprehensive income (loss)		729			1,950			1,204			3,883
Reclassification of accumulated other comprehensive income due to tax rate change		(167	)		(90	)		(2	)		(259	)
Ending Balance	$	(3,679	)	$	1,162		$	(10	)	$	(2,527	)

Summary of Significant Amounts Reclassified out off Accumulated Other Comprehensive Income (Loss)

The following were significant amounts reclassified out of each component of accumulated other comprehensive income (loss) for the years ended December 31, 2018, 2017 and 2016 (in thousands):

										Affected Line Item
Details about Accumulated Other	Year Ended			Year Ended			Year Ended			in the Statement Where
Comprehensive Income Components	December 31, 2018			December 31, 2017			December 31, 2016			Net Income is Presented
Unrealized losses on cash flow hedges	$	(441	)	$	(430	)	$	(151	)	Interest expense - money market
		(479	)		(429	)		(265	)	Interest expense - Federal Home Loan Bank advances
		72			89			—		Income tax benefit
	$	(848	)	$	(770	)	$	(416	)	Net of tax
Unrealized gains and (losses) on available-for-sale securities	$	3		$	(66	)	$	121		Net gain (loss) on sale of securities
		(1	)		25			(46	)	Income tax (expense) benefit
	$	2		$	(41	)	$	75		Net of tax
Unrealized losses on securities transferred to held-to-maturity	$	(14	)	$	(190	)	$	(167	)	Interest income - securities
		4			73			64		Income tax benefit
	$	(10	)	$	(117	)	$	(103	)	Net of tax

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Schedule of Components of Income Tax Expense (Benefit)

The components of income tax expense are summarized as follows (in thousands):

	2018			2017		2016
Current:
Federal	$	15		$	214	$	4,029
State		(23	)		36		759
		(8	)		250		4,788
Deferred:
Federal		872			4,218		(395	)
State		303			167		100
		1,175			4,385		(295	)
Total	$	1,167		$	4,635	$	4,493

Schedule of Reconciliation of Actual Income Tax Expense

	2018			2017			2016
Computed "expected" tax expense	$	2,272		$	2,086		$	4,621
State income taxes, net of effect of federal income taxes		221			134			567
Tax-exempt interest income		(298	)		(418	)		(394	)
Earnings on bank owned life insurance contracts		(559	)		(197	)		(204	)
Disallowed expenses		93			86			60
Excess tax benefits related to stock compensation		(857	)		(632	)		—
Write-down of deferred tax assets due to tax reform		—			3,562			—
Nondeductible merger expenses		281			—			—
Other		14			14			(157	)
Total	$	1,167		$	4,635		$	4,493

Schedule of Deferred Tax Assets and Liabilities

Significant items that gave rise to deferred taxes at December 31, 2018 and 2017 were as follows (in thousands):

	December 31, 2018		December 31, 2017
Deferred tax assets:
Allowance for loan losses	$	2,795	$	3,227
Depreciation		—		—
Net operating loss carryforward		2,002		843
Organization and preopening costs		457		557
Stock-based compensation		835		672
Acquired loans		1,319		124
Acquired deposits		106		22
Nonaccrual interest		75		25
Accrued incentive compensation		97		—
Reserve for contingencies		143		496
Accrued contributions		207		169
Unrealized loss on securities available-for-sale		845		193
Unrealized loss on securities held-to-maturity		—		4
Cash flow hedge		219		359
Accrued vacation		45		45
Other		—		134
Deferred tax assets		9,145		6,870
Deferred tax liabilities:
Prepaid expenses		77		134
Depreciation		645		39
Goodwill		81		138
Amortization of core deposit intangible		1,398		6
Other		334		—
Deferred tax liabilities		2,535		317
Net deferred tax asset	$	6,610	$	6,553

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2018

Commitments And Contingencies Disclosure [Abstract]

Schedule of Financial Instruments Representing Credit Risk

The following table sets forth outstanding financial instruments whose contract amounts represent credit risk as of December 31, 2018 and 2017 (in thousands):

	Contract or notional amount
	December 31, 2018		December 31, 2017
Financial instruments whose contract amounts represent credit risk:
Unused commitments to extend credit	$	707,675	$	584,494
Standby letters of credit		12,273		11,552
Total	$	719,948	$	596,046

- Definition

Tabular disclosure of all significant concentrations of risk, including credit risk and market risk, arising from all financial instruments (as defined), whether from an individual counterparty or groups of counterparties. The disclosure concerning concentrations of risk may consist of the following information: (1) for concentrations of credit risk disclosure may include: (a) information about the (shared) activity, region, or economic characteristic that identifies the concentration, (b) the maximum amount of loss due to credit risk that, based on the gross fair value of the financial instrument, the entity would incur if parties to the financial instruments that make up the concentration failed completely to perform according to the terms of the contracts and the collateral or other security, if any, for the amount due proved to be of no value to the entity, (c) the policy of requiring collateral or other security to support financial instruments subject to credit risk, information about the entity's access to that collateral or other security, and the nature and a brief description of the collateral or other security supporting those financial instruments, and (d) the policy of entering into master netting arrangements to mitigate the credit risk of financial instruments, information about the arrangements for which the entity is a party, and a brief description of the terms of those arrangements, including the extent to which they would reduce the entity's maximum amount of loss due to credit risk and (2) for disclosure of quantitative information about the market risks of financial instruments that is consistent with the way the company manages or adjusts those risks, disclosure may include: (a) more details about current positions and perhaps activity during the period, (b) the hypothetical effects on comprehensive income (or net assets), or annual income, of several possible changes in market prices, (c) a gap analysis of interest rate re-pricing or maturity dates, (d) the duration of the financial instruments, (e) the entity's value at risk from derivatives and from other positions at the end of the reporting period and the average value at risk during the year, or (f) other ways of reporting quantitative information as internally developed.

+ References + Details

Regulatory Matters And Restrictions On Dividends (Tables)

12 Months Ended

Dec. 31, 2018

Banking And Thrift [Abstract]

Schedule of Capital Amounts and Ratios

The Company’s and the Bank’s capital amounts and ratios are presented in the following table (dollars in thousands):

	Actual					Minimum capital requirement (1)					Minimum to be well-capitalized (2)
	Amount		Ratio			Amount		Ratio			Amount		Ratio
At December 31, 2018:
Total capital to risk-weighted assets:
CapStar Financial Holdings, Inc.	$	222,030		12.8	%	$	138,336		8.0	%	$ N/A		N/A
CapStar Bank		201,972		11.7			138,294		8.0			172,868		10.0
Tier I capital to risk-weighted assets:
CapStar Financial Holdings, Inc.		209,738		12.1			103,752		6.0		N/A		N/A
CapStar Bank		189,680		11.0			103,721		6.0			138,294		8.0
Common equity Tier 1 capital to risk weighted assets:
CapStar Financial Holdings, Inc.		200,738		11.6			77,814		4.5		N/A		N/A
CapStar Bank		173,180		10.0			77,791		4.5			112,364		6.5
Tier I capital to average assets:
CapStar Financial Holdings, Inc.		209,738		11.1			75,867		4.0		N/A		N/A
CapStar Bank		189,680		10.0			75,828		4.0			94,785		5.0
At December 31, 2017:
Total capital to risk-weighted assets:
CapStar Financial Holdings, Inc.	$	156,176		12.5	%	$	99,932		8.0	%	$ N/A		N/A
CapStar Bank		142,138		11.4			99,928		8.0			124,909		10.0
Tier I capital to risk-weighted assets:
CapStar Financial Holdings, Inc.		142,276		11.4			74,949		6.0		N/A		N/A
CapStar Bank		128,238		10.3			74,946		6.0			99,928		8.0
Common equity Tier 1 capital to risk weighted assets:
CapStar Financial Holdings, Inc.		133,445		10.7			56,212		4.5		N/A		N/A
CapStar Bank		111,907		9.0			56,209		4.5			81,191		6.5
Tier I capital to average assets:
CapStar Financial Holdings, Inc.		142,276		10.7			53,218		4.0		N/A		N/A
CapStar Bank		128,238		9.6			53,215		4.0			66,519		5.0

(1)

(2)

Stock Options and Restricted Shares (Tables)

12 Months Ended

Dec. 31, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Company Recognized Stock-Based Compensation Expense

	For the year ended December 31,
	2018			2017			2016
Stock-based compensation expense before income taxes	$	2,079		$	1,061		$	842
Less: deferred tax benefit		(543	)		(406	)		(322	)
Reduction of net income	$	1,536		$	655		$	520

Summary of Changes in Company's Nonvested Restricted Shares

A summary of the changes in the Company’s nonvested restricted shares for 2018 follows:

				Weighted
				Average
	Restricted			Grant Date
Nonvested Shares	Shares			Fair Value
Nonvested at beginning of period		187,253		$	14.21
Granted		140,131			16.73
Vested		(161,604	)		13.54
Forfeited		(8,164	)		15.92
Nonvested at end of period		157,616		$	17.00

Summary of Fair Value of Options Granted Using Weighted Average Assumptions

The fair value of options granted was determined using the following weighted average assumptions as of the grant date. There were no options granted during 2018 or 2017.

	2016
Dividend yield		—
Expected term (in years)		7.48
Expected stock price volatility		17.20	%
Risk-free interest rate		1.66	%
Pre-vest forfeiture rate		10.25	%

Summary of Activity in Stock Options

A summary of the activity in stock options for 2018 follows:

						Weighted
				Weighted		Average
				Average		Remaining
				Exercise		Contractual
	Shares			Price		Term (years)
Outstanding at beginning of period		756,050		$	10.50
Additions due to acquisition of Athens Bancshares		548,051		$	5.06
Granted		—			—
Exercised		(796,198	)		8.16
Forfeited or expired		—			—
Outstanding at end of period		507,903		$	8.66		4.0
Fully vested and expected to vest		506,783		$	8.66		4.1
Exercisable at end of period		480,403		$	8.46		4.0

Information Related to Stock Options

Information related to stock options during 2018, 2017 and 2016 follows:

	2018		2017		2016
Intrinsic value of options exercised	$	7,654,738	$	2,010,536	$	53,756
Cash received from option exercises		6,897,845		2,013,840		96,306
Tax benefit realized from option exercises		846,725		774,056		20,583
Weighted average fair value of options granted		—		—		3.16

Derivative Instruments (Tables)

12 Months Ended

Dec. 31, 2018

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Summary of Interest-Rate Swaps Designated as Cash Flow Hedges

Summary information about the interest-rate swaps designated as cash flow hedges was as follows (dollars in thousands):

	December 31, 2018			December 31, 2017
Notional amounts	$	20,000		$	20,000
Weighted average pay rates		3.54	%		3.54	%
Weighted average receive rates	3 month LIBOR			3 month LIBOR
Weighted average maturity	4.5 years			5.5 years
Fair value	$	(836	)	$	(1,375	)
Amount of unrealized loss recognized in accumulated other comprehensive income, net of tax	$	(617	)	$	(849	)

Summary of Customer Related Interest Rate Swaps

A summary of the Company’s customer related interest rate swaps is as follows (in thousands):

	December 31, 2018					December 31, 2017
	Notional		Estimated			Notional		Estimated
	amount		fair value			amount		fair value
Interest rate swap agreements:
Pay fixed/receive variable swaps	$	29,126	$	24		$	41,863	$	55
Pay variable/receive fixed swaps		29,126		(24	)		41,863		(55	)
Total	$	58,252	$	—		$	83,726	$	—

Related Party (Tables)

12 Months Ended

Dec. 31, 2018

	Total commitment			Total funded commitment
Year ended December 31, 2018
Beginning of period	$	49,409		$	21,890
New commitments/draw downs		3,631			1,038
Repayments		(8,228	)		(7,483	)
End of period	$	44,812		$	15,445

Year ended December 31, 2017
Beginning of period	$	31,076		$	20,325
New commitments/draw downs		21,203			4,320
Repayments		(2,870	)		(2,755	)
End of period	$	49,409		$	21,890

Fair Value (Tables)

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis

Assets and liabilities measured at fair value on a recurring basis are summarized below (in thousands):

	Fair value measurements at December 31, 2018
				Quoted prices
				in active		Significant
				markets for		other			Significant
				identical		observable			unobservable
	Carrying			assets		inputs			inputs
	Value			(Level 1)		(Level 2)			(Level 3)
Assets:
Securities available-for-sale:
U.S. government-sponsored agencies	$	10,706		$	—	$	10,706		$	—
Obligations of states and political subdivisions		61,926			—		61,926			—
Mortage-backed securities-residential		144,158			—		144,158			—
Asset-backed securities		15,284			—		15,284			—
Other debt securities		11,734			—		11,734			—
Total securities available-for-sale	$	243,808		$	—	$	243,808		$	—
Derivatives:
Interest rate swaps - customer related	$	494		$	—	$	494		$	—
Liabilities:
Derivatives:
Interest rate swaps - customer related	$	(494	)	$	—	$	(494	)	$	—
Interest rate swaps - cash flow hedges		(836	)		—		(836	)		—
Total derivatives	$	(1,330	)	$	—	$	(1,330	)	$	—

	Fair value measurements at December 31, 2017
				Quoted prices
				in active		Significant
				markets for		other			Significant
				identical		observable			unobservable
	Carrying			assets		inputs			inputs
	Value			(Level 1)		(Level 2)			(Level 3)
Assets:
Securities available-for-sale:
U.S. government-sponsored agencies	$	11,277		$	—	$	11,277		$	—
Obligations of states and political subdivisions		52,998			—		52,998			—
Mortage-backed securities-residential		106,562			—		106,562			—
Asset-backed securities		16,377			—		16,377			—
Other debt securities		5,407			—		5,407			—
Total securities available-for-sale	$	192,621		$	—	$	192,621		$	—
Derivatives:
Interest rate swaps - customer related	$	184		$	—	$	184		$	—
Liabilities:
Derivatives:
Interest rate swaps - customer related	$	(184	)	$	—	$	(184	)	$	—
Interest rate swaps - cash flow hedges		(1,375	)		—		(1,375	)		—
Total derivatives	$	(1,559	)	$	—	$	(1,559	)	$	—

Summary of Assets Measured at Fair Value on a Nonrecurring Basis

Assets measured at fair value on a nonrecurring basis are summarized below (in thousands). There were no assets measured at fair value on a nonrecurring basis at December 31, 2018:

Fair value measurements at December 31, 2017

Quoted prices

in active

Significant

markets for

other

Significant

identical

observable

unobservable

Carrying

assets

inputs

Value

(level 1)

(level 2)

(level 3)

Assets:

Impaired loans:

Commercial and industrial

1,388

—

1,388

Summary of Quantitative Information About Level 3 Fair Value Measurements for Assets Measured at Fair Value on a Non-recurring Basis

Range

Fair

Valuation

Unobservable

(Weighted-

December 31, 2017

Value

Technique(s)

Input(s)

Average)

Impaired loans:

Commercial and industrial

1,388

Sales comparison approach

Appraisal discounts

Summary of Carrying Value and Fair Values of the Company's Financial Instruments

The carrying value and estimated fair values of the Company’s financial instruments at December 31, 2018, 2017 and 2016 were as follows (in thousands):

	December 31, 2018				December 31, 2017
	Carrying				Carrying				Fair value
	amount		Fair value		amount		Fair value		level of input
Financial assets:
Cash and due from banks, interest-bearing deposits in financial institutions	$	94,681	$	94,681	$	78,078	$	78,078	Level 1
Federal funds sold		10,762		10,762		4,719		4,719	Level 1
Securities available-for-sale		243,808		243,808		192,621		192,621	Level 2
Securities held-to-maturity		3,734		3,785		3,759		3,848	Level 2
Loans held for sale		57,618		58,596		74,093		75,549	Level 2
Restricted equity securities		12,038	N/A			8,806	N/A		N/A
Loans, net of unearned income		1,429,794		1,442,082		947,537		944,037	Level 3
Accrued interest receivable		5,964		5,964		4,084		4,084	Level 2
Other assets		34,489		34,489		22,663		22,663	Level 2
Financial liabilities:
Deposits		1,570,008		1,504,101		1,119,866		1,065,669	Level 3
Federal Home Loan Bank advances		125,000		126,548		70,000		69,980	Level 2
Other liabilities		2,753		2,753		3,672		3,672	Level 3

Parent Company Only Financial Information (Tables)

12 Months Ended

Dec. 31, 2018

Condensed Financial Information Of Parent Company Only Disclosure [Abstract]

Condensed Balance Sheets

	December 31, 2018		December 31, 2017
Assets
Cash and cash equivalents	$	19,918	$	14,108
Investment in consolidated subsidiary		234,263		132,909
Other assets		499		61
Total assets	$	254,680	$	147,078
Liabilities and Shareholders’ Equity
Other liabilities	$	301		132
Total shareholders’ equity		254,379		146,946
Total liabilities and shareholders’ equity	$	254,680	$	147,078

Condensed Income Statements

	Year Ended			Year Ended
	December 31, 2018			December 31, 2017
Income - dividends from subsidiary	$	1,225		$	—
Expenses		1,054			879
Income before income taxes and equity in undistributed net income of subsidiary		171			(879	)
Income tax benefit		(242	)		(256	)
Income (loss) before equity in undistributed net income of subsidiary		413			(623	)
Equity in undistributed net income of subsidiary		9,242			2,124
Net income	$	9,655		$	1,501

Condensed Statements of Cash Flows

	Year Ended			Year Ended
	December 31, 2018			December 31, 2017
Cash flows from operating activities:
Net income	$	9,655		$	1,501
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Increase in other assets		(221	)		(62	)
Increase in other liabilities		169			77
Equity in undistributed net income of subsidiary		(9,242	)		(2,124	)
Net cash provided by (used in) operating activities		361			(608	)
Cash flows from investing activities:
Investments in subsidiary		—			(10,000	)
Cash received from acquisitions, net		1,421			—
Net cash provided by (used in) investing activities		1,421			(10,000	)
Cash flows from financing activities:
Issuance of common stock		—			—
Exercise of common stock options and warrants, net of repurchase of restricted shares		5,260			1,764
Common and preferred stock dividends paid		(1,232	)
Net cash provided by financing activities		4,028			1,764
Net increase (decrease) in cash and cash equivalents		5,810			(8,844	)
Cash and cash equivalents at beginning of period		14,108			22,952
Cash and cash equivalents at end of period	$	19,918		$	14,108

Quarterly Financial Results (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Summary of Quarterly Financial Results (Unaudited)

The following is a summary of quarterly financial results (unaudited) for 2018, 2017 and 2016:

	First Quarter			Second Quarter			Third Quarter			Fourth Quarter
2018
Interest income	$	13,744		$	15,354		$	15,782		$	22,900
Interest expense		2,898			3,767			4,239			5,184
Net interest income		10,846			11,587			11,543			17,716
Provision for loan losses		678			169			481			1,514
Net interest income after provision for loan losses		10,168			11,418			11,062			16,202
Noninterest income		3,088			2,765			3,218			6,387
Noninterest expense		9,580			10,005			10,070			23,832
Net income (loss) before income tax expense		3,676			4,178			4,210			(1,243	)
Income tax expense (benefit)		483			665			554			(535	)
Net income (loss)	$	3,193		$	3,513		$	3,656		$	(708	)
Net income (loss) per share, basic	$	0.27		$	0.30		$	0.30		$	(0.04	)
Net income (loss) per share, diluted	$	0.25		$	0.27		$	0.28		$	(0.04	)
2017
Interest income	$	11,979		$	12,891		$	13,521		$	13,124
Interest expense		2,047			2,320			2,678			2,606
Net interest income		9,932			10,571			10,843			10,518
Provision for loan losses		3,405			9,690			(195	)		(30	)
Net interest income after provision for loan losses		6,527			881			11,038			10,548
Noninterest income		2,133			2,666			3,372			2,736
Noninterest expense		8,376			8,217			8,475			8,699
Net income (loss) before income tax expense		284			(4,670	)		5,935			4,585
Income tax expense (benefit)		(47	)		(1,328	)		1,516			4,494
Net income (loss)	$	331		$	(3,342	)	$	4,419		$	91
Net income (loss) per share, basic	$	0.03		$	(0.30	)	$	0.39		$	0.01
Net income (loss) per share, diluted	$	0.03		$	(0.26	)	$	0.35		$	0.01
2016
Interest income	$	10,598		$	10,915		$	11,875		$	12,007
Interest expense		1,642			1,714			1,749			1,827
Net interest income		8,956			9,201			10,126			10,180
Provision for loan losses		937			183			1,639			70
Net interest income after provision for loan losses		8,019			9,018			8,487			10,110
Noninterest income		2,371			2,568			3,191			2,954
Noninterest expense		8,010			7,951			8,527			8,642
Net income before income tax expense		2,380			3,635			3,151			4,422
Income tax expense		796			1,159			1,042			1,495
Net income	$	1,584		$	2,476		$	2,109		$	2,927
Net income per share, basic	$	0.18		$	0.29		$	0.24		$	0.26
Net income per share, diluted	$	0.15		$	0.23		$	0.20		$	0.23

Summary of Significant Accounting Policies - Additional Information (Details)		12 Months Ended
	Sep. 27, 2016 USD ($) shares	Dec. 31, 2018 USD ($) Security shares	Dec. 31, 2017 USD ($) shares	Dec. 31, 2016 USD ($) shares
Summary Of Significant Accounting Policies [Line Items]
Date of acquisition		Feb. 05, 2016
Number of Securities \| Security		3
Accrual of interest on loans due discontinued period		90 days
Minimum loan losses exposure for formal credit review		$ 1,500,000
Look-back period		37 quarters	33 quarter	28 quarter
Noninterest income		$ 5,653,000	$ 6,238,000	$ 7,375,000
Deferred liability, operating lease rentals		$ 639,000
Income tax examination description		A tax position is recognized as a benefit only if it is “more likely than not” that the tax position would be sustained in a tax examination, with a tax examination being presumed to occur. The amount recognized is the largest amount of tax benefit that is greater than 50% likely of being realized on examination. For tax positions not meeting the “more likely than not” test, no tax benefit is recorded.
Tax benefit from income tax examination		$ 0
Advertising expense		383,000	310,000	252,000
Restricted balance of cash reserve with Federal Reserve Bank		$ 63,890,000	$ 43,940,000	40,902,000
Antidilutive stock options excluded from diluted earnings per share \| shares		0	0
Right-of-use asset		$ 12,800,000
Lease, Liability		13,400,000
Cumulative-effect adjustment to retained earnings		600,000
Income tax effects, accumulated other comprehensive income to retained earnings, amount		$ 259,000
Minimum
Summary Of Significant Accounting Policies [Line Items]
Premises and equipment, useful lives		3 years
Income tax benefit recognized percentage		50.00%
Minimum \| Core Deposit
Summary Of Significant Accounting Policies [Line Items]
Intangible assets, useful lives		6 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Premises and equipment, useful lives		39 years
Maximum \| Core Deposit
Summary Of Significant Accounting Policies [Line Items]
Intangible assets, useful lives		10 years
Bank Servicing
Summary Of Significant Accounting Policies [Line Items]
Noninterest income		$ 102,000,000	$ 0	$ 0
Consumer Loan
Summary Of Significant Accounting Policies [Line Items]
Accrual of interest on loans due charged off		180 days
Initial Public Offering \| Common Stock
Summary Of Significant Accounting Policies [Line Items]
Issuance of common stock \| shares	2,972,750
Preferred shares converted to common stock \| shares				731,707
Net proceeds from issuance	$ 21,600,000
Initial Public Offering by the Company \| Common Stock
Summary Of Significant Accounting Policies [Line Items]
Issuance of common stock \| shares	1,688,049
Initial Public Offering by certain selling shareholders \| Common Stock
Summary Of Significant Accounting Policies [Line Items]
Issuance of common stock \| shares	1,284,701
Preferred shares converted to common stock \| shares	731,707
Cashless exercise \| shares	79,166
Exercise of common stock warrants, shares \| shares	250,000
Net proceeds from issuance	$ 0

Summary of Significant Accounting Policies - Summary of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Basic net income per share calculation:
Numerator – Net income													$ 9,655	$ 1,501	$ 9,097
Denominator – Average common shares outstanding													13,277,614	11,280,580	9,328,236
Basic net income per share of common stock	$ (0.04)	$ 0.30	$ 0.30	$ 0.27	$ 0.01	$ 0.39	$ (0.30)	$ 0.03	$ 0.26	$ 0.24	$ 0.29	$ 0.18	$ 0.73	$ 0.13	$ 0.98
Diluted net income per share calculation:
Numerator – Net income													$ 9,655	$ 1,501	$ 9,097
Denominator – Average common shares outstanding													13,277,614	11,280,580	9,328,236
Dilutive shares contingently issuable													1,202,733	1,522,931	1,883,790
Average diluted common shares outstanding													14,480,347	12,803,511	11,212,026
Diluted net income per share of common stock	$ (0.04)	$ 0.28	$ 0.27	$ 0.25	$ 0.01	$ 0.35	$ (0.26)	$ 0.03	$ 0.23	$ 0.20	$ 0.23	$ 0.15	$ 0.67	$ 0.12	$ 0.81

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(19))
-URI http://asc.fasb.org/extlink&oid=114873790&loc=SL114874131-224263

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 7
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+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

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+ Details

Acquisitions - Additional Information (Detail) - Athens Bancshares - USD ($)	Dec. 31, 2018	Oct. 01, 2018
Business Acquisition [Line Items]
Percentage of voting interests acquired		100.00%
Common stock exchange ratio		2.864
Acquisition related costs	$ 9,803,000
Goodwill		$ 31,291,000

Acquisition - Schedule of Consideration Paid and Amounts of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Oct. 01, 2018	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Total cost of acquisition:
Goodwill	$ 37,510			$ 6,219	$ 6,219
Athens Bancshares
Assets:
Cash and cash equivalents		$ 12,053	$ 12,053
Securities		67,426	67,426
Loans, gross		344,833
Premises and equipment, net		9,208	9,208
Core deposit intangible		8,980
Other		30,510	30,510
Total		473,010
Liabilities:
Deposits		404,520
Other		6,863	6,863
Total		411,383
Net identifiable assets acquired		61,627
Total cost of acquisition:
Total cost of acquisition	92,918
Goodwill		31,291	$ 31,291
Athens Bancshares \| As recorded by Athens Bancshares
Assets:
Cash and cash equivalents		12,053
Securities		67,342
Loans, gross		349,597
Allowance for loan losses		(4,039)
Premises and equipment, net		7,637
Core deposit intangible		2,758
Other		29,566
Total		464,914
Liabilities:
Deposits		404,027
Other		5,363
Total		409,390
Athens Bancshares \| Initial Fair Value Adjustment
Assets:
Securities		84
Loans, gross		(4,764)
Allowance for loan losses		4,039
Premises and equipment, net		1,571
Core deposit intangible		6,222
Other		944
Total		8,096
Liabilities:
Deposits		493
Other		1,500
Total		$ 1,993
Total cost of acquisition:
Total cost of acquisition	92,918
Athens Bancshares \| Initial Fair Value Adjustment \| Rolled Stock Options
Total cost of acquisition:
Total cost of acquisition	6,380
Athens Bancshares \| Common Stock \| Initial Fair Value Adjustment
Total cost of acquisition:
Total cost of acquisition	$ 86,538

Acquisition - Schedule of Unaudited Pro Forma Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Net interest income	$ 17,716	$ 11,543	$ 11,587	$ 10,846	$ 10,518	$ 10,843	$ 10,571	$ 9,932	$ 10,180	$ 10,126	$ 9,201	$ 8,956		$ 51,692	$ 41,863	$ 38,464
Noninterest income	6,387	3,218	2,765	3,088	2,736	3,372	2,666	2,133	2,954	3,191	2,568	2,371		15,459	10,908	11,084
Net income	$ (708)	$ 3,656	$ 3,513	$ 3,193	$ 91	$ 4,419	$ (3,342)	$ 331	$ 2,927	$ 2,109	$ 2,476	$ 1,584		$ 9,655	$ 1,501	$ 9,097
Per share information:
Basic net income per share of common stock	$ (0.04)	$ 0.30	$ 0.30	$ 0.27	$ 0.01	$ 0.39	$ (0.30)	$ 0.03	$ 0.26	$ 0.24	$ 0.29	$ 0.18		$ 0.73	$ 0.13	$ 0.98
Diluted net income per share of common stock	$ (0.04)	$ 0.28	$ 0.27	$ 0.25	$ 0.01	$ 0.35	$ (0.26)	$ 0.03	$ 0.23	$ 0.20	$ 0.23	$ 0.15		$ 0.67	$ 0.12	$ 0.81
Athens Bancshares
Business Acquisition [Line Items]
Net interest income													$ 14,053	$ 66,935	$ 59,148
Noninterest income													5,233	20,692	17,540
Total revenue														87,627	76,688
Net income													$ 625	$ 21,167	$ 5,851
Per share information:
Basic net income per share of common stock													$ 0.36	$ 1.24	$ 0.36
Diluted net income per share of common stock													$ 0.35	$ 1.14	$ 0.32

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Investment Securities - Summary of Company's Classification of Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Securities available for sale [Abstract]
Amortized Cost	$ 247,042	$ 193,360
Gross unrealized gains	1,616	1,563
Gross unrealized (losses)	(4,850)	(2,302)
Estimated fair value	243,808	192,621
Securities held to maturity [Abstract]
Amortized Cost	3,734	3,759
Gross unrealized gains	54	89
Gross unrealized (losses)	(3)
Estimated fair value	3,785	3,848
U. S. government agency securities
Securities available for sale [Abstract]
Amortized Cost	11,053	11,433
Gross unrealized gains		12
Gross unrealized (losses)	(347)	(168)
Estimated fair value	10,706	11,277
State and municipal securities
Securities available for sale [Abstract]
Amortized Cost	62,142	51,790
Gross unrealized gains	765	1,430
Gross unrealized (losses)	(981)	(222)
Estimated fair value	61,926	52,998
Securities held to maturity [Abstract]
Amortized Cost	3,734	3,759
Gross unrealized gains	54	89
Gross unrealized (losses)	(3)
Estimated fair value	3,785	3,848
Mortgage-backed securities
Securities available for sale [Abstract]
Amortized Cost	146,547	108,236
Gross unrealized gains	776	40
Gross unrealized (losses)	(3,165)	(1,714)
Estimated fair value	144,158	106,562
Asset-backed securities
Securities available for sale [Abstract]
Amortized Cost	15,437	16,575
Gross unrealized gains	4
Gross unrealized (losses)	(157)	(198)
Estimated fair value	15,284	16,377
Other debt securities
Securities available for sale [Abstract]
Amortized Cost	11,863	5,326
Gross unrealized gains	71	81
Gross unrealized (losses)	(200)
Estimated fair value	$ 11,734	$ 5,407

Investment Securities - Additional Information (Details) - USD ($)	3 Months Ended
	Dec. 31, 2017	Sep. 30, 2013	Dec. 31, 2018
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities transferred to held to maturity		$ 36,789,000
Securities Other Than U S Government and Agencies
Schedule Of Available For Sale Securities [Line Items]
Holdings of securities of any one issuer greater than ten percent of stockholder's equity	$ 0		$ 0
Public Deposits, Derivative Positions and Federal Home Loan Bank Advances
Schedule Of Available For Sale Securities [Line Items]
Market value of securities	111,970,000		$ 171,542,000
Accounting Standards Update 2017-12
Schedule Of Available For Sale Securities [Line Items]
Held to maturity securities transferred to available for sale securities	$ 41,665,000

Investment Securities - Summary of Amortized Cost and Fair Value of Debt and Equity Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Available-for-sale, Amortized cost [Abstract]
Due in less than one year	$ 3,561
Due one to five years	23,294
Due five to ten years	45,662
Due beyond ten years	12,541
Amortized Cost	247,042	$ 193,360
Available-for-sale, Estimated fair value [Abstract]
Due in less than one year	3,573
Due one to five years	23,472
Due five to ten years	45,367
Due beyond ten years	11,954
Total	243,808	192,621
Held-to-maturity, Amortized cost [Abstract]
Due in less than one year	395
Due one to five years	3,339
Amortized Cost	3,734	3,759
Securities held to maturity [Abstract]
Due in less than one year	396
Due one to five years	3,389
Total	3,785	3,848
Mortgage-backed securities
Available-for-sale, Amortized cost [Abstract]
Amortized cost	146,547
Amortized Cost	146,547	108,236
Available-for-sale, Estimated fair value [Abstract]
Estimated fair value	144,158
Total	144,158	106,562
Asset-backed securities
Available-for-sale, Amortized cost [Abstract]
Amortized cost	15,437
Amortized Cost	15,437	16,575
Available-for-sale, Estimated fair value [Abstract]
Estimated fair value	15,284
Total	$ 15,284	$ 16,377

Investment Securities - Summary of Sale of Debt and Equity Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Investments Debt And Equity Securities [Abstract]
Proceeds	$ 38,322	$ 46,762	$ 46,700
Gross gains	116	121	216
Gross losses	$ (113)	$ (190)	$ (146)

Investment Securities - Summary of Securities with Unrealized Losses Aggregated by Major Security Type and Length of Time Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Available-for-sale securities, continuous unrealized loss position [Abstract]
Less than 12 months, Estimated fair value	$ 34,154	$ 44,697
Less than 12 months, Gross unrealized (losses)	(574)	(518)
12 months or more, Estimated fair value	117,753	91,900
12 months or more, Gross unrealized losses	(4,279)	(1,784)
Total, Estimated fair value	151,907	136,597
Total, Gross unrealized losses	(4,853)	(2,302)
U. S. government agency securities
Available-for-sale securities, continuous unrealized loss position [Abstract]
Less than 12 months, Estimated fair value		7,375
Less than 12 months, Gross unrealized (losses)		(90)
12 months or more, Estimated fair value	10,706	1,912
12 months or more, Gross unrealized losses	(347)	(78)
Total, Estimated fair value	10,706	9,287
Total, Gross unrealized losses	(347)	(168)
State and municipal securities
Available-for-sale securities, continuous unrealized loss position [Abstract]
Less than 12 months, Estimated fair value	13,455	7,490
Less than 12 months, Gross unrealized (losses)	(212)	(106)
12 months or more, Estimated fair value	17,376	5,798
12 months or more, Gross unrealized losses	(772)	(116)
Total, Estimated fair value	30,831	13,288
Total, Gross unrealized losses	(984)	(222)
Mortgage-backed securities
Available-for-sale securities, continuous unrealized loss position [Abstract]
Less than 12 months, Estimated fair value	7,075	29,832
Less than 12 months, Gross unrealized (losses)	(17)	(322)
12 months or more, Estimated fair value	87,232	67,813
12 months or more, Gross unrealized losses	(3,148)	(1,392)
Total, Estimated fair value	94,307	97,645
Total, Gross unrealized losses	(3,165)	(1,714)
Asset-backed securities
Available-for-sale securities, continuous unrealized loss position [Abstract]
Less than 12 months, Estimated fair value	8,262
Less than 12 months, Gross unrealized (losses)	(145)
12 months or more, Estimated fair value	2,439	16,377
12 months or more, Gross unrealized losses	(12)	(198)
Total, Estimated fair value	10,701	16,377
Total, Gross unrealized losses	(157)	$ (198)
Other debt securities
Available-for-sale securities, continuous unrealized loss position [Abstract]
Less than 12 months, Estimated fair value	5,362
Less than 12 months, Gross unrealized (losses)	(200)
Total, Estimated fair value	5,362
Total, Gross unrealized losses	$ (200)

Loans and Allowance for Loan Losses - Summary of Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Loans And Leases Receivable Disclosure [Line Items]
Total loans	$ 1,429,895	$ 947,882
Less net unearned income	(101)	(345)
Total loans	1,429,794	947,537
Allowance for loan losses	(12,113)	(13,721)	$ (11,634)	$ (10,132)
Loans, net	1,417,681	933,816
Commercial real estate
Loans And Leases Receivable Disclosure [Line Items]
Total loans	550,446	350,622
Allowance for loan losses	(3,309)	(3,324)	(2,655)	(2,879)
Consumer real estate
Loans And Leases Receivable Disclosure [Line Items]
Total loans	253,562	102,581
Allowance for loan losses	(1,005)	(1,063)	(1,013)	(968)
Construction and land development
Loans And Leases Receivable Disclosure [Line Items]
Total loans	174,670	82,586
Allowance for loan losses	(2,431)	(1,628)	(1,574)	(914)
Commercial and industrial
Loans And Leases Receivable Disclosure [Line Items]
Total loans	404,600	373,248
Allowance for loan losses	(5,036)	(7,209)	(5,618)	(4,693)
Consumer
Loans And Leases Receivable Disclosure [Line Items]
Total loans	25,615	6,862
Allowance for loan losses	(105)	(91)	(76)	(103)
Other
Loans And Leases Receivable Disclosure [Line Items]
Total loans	21,002	31,983
Allowance for loan losses	$ (227)	$ (406)	$ (698)	$ (575)

Loans and Allowance for Loan Losses - Additional Information (Details)	12 Months Ended
	Dec. 31, 2018 USD ($) Contract	Dec. 31, 2017 USD ($) Contract	Dec. 31, 2016 USD ($) Contract	Oct. 01, 2018 USD ($)
Loans And Leases Receivable Disclosure [Line Items]
Variable-rate loans	$ 827,491,000	$ 608,128,000
Fixed-rate loans	602,404,000	339,754,000
Minimum loan amount for loans analyzed by credit risk	500,000
Total loans	1,429,895,000	947,882,000
Interest income recognized on a cash basis for impaired loans	0	0	$ 0
Investments in TDR	2,100,000	1,200,000
Additional commitments related to TDR	$ 0	$ 0
New TDR identified during the period \| Contract	0	0	1
TDR, payment default within twelve months \| Contract	0	0	1
Allowance for loan and lease losses, charge-off	$ 4,954,000	$ 12,769,000	$ 1,452,000
Loan period considered as payment default			30 days
Recorded loans with a fair value				$ 344,800,000
Minimum
Loans And Leases Receivable Disclosure [Line Items]
Lease term	2 years
Maximum
Loans And Leases Receivable Disclosure [Line Items]
Lease term	6 years
Purchased Credit Impaired
Loans And Leases Receivable Disclosure [Line Items]
Recorded loans with a fair value				$ 1,700,000
Consumer
Loans And Leases Receivable Disclosure [Line Items]
Total loans	$ 25,615,000	6,862,000
TDR, payment default within twelve months \| Contract			1
Allowance for loan and lease losses, specific reserve			$ 0
Allowance for loan and lease losses, charge-off	84,000		146,000
Subsequent default TDR charge-off			$ 100,000
Doubtful
Loans And Leases Receivable Disclosure [Line Items]
Total loans	$ 0	$ 0

Loans and Allowance for Loan Losses - Summary of Changes in Allowance for Loan Losses by Loan Classification (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance				$ 13,721				$ 11,634				$ 10,132	$ 13,721	$ 11,634	$ 10,132
Charged-off loans													(4,954)	(12,769)	(1,452)
Recoveries													504	1,986	125
Provision for loan losses	$ 1,514	$ 481	$ 169	678	$ (30)	$ (195)	$ 9,690	3,405	$ 70	$ 1,639	$ 183	937	2,842	12,870	2,829
Ending Balance	12,113				13,721				11,634				12,113	13,721	11,634
Commercial real estate
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance				3,324				2,655				2,879	3,324	2,655	2,879
Charged-off loans															(350)
Recoveries													22	9	52
Provision for loan losses													(37)	660	74
Ending Balance	3,309				3,324				2,655				3,309	3,324	2,655
Consumer real estate
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance				1,063				1,013				968	1,063	1,013	968
Recoveries													4
Provision for loan losses													(62)	50	45
Ending Balance	1,005				1,063				1,013				1,005	1,063	1,013
Construction and land development
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance				1,628				1,574				914	1,628	1,574	914
Provision for loan losses													803	54	660
Ending Balance	2,431				1,628				1,574				2,431	1,628	1,574
Commercial and industrial
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance				7,209				5,618				4,693	7,209	5,618	4,693
Charged-off loans													(4,831)	(12,769)	(956)
Recoveries													395	1,865	23
Provision for loan losses													2,263	12,495	1,858
Ending Balance	5,036				7,209				5,618				5,036	7,209	5,618
Consumer
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance				91				76				103	91	76	103
Charged-off loans													(84)		(146)
Recoveries													75	112	50
Provision for loan losses													23	(97)	69
Ending Balance	105				91				76				105	91	76
Other
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance				$ 406				$ 698				$ 575	406	698	575
Charged-off loans													(39)
Recoveries													8
Provision for loan losses													(148)	(292)	123
Ending Balance	$ 227				$ 406				$ 698				$ 227	$ 406	$ 698

Loans and Allowance for Loan Losses - Summary of Breakdown of Allowance for Loan Losses and Loan Portfolio by Loan Category (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for Loan Losses:
Collectively evaluated for impairment	$ 12,113	$ 13,621
Individually evaluated for impairment		100
Allowance for Loan Losses, Ending Balance	12,113	13,721	$ 11,634	$ 10,132
Loans:
Collectively evaluated for impairment	1,425,997	945,187
Individually evaluated for impairment	3,898	2,695
Total	1,429,895	947,882
Commercial real estate
Allowance for Loan Losses:
Collectively evaluated for impairment	3,309	3,324
Allowance for Loan Losses, Ending Balance	3,309	3,324	2,655	2,879
Loans:
Collectively evaluated for impairment	549,055	349,415
Individually evaluated for impairment	1,391	1,207
Total	550,446	350,622
Consumer real estate
Allowance for Loan Losses:
Collectively evaluated for impairment	1,005	1,063
Allowance for Loan Losses, Ending Balance	1,005	1,063	1,013	968
Loans:
Collectively evaluated for impairment	252,640	102,581
Individually evaluated for impairment	922
Total	253,562	102,581
Construction and land development
Allowance for Loan Losses:
Collectively evaluated for impairment	2,431	1,628
Allowance for Loan Losses, Ending Balance	2,431	1,628	1,574	914
Loans:
Collectively evaluated for impairment	174,662	82,586
Individually evaluated for impairment	8
Total	174,670	82,586
Commercial and industrial
Allowance for Loan Losses:
Collectively evaluated for impairment	5,036	7,109
Individually evaluated for impairment		100
Allowance for Loan Losses, Ending Balance	5,036	7,209	5,618	4,693
Loans:
Collectively evaluated for impairment	403,054	371,760
Individually evaluated for impairment	1,546	1,488
Total	404,600	373,248
Consumer
Allowance for Loan Losses:
Collectively evaluated for impairment	105	91
Allowance for Loan Losses, Ending Balance	105	91	76	103
Loans:
Collectively evaluated for impairment	25,584	6,862
Individually evaluated for impairment	31
Total	25,615	6,862
Other
Allowance for Loan Losses:
Collectively evaluated for impairment	227	406
Allowance for Loan Losses, Ending Balance	227	406	$ 698	$ 575
Loans:
Collectively evaluated for impairment	21,002	31,983
Total	$ 21,002	$ 31,983

Loans and Allowance for Loan Losses - Allocation of ALL with Corresponding Percentage of Loans in Each Category to Total Loans, Net of Deferred Fee (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Loans And Leases Receivable Disclosure [Line Items]
Allowance for loan and lease losses, Amount	$ 12,113	$ 13,721	$ 11,634	$ 10,132
Allowance for loan and lease losses, Percentage of total loans, net of deferred fees	0.85%	1.45%
Commercial real estate
Loans And Leases Receivable Disclosure [Line Items]
Allowance for loan and lease losses, Amount	$ 3,309	$ 3,324	2,655	2,879
Allowance for loan and lease losses, Percentage of total loans, net of deferred fees	0.23%	0.35%
Consumer real estate
Loans And Leases Receivable Disclosure [Line Items]
Allowance for loan and lease losses, Amount	$ 1,005	$ 1,063	1,013	968
Allowance for loan and lease losses, Percentage of total loans, net of deferred fees	0.07%	0.11%
Construction and land development
Loans And Leases Receivable Disclosure [Line Items]
Allowance for loan and lease losses, Amount	$ 2,431	$ 1,628	1,574	914
Allowance for loan and lease losses, Percentage of total loans, net of deferred fees	0.17%	0.17%
Commercial and industrial
Loans And Leases Receivable Disclosure [Line Items]
Allowance for loan and lease losses, Amount	$ 5,036	$ 7,209	5,618	4,693
Allowance for loan and lease losses, Percentage of total loans, net of deferred fees	0.35%	0.76%
Consumer
Loans And Leases Receivable Disclosure [Line Items]
Allowance for loan and lease losses, Amount	$ 105	$ 91	76	103
Allowance for loan and lease losses, Percentage of total loans, net of deferred fees	0.01%	0.01%
Other
Loans And Leases Receivable Disclosure [Line Items]
Allowance for loan and lease losses, Amount	$ 227	$ 406	$ 698	$ 575
Allowance for loan and lease losses, Percentage of total loans, net of deferred fees	0.02%	0.04%

Loans and Allowance for Loan Losses - Summary of Information Related to Impaired Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Recorded investment	$ 3,898	$ 1,207
Impaired loans with no related allowance recorded, Unpaid principal balance	9,403	1,645
Impaired loans with an allowance recorded, Related allowance		100
Impaired loans with an allowance recorded, Recorded investment		1,488
Impaired loans with an allowance recorded, Unpaid principal balance		2,770
Recorded investment	3,898	2,695
Unpaid principal balance	9,403	4,415
Commercial real estate
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Recorded investment	1,391	1,207
Impaired loans with no related allowance recorded, Unpaid principal balance	1,775	1,645
Consumer real estate
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Recorded investment	922
Impaired loans with no related allowance recorded, Unpaid principal balance	1,204
Construction and land development
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Recorded investment	8
Impaired loans with no related allowance recorded, Unpaid principal balance	18
Commercial and industrial
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Recorded investment	1,546
Impaired loans with no related allowance recorded, Unpaid principal balance	6,350
Impaired loans with an allowance recorded, Related allowance		100
Impaired loans with an allowance recorded, Recorded investment		1,488
Impaired loans with an allowance recorded, Unpaid principal balance		$ 2,770
Consumer
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Recorded investment	31
Impaired loans with no related allowance recorded, Unpaid principal balance	$ 56

Loans and Allowance for Loan Losses - Summary of Average Recorded Investment and Interest Income Recognized on Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Average recorded investment	$ 7,041	$ 1,258	$ 1,020
Impaired loans with no related allowance recorded, Interest income recognized	281
Impaired loans with an allowance recorded, Average recorded investment		2,077	2,129
Impaired loans with an allowance recorded, Interest income recognized			44
Average recorded investment	7,041	3,335	3,149
Interest income recognized	281		44
Commercial real estate
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Average recorded investment	1,198	1,258	655
Impaired loans with no related allowance recorded, Interest income recognized	158
Impaired loans with an allowance recorded, Average recorded investment			974
Consumer real estate
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Average recorded investment	185		302
Construction and land development
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Average recorded investment	94
Impaired loans with no related allowance recorded, Interest income recognized	2
Commercial and industrial
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Average recorded investment	5,557
Impaired loans with no related allowance recorded, Interest income recognized	121
Impaired loans with an allowance recorded, Average recorded investment		$ 2,077	1,155
Impaired loans with an allowance recorded, Interest income recognized			44
Consumer
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Average recorded investment	$ 7		$ 63

Loans and Allowance for Loan Losses - Schedule of Aging of Recorded Investment in Past-due Loans, by Class of Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	$ 1,595	$ 2,407
Loans Not Past Due	1,428,300	945,475
Total	1,429,895	947,882
Commercial real estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	527
Loans Not Past Due	549,919	350,622
Total	550,446	350,622
Consumer real estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	919	218
Loans Not Past Due	252,643	102,363
Total	253,562	102,581
Construction and land development
Financing Receivable Recorded Investment Past Due [Line Items]
Loans Not Past Due	174,670	82,586
Total	174,670	82,586
Commercial and industrial
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	54	2,176
Loans Not Past Due	404,546	371,072
Total	404,600	373,248
Consumer
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	95	13
Loans Not Past Due	25,520	6,849
Total	25,615	6,862
Other
Financing Receivable Recorded Investment Past Due [Line Items]
Loans Not Past Due	21,002	31,983
Total	21,002	31,983
30 - 59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	475	1,967
30 - 59 Days Past Due [Member] \| Commercial real estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	300
30 - 59 Days Past Due [Member] \| Consumer real estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	69
30 - 59 Days Past Due [Member] \| Commercial and industrial
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	54	1,967
30 - 59 Days Past Due [Member] \| Consumer
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	52
60 - 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	302	209
60 - 89 Days Past Due [Member] \| Commercial real estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	227
60 - 89 Days Past Due [Member] \| Consumer real estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	75
60 - 89 Days Past Due [Member] \| Commercial and industrial
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		209
Greater than 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	818	231
Greater than 89 Days Past Due [Member] \| Consumer real estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	775	218
Greater than 89 Days Past Due [Member] \| Consumer
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	$ 43	$ 13

Loans and Allowance for Loan Losses - Schedule of Non-Accrual Loans, Past Due Loans over 89 Days and Accruing and Troubled Debt Restructurings (TDR) by Class of Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Non-Accrual	$ 2,078	$ 2,695
Past Due Over 89 Days and Accruing	214	231
Troubled Debt Restructurings	1,391	1,206
Commercial real estate
Accounts Notes And Loans Receivable [Line Items]
Non-Accrual		1,207
Troubled Debt Restructurings	1,391	1,206
Consumer real estate
Accounts Notes And Loans Receivable [Line Items]
Non-Accrual	1,187
Past Due Over 89 Days and Accruing	214	218
Construction and Land Development
Accounts Notes And Loans Receivable [Line Items]
Non-Accrual	19
Commercial and industrial
Accounts Notes And Loans Receivable [Line Items]
Non-Accrual	817	1,488
Consumer
Accounts Notes And Loans Receivable [Line Items]
Non-Accrual	$ 55
Past Due Over 89 Days and Accruing		$ 13

Loans and Allowance for Loan Losses - Schedule of Loans by Class Modified as TDR (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 Contract	Dec. 31, 2017 Contract	Dec. 31, 2016 USD ($) Contract
Financing Receivable Modifications [Line Items]
Number of contracts \| Contract	0	0	1
Pre modification outstanding recorded investment			$ 1,948
Post modification outstanding recorded investment, net of related allowance			$ 1,170
Commercial real estate
Financing Receivable Modifications [Line Items]
Number of contracts \| Contract			1
Pre modification outstanding recorded investment			$ 1,948
Post modification outstanding recorded investment, net of related allowance			$ 1,170

Loans and Allowance for Loan Losses - Schedule of Loans by Class Modified as TDR for Which There Was Payment Default Within Twelve Months Following Modification (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 Contract	Dec. 31, 2017 Contract	Dec. 31, 2016 USD ($) Contract
Financing Receivable Modifications [Line Items]
Number of contracts \| Contract	0	0	1
Recorded investment \| $			$ 124
Consumer
Financing Receivable Modifications [Line Items]
Number of contracts \| Contract			1
Recorded investment \| $			$ 124

Loans and Allowance for Loan Losses - Summary of the contractually required payments (Details) - Athens Bancshares $ in Thousands	Oct. 01, 2018 USD ($)
Purchased Credit Impaired
Certain Loans Acquired In Transfer Accounted For As Debt Securities Accretable Yield Movement Schedule [Line Items]
Contractually required payments	$ 3,151
Nonaccretable difference	(1,049)
Cash flows expected to be collected at acquisition	2,102
Accretable yield	(436)
Fair value of PCI loans at acquisition date	1,666
Purchased Non Impaired [Member]
Certain Loans Acquired In Transfer Accounted For As Debt Securities Accretable Yield Movement Schedule [Line Items]
Contractually required payments	404,692
Fair value of PCI loans at acquisition date	343,167
Contractual cash flows not expected to be collected	$ 1,807

Loans and Allowance for Loan Losses - Schedule of activity in purchased credit impaired loans (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)
Certain Loans Acquired In Transfer Accounted For As Debt Securities Accretable Yield Movement Schedule [Line Items]
Change due to payments received and accretion	$ (46)
Balance, ending, carrying value	1,620
Accretable Yield For PCI Loans [Member]
Certain Loans Acquired In Transfer Accounted For As Debt Securities Accretable Yield Movement Schedule [Line Items]
Other	13
Balance, ending, carrying value	440
Accretion	(9)
Athens Bancshares
Certain Loans Acquired In Transfer Accounted For As Debt Securities Accretable Yield Movement Schedule [Line Items]
Additions due to acquisition of Athens Bancshares	1,666
Athens Bancshares \| Accretable Yield For PCI Loans [Member]
Certain Loans Acquired In Transfer Accounted For As Debt Securities Accretable Yield Movement Schedule [Line Items]
Additions due to acquisition of Athens Bancshares	$ 436

Loans and Allowance for Loan Losses - Schedule of Components of Direct Financing Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Leases [Abstract]
Total minimum lease payments receivable	$ 379	$ 714
Less: Unearned income	(19)	(49)
Net leases	$ 360	$ 665

Loans and Allowance for Loan Losses - Summary of Future Minimum Lease Payments Receivable under Direct Financing Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Leases [Abstract]
2019	$ 178
2020	167
2021	34
Future minimum lease payments receivable	$ 379	$ 714

Loan Servicing - Additional Information (Details)	12 Months Ended
Loan Servicing - Additional Information (Details)	Dec. 31, 2017 Loan	Dec. 31, 2018 USD ($)
Transfers And Servicing [Abstract]
Loan principal balance		$ 170,100,000
Number of mortgage loans \| Loan	0
Custodial escrow balances maintained In connection with serviced loans		$ 462,000

Loan Servicing - Schedule of Activity for Loan Servicing Rights and Related Valuation Allowance (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)
Loan servicing rights:
Additions	$ 1,809
Amortized to offset other noninterest income	(73)
Balance at end of period	$ 1,736

Premises and Equipment - Summary of Premises and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property Plant And Equipment [Line Items]
Premises and equipment, gross	$ 21,654	$ 8,202
Less accumulated depreciation and amortization	(2,833)	(2,318)
Premises and equipment, net	$ 18,821	5,884
Minimum
Property Plant And Equipment [Line Items]
Premises and equipment, useful lives	3 years
Maximum
Property Plant And Equipment [Line Items]
Premises and equipment, useful lives	39 years
Buildings
Property Plant And Equipment [Line Items]
Premises and equipment, useful lives	39 years
Premises and equipment, gross	$ 9,965	3,586
Leasehold improvements
Property Plant And Equipment [Line Items]
Premises and equipment, gross	$ 939	777
Leasehold improvements \| Minimum
Property Plant And Equipment [Line Items]
Premises and equipment, useful lives	1 year
Leasehold improvements \| Maximum
Property Plant And Equipment [Line Items]
Premises and equipment, useful lives	17 years
Furniture and equipment
Property Plant And Equipment [Line Items]
Premises and equipment, gross	$ 3,730	2,659
Furniture and equipment \| Minimum
Property Plant And Equipment [Line Items]
Premises and equipment, useful lives	1 year
Furniture and equipment \| Maximum
Property Plant And Equipment [Line Items]
Premises and equipment, useful lives	7 years
Land
Property Plant And Equipment [Line Items]
Premises and equipment, gross	$ 2,997	$ 1,180
Fixed Assets In Process
Property Plant And Equipment [Line Items]
Premises and equipment, gross	$ 4,023

Premises and Equipment - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Premises and equipment depreciation and amortization expense	$ 516,000	$ 401,000	$ 360,000
Noncancelable lease arrangements
Property Plant And Equipment [Line Items]
Lease extension maturity period	2032
Rent expenses related to leases	$ 1,677,000	$ 1,521,000	$ 1,016,000

Premises and Equipment - Summary of Future Minimum Payments under Operating Leases (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Property Plant And Equipment [Abstract]
2019	$ 1,538
2020	1,539
2021	1,567
2022	1,453
2023	1,402
Thereafter	8,821
Total future minimum lease payments	$ 16,320

Goodwill And Intangible Assets - Summary of Change In Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Beginning of year	$ 6,219	$ 6,219
Acquired goodwill	31,291	0
Impairment	0	0
End of year	$ 37,510	$ 6,219

Goodwill And Intangible Assets - Summary of Acquired Intangible Assets (Details) - Core Deposit - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 9,267	$ 287
Accumulated Amortization	$ (729)	$ (264)

Goodwill And Intangible Assets - Summary of Estimated Amortization Expense (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
2019	$ 1,655
2020	1,477
2021	1,299
2022	1,121
2023	943
Thereafter	2,043
Total	$ 8,538

Other Real Estate Owned - Summary of Other Real Estate Owned Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Real Estate Roll Forward
Beginning balance	$ 0	$ 0	$ 216
Additions due to acquisition of Athens Bancshares	988	0	0
Loans transferred to other real estate owned	0	0	0
Direct write-downs	0	0	0
Sales of other real estate owned	0	0	(216)
End of year	$ 988	$ 0	$ 0

Other Real Estate Owned - Summary of Valuation Allowance Activity in Other Real Estate Owned (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Real Estate Owned Valuation Allowance Roll Forward
Beginning balance	$ 0	$ 0	$ 450
Additions/(recoveries) charged/(credited) to expense	0	0	0
Reductions from sales of other real estate owned	0	0	(450)
Direct write-downs	0	0	0
End of year	$ 0	$ 0	$ 0

Other Real Estate Owned - Summary of Expenses Related to Other Real Estate Owned (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Real Estate [Abstract]
Net (gain) loss on sales	$ 0	$ 0	$ (157)
Provision for unrealized losses	0	0	0
Operating expenses, net of rental income	0	0	14
Total	$ 0	$ 0	$ (143)

Deposits - Additional Information (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Deposits [Abstract]
FDIC deposit insurance limit	$ 250,000	$ 250,000
Time deposits	98,086,000	54,460,000
Deposit accounts in overdraft status reclassified to loans	$ 193,000	$ 19,000

Deposits - Scheduled Maturities of Time Deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Maturities Of Time Deposits [Abstract]
2019	$ 254,839
2020	57,800
2021	15,167
2022	12,068
2023	8,294
Thereafter	259
Total	$ 348,427	$ 176,197

Federal Home Loan Bank Advances - Additional Information (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Federal Home Loan Bank Advances [Line Items]
Outstanding borrowings	$ 125,000,000	$ 70,000,000
Investment securities, FHLB stock and commercial and residential real estate mortgage loans
Federal Home Loan Bank Advances [Line Items]
Federal Home Loan Bank Advances Collateralized Investment Securities Value	3,900,000
Mortgage loans collateralized amount	665,700,000
Amount of available credit	$ 71,900,000

Federal Home Loan Bank Advances - Summary of Contractual Maturities and Average Effective Rates of Outstanding Advances (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Federal Home Loan Bank Advances Maturities Summary [Abstract]
2018		$ 70,000,000
2019	$ 125,000,000
Total amount	$ 125,000,000	$ 70,000,000
2018		1.66%
2019	2.48%
Total interest rates	2.48%	1.66%

Accumulated Other Comprehensive Income (Loss) - Summary of Changes In Accumulated Other Comprehensive Income (Loss) By Component, Net of Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	$ 146,946	$ 139,207	$ 108,586
Other comprehensive income (loss) before reclassification, net of tax	67	4,811
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(856)	(928)
Net current period other comprehensive income (loss)	(789)	3,883	(1,237)
Ending balance	254,379	146,946	139,207
Gains and Losses on Cash Flow Hedges
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(3,679)	(4,241)
Other comprehensive income (loss) before reclassification, net of tax	1,891	1,499
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(848)	(770)
Net current period other comprehensive income (loss)	1,043	729
Reclassification of accumulated other comprehensive income due to tax rate change		(167)
Ending balance	(2,636)	(3,679)	(4,241)
Unrealized Gains and Losses on Available for Sale Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	1,162	(698)
Other comprehensive income (loss) before reclassification, net of tax	(1,844)	3,077
Amounts reclassified for securities transferredfrom held-to-maturity to available-for-sale		(1,086)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	2	(41)
Net current period other comprehensive income (loss)	(1,842)	1,950
Reclassification of accumulated other comprehensive income due to tax rate change		(90)
Ending balance	(680)	1,162	(698)
Unrealized Losses on Securities Transferred to Held to Maturity
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(10)	(1,212)
Other comprehensive income (loss) before reclassification, net of tax	20	235
Amounts reclassified for securities transferredfrom held-to-maturity to available-for-sale		1,086
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(10)	(117)
Net current period other comprehensive income (loss)	10	1,204
Reclassification of accumulated other comprehensive income due to tax rate change		(2)
Ending balance		(10)	(1,212)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(2,527)	(6,151)	(4,914)
Net current period other comprehensive income (loss)	(789)	3,883	(1,237)
Reclassification of accumulated other comprehensive income due to tax rate change		(259)
Ending balance	$ (3,316)	$ (2,527)	$ (6,151)

Accumulated Other Comprehensive Income (Loss) - Summary of Significant Amounts Reclassified out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Net (gain) loss on sale of securities													$ 3	$ (66)	$ 121
Interest expense - Federal Home Loan Bank advances													(2,533)	(1,559)	(475)
Income tax (expense) benefit	$ 535	$ (554)	$ (665)	$ (483)	$ (4,494)	$ (1,516)	$ 1,328	$ 47	$ (1,495)	$ (1,042)	$ (1,159)	$ (796)	(1,167)	(4,635)	(4,493)
Net income	$ (708)	$ 3,656	$ 3,513	$ 3,193	$ 91	$ 4,419	$ (3,342)	$ 331	$ 2,927	$ 2,109	$ 2,476	$ 1,584	9,655	1,501	9,097
Reclassification out of Accumulated Other Comprehensive Income \| Unrealized Losses on Cash Flow Hedges
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Interest expense money market													(441)	(430)	(151)
Interest expense - Federal Home Loan Bank advances													(479)	(429)	(265)
Income tax (expense) benefit													72	89
Net income													(848)	(770)	(416)
Reclassification out of Accumulated Other Comprehensive Income \| Unrealized Gains and (Losses) on Available for Sale Securities
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Net (gain) loss on sale of securities													3	(66)	121
Income tax (expense) benefit													(1)	25	(46)
Net income													2	(41)	75
Reclassification out of Accumulated Other Comprehensive Income \| Unrealized Losses on Securities Transferred to Held to Maturity
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Interest income - securities													(14)	(190)	(167)
Income tax (expense) benefit													4	73	64
Net income													$ (10)	$ (117)	$ (103)

Income Taxes - Schedule of Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal													$ 15	$ 214	$ 4,029
State													(23)	36	759
Total Current tax expense (Benefit)													(8)	250	4,788
Deferred:
Federal													872	4,218	(395)
State													303	167	100
Total deferred tax expense (Benefit)													1,175	4,385	(295)
Total	$ (535)	$ 554	$ 665	$ 483	$ 4,494	$ 1,516	$ (1,328)	$ (47)	$ 1,495	$ 1,042	$ 1,159	$ 796	$ 1,167	$ 4,635	$ 4,493

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Line Items]
Federal statutory income tax rate	21.00%	21.00%	21.00%
Decrease in net deferred tax assets due to tax reforms		$ 3,562,000
Increase in income tax expense due to tax reforms		3,600,000
Unrecognized income tax benefits	$ 0	0
Accrued interest related to uncertain tax positions	0	0
Accrued penalties related to uncertain tax positions	0	$ 0
Federal
Income Taxes [Line Items]
Federal net operating loss carryforwards	$ 8,561,000
Federal net operating loss carryforwards, start year	2030
Federal net operating loss carryforwards, end year	2032
Federal net operating loss carryforwards, not subject to expiration	$ 4,548,000

Income Taxes - Schedule of Reconciliation of Actual Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Computed "expected" tax expense													$ 2,272	$ 2,086	$ 4,621
State income taxes, net of effect of federal income taxes													221	134	567
Tax-exempt interest income													(298)	(418)	(394)
Earnings on bank owned life insurance contracts													(559)	(197)	(204)
Disallowed expenses													93	86	60
Excess tax benefits related to stock compensation													(857)	(632)
Write-down of deferred tax assets due to tax reform														3,562
Nondeductible merger expenses													281
Other													14	14	(157)
Total	$ (535)	$ 554	$ 665	$ 483	$ 4,494	$ 1,516	$ (1,328)	$ (47)	$ 1,495	$ 1,042	$ 1,159	$ 796	$ 1,167	$ 4,635	$ 4,493

Income Taxes - Schedule of Deferred Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Allowance for loan losses	$ 2,795	$ 3,227
Net operating loss carryforward	2,002	843
Organization and preopening costs	457	557
Stock-based compensation	835	672
Acquired loans	1,319	124
Acquired deposits	106	22
Nonaccrual interest	75	25
Accrued incentive compensation	97
Reserve for contingencies	143	496
Accrued contributions	207	169
Unrealized loss on securities available-for-sale	845	193
Unrealized loss on securities held-to-maturity		4
Cash flow hedge	219	359
Accrued vacation	45	45
Other		134
Deferred tax assets	9,145	6,870
Deferred tax liabilities:
Prepaid expenses	77	134
Depreciation	645	39
Goodwill	81	138
Amortization of core deposit intangible	1,398	6
Other	334
Deferred tax liabilities	2,535	317
Net deferred tax asset	$ 6,610	$ 6,553

Commitments and Contingencies - Schedule of Financial Instruments Representing Credit Risk (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Unused commitments to extend credit	$ 707,675	$ 584,494
Standby letters of credit	12,273	11,552
Total	$ 719,948	$ 596,046

Regulatory Matters And Restrictions On Dividends - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) Capital	Dec. 31, 2017 USD ($)
Banking And Thrift [Abstract]
Number of capital categories \| Capital	5
Dividends	$ 22.2	$ 19.3
Dividends paid	$ 1.2

Regulatory Matters And Restrictions On Dividends - Schedule of Capital Amounts and Ratios (Details) - USD ($)
$ in Thousands

Dec. 31, 2018

Dec. 31, 2017

CapStar Financial Holdings, Inc.

Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]

Total capital to risk-weighted assets, actual amount

$ 222,030

$ 156,176

Tier I capital to risk-weighted assets, actual amount

209,738

142,276

Tier I capital to average assets, actual amount

$ 209,738

$ 142,276

Total capital to risk-weighted assets, actual ratio

12.80%

12.50%

Tier I capital to risk-weighted assets, actual ratio

12.10%

11.40%

Tier I capital to average assets, actual ratio

11.10%

10.70%

Total capital to risk-weighted assets, minimum capital requirement amount

^[1]

$ 138,336

$ 99,932

Tier I capital to risk-weighted assets, minimum capital requirement amount

^[1]

103,752

74,949

Tier I capital to average assets, minimum capital requirement amount

^[1]

$ 75,867

$ 53,218

Total capital to risk-weighted assets, minimum capital requirement ratio

^[1]

8.00%

Tier I capital to risk-weighted assets, minimum capital requirement ratio

^[1]

6.00%

Tier I capital to average assets, minimum capital requirement ratio

^[1]

4.00%

CapStar Financial Holdings, Inc. | Common Stock

Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]

Tier I capital to risk-weighted assets, actual amount

$ 200,738

$ 133,445

Tier I capital to risk-weighted assets, actual ratio

11.60%

10.70%

Tier I capital to risk-weighted assets, minimum capital requirement amount

^[1]

$ 77,814

$ 56,212

Tier I capital to risk-weighted assets, minimum capital requirement ratio

^[1]

4.50%

CapStar Bank

Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]

Total capital to risk-weighted assets, actual amount

$ 201,972

$ 142,138

Tier I capital to risk-weighted assets, actual amount

189,680

128,238

Tier I capital to average assets, actual amount

$ 189,680

$ 128,238

Total capital to risk-weighted assets, actual ratio

11.70%

11.40%

Tier I capital to risk-weighted assets, actual ratio

11.00%

10.30%

Tier I capital to average assets, actual ratio

10.00%

9.60%

Total capital to risk-weighted assets, minimum capital requirement amount

^[1]

$ 138,294

$ 99,928

Tier I capital to risk-weighted assets, minimum capital requirement amount

^[1]

103,721

74,946

Tier I capital to average assets, minimum capital requirement amount

^[1]

$ 75,828

$ 53,215

Total capital to risk-weighted assets, minimum capital requirement ratio

^[1]

8.00%

Tier I capital to risk-weighted assets, minimum capital requirement ratio

^[1]

6.00%

Tier I capital to average assets, minimum capital requirement ratio

^[1]

4.00%

Total capital to risk-weighted assets, minimum to be well capitalized amount

^[2]

$ 172,868

$ 124,909

Tier I capital to risk-weighted assets, minimum to be well capitalized amount

^[2]

138,294

99,928

Tier I capital to average assets, minimum to be well capitalized amount

^[2]

$ 94,785

$ 66,519

Total capital to risk-weighted assets, minimum to be well capitalized ratio

^[2]

10.00%

Tier I capital to risk-weighted assets, minimum to be well capitalized ratio

^[2]

8.00%

Tier I capital to average assets, minimum to be well capitalized ratio

^[2]

5.00%

CapStar Bank | Common Stock

Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]

Tier I capital to risk-weighted assets, actual amount

$ 173,180

$ 111,907

Tier I capital to risk-weighted assets, actual ratio

10.00%

9.00%

Tier I capital to risk-weighted assets, minimum capital requirement amount

^[1]

$ 77,791

$ 56,209

Tier I capital to risk-weighted assets, minimum capital requirement ratio

^[1]

4.50%

Tier I capital to risk-weighted assets, minimum to be well capitalized amount

^[2]

$ 112,364

$ 81,191

Tier I capital to risk-weighted assets, minimum to be well capitalized ratio

^[2]

6.50%

[1]	For the calendar year 2018, the Company was required to maintain a capital conservation buffer of Tier 1 common equity capital in excess of minimum risk-based capital ratios by at least 1.875% to avoid limits on capital distributions and certain discretionary bonus payments to executive officers and similar employees.
[2]	For the Company to be well-capitalized, the Bank must be well-capitalized and the Company must not be subject to any written agreement, order, capital directive, or prompt corrective action directive issued by the Federal Reserve to meet and maintain a specific capital level for any capital measure.

Nonvoting and Series A Preferred Stock and Stock Warrants - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jul. 14, 2008
Class Of Stock [Line Items]
Preferred stock, shares issued	878,049	878,049
Expire period	10 years
Warrants grant date	Jul. 14, 2008
Warrants outstanding	0
Investor
Class Of Stock [Line Items]
Warrants issued to purchase common stock	238,319
Purchase price of share	$ 10.00
Expire period	10 years
Warrants grant date	Jul. 14, 2008
Warrants outstanding	0
Share issuance descriptions	Each subscriber for shares who is a Tennessee resident or any entity controlled by a Tennessee resident and invested a minimum of $500,000 in the offering, received a warrant to purchase additional shares of common stock equal to 5% of accepted subscriptions at the purchase price of $10.00 per share.
Accepted percentage of subscription on purchase price	5.00%
Investor \| Minimum
Class Of Stock [Line Items]
Common stock subscription, value	$ 500,000,000
Director
Class Of Stock [Line Items]
Warrants issued to purchase common stock	10,000
Warrants purchase price	$ 10.00
Organizer
Class Of Stock [Line Items]
Warrants issued to purchase common stock	60,000
Expire period	10 years
Warrants grant date	Jul. 14, 2008
Warrants outstanding	0
Initial Public Offering \| Common Stock
Class Of Stock [Line Items]
Preferred shares converted to common stock			731,707
Nonvoting
Class Of Stock [Line Items]
Common stock, shares authorized	5,000,000	5,000,000
Common stock, conversion basis	one-to-one basis
Common stock, shares outstanding	132,561	132,561
Warrants issued to purchase common stock				500,000
Purchase price of share				$ 10.25
Nonvoting \| Initial Public Offering
Class Of Stock [Line Items]
Stock issued and converted to common stock	79,166
Series A Preferred Stock
Class Of Stock [Line Items]
Preferred stock, shares issued				1,609,756

Stock Options and Restricted Shares - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost	$ 1,814,000
Total fair value of shares vested	$ 2,804,000	$ 1,174,000	$ 513,000
Vesting period	3 years
Contractual term	10 years
Expected dividend yield	0.00%
Options granted	0	0
Unrecognized compensation cost	$ 32,000
Restricted Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Cost expected to be recognized over a weighted-average period	2 years 1 month 6 days
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Cost expected to be recognized over a weighted-average period	10 months 24 days
CapStar Bank 2008 Stock Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of stock reserved for issuance of stock incentives	1,569,475
Shares issuable under both restricted share and stock option grants	422,900
CapStar Bank 2008 Stock Incentive Plan \| Director
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of stock reserved for issuance of stock incentives	400,000

Stock Options and Restricted Shares - Summary of Company Recognized Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based compensation expense before income taxes	$ 2,079	$ 1,061	$ 842
Less: deferred tax benefit	(543)	(406)	(322)
Reduction of net income	$ 1,536	$ 655	$ 520

Stock Options and Restricted Shares - Summary of Changes in Company's Nonvested Restricted Shares (Details)	12 Months Ended
	Dec. 31, 2018 $ / shares shares
Restricted Shares, Abstract
Restricted Shares, Nonvested Beginning Balance \| shares	187,253
Restricted Shares, Granted \| shares	140,131
Restricted Shares, Vested \| shares	(161,604)
Restricted Shares, Forfeited \| shares	(8,164)
Restricted Shares, Nonvested Ending Balance \| shares	157,616
Weighted Average Grant Date Fair Value, Abstract
Weighted Average Grant Date Fair Value, Nonvested Beginning Balance \| $ / shares	$ 14.21
Weighted Average Grant Date Fair Value, Granted \| $ / shares	16.73
Weighted Average Grant Date Fair Value, Vested \| $ / shares	13.54
Weighted Average Grant Date Fair Value, Forfeited \| $ / shares	15.92
Weighted Average Grant Date Fair Value, Nonvested Ending Balance \| $ / shares	$ 17.00

Stock Options and Restricted Shares - Summary of Fair Value of Options Granted Using Weighted Average Assumptions (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Expected dividend yield	0.00%
Expected term (in years)		7 years 5 months 23 days
Expected stock price volatility		17.20%
Risk-free interest rate		1.66%
Pre-vest forfeiture rate		10.25%

Stock Options and Restricted Shares - Summary of Activity in Stock Options (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Shares, Abstract
Shares Outstanding, Beginning Balance	756,050
Additions due to acquisition of Athens Bancshares	548,051
Shares Outstanding, Granted	0	0
Shares Outstanding, Exercised	(796,198)
Shares Outstanding, Ending Balance	507,903	756,050
Shares, Fully Vested and Expected to Vest	506,783
Shares, Exercisable at End of Period	480,403
Weighted Average Exercise Price, Abstract
Weighted Average Exercise Price Outstanding, Beginning Balance	$ 10.50
Additions due to acquisition of Athens Bancshares	5.06
Weighted Average Exercise Price Outstanding, Granted
Weighted Average Exercise Price Outstanding, Exercised	8.16
Weighted Average Exercise Price Outstanding, Forfeited or expired
Weighted Average Exercise Price Outstanding, Ending Balance	8.66	$ 10.50
Weighted Average Exercise Price, Fully vested and expected to vest	8.66
Weighted Average Exercise Price, Exercisable at End of Period	$ 8.46
Weighted Average Remaining Contractual Term (year), Abstract
Weighted Average Remaining Contractual Term Outstanding	4 years
Weighted Average Remaining Contractual Term, Fully Vested and Expected to Vest	4 years 1 month 6 days
Weighted Average Remaining Contractual Term, Exercisable at End of Period	4 years

Stock Options and Restricted Shares - Information Related to Stock Options (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Intrinsic value of options exercised	$ 7,654,738	$ 2,010,536	$ 53,756
Cash received from option exercises	6,897,845	2,013,840	96,306
Tax benefit realized from option exercises	$ 846,725	$ 774,056	$ 20,583
Weighted average fair value of options granted			$ 3.16

Employee Benefit Plans- Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Compensation And Retirement Disclosure [Abstract]
Annual contribution percentage	3.00%
Additional discretionary contribution of employees' salary percentage	6.00%
Company's contribution to 401(k) Plan	$ 639,000	$ 550,000	$ 536,000

Derivative Instruments - Additional Information (Details) - Designated as Hedging Instrument - Interest Rate Swaps - Cash Flow Hedges - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments [Line Items]
Notional amounts	$ 20,000,000	$ 20,000,000
Interest expense	275,000	$ 233,000
Investment securities pledged collateral to counterparties	2,038,000
Investment securities pledged collateral from counterparties	$ 0

Derivative Instruments - Summary of Interest-Rate Swaps Designated as Cash Flow Hedges (Details) - Designated as Hedging Instrument - Cash Flow Hedges - Interest Rate Swaps - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments [Line Items]
Notional amounts	$ 20,000,000	$ 20,000,000
Weighted average pay rates	3.54%	3.54%
Weighted average receive rates	Dec. 31, 2018: 3 month LIBOR and Dec. 31, 2017: 3 month LIBOR
Weighted average maturity	4 years 6 months	5 years 6 months
Fair value	$ (836,000)	$ (1,375,000)
Amount of unrealized loss recognized in accumulated other comprehensive income, net of tax	$ (617,000)	$ (849,000)

Derivative Instruments - Summary of Customer Related Interest Rate Swaps (Details) - Interest Rate Swaps - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments [Line Items]
Interest rate swap, Notional amount	$ 58,252,000	$ 83,726,000
Pay fixed/receive variable swaps
Derivative Instruments [Line Items]
Interest rate swap, Notional amount	29,126,000	41,863,000
Interest rate swap, Estimated fair value	24,000	55,000
Pay variable/receive fixed swaps
Derivative Instruments [Line Items]
Interest rate swap, Notional amount	29,126,000	41,863,000
Interest rate swap, Estimated fair value	$ (24,000)	$ (55,000)

Related Party - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Impairment of loans	$ 0	$ 0	$ 0
Directors Executive Officers, Shareholders and Affiliates
Related Party Transaction [Line Items]
Deposit from related parties	$ 11,400,000	$ 10,800,000

Related Party - Schedule of Related Party Transactions Activity within Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Total Commitment
Related Party Transaction [Line Items]
Beginning of period	$ 49,409	$ 31,076
New commitments/draw downs	3,631	21,203
Repayments	(8,228)	(2,870)
End of period	44,812	49,409
Total Funded Commitment
Related Party Transaction [Line Items]
Beginning of period	21,890	20,325
New commitments/draw downs	1,038	4,320
Repayments	(7,483)	(2,755)
End of period	$ 15,445	$ 21,890

Fair Value - Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets:
Total securities available-for-sale	$ 243,808	$ 192,621
Obligations of States and Political Subdivisions
Assets:
Total securities available-for-sale	61,926	52,998
Asset-backed securities
Assets:
Total securities available-for-sale	15,284	16,377
Other debt securities
Assets:
Total securities available-for-sale	11,734	5,407
Fair Value Measurements Recurring Basis
Assets:
Total securities available-for-sale	243,808	192,621
Liabilities:
Total derivatives	(1,330)	(1,559)
Fair Value Measurements Recurring Basis \| U.S. Government-sponsored Agencies
Assets:
Total securities available-for-sale	10,706	11,277
Fair Value Measurements Recurring Basis \| Obligations of States and Political Subdivisions
Assets:
Total securities available-for-sale	61,926	52,998
Fair Value Measurements Recurring Basis \| Mortgage-backed Securities-residential
Assets:
Total securities available-for-sale	144,158	106,562
Fair Value Measurements Recurring Basis \| Asset-backed securities
Assets:
Total securities available-for-sale	15,284	16,377
Fair Value Measurements Recurring Basis \| Other debt securities
Assets:
Total securities available-for-sale	11,734	5,407
Fair Value Measurements Recurring Basis \| Significant Other Observable Inputs (Level 2)
Assets:
Total securities available-for-sale	243,808	192,621
Liabilities:
Total derivatives	(1,330)	(1,559)
Fair Value Measurements Recurring Basis \| Significant Other Observable Inputs (Level 2) \| U.S. Government-sponsored Agencies
Assets:
Total securities available-for-sale	10,706	11,277
Fair Value Measurements Recurring Basis \| Significant Other Observable Inputs (Level 2) \| Obligations of States and Political Subdivisions
Assets:
Total securities available-for-sale	61,926	52,998
Fair Value Measurements Recurring Basis \| Significant Other Observable Inputs (Level 2) \| Mortgage-backed Securities-residential
Assets:
Total securities available-for-sale	144,158	106,562
Fair Value Measurements Recurring Basis \| Significant Other Observable Inputs (Level 2) \| Asset-backed securities
Assets:
Total securities available-for-sale	15,284	16,377
Fair Value Measurements Recurring Basis \| Significant Other Observable Inputs (Level 2) \| Other debt securities
Assets:
Total securities available-for-sale	11,734	5,407
Fair Value Measurements Recurring Basis \| Interest Rate Swaps - Customer Related
Assets:
Interest rate swaps - customer related	494	184
Liabilities:
Total derivatives	(494)	(184)
Fair Value Measurements Recurring Basis \| Interest Rate Swaps - Customer Related \| Significant Other Observable Inputs (Level 2)
Assets:
Interest rate swaps - customer related	494	184
Liabilities:
Total derivatives	(494)	(184)
Fair Value Measurements Recurring Basis \| Interest Rate Swaps - Cash Flow Hedges
Liabilities:
Total derivatives	(836)	(1,375)
Fair Value Measurements Recurring Basis \| Interest Rate Swaps - Cash Flow Hedges \| Significant Other Observable Inputs (Level 2)
Liabilities:
Total derivatives	$ (836)	$ (1,375)

Fair Value - Summary of Quantitative Information About Level 3 Fair Value Measurements for Assets Measured at Fair Value on a Non-Recurring Basis (Details) - Commercial and industrial - Fair Value, Measurements, Nonrecurring [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impaired loans	$ 1,388
Significant Unobservable Inputs (Level 3)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impaired loans	$ 1,388
Valuation Technique(s)	Sales comparison approach
Unobservable Input(s)	Appraisal discounts
Range (Weighted-Average)	15.00%

Fair Value - Summary of Carrying Value and Fair Values of the Company's Financial Instruments (Details) - USD ($)	Dec. 31, 2018	Oct. 01, 2018	Dec. 31, 2017
Financial assets:
Securities available-for-sale	$ 243,808,000		$ 192,621,000
Securities held to maturity, fair value	3,785,000		3,848,000
Loans held for sale	0		0
Loans, net of unearned income		$ 344,800,000
Carrying amount
Financial assets:
Restricted equity securities	12,038,000		8,806,000
Carrying amount \| Level 1
Financial assets:
Cash and due from banks, interest-bearing deposits in financial institutions	94,681,000		78,078,000
Federal funds sold	10,762,000		4,719,000
Carrying amount \| Level 2
Financial assets:
Securities available-for-sale	243,808,000		192,621,000
Securities held to maturity, fair value	3,734,000		3,759,000
Loans held for sale	57,618,000		74,093,000
Accrued interest receivable	5,964,000		4,084,000
Other assets	34,489,000		22,663,000
Financial liabilities:
Federal Home Loan Bank advances	125,000,000		70,000,000
Carrying amount \| Level 3 Fair Value Measurements
Financial assets:
Loans, net of unearned income	1,429,794,000		947,537,000
Financial liabilities:
Deposits	1,570,008,000		1,119,866,000
Other liabilities	2,753,000		3,672,000
Fair value \| Level 1
Financial assets:
Cash and due from banks, interest-bearing deposits in financial institutions	94,681,000		78,078,000
Federal funds sold	10,762,000		4,719,000
Fair value \| Level 2
Financial assets:
Securities available-for-sale	243,808,000		192,621,000
Securities held to maturity, fair value	3,785,000		3,848,000
Loans held for sale	58,596,000		75,549,000
Accrued interest receivable	5,964,000		4,084,000
Other assets	34,489,000		22,663,000
Financial liabilities:
Federal Home Loan Bank advances	126,548,000		69,980,000
Fair value \| Level 3 Fair Value Measurements
Financial assets:
Loans, net of unearned income	1,442,082,000		944,037,000
Financial liabilities:
Deposits	1,504,101,000		1,065,669,000
Other liabilities	$ 2,753,000		$ 3,672,000

Parent Company Only Financial Information - Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets
Other assets	$ 51,740	$ 32,327
Total assets	1,963,883	1,344,429
Liabilities and Shareholders’ Equity
Other liabilities	14,496	7,617
Total shareholders’ equity	254,379	146,946	$ 139,207	$ 108,586
Total liabilities and shareholders’ equity	1,963,883	1,344,429
CapStar Financial Holdings, Inc.
Assets
Cash and cash equivalents	19,918	14,108	$ 22,952
Investment in consolidated subsidiary	234,263	132,909
Other assets	499	61
Total assets	254,680	147,078
Liabilities and Shareholders’ Equity
Other liabilities	301	132
Total shareholders’ equity	254,379	146,946
Total liabilities and shareholders’ equity	$ 254,680	$ 147,078

Parent Company Only Financial Information - Condensed Income Statements (Details) - USD ($) $ in Thousands	3 Months Ended												9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income tax benefit	$ (535)	$ 554	$ 665	$ 483	$ 4,494	$ 1,516	$ (1,328)	$ (47)	$ 1,495	$ 1,042	$ 1,159	$ 796		$ 1,167	$ 4,635	$ 4,493
Net income	(708)	$ 3,656	$ 3,513	$ 3,193	$ 91	$ 4,419	$ (3,342)	$ 331	$ 2,927	$ 2,109	$ 2,476	$ 1,584		9,655	1,501	$ 9,097
CapStar Financial Holdings, Inc.
Income - dividends from subsidiary														1,225
Expenses														1,054	879
Income before income taxes and equity in undistributed net income of subsidiary														171	(879)
Income tax benefit	(535)												$ 1,702	(242)	(256)
Income (loss) before equity in undistributed net income of subsidiary														413	(623)
Equity in undistributed net income of subsidiary														9,242	2,124
Net income	$ (708)												$ 10,363	$ 9,655	$ 1,501

- Definition

This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.

+ References + Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Parent Company Only Financial Information - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended												9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ (708)	$ 3,656	$ 3,513	$ 3,193	$ 91	$ 4,419	$ (3,342)	$ 331	$ 2,927	$ 2,109	$ 2,476	$ 1,584		$ 9,655	$ 1,501	$ 9,097
Cash flows from investing activities:
Cash received from acquisitions, net														12,053
Cash flows from financing activities:
Proceeds from issuance of common stock																21,563
Exercise of common stock options and warrants, net of repurchase of restricted shares														4,814	1,294	295
Common and preferred stock dividends paid														(1,244)
CapStar Financial Holdings, Inc.
Cash flows from operating activities:
Net income	(708)												$ 10,363	9,655	1,501
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Increase in other assets														(221)	(62)
Increase in other liabilities														169	77
Equity in undistributed net income of subsidiary														(9,242)	(2,124)
Net cash provided by (used in) operating activities														361	(608)
Cash flows from investing activities:
Investments in subsidiary															(10,000)
Cash received from acquisitions, net														1,421
Net cash provided by (used in) investing activities														1,421	(10,000)
Cash flows from financing activities:
Exercise of common stock options and warrants, net of repurchase of restricted shares														5,260	1,764
Common and preferred stock dividends paid														(1,232)
Net cash provided by financing activities														4,028	1,764
Net increase (decrease) in cash and cash equivalents														5,810	(8,844)
Cash and cash equivalents at beginning of period				$ 14,108				$ 22,952					$ 14,108	14,108	22,952
Cash and cash equivalents at end of period	$ 19,918				$ 14,108				$ 22,952					$ 19,918	$ 14,108	$ 22,952

Quarterly Financial Results (Unaudited) - Summary of Quarterly Financial Results (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Interest income	$ 22,900	$ 15,782	$ 15,354	$ 13,744	$ 13,124	$ 13,521	$ 12,891	$ 11,979	$ 12,007	$ 11,875	$ 10,915	$ 10,598	$ 67,781	$ 51,515	$ 45,395
Interest expense	5,184	4,239	3,767	2,898	2,606	2,678	2,320	2,047	1,827	1,749	1,714	1,642	16,089	9,652	6,931
Net interest income	17,716	11,543	11,587	10,846	10,518	10,843	10,571	9,932	10,180	10,126	9,201	8,956	51,692	41,863	38,464
Provision for loan losses	1,514	481	169	678	(30)	(195)	9,690	3,405	70	1,639	183	937	2,842	12,870	2,829
Net interest income after provision for loan losses	16,202	11,062	11,418	10,168	10,548	11,038	881	6,527	10,110	8,487	9,018	8,019	48,850	28,993	35,635
Noninterest income	6,387	3,218	2,765	3,088	2,736	3,372	2,666	2,133	2,954	3,191	2,568	2,371	15,459	10,908	11,084
Noninterest expense	23,832	10,070	10,005	9,580	8,699	8,475	8,217	8,376	8,642	8,527	7,951	8,010	53,487	33,765	33,129
Income before income taxes	(1,243)	4,210	4,178	3,676	4,585	5,935	(4,670)	284	4,422	3,151	3,635	2,380	10,822	6,136	13,590
Income tax expense	(535)	554	665	483	4,494	1,516	(1,328)	(47)	1,495	1,042	1,159	796	1,167	4,635	4,493
Net income	$ (708)	$ 3,656	$ 3,513	$ 3,193	$ 91	$ 4,419	$ (3,342)	$ 331	$ 2,927	$ 2,109	$ 2,476	$ 1,584	$ 9,655	$ 1,501	$ 9,097
Net income (loss) per share, basic	$ (0.04)	$ 0.30	$ 0.30	$ 0.27	$ 0.01	$ 0.39	$ (0.30)	$ 0.03	$ 0.26	$ 0.24	$ 0.29	$ 0.18	$ 0.73	$ 0.13	$ 0.98
Net income (loss) per share, diluted	$ (0.04)	$ 0.28	$ 0.27	$ 0.25	$ 0.01	$ 0.35	$ (0.26)	$ 0.03	$ 0.23	$ 0.20	$ 0.23	$ 0.15	$ 0.67	$ 0.12	$ 0.81

Schedule I - Unaudited Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets
Cash and due from banks	$ 17,967		$ 9,506
Interest-bearing deposits in financial institutions	76,714		68,572
Federal funds sold	10,762		4,719
Total cash and cash equivalents	105,443		82,797
Securities available-for-sale, at fair value	243,808		192,621
Loans held for sale	57,618		74,093
Loans, net of unearned income	1,429,794		947,537
Allowance for loan losses	(12,113)		(13,721)	$ (11,634)	$ (10,132)
Loans, net	1,417,681		933,816
Premises and equipment, net	18,821		5,884
Restricted equity securities	12,038		8,806
Accrued interest receivable	5,964		4,084
Other real estate owned, net	988		0	0	216
Other assets	51,740		32,327
Total assets	1,963,883		1,344,429
Deposits:
Non-interest-bearing	289,552		301,742
Interest-bearing	434,921		274,681
Savings and money market accounts	497,108		367,246
Time	348,427		176,197
Total deposits	1,570,008		1,119,866
Other liabilities	14,496		7,617
Total liabilities	1,709,504		1,197,483
Shareholders’ equity:
Preferred stock, $.01 par value; 10,000,000 shares authorized; none issued	878		878
Additional paid-in capital	211,789		118,120
Retained earnings	27,303		18,892
Accumulated other comprehensive loss, net of income tax	(3,316)		(2,527)
Total shareholders’ equity	254,379		146,946	$ 139,207	$ 108,586
Total liabilities and shareholders’ equity	$ 1,963,883		1,344,429
Athens Bancshares Corporation & Subsidiary
Assets
Cash and due from banks		$ 6,489
Interest-bearing deposits in financial institutions		4,495
Federal funds sold		1,069
Total cash and cash equivalents		12,053
Securities available-for-sale, at fair value		67,342
Loans held for sale		476
Loans, net of unearned income		349,121
Allowance for loan losses		(4,039)	(3,961)
Loans, net		345,082
Premises and equipment, net		7,637
Restricted equity securities		3,220
Accrued interest receivable		1,410
Core deposit intangible, net		2,758
Other real estate owned, net		988
Other assets		23,948
Total assets		464,914
Deposits:
Non-interest-bearing		58,523
Interest-bearing		114,988
Savings and money market accounts		115,327
Time		115,189
Total deposits		404,027
Other liabilities		5,363
Total liabilities		409,390
Shareholders’ equity:
Preferred stock, $.01 par value; 10,000,000 shares authorized; none issued
Common stock, voting, $.01 par value; 50,000,000 shares authorized; 1,809,358 shares issued and outstanding		18
Additional paid-in capital		21,788
Retained earnings		35,273
Accumulated other comprehensive loss, net of income tax		(1,555)
Total shareholders’ equity		55,524	$ 52,544
Total liabilities and shareholders’ equity		$ 464,914

Schedule I - Unaudited Consolidated Balance Sheets (Parenthetical) (Details) - $ / shares	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Preferred stock, par value	$ 1		$ 1
Preferred stock, shares authorized	5,000,000		5,000,000
Preferred stock, shares issued	878,049		878,049
Athens Bancshares Corporation & Subsidiary
Preferred stock, par value		$ 0.01
Preferred stock, shares authorized		10,000,000
Preferred stock, shares issued		0
Common stock, par value		$ 0.01
Common stock, shares authorized		50,000,000
Common stock, shares issued		1,809,358
Common stock, shares outstanding		1,809,358

Schedule I - Unaudited Consolidated Statement of Income (Details) - USD ($)	3 Months Ended												9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest income:
Loans, including fees														$ 60,751,000	$ 45,601,000	$ 40,213,000
Securities:
Taxable														4,184,000	3,696,000	3,448,000
Tax-exempt														1,201,000	1,230,000	1,158,000
Federal funds sold														63,000	41,000	19,000
Restricted equity securities														571,000	396,000	281,000
Interest-bearing deposits in financial institutions														1,011,000	551,000	276,000
Interest income	$ 22,900,000	$ 15,782,000	$ 15,354,000	$ 13,744,000	$ 13,124,000	$ 13,521,000	$ 12,891,000	$ 11,979,000	$ 12,007,000	$ 11,875,000	$ 10,915,000	$ 10,598,000		67,781,000	51,515,000	45,395,000
Interest expense:
Interest-bearing deposits														4,164,000	2,447,000	1,489,000
Savings and money market accounts														5,446,000	3,188,000	2,859,000
Time deposits														3,940,000	2,445,000	2,085,000
Interest expense	5,184,000	4,239,000	3,767,000	2,898,000	2,606,000	2,678,000	2,320,000	2,047,000	1,827,000	1,749,000	1,714,000	1,642,000		16,089,000	9,652,000	6,931,000
Net interest income	17,716,000	11,543,000	11,587,000	10,846,000	10,518,000	10,843,000	10,571,000	9,932,000	10,180,000	10,126,000	9,201,000	8,956,000		51,692,000	41,863,000	38,464,000
Provision for loan losses														2,842,000	12,870,000	2,829,000
Net interest income after provision for loan losses	16,202,000	11,062,000	11,418,000	10,168,000	10,548,000	11,038,000	881,000	6,527,000	10,110,000	8,487,000	9,018,000	8,019,000		48,850,000	28,993,000	35,635,000
Noninterest income:
Noninterest income														5,653,000	6,238,000	7,375,000
Other noninterest income														3,490,000	1,640,000	1,754,000
Noninterest income	6,387,000	3,218,000	2,765,000	3,088,000	2,736,000	3,372,000	2,666,000	2,133,000	2,954,000	3,191,000	2,568,000	2,371,000		15,459,000	10,908,000	11,084,000
Noninterest expense:
Salaries and employee benefits														28,586,000	20,400,000	20,461,000
Data processing and software														3,835,000	2,786,000	2,373,000
Professional fees														1,608,000	1,522,000	1,554,000
Occupancy														2,336,000	2,025,000	1,498,000
Equipment														2,471,000	2,071,000	1,743,000
Regulatory fees														1,028,000	1,111,000	1,091,000
Merger related expenses														9,803,000
Amortization of intangibles														465,000	48,000	54,000
Other operating														3,355,000	3,802,000	4,355,000
Noninterest expense	23,832,000	10,070,000	10,005,000	9,580,000	8,699,000	8,475,000	8,217,000	8,376,000	8,642,000	8,527,000	7,951,000	8,010,000		53,487,000	33,765,000	33,129,000
Income before income taxes	(1,243,000)	4,210,000	4,178,000	3,676,000	4,585,000	5,935,000	(4,670,000)	284,000	4,422,000	3,151,000	3,635,000	2,380,000		10,822,000	6,136,000	13,590,000
Income tax expense	(535,000)	554,000	665,000	483,000	4,494,000	1,516,000	(1,328,000)	(47,000)	1,495,000	1,042,000	1,159,000	796,000		1,167,000	4,635,000	4,493,000
Net income	$ (708,000)	$ 3,656,000	$ 3,513,000	$ 3,193,000	$ 91,000	$ 4,419,000	$ (3,342,000)	$ 331,000	$ 2,927,000	$ 2,109,000	$ 2,476,000	$ 1,584,000		$ 9,655,000	$ 1,501,000	$ 9,097,000
Per share information:
Basic net income per share of common stock	$ (0.04)	$ 0.30	$ 0.30	$ 0.27	$ 0.01	$ 0.39	$ (0.30)	$ 0.03	$ 0.26	$ 0.24	$ 0.29	$ 0.18		$ 0.73	$ 0.13	$ 0.98
Diluted net income per share of common stock	$ (0.04)	$ 0.28	$ 0.27	$ 0.25	$ 0.01	$ 0.35	$ (0.26)	$ 0.03	$ 0.23	$ 0.20	$ 0.23	$ 0.15		$ 0.67	$ 0.12	$ 0.81
Weighted average shares outstanding:
Basic														13,277,614	11,280,580	9,328,236
Diluted														14,480,347	12,803,511	11,212,026
Treasury Management And Other Deposit Service Charges
Noninterest income:
Noninterest income														$ 2,150,000	$ 1,516,000	$ 1,108,000
Mortgage Banking Income
Noninterest income:
Noninterest income														$ 5,653,000	$ 6,238,000	$ 7,375,000
Athens Bancshares Corporation & Subsidiary
Interest income:
Loans, including fees													$ 13,443,000
Securities:
Taxable													772,000
Tax-exempt													593,000
Federal funds sold													135,000
Restricted equity securities													339,000
Interest-bearing deposits in financial institutions													183,000
Interest income													15,465,000
Interest expense:
Interest-bearing deposits													386,000
Savings and money market accounts													27,000
Time deposits													990,000
Note payable to bank													9,000
Interest expense													1,412,000
Net interest income													14,053,000
Provision for loan losses													146,000
Net interest income after provision for loan losses													13,907,000
Noninterest income:
Noninterest income													842,000
Other noninterest income													2,207,000
Noninterest income													5,233,000
Noninterest expense:
Salaries and employee benefits													7,065,000
Data processing and software													1,138,000
Professional fees													532,000
Occupancy													1,112,000
Equipment													568,000
Regulatory fees													269,000
Merger related expenses													4,731,000
Amortization of intangibles													273,000
Other operating													2,074,000
Noninterest expense													17,762,000
Income before income taxes													1,378,000
Income tax expense													753,000
Net income													$ 625,000
Per share information:
Basic net income per share of common stock													$ 0.36
Diluted net income per share of common stock													$ 0.35
Weighted average shares outstanding:
Basic													1,725,105
Diluted													1,802,595
Athens Bancshares Corporation & Subsidiary \| Treasury Management And Other Deposit Service Charges
Noninterest income:
Noninterest income													$ 2,184,000
Athens Bancshares Corporation & Subsidiary \| Mortgage Banking Income
Noninterest income:
Noninterest income													$ 842,000

Schedule I - Unaudited Consolidated Statement of Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended												9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net income	$ (708)	$ 3,656	$ 3,513	$ 3,193	$ 91	$ 4,419	$ (3,342)	$ 331	$ 2,927	$ 2,109	$ 2,476	$ 1,584		$ 9,655	$ 1,501	$ 9,097
Unrealized gains (losses) on securities available-for-sale:
Unrealized holding gains (losses) arising during the period														(2,491)	4,855	(1,181)
Tax effect														652	(1,884)	499
Net current period other comprehensive income (loss)														(789)	3,883	(1,237)
Comprehensive income														$ 8,866	$ 5,384	$ 7,860
Athens Bancshares Corporation & Subsidiary
Net income													$ 625
Unrealized gains (losses) on securities available-for-sale:
Unrealized holding gains (losses) arising during the period													(1,912)
Tax effect													500
Net current period other comprehensive income (loss)													(1,412)
Comprehensive income													$ (787)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Schedule I - Unaudited Consolidated Statement of Changes in Shareholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended												9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Beginning balance				$ 146,946				$ 139,207				$ 108,586	$ 146,946	$ 146,946	$ 139,207	$ 108,586
Stock-based compensation expense														2,079	1,061	842
Exercise of common stock options, net of withholdings to satisfy employee tax obligations														3,653	1,011	96
Common and preferred stock dividends declared ($0.04 per share)														(1,244)
Net income	$ (708)	$ 3,656	$ 3,513	3,193	$ 91	$ 4,419	$ (3,342)	331	$ 2,927	$ 2,109	$ 2,476	1,584		9,655	1,501	9,097
Other comprehensive income (loss)														(789)	3,883	(1,237)
Ending balance	254,379				146,946				139,207					254,379	146,946	139,207
Common Stock, Voting
Beginning balance				$ 11,450				$ 11,205				$ 8,577	$ 11,450	$ 11,450	$ 11,205	$ 8,577
Beginning balance, shares				11,449,465				11,204,515				8,577,051	11,449,465	11,449,465	11,204,515	8,577,051
Exercise of common stock options, net of withholdings to satisfy employee tax obligations														$ 667	$ 154	$ 8
Exercise of common stock options, net of withholdings to satisfy employee tax obligations, shares														666,964	154,050	8,125
Ending balance	$ 17,592				$ 11,450				$ 11,205					$ 17,592	$ 11,450	$ 11,205
Ending balance, shares	17,592,160				11,449,465				11,204,515					17,592,160	11,449,465	11,204,515
Additional Paid-in Capital
Beginning balance				$ 118,120				$ 116,143				$ 95,278	$ 118,120	$ 118,120	$ 116,143	$ 95,278
Stock-based compensation expense														2,079	1,061	842
Exercise of common stock options, net of withholdings to satisfy employee tax obligations														2,986	857	88
Ending balance	$ 211,789				$ 118,120				$ 116,143					211,789	118,120	116,143
Retained Earnings
Beginning balance				18,892				17,132				8,035	18,892	18,892	17,132	8,035
Common and preferred stock dividends declared ($0.04 per share)														(1,244)
Net income														9,655	1,501	9,097
Ending balance	27,303				18,892				17,132					27,303	18,892	17,132
Accumulated Other Comprehensive Loss
Beginning balance				(2,527)				$ (6,151)				$ (4,914)	(2,527)	(2,527)	(6,151)	(4,914)
Other comprehensive income (loss)														(789)	3,883	(1,237)
Ending balance	(3,316)				(2,527)				$ (6,151)					(3,316)	(2,527)	$ (6,151)
Athens Bancshares Corporation & Subsidiary
Beginning balance	55,524			52,544									52,544	52,544
Stock-based compensation expense													83
Exercise of common stock options, net of withholdings to satisfy employee tax obligations													295
Shares released by ESOP trust and termination of ESOP													3,647
Common and preferred stock dividends declared ($0.04 per share)													(258)
Net income													625
Other comprehensive income (loss)													(1,412)
Ending balance		55,524			52,544								55,524		52,544
Athens Bancshares Corporation & Subsidiary \| Common Stock, Voting
Beginning balance	$ 18			$ 18									$ 18	$ 18
Beginning balance, shares	1,809,358			1,806,084									1,806,084	1,806,084
Exercise of common stock options, net of withholdings to satisfy employee tax obligations, shares													25,663
Shares released by ESOP trust and termination of ESOP, Shares													(22,389)
Ending balance		$ 18			$ 18								$ 18		$ 18
Ending balance, shares		1,809,358			1,806,084								1,809,358		1,806,084
Athens Bancshares Corporation & Subsidiary \| Additional Paid-in Capital
Beginning balance	$ 21,788			$ 18,800									$ 18,800	$ 18,800
Stock-based compensation expense													83
Exercise of common stock options, net of withholdings to satisfy employee tax obligations													295
Shares released by ESOP trust and termination of ESOP													2,610
Ending balance		$ 21,788			$ 18,800								21,788		$ 18,800
Athens Bancshares Corporation & Subsidiary \| Common Stock Acquired By Benefit Plans
Beginning balance				(1,037)									(1,037)	(1,037)
Shares released by ESOP trust and termination of ESOP													1,037
Ending balance					(1,037)										(1,037)
Athens Bancshares Corporation & Subsidiary \| Retained Earnings
Beginning balance	35,273			34,906									34,906	34,906
Common and preferred stock dividends declared ($0.04 per share)													(258)
Net income													625
Ending balance		35,273			34,906								35,273		34,906
Athens Bancshares Corporation & Subsidiary \| Accumulated Other Comprehensive Loss
Beginning balance	$ (1,555)			$ (143)									(143)	$ (143)
Other comprehensive income (loss)													(1,412)
Ending balance		$ (1,555)			$ (143)								$ (1,555)		$ (143)

Schedule I - Unaudited Consolidated Statement of Cash Flows (Details) - USD ($)	3 Months Ended												9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ (708,000)	$ 3,656,000	$ 3,513,000	$ 3,193,000	$ 91,000	$ 4,419,000	$ (3,342,000)	$ 331,000	$ 2,927,000	$ 2,109,000	$ 2,476,000	$ 1,584,000		$ 9,655,000	$ 1,501,000	$ 9,097,000
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Provision for loan losses														2,842,000	12,870,000	2,829,000
Depreciation and amortization														1,028,000	450,000	422,000
Net amortization of premiums on investment securities														1,007,000	1,259,000	1,527,000
Mortgage banking income														$ (5,653,000)	$ (6,238,000)	$ (7,375,000)
Type of Revenue [Extensible List]														us-gaap:MortgageBankingMember	us-gaap:MortgageBankingMember	us-gaap:MortgageBankingMember
Net (gain) loss on sales														$ 0	$ 0	$ (157,000)
Stock-based compensation														2,079,000	1,061,000	842,000
Deferred income tax (benefit) expense														1,175,000	4,385,000	(295,000)
Origination of loans held for sale														(516,341,000)	(565,372,000)	(522,038,000)
Proceeds from loans held for sale														540,448,000	540,123,000	523,156,000
Net increase in accrued interest receivable and other assets														1,395,000	(1,760,000)	(1,537,000)
Net decrease in accrued interest payable and other liabilities														461,000	(2,448,000)	1,814,000
Activities in securities available-for-sale:
Maturities, prepayments and calls															1,560,000	1,656,000
Purchase of restricted equity securities														12,000	2,774,000	618,000
Net increase in loans														(139,124,000)	(20,916,000)	(126,505,000)
Purchase of premises and equipment														(4,244,000)	(1,075,000)	(814,000)
Cash flows from financing activities:
Net increase in deposits														45,622,000	(8,857,000)	90,262,000
Cash received from option exercises														6,897,845	2,013,840	96,306
Common and preferred stock dividends paid														(1,244,000)
Net increase (decrease) in repurchase agreements														221,000		(3,755,000)
Supplemental disclosures of cash paid:
Income taxes														1,716,000	1,047,000	$ 4,114,000
Athens Bancshares Corporation & Subsidiary
Cash flows from operating activities:
Net income													$ 625,000
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Provision for loan losses													146,000
Depreciation and amortization													591,000
Net amortization of premiums on investment securities													218,000
Mortgage banking income													$ (842,000)
Type of Revenue [Extensible List]													us-gaap:MortgageBankingMember
Net (gain) loss on sales													$ (74,000)
Stock-based compensation													83,000
Deferred income tax (benefit) expense													(630,000)
Origination of loans held for sale													(13,333,000)
Proceeds from loans held for sale													13,699,000
Net increase in accrued interest receivable and other assets													(7,721,000)
Net decrease in accrued interest payable and other liabilities													(1,941,000)
Net cash provided by (used in) operating activities													(9,179,000)
Activities in securities available-for-sale:
Maturities, prepayments and calls													7,336,000
Purchase of restricted equity securities													1,260,000
Net increase in loans													(25,999,000)
Purchase of premises and equipment													(716,000)
Net cash provided by (used in) investing activities													(18,119,000)
Cash flows from financing activities:
Net increase in deposits													1,004,000
Payments on note payable to bank													(1,383,000)
Cash received from option exercises													295,000
Common and preferred stock dividends paid													(258,000)
Termination of ESOP													3,647,000
Net increase (decrease) in repurchase agreements													(463,000)
Net cash provided by financing activities													2,842,000
Net decrease in cash and cash equivalents													(24,456,000)
Cash and cash equivalents at beginning of period	$ 12,053,000			$ 36,509,000									36,509,000	$ 36,509,000
Cash and cash equivalents at end of period		$ 12,053,000			$ 36,509,000								12,053,000		$ 36,509,000
Supplemental disclosures of cash paid:
Interest paid													1,445,000
Income taxes													$ 1,645,000

Schedule I - Loans and Allowance for Loan Losses - Summary of Loan Portfolio (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Loans And Leases Receivable Disclosure [Line Items]
Total loans	$ 1,429,895		$ 947,882
Less net unearned income	(101)		(345)
Total loans	1,429,794		947,537
Allowance for loan losses	(12,113)		(13,721)	$ (11,634)	$ (10,132)
Loans, net	1,417,681		933,816
Commercial real estate
Loans And Leases Receivable Disclosure [Line Items]
Total loans	550,446		350,622
Allowance for loan losses	(3,309)		(3,324)	(2,655)	(2,879)
Consumer real estate
Loans And Leases Receivable Disclosure [Line Items]
Total loans	253,562		102,581
Allowance for loan losses	(1,005)		(1,063)	(1,013)	(968)
Construction and land development
Loans And Leases Receivable Disclosure [Line Items]
Total loans	174,670		82,586
Allowance for loan losses	(2,431)		(1,628)	(1,574)	(914)
Commercial and industrial
Loans And Leases Receivable Disclosure [Line Items]
Total loans	404,600		373,248
Allowance for loan losses	$ (5,036)		(7,209)	$ (5,618)	$ (4,693)
Athens Bancshares Corporation & Subsidiary
Loans And Leases Receivable Disclosure [Line Items]
Total loans		$ 350,304
Less net unearned income		(1,183)
Total loans		349,121
Allowance for loan losses		(4,039)	(3,961)
Loans, net		345,082
Athens Bancshares Corporation & Subsidiary \| Commercial real estate
Loans And Leases Receivable Disclosure [Line Items]
Total loans		117,744
Allowance for loan losses		(1,350)	(1,333)
Athens Bancshares Corporation & Subsidiary \| Consumer real estate
Loans And Leases Receivable Disclosure [Line Items]
Total loans		138,255
Allowance for loan losses		(1,288)	(1,011)
Athens Bancshares Corporation & Subsidiary \| Construction and land development
Loans And Leases Receivable Disclosure [Line Items]
Total loans		51,872
Allowance for loan losses		(224)	(206)
Athens Bancshares Corporation & Subsidiary \| Commercial and industrial
Loans And Leases Receivable Disclosure [Line Items]
Total loans		23,885
Allowance for loan losses		(398)	(474)
Athens Bancshares Corporation & Subsidiary \| Consumer and other
Loans And Leases Receivable Disclosure [Line Items]
Total loans		18,548
Allowance for loan losses		$ (779)	$ (937)

Schedule I - Loans and Allowance for Loan Losses - Summary of Changes in Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended												9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance				$ 13,721				$ 11,634				$ 10,132	$ 13,721	$ 13,721	$ 11,634	$ 10,132
Charged-off loans														(4,954)	(12,769)	(1,452)
Recoveries														504	1,986	125
Provision for loan losses	$ 1,514	$ 481	$ 169	678	$ (30)	$ (195)	$ 9,690	3,405	$ 70	$ 1,639	$ 183	937		2,842	12,870	2,829
Ending Balance	12,113				13,721				11,634					12,113	13,721	11,634
Commercial real estate
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance				3,324				2,655				2,879	3,324	3,324	2,655	2,879
Charged-off loans																(350)
Recoveries														22	9	52
Provision for loan losses														(37)	660	74
Ending Balance	3,309				3,324				2,655					3,309	3,324	2,655
Consumer real estate
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance				1,063				1,013				968	1,063	1,063	1,013	968
Recoveries														4
Provision for loan losses														(62)	50	45
Ending Balance	1,005				1,063				1,013					1,005	1,063	1,013
Construction and land development
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance				1,628				1,574				914	1,628	1,628	1,574	914
Provision for loan losses														803	54	660
Ending Balance	2,431				1,628				1,574					2,431	1,628	1,574
Commercial and industrial
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance				7,209				$ 5,618				$ 4,693	7,209	7,209	5,618	4,693
Charged-off loans														(4,831)	(12,769)	(956)
Recoveries														395	1,865	23
Provision for loan losses														2,263	12,495	1,858
Ending Balance	5,036				7,209				$ 5,618					5,036	7,209	$ 5,618
Athens Bancshares Corporation & Subsidiary
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	4,039			3,961									3,961	3,961
Charged-off loans													(181)
Recoveries													113
Provision for loan losses													146
Ending Balance		4,039			3,961								4,039		3,961
Athens Bancshares Corporation & Subsidiary \| Commercial real estate
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	1,350			1,333									1,333	1,333
Recoveries													20
Provision for loan losses													(3)
Ending Balance		1,350			1,333								1,350		1,333
Athens Bancshares Corporation & Subsidiary \| Consumer real estate
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	1,288			1,011									1,011	1,011
Recoveries													17
Provision for loan losses													260
Ending Balance		1,288			1,011								1,288		1,011
Athens Bancshares Corporation & Subsidiary \| Construction and land development
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	224			206									206	206
Recoveries													1
Provision for loan losses													17
Ending Balance		224			206								224		206
Athens Bancshares Corporation & Subsidiary \| Commercial and industrial
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	398			474									474	474
Provision for loan losses													(76)
Ending Balance		398			474								398		474
Athens Bancshares Corporation & Subsidiary \| Consumer and other
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	$ 779			$ 937									937	$ 937
Charged-off loans													(181)
Recoveries													75
Provision for loan losses													(52)
Ending Balance		$ 779			$ 937								$ 779		$ 937

Schedule I - Loans and Allowance for Loan Losses - Summary of Breakdown of Allowance for Loan Losses and Loan Portfolio by Loan Category (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for Loan Losses:
Collectively evaluated for impairment	$ 12,113		$ 13,621
Individually evaluated for impairment			100
Allowance for Loan Losses, Ending Balance	12,113		13,721	$ 11,634	$ 10,132
Loans:
Collectively evaluated for impairment	1,425,997		945,187
Individually evaluated for impairment	3,898		2,695
Total	1,429,895		947,882
Commercial real estate
Allowance for Loan Losses:
Collectively evaluated for impairment	3,309		3,324
Allowance for Loan Losses, Ending Balance	3,309		3,324	2,655	2,879
Loans:
Collectively evaluated for impairment	549,055		349,415
Individually evaluated for impairment	1,391		1,207
Total	550,446		350,622
Consumer real estate
Allowance for Loan Losses:
Collectively evaluated for impairment	1,005		1,063
Allowance for Loan Losses, Ending Balance	1,005		1,063	1,013	968
Loans:
Collectively evaluated for impairment	252,640		102,581
Individually evaluated for impairment	922
Total	253,562		102,581
Construction and land development
Allowance for Loan Losses:
Collectively evaluated for impairment	2,431		1,628
Allowance for Loan Losses, Ending Balance	2,431		1,628	1,574	914
Loans:
Collectively evaluated for impairment	174,662		82,586
Individually evaluated for impairment	8
Total	174,670		82,586
Commercial and industrial
Allowance for Loan Losses:
Collectively evaluated for impairment	5,036		7,109
Individually evaluated for impairment			100
Allowance for Loan Losses, Ending Balance	5,036		7,209	$ 5,618	$ 4,693
Loans:
Collectively evaluated for impairment	403,054		371,760
Individually evaluated for impairment	1,546		1,488
Total	$ 404,600		373,248
Athens Bancshares Corporation & Subsidiary
Allowance for Loan Losses:
Collectively evaluated for impairment		$ 3,929
Individually evaluated for impairment		110
Allowance for Loan Losses, Ending Balance		4,039	3,961
Loans:
Collectively evaluated for impairment		347,245
Individually evaluated for impairment		3,059
Total		350,304
Athens Bancshares Corporation & Subsidiary \| Commercial real estate
Allowance for Loan Losses:
Collectively evaluated for impairment		1,284
Individually evaluated for impairment		66
Allowance for Loan Losses, Ending Balance		1,350	1,333
Loans:
Collectively evaluated for impairment		117,562
Individually evaluated for impairment		182
Total		117,744
Athens Bancshares Corporation & Subsidiary \| Consumer real estate
Allowance for Loan Losses:
Collectively evaluated for impairment		1,288
Allowance for Loan Losses, Ending Balance		1,288	1,011
Loans:
Collectively evaluated for impairment		136,983
Individually evaluated for impairment		1,272
Total		138,255
Athens Bancshares Corporation & Subsidiary \| Construction and land development
Allowance for Loan Losses:
Collectively evaluated for impairment		224
Allowance for Loan Losses, Ending Balance		224	206
Loans:
Collectively evaluated for impairment		51,850
Individually evaluated for impairment		22
Total		51,872
Athens Bancshares Corporation & Subsidiary \| Commercial and industrial
Allowance for Loan Losses:
Collectively evaluated for impairment		356
Individually evaluated for impairment		42
Allowance for Loan Losses, Ending Balance		398	474
Loans:
Collectively evaluated for impairment		22,370
Individually evaluated for impairment		1,515
Total		23,885
Athens Bancshares Corporation & Subsidiary \| Consumer and other
Allowance for Loan Losses:
Collectively evaluated for impairment		777
Individually evaluated for impairment		2
Allowance for Loan Losses, Ending Balance		779	$ 937
Loans:
Collectively evaluated for impairment		18,480
Individually evaluated for impairment		68
Total		$ 18,548

Schedule I - Loans and Allowance for Loan Losses - Summary of Impaired Loans Evaluated for Specific Loss Allowance (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Recorded investment	$ 3,898		$ 1,207
Impaired loans with no related allowance recorded, Unpaid principal balance	9,403		1,645
Impaired loans with an allowance recorded, Related allowance			100
Impaired loans with an allowance recorded, Recorded investment			1,488
Impaired loans with an allowance recorded, Unpaid principal balance			2,770
Recorded investment	3,898		2,695
Unpaid principal balance	9,403		4,415
Commercial real estate
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Recorded investment	1,391		1,207
Impaired loans with no related allowance recorded, Unpaid principal balance	1,775		1,645
Consumer real estate
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Recorded investment	922
Impaired loans with no related allowance recorded, Unpaid principal balance	1,204
Construction and land development
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Recorded investment	8
Impaired loans with no related allowance recorded, Unpaid principal balance	18
Commercial and industrial
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Recorded investment	1,546
Impaired loans with no related allowance recorded, Unpaid principal balance	6,350
Impaired loans with an allowance recorded, Related allowance			100
Impaired loans with an allowance recorded, Recorded investment			1,488
Impaired loans with an allowance recorded, Unpaid principal balance			$ 2,770
Consumer
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Recorded investment	31
Impaired loans with no related allowance recorded, Unpaid principal balance	$ 56
Athens Bancshares Corporation & Subsidiary
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Recorded investment		$ 1,294
Impaired loans with no related allowance recorded, Unpaid principal balance		1,294
Impaired loans with an allowance recorded, Related allowance		110
Impaired loans with an allowance recorded, Recorded investment		1,765
Impaired loans with an allowance recorded, Unpaid principal balance		1,765
Recorded investment		3,059
Unpaid principal balance		3,059
Athens Bancshares Corporation & Subsidiary \| Commercial real estate
Financing Receivable Impaired [Line Items]
Impaired loans with an allowance recorded, Related allowance		66
Impaired loans with an allowance recorded, Recorded investment		182
Impaired loans with an allowance recorded, Unpaid principal balance		182
Athens Bancshares Corporation & Subsidiary \| Consumer real estate
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Recorded investment		1,272
Impaired loans with no related allowance recorded, Unpaid principal balance		1,272
Athens Bancshares Corporation & Subsidiary \| Construction and land development
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Recorded investment		22
Impaired loans with no related allowance recorded, Unpaid principal balance		22
Athens Bancshares Corporation & Subsidiary \| Commercial and industrial
Financing Receivable Impaired [Line Items]
Impaired loans with an allowance recorded, Related allowance		42
Impaired loans with an allowance recorded, Recorded investment		1,515
Impaired loans with an allowance recorded, Unpaid principal balance		1,515
Athens Bancshares Corporation & Subsidiary \| Consumer
Financing Receivable Impaired [Line Items]
Impaired loans with an allowance recorded, Related allowance		2
Impaired loans with an allowance recorded, Recorded investment		68
Impaired loans with an allowance recorded, Unpaid principal balance		$ 68

Schedule I - Loans and Allowance for Loan Losses - Schedule of Non-Accrual Loans, Past Due Loans over 89 Days Outstanding and Accruing and Troubled Debt Restructurings (TDR) by Class of Loans (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Non-Accrual		$ 2,078	$ 2,695
Troubled Debt Restructurings		1,391	1,206
Commercial real estate
Accounts Notes And Loans Receivable [Line Items]
Non-Accrual			1,207
Troubled Debt Restructurings		1,391	1,206
Consumer real estate
Accounts Notes And Loans Receivable [Line Items]
Non-Accrual		1,187
Construction and Land Development
Accounts Notes And Loans Receivable [Line Items]
Non-Accrual		19
Commercial and industrial
Accounts Notes And Loans Receivable [Line Items]
Non-Accrual		$ 817	$ 1,488
Athens Bancshares Corporation & Subsidiary
Accounts Notes And Loans Receivable [Line Items]
Non-Accrual	$ 1,072
Troubled Debt Restructurings	2,495
Athens Bancshares Corporation & Subsidiary \| Commercial real estate
Accounts Notes And Loans Receivable [Line Items]
Troubled Debt Restructurings	182
Athens Bancshares Corporation & Subsidiary \| Consumer real estate
Accounts Notes And Loans Receivable [Line Items]
Non-Accrual	987
Troubled Debt Restructurings	783
Athens Bancshares Corporation & Subsidiary \| Construction and Land Development
Accounts Notes And Loans Receivable [Line Items]
Non-Accrual	21
Athens Bancshares Corporation & Subsidiary \| Commercial and industrial
Accounts Notes And Loans Receivable [Line Items]
Troubled Debt Restructurings	1,510
Athens Bancshares Corporation & Subsidiary \| Consumer and other
Accounts Notes And Loans Receivable [Line Items]
Non-Accrual	64
Troubled Debt Restructurings	$ 20

Schedule I - Stock Options - Summary of Company Recognized Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense before income taxes		$ 2,079	$ 1,061	$ 842
Less: deferred tax benefit		(543)	(406)	(322)
Reduction of net income		$ 1,536	$ 655	$ 520
Athens Bancshares Corporation & Subsidiary
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense before income taxes	$ 83
Less: deferred tax benefit	(22)
Reduction of net income	$ 61

Schedule I - Stock Options - Summary of Activity in Stock Options (Details) - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Shares, Abstract
Shares Outstanding, Beginning Balance	756,050	756,050
Shares Outstanding, Granted		0	0
Shares Outstanding, Exercised		(796,198)
Shares Outstanding, Ending Balance		507,903	756,050
Shares, Fully Vested and Expected to Vest		506,783
Shares, Exercisable at End of Period		480,403
Weighted Average Exercise Price, Abstract
Weighted Average Exercise Price Outstanding, Beginning Balance	$ 10.50	$ 10.50
Weighted Average Exercise Price Outstanding, Granted
Weighted Average Exercise Price Outstanding, Exercised		8.16
Weighted Average Exercise Price Outstanding, Forfeited or expired
Weighted Average Exercise Price Outstanding, Ending Balance		8.66	$ 10.50
Weighted Average Exercise Price, Fully vested and expected to vest		8.66
Weighted Average Exercise Price, Exercisable at End of Period		$ 8.46
Weighted Average Remaining Contractual Term (year), Abstract
Weighted Average Remaining Contractual Term Outstanding		4 years
Weighted Average Remaining Contractual Term, Fully Vested and Expected to Vest		4 years 1 month 6 days
Weighted Average Remaining Contractual Term, Exercisable at End of Period		4 years
Athens Bancshares Corporation & Subsidiary
Shares, Abstract
Shares Outstanding, Beginning Balance	217,024	217,024
Shares Outstanding, Exercised	(25,663)
Shares Outstanding, Ending Balance	191,361		217,024
Shares, Fully Vested and Expected to Vest	191,361
Shares, Exercisable at End of Period	191,361
Weighted Average Exercise Price, Abstract
Weighted Average Exercise Price Outstanding, Beginning Balance	$ 14.12	$ 14.12
Weighted Average Exercise Price Outstanding, Exercised	11.50
Weighted Average Exercise Price Outstanding, Ending Balance	14.48		$ 14.12
Weighted Average Exercise Price, Fully vested and expected to vest	14.48
Weighted Average Exercise Price, Exercisable at End of Period	$ 14.48
Weighted Average Remaining Contractual Term (year), Abstract
Weighted Average Remaining Contractual Term Outstanding	3 years 1 month 6 days
Weighted Average Remaining Contractual Term, Fully Vested and Expected to Vest	3 years 1 month 6 days
Weighted Average Remaining Contractual Term, Exercisable at End of Period	3 years 1 month 6 days

Schedule I - Stock Options - Information Related to Stock Options (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Intrinsic value of options exercised		$ 7,654,738	$ 2,010,536	$ 53,756
Cash received from option exercises		6,897,845	2,013,840	96,306
Tax benefit realized from option exercises		$ 846,725	$ 774,056	$ 20,583
Weighted average fair value of options granted				$ 3.16
Athens Bancshares Corporation & Subsidiary
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Intrinsic value of options exercised	$ 1,038,000
Cash received from option exercises	295,000
Tax benefit realized from option exercises	$ 189,000

Schedule I - Earnings Per Share - Summary of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Basic net income per share calculation:
Numerator – Net income														$ 9,655	$ 1,501	$ 9,097
Denominator – Average common shares outstanding														13,277,614	11,280,580	9,328,236
Basic net income per share of common stock	$ (0.04)	$ 0.30	$ 0.30	$ 0.27	$ 0.01	$ 0.39	$ (0.30)	$ 0.03	$ 0.26	$ 0.24	$ 0.29	$ 0.18		$ 0.73	$ 0.13	$ 0.98
Diluted net income per share calculation:
Numerator – Net income														$ 9,655	$ 1,501	$ 9,097
Dilutive shares contingently issuable														1,202,733	1,522,931	1,883,790
Average diluted common shares outstanding														14,480,347	12,803,511	11,212,026
Diluted net income per share of common stock	$ (0.04)	$ 0.28	$ 0.27	$ 0.25	$ 0.01	$ 0.35	$ (0.26)	$ 0.03	$ 0.23	$ 0.20	$ 0.23	$ 0.15		$ 0.67	$ 0.12	$ 0.81
Athens Bancshares Corporation & Subsidiary
Basic net income per share calculation:
Numerator – Net income													$ 625
Denominator – Average common shares outstanding													1,725,105
Basic net income per share of common stock													$ 0.36
Diluted net income per share calculation:
Numerator – Net income													$ 625
Dilutive shares contingently issuable													77,490
Average diluted common shares outstanding													1,802,595
Diluted net income per share of common stock													$ 0.35

Schedule I - Employee Stock Ownership Plan - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2018
Restructuring Cost And Reserve [Line Items]
Vesting period		3 years
Athens Bancshares Corporation & Subsidiary
Restructuring Cost And Reserve [Line Items]
Purchase of share under ESOP	222,180
Loan repayment period	15 years
Loan interest rate	3.25%
Vesting period	4 years
Recognized compensation expense	$ 3.6

Schedule I - Subsequent Events - Additional Information (Details) $ / shares in Units, $ in Millions	Oct. 02, 2018 USD ($) $ / shares shares	Dec. 31, 2018 shares	Sep. 30, 2018 $ / shares
Subsequent Event [Line Items]
Converted options right to purchase shares of CapStar Common Stock, shares \| shares		0
Athens Bancshares Corporation & Subsidiary
Subsequent Event [Line Items]
Common stock, par value \| $ / shares			$ 0.01
Purchase price consideration \| $	$ 92.9
Athens Bancshares Corporation & Subsidiary \| Athens Bancshares
Subsequent Event [Line Items]
Common stock, par value \| $ / shares	$ 0.01
Athens Bancshares Corporation & Subsidiary \| CapStar Financial Holdings, Inc.
Subsequent Event [Line Items]
Conversion of debt exchange ratio	2.864
Issuance of common stock, shares \| shares	5,181,916
Converted options right to purchase shares of CapStar Common Stock, shares \| shares	548,051
Converted options right to purchase shares of CapStar Common Stock, per share \| $ / shares	$ 5.06

Schedule II - Unaudited Pro Forma Combined Consolidated Statement of Income (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest income:
Loans, including fees														$ 60,751	$ 45,601	$ 40,213
Securities:
Taxable														4,184	3,696	3,448
Tax-exempt														1,201	1,230	1,158
Federal funds sold														63	41	19
Restricted equity securities														571	396	281
Interest-bearing deposits in financial institutions														1,011	551	276
Total interest income	$ 22,900	$ 15,782	$ 15,354	$ 13,744	$ 13,124	$ 13,521	$ 12,891	$ 11,979	$ 12,007	$ 11,875	$ 10,915	$ 10,598		67,781	51,515	45,395
Interest expense:
Time deposits														3,940	2,445	2,085
Federal funds purchased														3	13	22
Securities sold under agreements to repurchase														3		1
Federal Home Loan Bank advances														2,533	1,559	475
Total interest expense	5,184	4,239	3,767	2,898	2,606	2,678	2,320	2,047	1,827	1,749	1,714	1,642		16,089	9,652	6,931
Net interest income	17,716	11,543	11,587	10,846	10,518	10,843	10,571	9,932	10,180	10,126	9,201	8,956		51,692	41,863	38,464
Provision for loan losses														2,842	12,870	2,829
Net interest income after provision for loan losses	16,202	11,062	11,418	10,168	10,548	11,038	881	6,527	10,110	8,487	9,018	8,019		48,850	28,993	35,635
Noninterest income:
Noninterest income														5,653	6,238	7,375
Net gain (loss) on sale of securities														3	(66)	121
Tri-Net fees														1,503	1,002	125
Other noninterest income														3,490	1,640	1,754
Total noninterest income	6,387	3,218	2,765	3,088	2,736	3,372	2,666	2,133	2,954	3,191	2,568	2,371		15,459	10,908	11,084
Noninterest expense:
Salaries and employee benefits														28,586	20,400	20,461
Data processing and software														3,835	2,786	2,373
Professional fees														1,608	1,522	1,554
Occupancy														2,336	2,025	1,498
Equipment														2,471	2,071	1,743
Regulatory fees														1,028	1,111	1,091
Merger related expenses														9,803
Other operating														3,355	3,802	4,355
Total noninterest expense	23,832	10,070	10,005	9,580	8,699	8,475	8,217	8,376	8,642	8,527	7,951	8,010		53,487	33,765	33,129
Income before income taxes	(1,243)	4,210	4,178	3,676	4,585	5,935	(4,670)	284	4,422	3,151	3,635	2,380		10,822	6,136	13,590
Income tax expense	(535)	554	665	483	4,494	1,516	(1,328)	(47)	1,495	1,042	1,159	796		1,167	4,635	4,493
Net income	$ (708)	$ 3,656	$ 3,513	$ 3,193	$ 91	$ 4,419	$ (3,342)	$ 331	$ 2,927	$ 2,109	$ 2,476	$ 1,584		$ 9,655	$ 1,501	$ 9,097
Per share information:
Basic net income per share of common stock	$ (0.04)	$ 0.30	$ 0.30	$ 0.27	$ 0.01	$ 0.39	$ (0.30)	$ 0.03	$ 0.26	$ 0.24	$ 0.29	$ 0.18		$ 0.73	$ 0.13	$ 0.98
Diluted net income per share of common stock	$ (0.04)	$ 0.28	$ 0.27	$ 0.25	$ 0.01	$ 0.35	$ (0.26)	$ 0.03	$ 0.23	$ 0.20	$ 0.23	$ 0.15		$ 0.67	$ 0.12	$ 0.81
Weighted average shares outstanding:
Basic														13,277,614	11,280,580	9,328,236
Diluted														14,480,347	12,803,511	11,212,026
Pro Forma
Interest income:
Loans, including fees														$ 75,197
Securities:
Taxable														4,958
Tax-exempt														1,793
Federal funds sold														199
Restricted equity securities														909
Interest-bearing deposits in financial institutions														1,192
Total interest income														84,248
Interest expense:
Time deposits														14,775
Federal funds purchased														3
Securities sold under agreements to repurchase														3
Federal Home Loan Bank advances														2,532
Total interest expense														17,313
Net interest income														66,935
Provision for loan losses														2,988
Net interest income after provision for loan losses														63,947
Noninterest income:
Net gain (loss) on sale of securities														3
Tri-Net fees														1,503
Other noninterest income														8,357
Total noninterest income														20,692
Noninterest expense:
Salaries and employee benefits														35,651
Data processing and software														4,973
Professional fees														2,140
Occupancy														3,448
Equipment														3,039
Regulatory fees														1,297
Other operating														7,151
Total noninterest expense														57,699
Income before income taxes														26,940
Income tax expense														5,773
Net income														$ 21,167
Per share information:
Basic net income per share of common stock														$ 1.24
Diluted net income per share of common stock														$ 1.14
Weighted average shares outstanding:
Basic														17,033,392
Diluted														18,616,669
Pro Forma Adjustments
Interest income:
Loans, including fees														$ 1,003
Securities:
Total interest income														1,003
Interest expense:
Time deposits														(178)
Note payable to bank														(9)
Total interest expense														(187)
Net interest income														1,190
Net interest income after provision for loan losses														1,190
Noninterest expense:
Merger related expenses														(14,535)
Other operating														985
Total noninterest expense														(13,550)
Income before income taxes														14,740
Income tax expense														3,853
Net income														$ 10,887
Weighted average shares outstanding:
Basic														3,456,811
Diluted														3,761,316
Athens Bancshares Corporation
Interest income:
Loans, including fees													$ 13,443
Securities:
Taxable													772
Tax-exempt													593
Federal funds sold													135
Restricted equity securities													339
Interest-bearing deposits in financial institutions													183
Total interest income													15,465
Interest expense:
Time deposits													1,403
Note payable to bank													9
Total interest expense													1,412
Net interest income													14,053	$ 66,935	$ 59,148
Provision for loan losses													146
Net interest income after provision for loan losses													13,907
Noninterest income:
Other noninterest income													2,207
Total noninterest income													5,233	20,692	17,540
Noninterest expense:
Salaries and employee benefits													7,065
Data processing and software													1,138
Professional fees													532
Occupancy													1,112
Equipment													568
Regulatory fees													269
Merger related expenses													4,731
Other operating													2,347
Total noninterest expense													17,762
Income before income taxes													1,378
Income tax expense													753
Net income													$ 625	$ 21,167	$ 5,851
Per share information:
Basic net income per share of common stock													$ 0.36	$ 1.24	$ 0.36
Diluted net income per share of common stock													$ 0.35	$ 1.14	$ 0.32
Weighted average shares outstanding:
Basic													1,725,105	5,181,916
Diluted													1,802,595	5,563,911
Athens Bancshares Corporation \| Pro Forma Adjustments
Noninterest expense:
Income tax expense	$ 3,853
CapStar Financial Holdings, Inc.
Interest income:
Loans, including fees	20,554												$ 40,197
Securities:
Taxable	1,411												2,775
Tax-exempt	416												784
Federal funds sold	8												56
Restricted equity securities	181												389
Interest-bearing deposits in financial institutions	330												679
Total interest income	22,900												44,880
Interest expense:
Time deposits	4,462												9,088
Federal funds purchased													3
Securities sold under agreements to repurchase	3
Federal Home Loan Bank advances	719												1,813
Total interest expense	5,184												10,904
Net interest income	17,716												33,976
Provision for loan losses	1,514												1,328
Net interest income after provision for loan losses	16,202												32,648
Noninterest income:
Net gain (loss) on sale of securities	1												2
Tri-Net fees	276												1,227
Other noninterest income	3,993												2,157
Total noninterest income	6,387												9,072
Noninterest expense:
Salaries and employee benefits	9,475												19,111
Data processing and software	1,424												2,411
Professional fees	534												1,074
Occupancy	736												1,600
Equipment	810												1,661
Regulatory fees	364												664
Merger related expenses	8,929												875
Other operating	1,560												2,259
Total noninterest expense	23,832												29,655
Income before income taxes	(1,243)												12,065
Income tax expense	(535)												1,702	$ (242)	$ (256)
Net income	$ (708)												$ 10,363	$ 9,655	1,501
Per share information:
Basic net income per share of common stock	$ (0.04)												$ 0.87
Diluted net income per share of common stock	$ (0.04)												$ 0.79
Weighted average shares outstanding:
Basic	17,509,525												11,851,476	11,851,476
Diluted	18,716,562												13,052,758	13,052,758
Treasury Management And Other Deposit Service Charges
Noninterest income:
Noninterest income														$ 2,150	1,516	$ 1,108
Treasury Management And Other Deposit Service Charges \| Pro Forma
Noninterest income:
Noninterest income														4,334
Treasury Management And Other Deposit Service Charges \| Athens Bancshares Corporation
Noninterest income:
Noninterest income													$ 2,184
Treasury Management And Other Deposit Service Charges \| CapStar Financial Holdings, Inc.
Noninterest income:
Noninterest income	$ 793												1,357
Mortgage Banking Income
Noninterest income:
Noninterest income														5,653	$ 6,238	$ 7,375
Mortgage Banking Income \| Pro Forma
Noninterest income:
Noninterest income														$ 6,495
Mortgage Banking Income \| Athens Bancshares Corporation
Noninterest income:
Noninterest income													842
Mortgage Banking Income \| CapStar Financial Holdings, Inc.
Noninterest income:
Noninterest income	$ 1,324												$ 4,329

Schedule II - Summary of Acquisition Consideration (Details) - Athens Bancshares $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2018 USD ($) shares	Dec. 31, 2018 USD ($) $ / shares	Oct. 01, 2018	Sep. 30, 2018 $ / shares
Business Acquisition [Line Items]
Per share exchange ratio			2.864
Total cost of acquisition		$ 92,918
Estimated fair value of stock options rolled ("Rolled Stock Options Consideration")		$ 92,918
CapStar Financial Holdings, Inc.
Business Acquisition [Line Items]
Total number of common shares as provided by Athens management \| shares	1,809,358
Total number of Athens common stock to exchange \| shares	1,809,358
Per share exchange ratio	2.864		2.864
Number of shares of CapStar common stock as exchanged \| shares	5,181,916
Multiplied by CapStar common stock price per share on September 30, 2018 \| $ / shares				$ 16.70
Estimated fair value of CapStar common stock issued (“Stock Consideration”)	$ 86,538
Total number of stock options outstanding as provided by Athens management to exchange \| shares	548,051
Intrinsic value per stock option outstanding \| $ / shares		$ 11.64
Total cost of acquisition	$ 6,380
Estimated fair value of stock options rolled ("Rolled Stock Options Consideration")	6,380
Total Preliminary Estimated Acquisition Consideration	$ 92,918

Schedule II - Summary of Preliminary Estimated Acquisition Consideration Allocation (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Oct. 01, 2018	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill	$ 37,510			$ 6,219	$ 6,219
Athens Bancshares
Business Acquisition [Line Items]
Cash and cash equivalents		$ 12,053	$ 12,053
Securities		67,426	67,426
Loans			344,833
Premises and equipment, net		9,208	9,208
Goodwill		31,291	31,291
Core deposit intangible	$ 8,980		8,980
Other		30,510	30,510
Deposits			(404,520)
Other liabilities		$ (6,863)	(6,863)
Total acquisition consideration			$ 92,918

Schedule II - Preliminary Unaudited Pro Forma and Acquisition Accounting Adjustments - Income Statement - Pro Forma Adjustments (Details) - USD ($)	3 Months Ended												9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Amortization of intangibles														$ 465,000	$ 48,000	$ 54,000
Income tax expense	$ (535,000)	$ 554,000	$ 665,000	$ 483,000	$ 4,494,000	$ 1,516,000	$ (1,328,000)	$ (47,000)	$ 1,495,000	$ 1,042,000	$ 1,159,000	$ 796,000		1,167,000	$ 4,635,000	$ 4,493,000
Pro Forma Adjustments
Business Acquisition [Line Items]
Income tax expense														3,853,000
Athens Bancshares
Business Acquisition [Line Items]
Amortization of intangibles														$ 1,700,000
Income tax expense													$ 753,000
Athens Bancshares \| Pro Forma Adjustments
Business Acquisition [Line Items]
Remove one-time merger related expenses	14,535,000
Elimination of intercompany income/expense	9,000
Remove amortization of existing CDI	273,000
Amortization of intangibles	1,258,000
Deposit premium amortization	178,000
Estimate of loan interest accretion	1,012,000
Income tax expense	$ 3,853,000

Schedule II - Preliminary Unaudited Pro Forma and Acquisition Accounting Adjustments - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2018
Business Acquisition [Line Items]
Amortization of intangibles	$ 465,000	$ 48,000	$ 54,000
Athens Bancshares
Business Acquisition [Line Items]
Core deposit intangible	8,980,000			$ 8,980,000
Amortization of intangibles	1,700,000
Interest accretion amount	$ 4,800,000
Incremental effective tax rate	26.14%

Schedule II - Earnings per Common Share - Summary of Unaudited Pro Forma Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pro forma net income available to common shareholders			$ 9,655	$ 1,501	$ 9,097
Weighted average shares outstanding:
Basic			13,277,614	11,280,580	9,328,236
Pro forma net income per common share			$ 1.24
Pro forma net income available to common shareholders			$ 9,655	$ 1,501	$ 9,097
Diluted			14,480,347	12,803,511	11,212,026
Pro forma net income per common share			$ 1.14
CapStar Financial Holdings, Inc.
Weighted average shares outstanding:
Basic	17,509,525	11,851,476	11,851,476
Diluted	18,716,562	13,052,758	13,052,758
Athens Bancshares
Weighted average shares outstanding:
Basic		1,725,105	5,181,916
Diluted		1,802,595	5,563,911
Pro Forma
Pro forma net income available to common shareholders			$ 21,167
Weighted average shares outstanding:
Basic			17,033,392
Pro forma net income available to common shareholders			$ 21,167
Diluted			18,616,669

Concentration of Credit Risk - Additional Information (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Concentration Risk [Line Items]
Cash due from banks, federal funds sold and interest bearing deposits	$ 105,443,000	$ 82,797,000
Excess Of Insured Limits
Concentration Risk [Line Items]
Cash due from banks, federal funds sold and interest bearing deposits	$ 89,000,000	$ 38,000,000

Regulatory Matters And Restrictions On Dividends - Schedule of Capital Amounts and Ratios (Parenthetical) (Details)	Dec. 31, 2018
Banking And Thrift [Abstract]
Minimum risk based capital ratios	1.875%

Shareholders' Agreement - Additional Information (Details)	12 Months Ended
	Dec. 31, 2018 Nominee shares	Dec. 21, 2018 shares
Share Based Compensation [Abstract]
Shareholders' agreement date	Aug. 22, 2016
Number of nominee \| Nominee	1
Registrable securities	500,000
Number of additional shares registered		3,652,094

Fair Value - Additional Information (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Other real estate owned at fair value	$ 0	$ 0
Loans held for sale carried at fair value	$ 0	$ 0