Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2017	May 02, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q1
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	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		11,223,536

Consolidated Balance Sheets - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Assets
Cash and due from banks	$ 8,635,982	$ 9,133,502
Interest-bearing deposits in financial institutions	49,992,644	54,322,823
Federal funds sold	1,410,000	16,654,481
Total cash and cash equivalents	60,038,626	80,110,806
Securities available for sale, at fair value	188,516,087	182,354,987
Securities held to maturity, fair value of $49,769,285, and $49,731,169 at March 31, 2017 and December 31, 2016, respectively	46,854,518	46,863,640
Loans held for sale	35,370,814	42,110,581
Loans and leases	1,003,433,910	935,250,703
Less allowance for loan and lease losses	(13,996,869)	(11,633,531)
Loans and leases, net	989,437,041	923,617,172
Premises and equipment, net	5,859,025	5,350,226
Restricted equity securities	6,544,250	6,031,700
Accrued interest receivable	4,012,367	3,941,609
Goodwill	6,218,867	6,218,867
Core deposit intangible	57,379	70,912
Deferred tax assets	13,461,531	12,956,059
Bank owned life insurance	22,044,193	21,900,465
Other assets	3,287,898	2,148,039
Total assets	1,381,702,596	1,333,675,063
Deposits:
Non-interest-bearing	223,449,870	197,787,618
Interest-bearing	335,571,747	299,620,783
Savings and money market accounts	421,202,733	447,685,909
Time	177,770,839	183,627,943
Total deposits	1,157,995,189	1,128,722,253
Federal Home Loan Bank advances	75,000,000	55,000,000
Accrued interest payable	235,895	211,578
Other liabilities	8,260,090	10,533,836
Total liabilities	1,241,491,174	1,194,467,667
Shareholders’ equity:
Series A convertible preferred stock, $1 par value; 5,000,000 shares authorized; 878,049 shares issued and outstanding at March 31, 2017 and December 31, 2016	878,049	878,049
Common stock, voting, $1 par value; 20,000,000 shares authorized; 11,218,328 and 11,204,515 shares issued and outstanding at March 31, 2017 and December 31, 2016, respectively	11,218,328	11,204,515
Additional paid-in capital	116,263,244	116,142,894
Retained earnings	17,464,547	17,132,489
Accumulated other comprehensive loss, net of income tax	(5,612,746)	(6,150,551)
Total shareholders’ equity	140,211,422	139,207,396
Total liabilities and shareholders’ equity	$ 1,381,702,596	$ 1,333,675,063

Consolidated Balance Sheets (Parenthetical) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Securities held to maturity, fair value	$ 49,769,285	$ 49,731,169
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
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	20,000,000	20,000,000
Common stock, shares issued	11,218,328	11,204,515
Common stock, shares outstanding	11,218,328	11,204,515

Consolidated Statements of Income (Unaudited) - USD ($)	3 Months Ended
Consolidated Statements of Income (Unaudited) - USD ($)	Mar. 31, 2017	Mar. 31, 2016
Interest income:
Loans, including fees	$ 10,466,758	$ 9,268,272
Securities:
Taxable	1,002,896	898,038
Tax-exempt	325,916	282,244
Federal funds sold	2,305	4,138
Restricted equity securities	76,286	69,108
Interest-bearing deposits in financial institutions	104,791	76,378
Total interest income	11,978,952	10,598,178
Interest expense:
Interest-bearing deposits	617,466	301,633
Savings and money market accounts	815,092	731,702
Time deposits	470,645	514,445
Federal funds purchased	3,910	2,083
Securities sold under agreements to repurchase		1,311
Federal Home Loan Bank advances	140,259	90,728
Total interest expense	2,047,372	1,641,902
Net interest income	9,931,580	8,956,276
Provision for loan and lease losses	3,404,799	937,216
Net interest income after provision for loan and lease losses	6,526,781	8,019,060
Noninterest income:
Service charges on deposit accounts	328,585	225,427
Loan commitment fees	236,274	430,122
Net gain (loss) on sale of securities	(6,229)	38,961
Mortgage banking income	1,216,362	1,347,452
Other noninterest income	358,554	328,810
Total noninterest income	2,133,546	2,370,772
Noninterest expense:
Salaries and employee benefits	5,086,451	5,217,755
Data processing and software	620,508	568,477
Professional fees	364,553	330,738
Occupancy	448,798	409,881
Equipment	496,196	406,571
Regulatory fees	307,060	227,260
Other operating	1,051,871	849,059
Total noninterest expense	8,375,437	8,009,741
Income before income taxes	284,890	2,380,091
Income tax expense (benefit)	(47,168)	796,245
Net income	$ 332,058	$ 1,583,846
Per share information:
Basic net income per share of common stock	$ 0.03	$ 0.18
Diluted net income per share of common stock	$ 0.03	$ 0.15
Weighted average shares outstanding:
Basic	11,210,948	8,628,683
Diluted	12,784,117	10,572,193

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 332,058	$ 1,583,846
Unrealized gains on securities available for sale:
Unrealized holding gains arising during the period	574,536	2,138,520
Reclassification adjustment for (gains) losses included in net income	6,229	(38,961)
Tax effect	(222,375)	(803,921)
Net of tax	358,390	1,295,638
Unrealized losses on securities transferred to held to maturity:
Reclassification adjustment for losses included in net income	41,720	41,720
Tax effect	(15,975)	(15,975)
Net of tax	25,745	25,745
Unrealized gains (losses) on cash flow hedges:
Unrealized holding losses arising during the period	(747)	(1,502,087)
Reclassification adjustment for losses included in net income	154,131	86,080
Tax effect	286	575,149
Net of tax	153,670	(840,858)
Other comprehensive income	537,805	480,525
Comprehensive income	$ 869,863	$ 2,064,371

Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($)	Total	Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning balance at Dec. 31, 2015	$ 108,586,107	$ 1,609,756	$ 8,577,051	$ 95,277,969	$ 8,035,711	$ (4,914,380)
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			$ 99,851	(99,851)
Issuance of restricted common stock, net of forfeitures and withholdings to satisfy employee tax obligations, shares			99,851
Stock-based compensation expense	195,787			195,787
Excess tax benefit from stock compensation	2,539			2,539
Exercise of common stock warrants	10,000		$ 1,000	9,000
Exercise of common stock warrants, shares			1,000
Net income	1,583,846				1,583,846
Other comprehensive income	480,525					480,525
Ending balance at Mar. 31, 2016	110,858,804	1,609,756	$ 8,677,902	95,385,444	9,619,557	(4,433,855)
Ending balance, shares at Mar. 31, 2016			8,677,902
Beginning balance at Dec. 31, 2016	139,207,396	878,049	$ 11,204,515	116,142,894	17,132,489	(6,150,551)
Beginning balance, shares at Dec. 31, 2016			11,204,515
Issuance of restricted common stock, net of forfeitures and withholdings to satisfy employee tax obligations	(188,914)		$ (2,054)	(186,860)
Issuance of restricted common stock, net of forfeitures and withholdings to satisfy employee tax obligations, shares			(2,054)
Stock-based compensation expense	235,597			235,597
Exercise of employee common stock options	$ 22,480		$ 9,367	13,113
Exercise of employee common stock options, shares	20,000		9,367
Exercise of common stock warrants	$ 65,000		$ 6,500	58,500
Exercise of common stock warrants, shares			6,500
Net income	332,058				332,058
Other comprehensive income	537,805					537,805
Ending balance at Mar. 31, 2017	$ 140,211,422	$ 878,049	$ 11,218,328	$ 116,263,244	$ 17,464,547	$ (5,612,746)
Ending balance, shares at Mar. 31, 2017			11,218,328

Consolidated Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net income	$ 332,058	$ 1,583,846
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan and lease losses	3,404,799	937,216
Accretion of discounts on acquired loans and deferred fees	(159,331)	(440,249)
Depreciation and amortization	107,376	113,113
Net amortization of premiums on investment securities	358,327	286,011
Securities (gains) losses, net	6,229	(38,961)
Mortgage banking income	(1,216,362)	(1,347,452)
Net loss on disposal of premises and equipment	137,493
Net (gain) loss on sale of other real estate owned		(72,669)
Stock-based compensation	235,597	195,787
Excess tax benefit from stock compensation		(2,539)
Deferred income tax expense	(743,536)	33,697
Origination of loans held for sale	(93,162,136)	(85,107,642)
Proceeds from loans held for sale	101,118,265	92,654,273
Net increase in accrued interest receivable and other assets	(1,331,081)	(1,226,422)
Net increase in accrued interest payable and other liabilities	(2,120,362)	(1,449,958)
Net cash provided by operating activities	6,967,336	6,118,051
Activities in securities available for sale:
Purchases	(11,754,186)	(37,585,142)
Sales	644,983	18,750,334
Maturities, prepayments and calls	5,185,819	4,281,887
Activities in securities held to maturity:
Maturities, prepayments and calls	29,335	162,709
Purchase of restricted equity securities	(512,550)	(4,550)
Net increase in loans	(69,065,337)	(29,624,468)
Purchase of premises and equipment	(742,375)
Proceeds from the sale of premises and equipment	3,293
Proceeds from sale of other real estate		288,923
Net cash used in investing activities	(76,211,018)	(43,730,307)
Cash flows from financing activities:
Net increase in deposits	29,272,936	47,876,455
Proceeds from Federal Home Loan Bank advances	20,000,000
Payments on Federal Home Loan Bank advances		(30,000,000)
Exercise of common stock options and warrants, net of repurchase of restricted shares	(101,434)	10,000
Excess tax benefit from stock compensation		2,539
Net decrease in repurchase agreements		(3,755,000)
Net cash provided by financing activities	49,171,502	14,133,994
Net decrease in cash and cash equivalents	(20,072,180)	(23,478,262)
Cash and cash equivalents at beginning of period	80,110,806	100,184,841
Cash and cash equivalents at end of period	60,038,626	76,706,579
Supplemental disclosures of cash paid:
Interest paid	2,023,056	1,620,198
Income taxes		807,369
Supplemental disclosures of noncash transactions:
Loans charged off to the allowance for loan and lease losses	$ 1,124,350	$ 773,736

Summary of Significant Accounting Policies	3 Months Ended
Summary of Significant Accounting Policies	Mar. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	NOTE 1 – SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation The accompanying unaudited consolidated financial statements as of and for the period ended March 31, 2017 include CapStar Financial Holdings, Inc. and its 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 accompanying unaudited consolidated financial statements have been prepared in accordance with instructions to Form 10-Q and do not include all information and footnotes required by U.S. generally accepted accounting principles (“U.S. GAAP”) for complete financial statements. All adjustments consisting of normally recurring accruals that, in the opinion of management, are necessary for a fair presentation of the financial position and results of operations for the periods presented have been included. These unaudited consolidated financial statements should be read in conjunction with the Company’s consolidated financial statements and related notes appearing in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016. Initial Public Offering On September 21, 2016, the Securities and Exchange Commission (“SEC”) declared effective our registration statement on Form S-1 registering the 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 preferred shares converted to common shares and 79,166 from the cashless exercise of 250,000 common share warrants. We received net proceeds of approximately $21.9 million from the offering, after deducting the underwriting discounts and commissions and estimated offering expenses. We did not receive any proceeds from the sale of shares by the selling shareholders. 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 and lease losses, determination of impairment of intangible assets, including goodwill, the valuation of our investment portfolio, deferred tax assets and estimated liabilities. There have been no significant changes to the Company’s critical accounting policies as disclosed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016. 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 March 31, 2017 through the date of the issued financial statements.

Securities

3 Months Ended

Mar. 31, 2017

Investments Debt And Equity Securities [Abstract]

Securities

NOTE 2 – SECURITIES

The amortized cost and fair value of securities available-for-sale and held-to-maturity at March 31, 2017 and December 31, 2016 are summarized as follows (in thousands):

	March 31, 2017									December 31, 2016
	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	$	11,531	$	—	$	(217	)	$	11,314	$	9,517	$	—	$	(143	)	$	9,374
State and municipal securities		27,781		101		(542	)		27,340		28,480		65		(632	)		27,913
Mortgage-backed securities		131,232		3		(2,097	)		129,138		126,637		17		(2,059	)		124,595
Asset-backed securities		21,291		—		(567	)		20,724		21,620		—		(1,147	)		20,473
Total	$	191,835	$	104	$	(3,423	)	$	188,516	$	186,254	$	82	$	(3,981	)	$	182,355
Securities held to maturity:
State and municipal securities	$	36,865	$	2,818	$	—		$	39,683	$	36,842	$	2,784	$	—		$	39,626
Mortgage-backed securities		4,657		63		—			4,720		4,687		79		—			4,766
Other debt securities		5,333		33		—			5,366		5,335		11		(7	)		5,339
Total	$	46,855	$	2,914	$	—		$	49,769	$	46,864	$	2,874	$	(7	)	$	49,731

Security fair values are established by an independent pricing service as of the dates indicated. The difference between amortized cost and fair value reflects current interest rates and represents the potential gain (loss) had the portfolio been liquidated on those dates. Security gains (losses) are realized only in the event of dispositions prior to maturity or other-than-temporary impairment. Securities with unrealized losses as of March 31, 2017 and December 31, 2016, and the length of time they were in continuous loss positions as of such dates are as follows (in thousands):

	Less than 12 months					12 months or more					Total
March 31, 2017	Estimated fair value		Gross unrealized losses			Estimated fair value		Gross unrealized losses			Estimated fair value		Gross unrealized losses
U. S. government agency securities	$	9,297	$	(217	)	$	—	$	—		$	9,297	$	(217	)
State and municipal securities		15,691		(542	)		—		—			15,691		(542	)
Mortgage-backed securities		114,688		(1,949	)		8,720		(148	)		123,408		(2,097	)
Asset-backed securities		—		—			20,724		(567	)		20,724		(567	)
Total temporarily impaired securities	$	139,676	$	(2,708	)	$	29,444	$	(715	)	$	169,120	$	(3,423	)
December 31, 2016
U. S. government agency securities	$	9,374	$	(143	)	$	—	$	—		$	9,374	$	(143	)
State and municipal securities		20,279		(632	)		—		—			20,279		(632	)
Mortgage-backed securities		110,563		(1,955	)		4,150		(104	)		114,713		(2,059	)
Asset-backed securities		—		—			20,473		(1,147	)		20,473		(1,147	)
Other debt securities		2,029		(7	)		—		—			2,029		(7	)
Total temporarily impaired securities	$	142,245	$	(2,737	)	$	24,623	$	(1,251	)	$	166,868	$	(3,988	)

As noted in the table above, as of March 31, 2017, the Company had unrealized losses of $3.4 million in its investment securities portfolio. The unrealized losses associated with these investment securities are driven by changes in interest rates and are recorded as a component of equity. These investment securities will continue to be monitored as a part of our ongoing impairment analysis. Management evaluates the financial performance of the issuers on a quarterly basis to determine if it is probable that the issuers can make all contractual principal and interest payments. If a shortfall in future cash flows is identified, a credit loss will be deemed to have occurred and will be recognized as a charge to earnings and a new cost basis for the security will be established.

Because the Company currently does not intend to sell any investment securities that have an unrealized loss at March 31, 2017, and it is not more-likely-than-not that we will be required to sell these investment securities before recovery of their amortized cost bases, which may be at maturity, we do not consider these securities to be other-than-temporarily impaired at March 31, 2017.

Securities with a carrying value of $120.2 million at March 31, 2017 were pledged to collateralize public deposits, derivative positions and Federal Home Loan Bank advances.

The proceeds from sales and calls of securities and the associated gains and losses are listed below:

	Three Months Ended			Three Months Ended
	March 31, 2017			March 31, 2016
Proceeds	$	5,860		$	23,195
Gross gains		—			85
Gross losses		(6	)		(46	)

The amortized cost and fair value of securities at March 31, 2017, 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 one to five years	$	13,294	$	13,304	$	22,204	$	23,436
Due five to ten years		20,526		20,220		14,562		15,548
Due beyond ten years		5,492		5,130		5,432		6,065
Mortgage-backed securities		131,232		129,138		4,657		4,720
Asset-backed securities		21,291		20,724		—		—
	$	191,835	$	188,516	$	46,855	$	49,769

- Definition

The entire disclosure for investments in certain debt and equity securities.

+ References + Details

Loans and Allowance for Loan and Lease Losses

3 Months Ended

Mar. 31, 2017

Receivables [Abstract]

Loans and Allowance for Loan and Lease Losses

NOTE 3 – LOANS AND ALLOWANCE FOR LOAN AND LEASE LOSSES

A summary of the loan portfolio as of March 31, 2017 and December 31, 2016 follows (in thousands):

	March 31, 2017			December 31, 2016
Commercial real estate	$	360,955		$	302,322
Consumer real estate		99,952			97,015
Construction and land development		74,007			94,491
Commercial and industrial		420,825			379,620
Consumer		4,495			5,974
Other		43,984			56,796
Total		1,004,218			936,218
Less net unearned income		(784	)		(967	)
		1,003,434			935,251
Allowance for loan and lease losses		(13,997	)		(11,634	)
	$	989,437		$	923,617

The adequacy of the allowance for loan and lease losses (ALLL) is assessed at the end of each quarter. The ALLL includes a specific component related to loans that are individually evaluated for impairment and a general component related to loans that are segregated into homogenous pools and collectively evaluated for impairment. The ALLL factors applied to these pools are an estimate of probable incurred losses based on management’s evaluation of historical net losses from loans with similar characteristics, which are adjusted by management to reflect current events, trends, and conditions. The adjustments 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.

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 tables present the loan balances by category as well as risk rating (in thousands):

	Performing Loans
March 31, 2017	Pass/Watch		Special Mention		Substandard		Total Performing		Total Impaired Loans		Total
Commercial real estate	$	359,668	$	—	$	—	$	359,668	$	1,287	$	360,955
Consumer real estate		99,661		—		291		99,952		—		99,952
Construction and land development		74,007		—		—		74,007		—		74,007
Commercial and industrial		385,188		16,288		7,012		408,488		12,337		420,825
Consumer		4,480		—		15		4,495		—		4,495
Other		43,984		—		—		43,984		—		43,984
Total	$	966,988	$	16,288	$	7,318	$	990,594	$	13,624	$	1,004,218
December 31, 2016
Commercial real estate	$	301,012	$	—	$	—	$	301,012	$	1,310	$	302,322
Consumer real estate		96,722		—		293		97,015		—		97,015
Construction and land development		94,491		—		—		94,491		—		94,491
Commercial and industrial		349,857		11,035		16,419		377,311		2,309		379,620
Consumer		5,958		—		16		5,974		—		5,974
Other		56,796		—		—		56,796		—		56,796
Total	$	904,836	$	11,035	$	16,728	$	932,599	$	3,619	$	936,218

None of the Company’s loans had a risk rating of “Doubtful” as of March 31, 2017 or December 31, 2016.

The following table details the changes in the ALLL for the three months ended March 31, 2017 and 2016 (in thousands):

	Commercial real estate			Consumer real estate			Construction and land development			Commercial and industrial			Consumer			Other			Total
Three Months Ended March 31, 2017
Balance, beginning of year	$	2,655		$	1,013		$	1,574		$	5,618		$	76		$	698		$	11,634
Charged-off loans		—			—			—			(1,124	)		—			—			(1,124	)
Recoveries		—			—			—			2			80			—			82
Provision for loan and lease losses		602			35			(484	)		3,517			(96	)		(169	)		3,405
Balance, end of period	$	3,257		$	1,048		$	1,090		$	8,013		$	60		$	529		$	13,997

Three Months Ended March 31, 2016
Balance, beginning of year	$	2,879		$	968		$	914		$	4,693		$	103		$	575		$	10,132
Charged-off loans		(350	)		—			—			(300	)		(124	)		—			(774	)
Recoveries		—			—			—			4			—			—			4
Provision for loan and lease losses		441			(5	)		(115	)		527			134			(45	)		937
Balance, end of period	$	2,970		$	963		$	799		$	4,924		$	113		$	530		$	10,299

A breakdown of the ALLL and the loan portfolio by loan category at March 31, 2017 and December 31, 2016 follows (in thousands):

	Commercial real estate		Consumer real estate		Construction and land development		Commercial and industrial		Consumer		Other		Total
March 31, 2017
Allowance for Loan and Lease Losses:
Collectively evaluated for impairment	$	3,257	$	1,048	$	1,090	$	5,401	$	60	$	529	$	11,385
Individually evaluated for impairment		—		—		—		2,612		—		—		2,612
Balances, end of period	$	3,257	$	1,048	$	1,090	$	8,013	$	60	$	529	$	13,997
Loans:
Collectively evaluated for impairment	$	359,668	$	99,952	$	74,007	$	408,488	$	4,495	$	43,984	$	990,594
Individually evaluated for impairment		1,287		—		—		12,337		—		—		13,624
Balances, end of period	$	360,955	$	99,952	$	74,007	$	420,825	$	4,495	$	43,984	$	1,004,218

December 31, 2016
Allowance for Loan and Lease Losses:
Collectively evaluated for impairment	$	2,655	$	1,013	$	1,574	$	3,006	$	76	$	698	$	9,022
Individually evaluated for impairment		—		—		—		2,612		—		—		2,612
Balances, end of period	$	2,655	$	1,013	$	1,574	$	5,618	$	76	$	698	$	11,634
Loans:
Collectively evaluated for impairment	$	301,012	$	97,015	$	94,491	$	377,311	$	5,974	$	56,796	$	932,599
Individually evaluated for impairment		1,310		—		—		2,309		—		—		3,619
Balances, end of period	$	302,322	$	97,015	$	94,491	$	379,620	$	5,974	$	56,796	$	936,218

The following table presents the allocation of the ALLL for each respective loan category with the corresponding percentage of the ALLL in each category to total loans, net of deferred fees as of March 31, 2017 and December 31, 2016 (dollars in thousands):

	March 31, 2017					December 31, 2016
	Amount		Percent of total loans, net of deferred fees			Amount		Percent of total loans, net of deferred fees
Commercial real estate	$	3,257		0.32	%	$	2,655		0.28	%
Consumer real estate		1,048		0.10			1,013		0.11
Construction and land development		1,090		0.11			1,574		0.17
Commercial and industrial		8,013		0.80			5,618		0.60
Consumer		60		0.01			76		0.01
Other		529		0.05			698		0.07
Total allowance for loan and lease losses	$	13,997		1.39	%	$	11,634		1.24	%

The following table presents the Company’s impaired loans that were evaluated for specific loss allowance as of March 31, 2017 and December 31, 2016 (in thousands):


	March 31, 2017						December 31, 2016
	Recorded investment		Unpaid principal balance		Related allowance		Recorded investment		Unpaid principal balance		Related allowance
With no related allowance recorded:
Commercial real estate	$	1,287	$	1,682	$	—	$	1,310	$	1,686	$	—
Consumer real estate		—		—		—		—		—		—
Construction and land development		—		—		—		—		—		—
Commercial and industrial		—		—		—		—		—		—
Consumer		—		—		—		—		—		—
Other		—		—		—		—		—		—
Subtotal		1,287		1,682		—		1,310		1,686		—
With an allowance recorded:
Commercial real estate		—		—		—		—		—		—
Consumer real estate		—		—		—		—		—		—
Construction and land development		—		—		—		—		—		—
Commercial and industrial		12,337		14,237		2,612		2,309		2,921		500
Consumer		—		—		—		—		—		—
Other		—		—		—		—		—		—
Subtotal		12,337		14,237		2,612		2,309		2,921		500
Total	$	13,624	$	15,919	$	2,612	$	3,619	$	4,607	$	500

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

	Three Months Ended				Three Months Ended
	March 31, 2017				March 31, 2016
	Average recorded investment		Interest income recognized		Average recorded investment		Interest income recognized
With no related allowance recorded:
Commercial real estate	$	1,299	$	—	$	—	$	—
Consumer real estate		—		—		240		—
Construction and land development		—		—		—		—
Commercial and industrial		—		—		3,596		—
Consumer		—		—		—		—
Other		—		—		—		—
Subtotal		1,299		—		3,836		—
With an allowance recorded:
Commercial real estate		—		—		1,944		—
Consumer real estate		—		—		—		—
Construction and land development		—		—		—		—
Commercial and industrial		13,106		—		—		—
Consumer		—		—		—		—
Other		—		—		—		—
Subtotal		13,106		—		1,944		—
Total	$	14,405	$	—	$	5,780	$	—

There was no interest income recognized on a cash basis for impaired loans for the three months ended March 31, 2017 or 2016.

The following table presents the aging of the recorded investment in past-due loans as of March 31, 2017 and December 31, 2016 by class of loans (in thousands):

	30 - 59		60 - 89		Greater Than
	Days		Days		89 Days		Total		Loans Not
March 31, 2017	Past Due		Past Due		Past Due		Past Due		Past Due		Total
Commercial real estate	$	—	$	—	$	—	$	—	$	360,955	$	360,955
Consumer real estate		143		—		—		143		99,809		99,952
Construction and land development		—		—		—		—		74,007		74,007
Commercial and industrial		8,948		—		—		8,948		411,877		420,825
Consumer		—		—		—		—		4,495		4,495
Other		90		—		—		90		43,894		43,984
Total	$	9,181	$	—	$	—	$	9,181	$	995,037	$	1,004,218
December 31, 2016
Commercial real estate	$	—	$	—	$	—	$	—	$	302,322	$	302,322
Consumer real estate		81		282		—		363		96,652		97,015
Construction and land development		—		—		—		—		94,491		94,491
Commercial and industrial		—		—		—		—		379,620		379,620
Consumer		—		—		—		—		5,974		5,974
Other		—		—		—		—		56,796		56,796
Total	$	81	$	282	$	—	$	363	$	935,855	$	936,218

The Company had no loans past due 90 days or more that were not on nonaccrual status as of March 31, 2017 and December 31, 2016.

The following table presents the recorded investment in non-accrual loans and troubled debt restructurings (“TDR”) by class of loans as of March 31, 2017 and December 31, 2016 (in thousands):

	Non-Accrual				Troubled Debt Restructurings
	March 31, 2017		December 31, 2016		March 31, 2017		December 31, 2016
Commercial real estate	$	1,287	$	1,310	$	1,256	$	1,272
Consumer real estate		—		—		—		—
Construction and land development		—		—		—		—
Commercial and industrial		12,337		2,309		—		—
Consumer		—		—		—		—
Other		—		—		—		—
Total	$	13,624	$	3,619	$	1,256	$	1,272

As of March 31, 2017 and December 31, 2016, all loans classified as nonperforming were deemed to be impaired.

As of March 31, 2017 and December 31, 2016, the Company had a recorded investment in TDR of $1.3 million and $1.3 million, respectively. The Company had no specific allowance for those loans at March 31, 2017 or December 31, 2016 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 Bank’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 three months ended March 31, 2016 (in thousands). There were no TDR identified during the three months ended March 31, 2017.

	Three Months Ended
	March 31,
	Number of contracts		Pre modification outstanding recorded investment		Post modification outstanding recorded investment, net of related allowance
2016
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 three months ended March 31, 2016 (in thousands). There were no TDR for which there was a payment default within twelve months following the modification during the three months ended March 31, 2017.

	Three Months Ended
	March 31,
	Number of contracts		Recorded investment
2016
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 three months ended March 31, 2016 had no specific reserve in the allowance for loan and lease losses 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.

- 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

Federal Home Loan Bank Advances

3 Months Ended

Mar. 31, 2017

Federal Home Loan Banks [Abstract]

Federal Home Loan Bank Advances

NOTE 4 – FEDERAL HOME LOAN BANK ADVANCES

The Company had outstanding borrowings totaling of $75.0 million and $55.0 million at March 31, 2017 and December 31, 2016, respectively, via two separate 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):

	March 31, 2017					December 31, 2016
Year	Amount		Interest Rates			Amount		Interest Rates
2017	$	75,000		0.96	%	$	55,000		0.80	%
2018		—		—			—		—
2019		—		—			—		—
2020		—		—			—		—
2021		—		—			—		—
Thereafter		—		—			—		—
Total	$	75,000		0.96	%	$	55,000		0.80	%

Advances from the FHLB are collateralized by investment securities, FHLB stock and certain commercial and residential real estate mortgage loans totaling $400.2 million under a blanket mortgage collateral agreement. At March 31, 2017, the amount of available credit from the FHLB totaled $91.2 million.

Accumulated Other Comprehensive Income (Loss)

3 Months Ended

Mar. 31, 2017

Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]

Accumulated Other Comprehensive Income (Loss)

NOTE 5 – ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)

The following were changes in accumulated other comprehensive income (loss) by component, net of tax, for the periods ended March 31, 2017 and 2016 (in thousands):

				Unrealized Gains			Unrealized
	Gains and			and Losses			Losses on
	Losses on			on Available			Securities
	Cash Flow			for Sale			Transferred to
Three Months Ended March 31, 2017	Hedges			Securities			Held to Maturity			Total
Beginning Balance	$	(4,241	)	$	(698	)	$	(1,212	)	$	(6,151	)
Other comprehensive income (loss) before reclassification		—			354			—			354
Amounts reclassified from accumulated other comprehensive income (loss)		154			4			26			184
Net current period other comprehensive income (loss)		154			358			26			538
Ending Balance	$	(4,087	)	$	(340	)	$	(1,186	)	$	(5,613	)

Three Months Ended March 31, 2016
Beginning Balance	$	(3,705	)	$	105		$	(1,315	)	$	(4,915	)
Other comprehensive income (loss) before reclassification		(927	)		1,320			—			393
Amounts reclassified from accumulated other comprehensive income (loss)		86			(24	)		26			88
Net current period other comprehensive income (loss)		(841	)		1,296			26			481
Ending Balance	$	(4,546	)	$	1,401		$	(1,289	)	$	(4,434	)

The following were significant amounts reclassified out of each component of accumulated other comprehensive income (loss) for the three months ended March 31, 2017 (in thousands):

	Amount Reclassified from			Affected Line Item
Details about Accumulated Other	Accumulated Other			in the Statement Where
Comprehensive Income Components	Comprehensive Income			Net Income is Presented
Unrealized losses on cash flow hedges	$	105		Interest expense - money market
		49		Interest expense - Federal Home Loan Bank advances
	$	154		Net of tax
Unrealized gains and losses on available for sale securities	$	6		Net loss on sale of securities
		(2	)	Income tax expense (benefit)
	$	4		Net of tax
Unrealized losses on securities transferred to held to maturity	$	42		Interest income - securities
		(16	)	Income tax expense (benefit)
	$	26		Net of tax

The following were significant amounts reclassified out of each component of accumulated other comprehensive income (loss) for the three months ended March 31, 2016 (in thousands):

	Amount Reclassified from			Affected Line Item
Details about Accumulated Other	Accumulated Other			in the Statement Where
Comprehensive Income Components	Comprehensive Income			Net Income is Presented
Unrealized losses on cash flow hedges	$	37		Interest expense - money market
		49		Interest expense - Federal Home Loan Bank Advances
	$	86		Net of tax
Unrealized gains and losses on available for sale securities	$	(39	)	Net gain on sale of securities
		15		Income tax expense (benefit)
	$	(24	)	Net of tax
Unrealized losses on securities transferred to held to maturity	$	42		Interest income - securities
		(16	)	Income tax expense (benefit)
	$	26		Net of tax

- Definition

The entire disclosure for comprehensive income, which includes, but is not limited to, 1) the amount of income tax expense or benefit allocated to each component of other comprehensive income, including reclassification adjustments, 2) the reclassification adjustments for each classification of other comprehensive income and 3) the ending accumulated balances for each component of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e689-108580

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=66004124&loc=SL7669619-108580

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e640-108580

Reference 4: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 17
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Reference 5: http://www.xbrl.org/2003/role/presentationRef
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-Topic 220
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-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e709-108580

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
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-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e637-108580

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
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-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e681-108580

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Reclassification Adjustments
-URI http://asc.fasb.org/extlink&oid=6522872

+ Details

Income Taxes	3 Months Ended
Income Taxes	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 6 – INCOME TAXES The Company’s effective tax rate for the three months ended March 31, 2017 was -16.6% compared to 33.5% for the three months ended March 31, 2016. In March 2016, the FASB issued guidance to simplify several aspects of the accounting for share-based payment award transactions, including income tax consequences. In addition to other changes, the guidance changes the accounting for excess tax benefits and tax deficiencies from generally being recognized in additional paid-in capital to recognition as income tax expense or benefit in the period they occur. The Company adopted the new guidance in the first quarter of 2017. As a result, the Company’s income tax expense was reduced by $145,000 for the period ended March 31, 2017. The effective tax rate compared favorably to the statutory federal rate of 34% and Tennessee excise tax rate of 6.5% primarily due to investments in qualified municipal securities, company owned life insurance, state tax credits, net of the effect of certain non-deductible expenses and the recognition of excess tax benefits related to stock compensation.

Commitments and Contingencies

3 Months Ended

Mar. 31, 2017

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

NOTE 7 – 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 March 31, 2017 and December 31, 2016 (in thousands):

	Contract or notional amount
	March 31, 2017		December 31, 2016
Financial instruments whose contract amounts represent credit risk:
Unused commitments to extend credit	$	542,542	$	508,990
Standby letters of credit		11,401		10,886
Total	$	553,943	$	519,876

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 March 31, 2017, will not have a material impact on the financial statements of the Company.

Derivatives

3 Months Ended

Mar. 31, 2017

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Derivatives

NOTE 8 – DERIVATIVES

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 and $20 million as of March 31, 2017 and December 31, 2016, respectively, 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):

	March 31, 2017			December 31, 2016
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	6.2 years			6.5 years
Fair value	$	(1,535	)	$	(1,535	)
Amount of unrealized loss recognized in accumulated other comprehensive income, net of tax	$	(947	)	$	(947	)

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 $2.3 million at March 31, 2017. There was no collateral posted from the counterparties to the Company as of March 31, 2017. 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 was as follows (in thousands):

	March 31, 2017					December 31, 2016
	Notional		Estimated			Notional		Estimated
	amount		fair value			amount		fair value
Interest rate swap agreements:
Pay fixed/receive variable swaps	$	41,703	$	214		$	41,254	$	460
Pay variable/receive fixed swaps		41,703		(214	)		41,254		(460	)
Total	$	83,406	$	—		$	82,508	$	—

- Definition

The entire disclosure for derivative instruments and hedging activities including, but not limited to, risk management strategies, non-hedging derivative instruments, assets, liabilities, revenue and expenses, and methodologies and assumptions used in determining the amounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6441202&loc=d3e80720-113993

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

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-Name Accounting Standards Codification
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-Name Accounting Standards Codification
-Topic 815
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-Name Accounting Standards Codification
-Topic 815
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 815
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-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80784-113994

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-Name Accounting Standards Codification
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-Name Accounting Standards Codification
-Topic 815
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-Publisher FASB
-Name Accounting Standards Codification
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+ Details

Stock Options and Restricted Shares

3 Months Ended

Mar. 31, 2017

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock Options and Restricted Shares

NOTE 9 - STOCK OPTIONS AND RESTRICTED SHARES

During 2008, the board of directors of the Bank approved the CapStar Bank 2008 Stock Incentive Plan (the Plan). The Plan was intended to provide incentives to certain officers, employees, and directors to stimulate their efforts toward the continued success of the Bank and to operate and manage the business in a manner that will provide for the long‑term growth and profitability of the Bank. Additionally the Plan was intended to encourage stock ownership to align the interests of employees and shareholders and to provide a means of obtaining, rewarding and retaining officers, employees, and directors.

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 CapStar Financial Holdings, Inc. Stock Incentive Plan, which the board of directors adopted in 2016. The Stock Incentive 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 reserved 1,569,475 shares of stock for issuance of stock incentives. Stock incentives include both restricted share and stock option grants. Total shares issuable under the plan were 199,891 at March 31, 2017.

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):

	Three Months Ended
	March 31,
	2017			2016
Stock-based compensation expense before income taxes	$	236		$	196
Less: deferred tax benefit		(90	)		(75	)
Reduction of net income	$	146		$	121

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 fair value of each restricted stock grant is based on valuations performed by independent consultants. 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 the three months ended March 31, 2017 follows:

				Weighted
				Average
	Restricted			Grant Date
Nonvested Shares	Shares			Fair Value
Nonvested at beginning of period		199,641		$	12.34
Granted		7,333			19.85
Vested		(43,002	)		12.24
Forfeited		(1,500	)		13.22
Nonvested at end of period		162,472		$	12.70

As of March 31, 2017, there was $1.4 million of unrecognized compensation cost related to nonvested shares granted under the Plan. The cost is expected to be recognized over a weighted-average period of 1.9 years. The total fair value of shares vested during the three months ended March 31, 2017 and 2016 was $0.5 million and $0.2 million.

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. The Company’s expected dividend yield is 0.00% because the Company has not paid dividends in the past. 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. There were no options granted in 2017.

The fair value of options granted was determined using the following weighted average assumptions as of the grant date:

	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 the three months ended March 31, 2017 follows:

						Weighted
				Weighted		Average
				Average		Remaining
				Exercise		Contractual
	Shares			Price		Term (years)
Outstanding at beginning of period		1,006,000		$	10.48
Granted		—			—
Exercised		(20,000	)		10.00
Forfeited or expired		—			—
Outstanding at end of period		986,000		$	10.49		2.9
Fully vested and expected to vest		978,308		$	10.47		2.9
Exercisable at end of period		931,000		$	10.39		2.6

Information related to stock options during each year follows:

	2017		2016
Intrinsic value of options exercised	$	193,800	$	53,756
Cash received from option exercises		200,000		96,306
Tax benefit realized from option exercises		74,206		20,583
Weighted average fair value of options granted		—		3.16

As of March 31, 2017, there was $0.1 million of 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 2.3 years.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References + Details

Regulatory Capital Requirements

3 Months Ended

Mar. 31, 2017

Banking And Thrift [Abstract]

Regulatory Capital Requirements

NOTE 10 – REGULATORY CAPITAL REQUIREMENTS

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 Banking Supervision’s capital guidelines for U.S. banks (Basel III rules) became effective for the Bank 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 March 31, 2017, the Company and the Bank met all regulatory capital adequacy requirements to which they are subject.

The Company’s and the Bank’s capital amounts and ratios as of March 31, 2017 and December 31, 2016 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 March 31, 2017:
Total capital to risk-weighted assets:
CapStar Financial Holdings, Inc.	$	152,445		12.1	%	$	100,502		8.0	%	N/A		N/A
CapStar Bank		129,571		10.3			100,483		8.0		$	125,604		10.0
Tier I capital to risk-weighted assets:
CapStar Financial Holdings, Inc.		138,375		11.0			75,377		6.0		N/A		N/A
CapStar Bank		115,501		9.2			75,362		6.0			100,483		8.0
Common equity Tier 1 capital to risk weighted assets:
CapStar Financial Holdings, Inc.		129,685		10.3			56,533		4.5		N/A		N/A
CapStar Bank		99,311		7.9			56,522		4.5			81,643		6.5
Tier I capital to average assets:
CapStar Financial Holdings, Inc.		138,375		10.4			53,396		4.0		N/A		N/A
CapStar Bank		115,501		8.7			53,394		4.0			66,742		5.0
At December 31, 2016:
Total capital to risk-weighted assets:
CapStar Financial Holdings, Inc.	$	149,616		12.6	%	$	95,028		8.0	%	N/A		N/A
CapStar Bank		126,718		10.7			95,028		8.0		$	118,785		10.0
Tier I capital to risk-weighted assets:
CapStar Financial Holdings, Inc.		137,909		11.6			71,271		6.0		N/A		N/A
CapStar Bank		115,011		9.7			71,271		6.0			95,028		8.0
Common equity Tier 1 capital to risk weighted assets:
CapStar Financial Holdings, Inc.		129,528		10.9			53,453		4.5		N/A		N/A
CapStar Bank		99,130		8.3			53,453		4.5			77,210		6.5
Tier I capital to average assets:
CapStar Financial Holdings, Inc.		137,909		10.5			52,727		4.0		N/A		N/A
CapStar Bank		115,011		8.7			52,727		4.0			65,909		5.0

(1)

For the calendar year 2017, the Company must maintain a capital conservation buffer of Tier 1 common equity capital in excess of minimum risk-based capital ratios by at least 1.25% 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.

- 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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1G
-URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958577-112826

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
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-Section 50
-Paragraph 1C
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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Reference 6: http://www.xbrl.org/2003/role/presentationRef
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-URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958570-112826

Reference 7: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
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Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1D
-URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958573-112826

+ Details

Earnings Per Share

3 Months Ended

Mar. 31, 2017

Earnings Per Share [Abstract]

Earnings Per Share

NOTE 11 – EARNINGS PER SHARE

The following is a summary of the basic and diluted earnings per share calculation for the three months ended March 31, 2017 and 2016:

	Three Months Ended
	March 31,
	2017		2016
Basic net income per share calculation:
Numerator – Net income	$	332,058	$	1,583,846
Denominator – Average common shares outstanding		11,210,948		8,628,683
Basic net income per share	$	0.03	$	0.18
Diluted net income per share calculation:
Numerator – Net income	$	332,058	$	1,583,846
Denominator – Average common shares outstanding		11,210,948		8,628,683
Dilutive shares contingently issuable		1,573,169		1,943,510
Average diluted common shares outstanding		12,784,117		10,572,193
Diluted net income per share	$	0.03	$	0.15

Fair Value

3 Months Ended

Mar. 31, 2017

Fair Value Disclosures [Abstract]

Fair Value

NOTE 12 – 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 Bank 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 Bank’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 and lease 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 at March 31, 2017 or December 31, 2016.

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 March 31, 2017 or December 31, 2016.

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

	Fair value measurements at March 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	$	11,314		$	—	$	11,314		$	—
Obligations of states and political subdivisions		27,340			—		27,340			—
Mortgage-backed securities-residential		129,138			—		129,138			—
Asset-backed securities		20,724			—		20,724			—
Total securities available for sale	$	188,516		$	—	$	188,516		$	—
Derivatives:
Interest rate swaps - customer related	$	328		$	—	$	328		$	—
Liabilities:
Derivatives:
Interest rate swaps - customer related	$	(328	)	$	—	$	(328	)	$	—
Interest rate swaps - cash flow hedges		(1,535	)		—		(1,535	)		—
Total derivatives	$	(1,863	)	$	—	$	(1,863	)	$	—

	Fair value measurements at December 31, 2016
				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	$	9,374		$	—	$	9,374		$	—
Obligations of states and political subdivisions		27,913			—		27,913			—
Mortgage-backed securities-residential		124,595			—		124,595			—
Asset-backed securities		20,473			—		20,473			—
Total securities available for sale	$	182,355		$	—	$	182,355		$	—
Derivatives:
Interest rate swaps - customer related	$	460		$	—	$	460		$	—
Liabilities:
Derivatives:
Interest rate swaps - customer related	$	(460	)	$	—	$	(460	)	$	—
Interest rate swaps - cash flow hedges		(1,535	)		—		(1,535	)		—
Total derivatives	$	(1,995	)	$	—	$	(1,995	)	$	—

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

Fair value measurements at March 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

9,725

—

9,725

Fair value measurements at December 31, 2016

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

1,809

—

1,809

The following table presents quantitative information about Level 3 fair value measurements for assets measured at fair value on a non-recurring basis at March 31, 2017 and December 31, 2016 (dollars in thousands):

					Range
	Fair		Valuation		(Weighted-
March 31, 2017	Value		Technique(s)	Unobservable Input(s)	Average)
Impaired loans:
Commercial and industrial	$	9,725	Sales comparison approach	Appraisal discounts	10 - 25%

Range

Fair

Valuation

(Weighted-

December 31, 2016

Value

Technique(s)

Unobservable Input(s)

Average)

Impaired loans:

Commercial and industrial

1,809

Sales comparison approach

Appraisal discounts

Fair Value of Financial Instruments

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

	March 31, 2017				December 31, 2016
	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	$	58,629	$	58,629	$	63,456	$	63,456	Level 1
Federal funds sold		1,410		1,410		16,654		16,654	Level 1
Securities available for sale		188,516		188,516		182,355		182,355	Level 2
Securities held to maturity		46,855		49,769		46,864		49,731	Level 2
Loans held for sale		35,371		35,410		42,111		42,302	Level 2
Restricted equity securities		6,544	N/A			6,032	N/A		N/A
Loans, net		1,003,434		1,002,131		935,251		934,628	Level 3
Accrued interest receivable		4,012		4,012		3,942		3,942	Level 2
Bank owned life insurance		22,044		22,044		21,900		21,900	Level 2
Other assets		328		328		460		460	Level 2
Financial liabilities:
Deposits		1,157,995		1,116,924		1,128,722		1,088,758	Level 3
Federal Home Loan Bank advances		75,000		74,993		55,000		54,989	Level 2
Accrued interest payable		236		236		212		212	Level 2
Other liabilities		3,789		3,789		5,349		5,349	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

The fair value of the Bank’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 Bank’s loan portfolio is initially fair valued using a segmented approach. The Bank 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.

(e)	Bank Owned Life Insurance

For bank owned life insurance, the carrying amount is based on the cash surrender value and is a reasonable estimate of fair value.

(f)	Other Assets

Included in other assets are 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.

(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)	Accrued Interest Receivable/Payable

The carrying amounts of accrued interest approximate fair value.

(j)	Other Liabilities

Included in other liabilities are 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.

(k)	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.

(l)	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 Bank’s entire holdings of a particular instrument. Because no market exists for a significant portion of the Bank’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

Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited consolidated financial statements as of and for the period ended March 31, 2017 include CapStar Financial Holdings, Inc. and its 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 accompanying unaudited consolidated financial statements have been prepared in accordance with instructions to Form 10-Q and do not include all information and footnotes required by U.S. generally accepted accounting principles (“U.S. GAAP”) for complete financial statements. All adjustments consisting of normally recurring accruals that, in the opinion of management, are necessary for a fair presentation of the financial position and results of operations for the periods presented have been included. These unaudited consolidated financial statements should be read in conjunction with the Company’s consolidated financial statements and related notes appearing in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016.
Initial Public Offering	Initial Public Offering On September 21, 2016, the Securities and Exchange Commission (“SEC”) declared effective our registration statement on Form S-1 registering the 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 preferred shares converted to common shares and 79,166 from the cashless exercise of 250,000 common share warrants. We received net proceeds of approximately $21.9 million from the offering, after deducting the underwriting discounts and commissions and estimated offering expenses. We did not receive any proceeds from the sale of shares by the selling shareholders.
Use of Estimates	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 and lease losses, determination of impairment of intangible assets, including goodwill, the valuation of our investment portfolio, deferred tax assets and estimated liabilities. There have been no significant changes to the Company’s critical accounting policies as disclosed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016.
Subsequent Events	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 March 31, 2017 through the date of the issued financial statements.

Securities (Tables)

3 Months Ended

Mar. 31, 2017

Investments Debt And Equity Securities [Abstract]

Summary of Amortized Cost and Fair Value of Available-for-sale and Held-to-maturity Securities

The amortized cost and fair value of securities available-for-sale and held-to-maturity at March 31, 2017 and December 31, 2016 are summarized as follows (in thousands):

	March 31, 2017									December 31, 2016
	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	$	11,531	$	—	$	(217	)	$	11,314	$	9,517	$	—	$	(143	)	$	9,374
State and municipal securities		27,781		101		(542	)		27,340		28,480		65		(632	)		27,913
Mortgage-backed securities		131,232		3		(2,097	)		129,138		126,637		17		(2,059	)		124,595
Asset-backed securities		21,291		—		(567	)		20,724		21,620		—		(1,147	)		20,473
Total	$	191,835	$	104	$	(3,423	)	$	188,516	$	186,254	$	82	$	(3,981	)	$	182,355
Securities held to maturity:
State and municipal securities	$	36,865	$	2,818	$	—		$	39,683	$	36,842	$	2,784	$	—		$	39,626
Mortgage-backed securities		4,657		63		—			4,720		4,687		79		—			4,766
Other debt securities		5,333		33		—			5,366		5,335		11		(7	)		5,339
Total	$	46,855	$	2,914	$	—		$	49,769	$	46,864	$	2,874	$	(7	)	$	49,731

Summary of Securities with Unrealized Losses and Length of Time Continuous Loss Positions

	Less than 12 months					12 months or more					Total
March 31, 2017	Estimated fair value		Gross unrealized losses			Estimated fair value		Gross unrealized losses			Estimated fair value		Gross unrealized losses
U. S. government agency securities	$	9,297	$	(217	)	$	—	$	—		$	9,297	$	(217	)
State and municipal securities		15,691		(542	)		—		—			15,691		(542	)
Mortgage-backed securities		114,688		(1,949	)		8,720		(148	)		123,408		(2,097	)
Asset-backed securities		—		—			20,724		(567	)		20,724		(567	)
Total temporarily impaired securities	$	139,676	$	(2,708	)	$	29,444	$	(715	)	$	169,120	$	(3,423	)
December 31, 2016
U. S. government agency securities	$	9,374	$	(143	)	$	—	$	—		$	9,374	$	(143	)
State and municipal securities		20,279		(632	)		—		—			20,279		(632	)
Mortgage-backed securities		110,563		(1,955	)		4,150		(104	)		114,713		(2,059	)
Asset-backed securities		—		—			20,473		(1,147	)		20,473		(1,147	)
Other debt securities		2,029		(7	)		—		—			2,029		(7	)
Total temporarily impaired securities	$	142,245	$	(2,737	)	$	24,623	$	(1,251	)	$	166,868	$	(3,988	)

Summary of Proceeds from Sales and Calls of Securities and Associated Gains and Losses

The proceeds from sales and calls of securities and the associated gains and losses are listed below:

	Three Months Ended			Three Months Ended
	March 31, 2017			March 31, 2016
Proceeds	$	5,860		$	23,195
Gross gains		—			85
Gross losses		(6	)		(46	)

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 one to five years	$	13,294	$	13,304	$	22,204	$	23,436
Due five to ten years		20,526		20,220		14,562		15,548
Due beyond ten years		5,492		5,130		5,432		6,065
Mortgage-backed securities		131,232		129,138		4,657		4,720
Asset-backed securities		21,291		20,724		—		—
	$	191,835	$	188,516	$	46,855	$	49,769

- Definition

Tabular disclosure of available-for-sale securities which includes, but is not limited to, changes in the cost basis and fair value, fair value and gross unrealized gain (loss), fair values by type of security, contractual maturity and classification, amortized cost basis, contracts to acquire securities to be accounted for as available-for-sale, debt maturities, transfers to trading, change in net unrealized holding gain (loss) net of tax, continuous unrealized loss position fair value, aggregate losses qualitative disclosures, other than temporary impairment (OTTI) losses or other disclosures related to available for sale securities.

+ References + Details

Loans and Allowance for Loan and Lease Losses (Tables)

3 Months Ended

Mar. 31, 2017

Receivables [Abstract]

Summary of Loan Portfolio

A summary of the loan portfolio as of March 31, 2017 and December 31, 2016 follows (in thousands):

	March 31, 2017			December 31, 2016
Commercial real estate	$	360,955		$	302,322
Consumer real estate		99,952			97,015
Construction and land development		74,007			94,491
Commercial and industrial		420,825			379,620
Consumer		4,495			5,974
Other		43,984			56,796
Total		1,004,218			936,218
Less net unearned income		(784	)		(967	)
		1,003,434			935,251
Allowance for loan and lease losses		(13,997	)		(11,634	)
	$	989,437		$	923,617

Summary of Loans by Risk Rating

The following tables present the loan balances by category as well as risk rating (in thousands):

	Performing Loans
March 31, 2017	Pass/Watch		Special Mention		Substandard		Total Performing		Total Impaired Loans		Total
Commercial real estate	$	359,668	$	—	$	—	$	359,668	$	1,287	$	360,955
Consumer real estate		99,661		—		291		99,952		—		99,952
Construction and land development		74,007		—		—		74,007		—		74,007
Commercial and industrial		385,188		16,288		7,012		408,488		12,337		420,825
Consumer		4,480		—		15		4,495		—		4,495
Other		43,984		—		—		43,984		—		43,984
Total	$	966,988	$	16,288	$	7,318	$	990,594	$	13,624	$	1,004,218
December 31, 2016
Commercial real estate	$	301,012	$	—	$	—	$	301,012	$	1,310	$	302,322
Consumer real estate		96,722		—		293		97,015		—		97,015
Construction and land development		94,491		—		—		94,491		—		94,491
Commercial and industrial		349,857		11,035		16,419		377,311		2,309		379,620
Consumer		5,958		—		16		5,974		—		5,974
Other		56,796		—		—		56,796		—		56,796
Total	$	904,836	$	11,035	$	16,728	$	932,599	$	3,619	$	936,218

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

The following table details the changes in the ALLL for the three months ended March 31, 2017 and 2016 (in thousands):

	Commercial real estate			Consumer real estate			Construction and land development			Commercial and industrial			Consumer			Other			Total
Three Months Ended March 31, 2017
Balance, beginning of year	$	2,655		$	1,013		$	1,574		$	5,618		$	76		$	698		$	11,634
Charged-off loans		—			—			—			(1,124	)		—			—			(1,124	)
Recoveries		—			—			—			2			80			—			82
Provision for loan and lease losses		602			35			(484	)		3,517			(96	)		(169	)		3,405
Balance, end of period	$	3,257		$	1,048		$	1,090		$	8,013		$	60		$	529		$	13,997

Three Months Ended March 31, 2016
Balance, beginning of year	$	2,879		$	968		$	914		$	4,693		$	103		$	575		$	10,132
Charged-off loans		(350	)		—			—			(300	)		(124	)		—			(774	)
Recoveries		—			—			—			4			—			—			4
Provision for loan and lease losses		441			(5	)		(115	)		527			134			(45	)		937
Balance, end of period	$	2,970		$	963		$	799		$	4,924		$	113		$	530		$	10,299

A breakdown of the ALLL and the loan portfolio by loan category at March 31, 2017 and December 31, 2016 follows (in thousands):

	Commercial real estate		Consumer real estate		Construction and land development		Commercial and industrial		Consumer		Other		Total
March 31, 2017
Allowance for Loan and Lease Losses:
Collectively evaluated for impairment	$	3,257	$	1,048	$	1,090	$	5,401	$	60	$	529	$	11,385
Individually evaluated for impairment		—		—		—		2,612		—		—		2,612
Balances, end of period	$	3,257	$	1,048	$	1,090	$	8,013	$	60	$	529	$	13,997
Loans:
Collectively evaluated for impairment	$	359,668	$	99,952	$	74,007	$	408,488	$	4,495	$	43,984	$	990,594
Individually evaluated for impairment		1,287		—		—		12,337		—		—		13,624
Balances, end of period	$	360,955	$	99,952	$	74,007	$	420,825	$	4,495	$	43,984	$	1,004,218

December 31, 2016
Allowance for Loan and Lease Losses:
Collectively evaluated for impairment	$	2,655	$	1,013	$	1,574	$	3,006	$	76	$	698	$	9,022
Individually evaluated for impairment		—		—		—		2,612		—		—		2,612
Balances, end of period	$	2,655	$	1,013	$	1,574	$	5,618	$	76	$	698	$	11,634
Loans:
Collectively evaluated for impairment	$	301,012	$	97,015	$	94,491	$	377,311	$	5,974	$	56,796	$	932,599
Individually evaluated for impairment		1,310		—		—		2,309		—		—		3,619
Balances, end of period	$	302,322	$	97,015	$	94,491	$	379,620	$	5,974	$	56,796	$	936,218

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

	March 31, 2017					December 31, 2016
	Amount		Percent of total loans, net of deferred fees			Amount		Percent of total loans, net of deferred fees
Commercial real estate	$	3,257		0.32	%	$	2,655		0.28	%
Consumer real estate		1,048		0.10			1,013		0.11
Construction and land development		1,090		0.11			1,574		0.17
Commercial and industrial		8,013		0.80			5,618		0.60
Consumer		60		0.01			76		0.01
Other		529		0.05			698		0.07
Total allowance for loan and lease losses	$	13,997		1.39	%	$	11,634		1.24	%

Summary of Impaired Loans

The following table presents the Company’s impaired loans that were evaluated for specific loss allowance as of March 31, 2017 and December 31, 2016 (in thousands):


	March 31, 2017						December 31, 2016
	Recorded investment		Unpaid principal balance		Related allowance		Recorded investment		Unpaid principal balance		Related allowance
With no related allowance recorded:
Commercial real estate	$	1,287	$	1,682	$	—	$	1,310	$	1,686	$	—
Consumer real estate		—		—		—		—		—		—
Construction and land development		—		—		—		—		—		—
Commercial and industrial		—		—		—		—		—		—
Consumer		—		—		—		—		—		—
Other		—		—		—		—		—		—
Subtotal		1,287		1,682		—		1,310		1,686		—
With an allowance recorded:
Commercial real estate		—		—		—		—		—		—
Consumer real estate		—		—		—		—		—		—
Construction and land development		—		—		—		—		—		—
Commercial and industrial		12,337		14,237		2,612		2,309		2,921		500
Consumer		—		—		—		—		—		—
Other		—		—		—		—		—		—
Subtotal		12,337		14,237		2,612		2,309		2,921		500
Total	$	13,624	$	15,919	$	2,612	$	3,619	$	4,607	$	500

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

	Three Months Ended				Three Months Ended
	March 31, 2017				March 31, 2016
	Average recorded investment		Interest income recognized		Average recorded investment		Interest income recognized
With no related allowance recorded:
Commercial real estate	$	1,299	$	—	$	—	$	—
Consumer real estate		—		—		240		—
Construction and land development		—		—		—		—
Commercial and industrial		—		—		3,596		—
Consumer		—		—		—		—
Other		—		—		—		—
Subtotal		1,299		—		3,836		—
With an allowance recorded:
Commercial real estate		—		—		1,944		—
Consumer real estate		—		—		—		—
Construction and land development		—		—		—		—
Commercial and industrial		13,106		—		—		—
Consumer		—		—		—		—
Other		—		—		—		—
Subtotal		13,106		—		1,944		—
Total	$	14,405	$	—	$	5,780	$	—

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 March 31, 2017 and December 31, 2016 by class of loans (in thousands):

	30 - 59		60 - 89		Greater Than
	Days		Days		89 Days		Total		Loans Not
March 31, 2017	Past Due		Past Due		Past Due		Past Due		Past Due		Total
Commercial real estate	$	—	$	—	$	—	$	—	$	360,955	$	360,955
Consumer real estate		143		—		—		143		99,809		99,952
Construction and land development		—		—		—		—		74,007		74,007
Commercial and industrial		8,948		—		—		8,948		411,877		420,825
Consumer		—		—		—		—		4,495		4,495
Other		90		—		—		90		43,894		43,984
Total	$	9,181	$	—	$	—	$	9,181	$	995,037	$	1,004,218
December 31, 2016
Commercial real estate	$	—	$	—	$	—	$	—	$	302,322	$	302,322
Consumer real estate		81		282		—		363		96,652		97,015
Construction and land development		—		—		—		—		94,491		94,491
Commercial and industrial		—		—		—		—		379,620		379,620
Consumer		—		—		—		—		5,974		5,974
Other		—		—		—		—		56,796		56,796
Total	$	81	$	282	$	—	$	363	$	935,855	$	936,218

Schedule of Recorded In Non Accrual Loans and Troubled Debt Restructurings

The following table presents the recorded investment in non-accrual loans and troubled debt restructurings (“TDR”) by class of loans as of March 31, 2017 and December 31, 2016 (in thousands):

	Non-Accrual				Troubled Debt Restructurings
	March 31, 2017		December 31, 2016		March 31, 2017		December 31, 2016
Commercial real estate	$	1,287	$	1,310	$	1,256	$	1,272
Consumer real estate		—		—		—		—
Construction and land development		—		—		—		—
Commercial and industrial		12,337		2,309		—		—
Consumer		—		—		—		—
Other		—		—		—		—
Total	$	13,624	$	3,619	$	1,256	$	1,272

Schedule of Presents Loans by Class Modified as TDR

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

	Three Months Ended
	March 31,
	Number of contracts		Pre modification outstanding recorded investment		Post modification outstanding recorded investment, net of related allowance
2016
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

	Three Months Ended
	March 31,
	Number of contracts		Recorded investment
2016
Commercial real estate		—	$	—
Consumer real estate		—		—
Construction and land development		—		—
Commercial and industrial		—		—
Consumer		1		124
Other		—		—
Total		1	$	124

Federal Home Loan Bank Advances (Tables)

3 Months Ended

Mar. 31, 2017

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):

	March 31, 2017					December 31, 2016
Year	Amount		Interest Rates			Amount		Interest Rates
2017	$	75,000		0.96	%	$	55,000		0.80	%
2018		—		—			—		—
2019		—		—			—		—
2020		—		—			—		—
2021		—		—			—		—
Thereafter		—		—			—		—
Total	$	75,000		0.96	%	$	55,000		0.80	%

Accumulated Other Comprehensive Income (Loss) (Tables)

3 Months Ended

Mar. 31, 2017

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 periods ended March 31, 2017 and 2016 (in thousands):

				Unrealized Gains			Unrealized
	Gains and			and Losses			Losses on
	Losses on			on Available			Securities
	Cash Flow			for Sale			Transferred to
Three Months Ended March 31, 2017	Hedges			Securities			Held to Maturity			Total
Beginning Balance	$	(4,241	)	$	(698	)	$	(1,212	)	$	(6,151	)
Other comprehensive income (loss) before reclassification		—			354			—			354
Amounts reclassified from accumulated other comprehensive income (loss)		154			4			26			184
Net current period other comprehensive income (loss)		154			358			26			538
Ending Balance	$	(4,087	)	$	(340	)	$	(1,186	)	$	(5,613	)

Three Months Ended March 31, 2016
Beginning Balance	$	(3,705	)	$	105		$	(1,315	)	$	(4,915	)
Other comprehensive income (loss) before reclassification		(927	)		1,320			—			393
Amounts reclassified from accumulated other comprehensive income (loss)		86			(24	)		26			88
Net current period other comprehensive income (loss)		(841	)		1,296			26			481
Ending Balance	$	(4,546	)	$	1,401		$	(1,289	)	$	(4,434	)

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 three months ended March 31, 2017 (in thousands):

	Amount Reclassified from			Affected Line Item
Details about Accumulated Other	Accumulated Other			in the Statement Where
Comprehensive Income Components	Comprehensive Income			Net Income is Presented
Unrealized losses on cash flow hedges	$	105		Interest expense - money market
		49		Interest expense - Federal Home Loan Bank advances
	$	154		Net of tax
Unrealized gains and losses on available for sale securities	$	6		Net loss on sale of securities
		(2	)	Income tax expense (benefit)
	$	4		Net of tax
Unrealized losses on securities transferred to held to maturity	$	42		Interest income - securities
		(16	)	Income tax expense (benefit)
	$	26		Net of tax

The following were significant amounts reclassified out of each component of accumulated other comprehensive income (loss) for the three months ended March 31, 2016 (in thousands):

	Amount Reclassified from			Affected Line Item
Details about Accumulated Other	Accumulated Other			in the Statement Where
Comprehensive Income Components	Comprehensive Income			Net Income is Presented
Unrealized losses on cash flow hedges	$	37		Interest expense - money market
		49		Interest expense - Federal Home Loan Bank Advances
	$	86		Net of tax
Unrealized gains and losses on available for sale securities	$	(39	)	Net gain on sale of securities
		15		Income tax expense (benefit)
	$	(24	)	Net of tax
Unrealized losses on securities transferred to held to maturity	$	42		Interest income - securities
		(16	)	Income tax expense (benefit)
	$	26		Net of tax

Commitments and Contingencies (Tables)

3 Months Ended

Mar. 31, 2017

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 March 31, 2017 and December 31, 2016 (in thousands):

	Contract or notional amount
	March 31, 2017		December 31, 2016
Financial instruments whose contract amounts represent credit risk:
Unused commitments to extend credit	$	542,542	$	508,990
Standby letters of credit		11,401		10,886
Total	$	553,943	$	519,876

- 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

Derivatives (Tables)

3 Months Ended

Mar. 31, 2017

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):

	March 31, 2017			December 31, 2016
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	6.2 years			6.5 years
Fair value	$	(1,535	)	$	(1,535	)
Amount of unrealized loss recognized in accumulated other comprehensive income, net of tax	$	(947	)	$	(947	)

Summary of Customer Related Interest Rate Swaps

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

	March 31, 2017					December 31, 2016
	Notional		Estimated			Notional		Estimated
	amount		fair value			amount		fair value
Interest rate swap agreements:
Pay fixed/receive variable swaps	$	41,703	$	214		$	41,254	$	460
Pay variable/receive fixed swaps		41,703		(214	)		41,254		(460	)
Total	$	83,406	$	—		$	82,508	$	—

Stock Options and Restricted Shares (Tables)

3 Months Ended

Mar. 31, 2017

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Company Recognized Stock-Based Compensation Expense

	Three Months Ended
	March 31,
	2017			2016
Stock-based compensation expense before income taxes	$	236		$	196
Less: deferred tax benefit		(90	)		(75	)
Reduction of net income	$	146		$	121

Summary of Changes in Company's Nonvested Restricted Shares

A summary of the changes in the Company’s nonvested restricted shares for the three months ended March 31, 2017 follows:

				Weighted
				Average
	Restricted			Grant Date
Nonvested Shares	Shares			Fair Value
Nonvested at beginning of period		199,641		$	12.34
Granted		7,333			19.85
Vested		(43,002	)		12.24
Forfeited		(1,500	)		13.22
Nonvested at end of period		162,472		$	12.70

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:

	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 the three months ended March 31, 2017 follows:

						Weighted
				Weighted		Average
				Average		Remaining
				Exercise		Contractual
	Shares			Price		Term (years)
Outstanding at beginning of period		1,006,000		$	10.48
Granted		—			—
Exercised		(20,000	)		10.00
Forfeited or expired		—			—
Outstanding at end of period		986,000		$	10.49		2.9
Fully vested and expected to vest		978,308		$	10.47		2.9
Exercisable at end of period		931,000		$	10.39		2.6

Information Related to Stock Options

Information related to stock options during each year follows:

	2017		2016
Intrinsic value of options exercised	$	193,800	$	53,756
Cash received from option exercises		200,000		96,306
Tax benefit realized from option exercises		74,206		20,583
Weighted average fair value of options granted		—		3.16

Regulatory Capital Requirements (Tables)

3 Months Ended

Mar. 31, 2017

Banking And Thrift [Abstract]

Schedule of Capital Amounts and Ratios

The Company’s and the Bank’s capital amounts and ratios as of March 31, 2017 and December 31, 2016 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 March 31, 2017:
Total capital to risk-weighted assets:
CapStar Financial Holdings, Inc.	$	152,445		12.1	%	$	100,502		8.0	%	N/A		N/A
CapStar Bank		129,571		10.3			100,483		8.0		$	125,604		10.0
Tier I capital to risk-weighted assets:
CapStar Financial Holdings, Inc.		138,375		11.0			75,377		6.0		N/A		N/A
CapStar Bank		115,501		9.2			75,362		6.0			100,483		8.0
Common equity Tier 1 capital to risk weighted assets:
CapStar Financial Holdings, Inc.		129,685		10.3			56,533		4.5		N/A		N/A
CapStar Bank		99,311		7.9			56,522		4.5			81,643		6.5
Tier I capital to average assets:
CapStar Financial Holdings, Inc.		138,375		10.4			53,396		4.0		N/A		N/A
CapStar Bank		115,501		8.7			53,394		4.0			66,742		5.0
At December 31, 2016:
Total capital to risk-weighted assets:
CapStar Financial Holdings, Inc.	$	149,616		12.6	%	$	95,028		8.0	%	N/A		N/A
CapStar Bank		126,718		10.7			95,028		8.0		$	118,785		10.0
Tier I capital to risk-weighted assets:
CapStar Financial Holdings, Inc.		137,909		11.6			71,271		6.0		N/A		N/A
CapStar Bank		115,011		9.7			71,271		6.0			95,028		8.0
Common equity Tier 1 capital to risk weighted assets:
CapStar Financial Holdings, Inc.		129,528		10.9			53,453		4.5		N/A		N/A
CapStar Bank		99,130		8.3			53,453		4.5			77,210		6.5
Tier I capital to average assets:
CapStar Financial Holdings, Inc.		137,909		10.5			52,727		4.0		N/A		N/A
CapStar Bank		115,011		8.7			52,727		4.0			65,909		5.0

(1)

(2)

Earnings Per Share (Tables)

3 Months Ended

Mar. 31, 2017

Earnings Per Share [Abstract]

Summary of Basic and Diluted Earnings Per Share

The following is a summary of the basic and diluted earnings per share calculation for the three months ended March 31, 2017 and 2016:

	Three Months Ended
	March 31,
	2017		2016
Basic net income per share calculation:
Numerator – Net income	$	332,058	$	1,583,846
Denominator – Average common shares outstanding		11,210,948		8,628,683
Basic net income per share	$	0.03	$	0.18
Diluted net income per share calculation:
Numerator – Net income	$	332,058	$	1,583,846
Denominator – Average common shares outstanding		11,210,948		8,628,683
Dilutive shares contingently issuable		1,573,169		1,943,510
Average diluted common shares outstanding		12,784,117		10,572,193
Diluted net income per share	$	0.03	$	0.15

Fair Value (Tables)

3 Months Ended

Mar. 31, 2017

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 March 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	$	11,314		$	—	$	11,314		$	—
Obligations of states and political subdivisions		27,340			—		27,340			—
Mortgage-backed securities-residential		129,138			—		129,138			—
Asset-backed securities		20,724			—		20,724			—
Total securities available for sale	$	188,516		$	—	$	188,516		$	—
Derivatives:
Interest rate swaps - customer related	$	328		$	—	$	328		$	—
Liabilities:
Derivatives:
Interest rate swaps - customer related	$	(328	)	$	—	$	(328	)	$	—
Interest rate swaps - cash flow hedges		(1,535	)		—		(1,535	)		—
Total derivatives	$	(1,863	)	$	—	$	(1,863	)	$	—

	Fair value measurements at December 31, 2016
				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	$	9,374		$	—	$	9,374		$	—
Obligations of states and political subdivisions		27,913			—		27,913			—
Mortgage-backed securities-residential		124,595			—		124,595			—
Asset-backed securities		20,473			—		20,473			—
Total securities available for sale	$	182,355		$	—	$	182,355		$	—
Derivatives:
Interest rate swaps - customer related	$	460		$	—	$	460		$	—
Liabilities:
Derivatives:
Interest rate swaps - customer related	$	(460	)	$	—	$	(460	)	$	—
Interest rate swaps - cash flow hedges		(1,535	)		—		(1,535	)		—
Total derivatives	$	(1,995	)	$	—	$	(1,995	)	$	—

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):

Fair value measurements at March 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

9,725

—

9,725

Fair value measurements at December 31, 2016

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

1,809

—

1,809

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

					Range
	Fair		Valuation		(Weighted-
March 31, 2017	Value		Technique(s)	Unobservable Input(s)	Average)
Impaired loans:
Commercial and industrial	$	9,725	Sales comparison approach	Appraisal discounts	10 - 25%

Range

Fair

Valuation

(Weighted-

December 31, 2016

Value

Technique(s)

Unobservable Input(s)

Average)

Impaired loans:

Commercial and industrial

1,809

Sales comparison approach

Appraisal discounts

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

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

	March 31, 2017				December 31, 2016
	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	$	58,629	$	58,629	$	63,456	$	63,456	Level 1
Federal funds sold		1,410		1,410		16,654		16,654	Level 1
Securities available for sale		188,516		188,516		182,355		182,355	Level 2
Securities held to maturity		46,855		49,769		46,864		49,731	Level 2
Loans held for sale		35,371		35,410		42,111		42,302	Level 2
Restricted equity securities		6,544	N/A			6,032	N/A		N/A
Loans, net		1,003,434		1,002,131		935,251		934,628	Level 3
Accrued interest receivable		4,012		4,012		3,942		3,942	Level 2
Bank owned life insurance		22,044		22,044		21,900		21,900	Level 2
Other assets		328		328		460		460	Level 2
Financial liabilities:
Deposits		1,157,995		1,116,924		1,128,722		1,088,758	Level 3
Federal Home Loan Bank advances		75,000		74,993		55,000		54,989	Level 2
Accrued interest payable		236		236		212		212	Level 2
Other liabilities		3,789		3,789		5,349		5,349	Level 3

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)		3 Months Ended
	Sep. 27, 2016	Mar. 31, 2017	Mar. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Date of acquisition		Feb. 05, 2016
Common Stock
Summary Of Significant Accounting Policies [Line Items]
Exercise of common stock warrants, shares		6,500	1,000
Initial Public Offering \| Common Stock
Summary Of Significant Accounting Policies [Line Items]
Issuance of common stock	2,972,750
Net proceeds from issuance	$ 21,900,000
Initial Public Offering by the Company \| Common Stock
Summary Of Significant Accounting Policies [Line Items]
Issuance of common stock	1,688,049
Initial Public Offering by certain selling shareholders \| Common Stock
Summary Of Significant Accounting Policies [Line Items]
Issuance of common stock	1,284,701
Preferred shares converted to common stock	731,707
Cashless exercise	79,166
Exercise of common stock warrants, shares	250,000
Net proceeds from issuance	$ 0

Securities - Summary of Fair Value of Available for Sale Held to Maturity (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Securities available for sale [Abstract]
Amortized Cost	$ 191,835,000	$ 186,254,000
Gross unrealized gains	104,000	82,000
Gross unrealized (losses)	(3,423,000)	(3,981,000)
Securities available for sale, at fair value	188,516,087	182,354,987
Securities held to maturity [Abstract]
Amortized Cost	46,855,000	46,864,000
Gross unrealized gains	2,914,000	2,874,000
Gross unrealized (losses)		(7,000)
Estimated fair value	49,769,285	49,731,169
U. S. government agency securities
Securities available for sale [Abstract]
Amortized Cost	11,531,000	9,517,000
Gross unrealized (losses)	(217,000)	(143,000)
Securities available for sale, at fair value	11,314,000	9,374,000
State and municipal securities
Securities available for sale [Abstract]
Amortized Cost	27,781,000	28,480,000
Gross unrealized gains	101,000	65,000
Gross unrealized (losses)	(542,000)	(632,000)
Securities available for sale, at fair value	27,340,000	27,913,000
Securities held to maturity [Abstract]
Amortized Cost	36,865,000	36,842,000
Gross unrealized gains	2,818,000	2,784,000
Estimated fair value	39,683,000	39,626,000
Mortgage-backed securities
Securities available for sale [Abstract]
Amortized Cost	131,232,000	126,637,000
Gross unrealized gains	3,000	17,000
Gross unrealized (losses)	(2,097,000)	(2,059,000)
Securities available for sale, at fair value	129,138,000	124,595,000
Securities held to maturity [Abstract]
Amortized Cost	4,657,000	4,687,000
Gross unrealized gains	63,000	79,000
Estimated fair value	4,720,000	4,766,000
Asset-backed securities
Securities available for sale [Abstract]
Amortized Cost	21,291,000	21,620,000
Gross unrealized (losses)	(567,000)	(1,147,000)
Securities available for sale, at fair value	20,724,000	20,473,000
Other debt securities
Securities held to maturity [Abstract]
Amortized Cost	5,333,000	5,335,000
Gross unrealized gains	33,000	11,000
Gross unrealized (losses)		(7,000)
Estimated fair value	$ 5,366,000	$ 5,339,000

Securities - Summary of Securities with Unrealized Losses and Length of Time Continuous Loss Positions (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Available-for-sale securities, continuous unrealized loss position [Abstract]
Less than 12 months, Estimated fair value	$ 139,676	$ 142,245
Less than 12 months, Gross unrealized (losses)	(2,708)	(2,737)
12 months or more, Estimated fair value	29,444	24,623
12 months or more, Gross unrealized losses	(715)	(1,251)
Total, Estimated fair value	169,120	166,868
Total, Gross unrealized losses	(3,423)	(3,988)
U. S. government agency securities
Available-for-sale securities, continuous unrealized loss position [Abstract]
Less than 12 months, Estimated fair value	9,297	9,374
Less than 12 months, Gross unrealized (losses)	(217)	(143)
Total, Estimated fair value	9,297	9,374
Total, Gross unrealized losses	(217)	(143)
State and municipal securities
Available-for-sale securities, continuous unrealized loss position [Abstract]
Less than 12 months, Estimated fair value	15,691	20,279
Less than 12 months, Gross unrealized (losses)	(542)	(632)
Total, Estimated fair value	15,691	20,279
Total, Gross unrealized losses	(542)	(632)
Mortgage-backed securities
Available-for-sale securities, continuous unrealized loss position [Abstract]
Less than 12 months, Estimated fair value	114,688	110,563
Less than 12 months, Gross unrealized (losses)	(1,949)	(1,955)
12 months or more, Estimated fair value	8,720	4,150
12 months or more, Gross unrealized losses	(148)	(104)
Total, Estimated fair value	123,408	114,713
Total, Gross unrealized losses	(2,097)	(2,059)
Asset-backed securities
Available-for-sale securities, continuous unrealized loss position [Abstract]
12 months or more, Estimated fair value	20,724	20,473
12 months or more, Gross unrealized losses	(567)	(1,147)
Total, Estimated fair value	20,724	20,473
Total, Gross unrealized losses	$ (567)	(1,147)
Other debt securities
Available-for-sale securities, continuous unrealized loss position [Abstract]
Less than 12 months, Estimated fair value		2,029
Less than 12 months, Gross unrealized (losses)		(7)
Total, Estimated fair value		2,029
Total, Gross unrealized losses		$ (7)

Securities - Additional Information (Details) $ in Millions	3 Months Ended
Securities - Additional Information (Details) $ in Millions	Mar. 31, 2017 USD ($)
Schedule Of Available For Sale Securities [Line Items]
Unrealized losses in investment securities portfolio	$ 3.4
Public Deposits, Derivative Positions and Federal Home Loan Bank Advances
Schedule Of Available For Sale Securities [Line Items]
Carrying value of securities	$ 120.2

Securities - Summary of Proceeds from Sales and Calls of Securities and Associated Gains and Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Investments Debt And Equity Securities [Abstract]
Proceeds	$ 5,860	$ 23,195
Gross gains		85
Gross losses	$ (6)	$ (46)

Securities - Summary of Amortized Cost and Fair Value of Debt and Equity Securities by Contractual Maturity (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Available-for-sale, Amortized cost [Abstract]
Due one to five years	$ 13,294,000
Due five to ten years	20,526,000
Due beyond ten years	5,492,000
Mortgage-backed securities	131,232,000
Asset-backed securities	21,291,000
Amortized Cost	191,835,000	$ 186,254,000
Available-for-sale, Estimated fair value [Abstract]
Due one to five years	13,304,000
Due five to ten years	20,220,000
Due beyond ten years	5,130,000
Mortgage-backed securities	129,138,000
Asset-backed securities	20,724,000
Estimated fair value	188,516,087	182,354,987
Held-to-maturity, Amortized cost [Abstract]
Due one to five years	22,204,000
Due five to ten years	14,562,000
Due beyond ten years	5,432,000
Mortgage-backed securities	4,657,000
Amortized Cost	46,855,000	46,864,000
Securities held to maturity [Abstract]
Due one to five years	23,436,000
Due five to ten years	15,548,000
Due beyond ten years	6,065,000
Mortgage-backed securities	4,720,000
Estimated fair value	$ 49,769,285	$ 49,731,169

Loans and Allowance for Loan And Lease Losses - Summary of Loan Portfolio (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Loans And Leases Receivable Disclosure [Line Items]
Total loans	$ 1,004,218,000	$ 936,218,000
Less net unearned income	(784,000)	(967,000)
Loans and leases , net of unearned income	1,003,433,910	935,250,703
Less allowance for loan and lease losses	(13,996,869)	(11,633,531)	$ (10,299,000)	$ (10,132,000)
Loans and leases, net	989,437,041	923,617,172
Commercial real estate
Loans And Leases Receivable Disclosure [Line Items]
Total loans	360,955,000	302,322,000
Less allowance for loan and lease losses	(3,257,000)	(2,655,000)	(2,970,000)	(2,879,000)
Consumer real estate
Loans And Leases Receivable Disclosure [Line Items]
Total loans	99,952,000	97,015,000
Less allowance for loan and lease losses	(1,048,000)	(1,013,000)	(963,000)	(968,000)
Construction and land development
Loans And Leases Receivable Disclosure [Line Items]
Total loans	74,007,000	94,491,000
Less allowance for loan and lease losses	(1,090,000)	(1,574,000)	(799,000)	(914,000)
Commercial and industrial
Loans And Leases Receivable Disclosure [Line Items]
Total loans	420,825,000	379,620,000
Less allowance for loan and lease losses	(8,013,000)	(5,618,000)	(4,924,000)	(4,693,000)
Consumer
Loans And Leases Receivable Disclosure [Line Items]
Total loans	4,495,000	5,974,000
Less allowance for loan and lease losses	(60,000)	(76,000)	(113,000)	(103,000)
Other
Loans And Leases Receivable Disclosure [Line Items]
Total loans	43,984,000	56,796,000
Less allowance for loan and lease losses	$ (529,000)	$ (698,000)	$ (530,000)	$ (575,000)

Loans and Allowance for Loan And Lease Losses - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2017 USD ($) Contract	Mar. 31, 2016 USD ($) Contract	Dec. 31, 2016 USD ($)
Loans And Leases Receivable Disclosure [Line Items]
Minimum loan amount for loans analyzed by credit risk	$ 500,000
Total loans	1,004,218,000		$ 936,218,000
Interest income recognized on a cash basis for impaired loans	0	$ 0
Loans past due not on nonaccrual status	0		0
Investment in TDR	1,300,000		1,300,000
Specific allowance related to loans	2,612,000		500,000
Additional commitments related to TDR	$ 0		0
TDR identified during the period \| Contract	0	1
TDR, payment default within twelve months \| Contract	0	1
Loan period considered as payment default	30 days
Consumer
Loans And Leases Receivable Disclosure [Line Items]
Total loans	$ 4,495,000		5,974,000
TDR, payment default within twelve months \| Contract		1
Allowance for loan and lease losses, specific reserve		$ 0
Subsequent default TDR charge-off		$ 100,000
Troubled Debt Restructurings
Loans And Leases Receivable Disclosure [Line Items]
Specific allowance related to loans	0		0
Doubtful
Loans And Leases Receivable Disclosure [Line Items]
Total loans	$ 0		$ 0

Loans and Allowance for Loan And Lease Losses - Summary of Loan Balances by Category as well as Risk Rating (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 1,004,218	$ 936,218
Total Impaired Loans
Financing Receivable Recorded Investment [Line Items]
Total loans	13,624	3,619
Performing Loans
Financing Receivable Recorded Investment [Line Items]
Total loans	990,594	932,599
Performing Loans \| Pass/Watch
Financing Receivable Recorded Investment [Line Items]
Total loans	966,988	904,836
Performing Loans \| Special Mention
Financing Receivable Recorded Investment [Line Items]
Total loans	16,288	11,035
Performing Loans \| Substandard
Financing Receivable Recorded Investment [Line Items]
Total loans	7,318	16,728
Commercial real estate
Financing Receivable Recorded Investment [Line Items]
Total loans	360,955	302,322
Commercial real estate \| Total Impaired Loans
Financing Receivable Recorded Investment [Line Items]
Total loans	1,287	1,310
Commercial real estate \| Performing Loans
Financing Receivable Recorded Investment [Line Items]
Total loans	359,668	301,012
Commercial real estate \| Performing Loans \| Pass/Watch
Financing Receivable Recorded Investment [Line Items]
Total loans	359,668	301,012
Consumer real estate
Financing Receivable Recorded Investment [Line Items]
Total loans	99,952	97,015
Consumer real estate \| Performing Loans
Financing Receivable Recorded Investment [Line Items]
Total loans	99,952	97,015
Consumer real estate \| Performing Loans \| Pass/Watch
Financing Receivable Recorded Investment [Line Items]
Total loans	99,661	96,722
Consumer real estate \| Performing Loans \| Substandard
Financing Receivable Recorded Investment [Line Items]
Total loans	291	293
Construction and land development
Financing Receivable Recorded Investment [Line Items]
Total loans	74,007	94,491
Construction and land development \| Performing Loans
Financing Receivable Recorded Investment [Line Items]
Total loans	74,007	94,491
Construction and land development \| Performing Loans \| Pass/Watch
Financing Receivable Recorded Investment [Line Items]
Total loans	74,007	94,491
Commercial and industrial
Financing Receivable Recorded Investment [Line Items]
Total loans	420,825	379,620
Commercial and industrial \| Total Impaired Loans
Financing Receivable Recorded Investment [Line Items]
Total loans	12,337	2,309
Commercial and industrial \| Performing Loans
Financing Receivable Recorded Investment [Line Items]
Total loans	408,488	377,311
Commercial and industrial \| Performing Loans \| Pass/Watch
Financing Receivable Recorded Investment [Line Items]
Total loans	385,188	349,857
Commercial and industrial \| Performing Loans \| Special Mention
Financing Receivable Recorded Investment [Line Items]
Total loans	16,288	11,035
Commercial and industrial \| Performing Loans \| Substandard
Financing Receivable Recorded Investment [Line Items]
Total loans	7,012	16,419
Consumer
Financing Receivable Recorded Investment [Line Items]
Total loans	4,495	5,974
Consumer \| Performing Loans
Financing Receivable Recorded Investment [Line Items]
Total loans	4,495	5,974
Consumer \| Performing Loans \| Pass/Watch
Financing Receivable Recorded Investment [Line Items]
Total loans	4,480	5,958
Consumer \| Performing Loans \| Substandard
Financing Receivable Recorded Investment [Line Items]
Total loans	15	16
Other
Financing Receivable Recorded Investment [Line Items]
Total loans	43,984	56,796
Other \| Performing Loans
Financing Receivable Recorded Investment [Line Items]
Total loans	43,984	56,796
Other \| Performing Loans \| Pass/Watch
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 43,984	$ 56,796

Loans and Allowance for Loan and Lease Losses - Summary of Changes in Allowance for Loan and Lease Losses (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	$ 11,633,531	$ 10,132,000
Charged-off loans	(1,124,000)	(774,000)
Recoveries	82,000	4,000
Provision for loan and lease losses	3,404,799	937,216
Ending Balance	13,996,869	10,299,000
Commercial real estate
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	2,655,000	2,879,000
Charged-off loans		(350,000)
Provision for loan and lease losses	602,000	441,000
Ending Balance	3,257,000	2,970,000
Consumer real estate
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	1,013,000	968,000
Provision for loan and lease losses	35,000	(5,000)
Ending Balance	1,048,000	963,000
Construction and land development
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	1,574,000	914,000
Provision for loan and lease losses	(484,000)	(115,000)
Ending Balance	1,090,000	799,000
Commercial and industrial
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	5,618,000	4,693,000
Charged-off loans	(1,124,000)	(300,000)
Recoveries	2,000	4,000
Provision for loan and lease losses	3,517,000	527,000
Ending Balance	8,013,000	4,924,000
Consumer
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	76,000	103,000
Charged-off loans		(124,000)
Recoveries	80,000
Provision for loan and lease losses	(96,000)	134,000
Ending Balance	60,000	113,000
Other
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning Balance	698,000	575,000
Provision for loan and lease losses	(169,000)	(45,000)
Ending Balance	$ 529,000	$ 530,000

Loans and Allowance for Loan and Lease Losses - Summary of Breakdown of Allowance for Loan and Lease Losses and Loan Portfolio by Loan Category (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Allowance for Loan and Lease Losses:
Collectively evaluated for impairment	$ 11,385,000	$ 9,022,000
Individually evaluated for impairment	2,612,000	2,612,000
Allowance for Loan and Lease Losses, Ending Balance	13,996,869	11,633,531	$ 10,299,000	$ 10,132,000
Loans:
Collectively evaluated for impairment	990,594,000	932,599,000
Individually evaluated for impairment	13,624,000	3,619,000
Total	1,004,218,000	936,218,000
Commercial real estate
Allowance for Loan and Lease Losses:
Collectively evaluated for impairment	3,257,000	2,655,000
Individually evaluated for impairment	0
Allowance for Loan and Lease Losses, Ending Balance	3,257,000	2,655,000	2,970,000	2,879,000
Loans:
Collectively evaluated for impairment	359,668,000	301,012,000
Individually evaluated for impairment	1,287,000	1,310,000
Total	360,955,000	302,322,000
Consumer real estate
Allowance for Loan and Lease Losses:
Collectively evaluated for impairment	1,048,000	1,013,000
Individually evaluated for impairment	0
Allowance for Loan and Lease Losses, Ending Balance	1,048,000	1,013,000	963,000	968,000
Loans:
Collectively evaluated for impairment	99,952,000	97,015,000
Individually evaluated for impairment		0
Total	99,952,000	97,015,000
Construction and land development
Allowance for Loan and Lease Losses:
Collectively evaluated for impairment	1,090,000	1,574,000
Individually evaluated for impairment	0
Allowance for Loan and Lease Losses, Ending Balance	1,090,000	1,574,000	799,000	914,000
Loans:
Collectively evaluated for impairment	74,007,000	94,491,000
Individually evaluated for impairment		0
Total	74,007,000	94,491,000
Commercial and industrial
Allowance for Loan and Lease Losses:
Collectively evaluated for impairment	5,401,000	3,006,000
Individually evaluated for impairment	2,612,000	2,612,000
Allowance for Loan and Lease Losses, Ending Balance	8,013,000	5,618,000	4,924,000	4,693,000
Loans:
Collectively evaluated for impairment	408,488,000	377,311,000
Individually evaluated for impairment	12,337,000	2,309,000
Total	420,825,000	379,620,000
Consumer
Allowance for Loan and Lease Losses:
Collectively evaluated for impairment	60,000	76,000
Individually evaluated for impairment	0
Allowance for Loan and Lease Losses, Ending Balance	60,000	76,000	113,000	103,000
Loans:
Collectively evaluated for impairment	4,495,000	5,974,000
Individually evaluated for impairment		0
Total	4,495,000	5,974,000
Other
Allowance for Loan and Lease Losses:
Collectively evaluated for impairment	529,000	698,000
Individually evaluated for impairment	0
Allowance for Loan and Lease Losses, Ending Balance	529,000	698,000	$ 530,000	$ 575,000
Loans:
Collectively evaluated for impairment	43,984,000	56,796,000
Individually evaluated for impairment		0
Total	$ 43,984,000	$ 56,796,000

Loans and Allowance for Loan and Lease Losses - Allocation of ALLL with Corresponding Percentage of ALLL in Each Category to Total Loans, Net of Deferred Fee (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Loans And Leases Receivable Disclosure [Line Items]
Allowance for loan and lease losses, Amount	$ 13,996,869	$ 11,633,531	$ 10,299,000	$ 10,132,000
Allowance for loan and lease losses, Percentage of total loans, net of deferred fees	1.39%	1.24%
Commercial real estate
Loans And Leases Receivable Disclosure [Line Items]
Allowance for loan and lease losses, Amount	$ 3,257,000	$ 2,655,000	2,970,000	2,879,000
Allowance for loan and lease losses, Percentage of total loans, net of deferred fees	0.32%	0.28%
Consumer real estate
Loans And Leases Receivable Disclosure [Line Items]
Allowance for loan and lease losses, Amount	$ 1,048,000	$ 1,013,000	963,000	968,000
Allowance for loan and lease losses, Percentage of total loans, net of deferred fees	0.10%	0.11%
Construction and land development
Loans And Leases Receivable Disclosure [Line Items]
Allowance for loan and lease losses, Amount	$ 1,090,000	$ 1,574,000	799,000	914,000
Allowance for loan and lease losses, Percentage of total loans, net of deferred fees	0.11%	0.17%
Commercial and industrial
Loans And Leases Receivable Disclosure [Line Items]
Allowance for loan and lease losses, Amount	$ 8,013,000	$ 5,618,000	4,924,000	4,693,000
Allowance for loan and lease losses, Percentage of total loans, net of deferred fees	0.80%	0.60%
Consumer
Loans And Leases Receivable Disclosure [Line Items]
Allowance for loan and lease losses, Amount	$ 60,000	$ 76,000	113,000	103,000
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	$ 529,000	$ 698,000	$ 530,000	$ 575,000
Allowance for loan and lease losses, Percentage of total loans, net of deferred fees	0.05%	0.07%

Loans and Allowance for Loan and Lease Losses - Summary of Impaired Loans Evaluated for Specific Loss Allowance (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Recorded investment	$ 1,287	$ 1,310
Impaired loans with no related allowance recorded, Unpaid principal balance	1,682	1,686
Impaired loans with an allowance recorded, Related allowance	2,612	500
Impaired loans with an allowance recorded, Recorded investment	12,337	2,309
Impaired loans with an allowance recorded, Unpaid principal balance	14,237	2,921
Recorded investment	13,624	3,619
Unpaid principal balance	15,919	4,607
Commercial real estate
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Recorded investment	1,287	1,310
Impaired loans with no related allowance recorded, Unpaid principal balance	1,682	1,686
Commercial and industrial
Financing Receivable Impaired [Line Items]
Impaired loans with an allowance recorded, Related allowance	2,612	500
Impaired loans with an allowance recorded, Recorded investment	12,337	2,309
Impaired loans with an allowance recorded, Unpaid principal balance	$ 14,237	$ 2,921

Loans and Allowance for Loan and Lease Losses - Summary of Average Recorded Investment and Interest Income Recognized on Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Average recorded investment	$ 1,299	$ 3,836
Impaired loans with an allowance recorded, Average recorded investment	13,106	1,944
Average recorded investment	14,405	5,780
Commercial real estate
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Average recorded investment	1,299
Impaired loans with an allowance recorded, Average recorded investment		1,944
Consumer real estate
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Average recorded investment		240
Commercial and industrial
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Average recorded investment		$ 3,596
Impaired loans with an allowance recorded, Average recorded investment	$ 13,106

Loans and Allowance for Loan and Lease Losses - Schedule of Aging of Recorded Investment in Past-due Loans, by Class of Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	$ 9,181	$ 363
Loans Not Past Due	995,037	935,855
Total	1,004,218	936,218
Commercial real estate
Financing Receivable Recorded Investment Past Due [Line Items]
Loans Not Past Due	360,955	302,322
Total	360,955	302,322
Consumer real estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	143	363
Loans Not Past Due	99,809	96,652
Total	99,952	97,015
Construction and land development
Financing Receivable Recorded Investment Past Due [Line Items]
Loans Not Past Due	74,007	94,491
Total	74,007	94,491
Commercial and industrial
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	8,948
Loans Not Past Due	411,877	379,620
Total	420,825	379,620
Consumer
Financing Receivable Recorded Investment Past Due [Line Items]
Loans Not Past Due	4,495	5,974
Total	4,495	5,974
Other
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	90
Loans Not Past Due	43,894	56,796
Total	43,984	56,796
30 - 59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	9,181	81
30 - 59 Days Past Due [Member] \| Consumer real estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	143	81
30 - 59 Days Past Due [Member] \| Commercial and industrial
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	8,948
30 - 59 Days Past Due [Member] \| Other
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	$ 90
60 - 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		282
60 - 89 Days Past Due [Member] \| Consumer real estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		$ 282

Loans and Allowance for Loan and Lease Losses - Schedule of Non-Accrual Loans and Troubled Debt Restructurings (TDR) by Class of Loans (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Accounts Notes And Loans Receivable [Line Items]
Non-Accrual	$ 13,624	$ 3,619
Troubled Debt Restructurings	1,256	1,272
Commercial real estate
Accounts Notes And Loans Receivable [Line Items]
Non-Accrual	1,287	1,310
Troubled Debt Restructurings	1,256	1,272
Commercial and industrial
Accounts Notes And Loans Receivable [Line Items]
Non-Accrual	$ 12,337	$ 2,309

Loans and Allowance for Loan And Lease Losses - Schedule of Presents Loans by Class Modified as TDR (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017 Contract	Mar. 31, 2016 USD ($) Contract
Financing Receivable Modifications [Line Items]
Number of contracts \| Contract	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 and Lease Losses - Schedule of Loans by Class Modified as TDR for the Payment Default Within Twelve Months(Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2017 Contract	Mar. 31, 2016 USD ($) Contract
Financing Receivable Modifications [Line Items]
Number of contracts \| Contract	0	1
Recorded investment \| $		$ 124
Consumer
Financing Receivable Modifications [Line Items]
Number of contracts \| Contract		1
Recorded investment \| $		$ 124

Federal Home Loan Bank Advances - Additional Information (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Federal Home Loan Bank Advances [Line Items]
Outstanding borrowings	$ 75,000	$ 55,000
Investment securities, FHLB stock and commercial and residential real estate mortgage loans
Federal Home Loan Bank Advances [Line Items]
Mortgage loans collateralized amount	400,200
Amount of available credit	$ 91,200

Federal Home Loan Bank Advances - Summary of Contractual Maturities and Average Effective Rates of Outstanding Advances (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Federal Home Loan Bank Advances Maturities Summary [Abstract]
2017	$ 75,000	$ 55,000
Total amount	$ 75,000	$ 55,000
2017	0.96%	0.80%
Total interest rates	0.96%	0.80%

Accumulated Other Comprehensive Income (Loss) - Summary of Changes In Accumulated Other Comprehensive Income (Loss) By Component, Net of Tax (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	$ 139,207,396	$ 108,586,107
Other comprehensive income (loss) before reclassification	354,000	393,000
Amounts reclassified from accumulated other comprehensive income (loss)	184,000	88,000
Other comprehensive income	537,805	480,525
Ending balance	140,211,422	110,858,804
Gains and Losses on Cash Flow Hedges
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(4,241,000)	(3,705,000)
Other comprehensive income (loss) before reclassification		(927,000)
Amounts reclassified from accumulated other comprehensive income (loss)	154,000	86,000
Other comprehensive income	154,000	(841,000)
Ending balance	(4,087,000)	(4,546,000)
Unrealized Gains and Losses on Available for Sale Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(698,000)	105,000
Other comprehensive income (loss) before reclassification	354,000	1,320,000
Amounts reclassified from accumulated other comprehensive income (loss)	4,000	(24,000)
Other comprehensive income	358,000	1,296,000
Ending balance	(340,000)	1,401,000
Unrealized Losses on Securities Transferred to Held to Maturity
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(1,212,000)	(1,315,000)
Amounts reclassified from accumulated other comprehensive income (loss)	26,000	26,000
Other comprehensive income	26,000	26,000
Ending balance	(1,186,000)	(1,289,000)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(6,150,551)	(4,914,380)
Other comprehensive income	537,805	480,525
Ending balance	$ (5,612,746)	$ (4,433,855)

Accumulated Other Comprehensive Income (Loss) - Summary of Significant Amounts Reclassified out off Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income On Derivatives [Line Items]
Net loss (gain) on sale of securities	$ 6,229	$ (38,961)
Interest expense - Federal Home Loan Bank advances	140,259	90,728
Income tax expense (benefit)	(47,168)	796,245
Net of tax	(332,058)	(1,583,846)
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	105,000	37,000
Interest expense - Federal Home Loan Bank advances	49,000	49,000
Net of tax	154,000	86,000
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 loss (gain) on sale of securities	6,000	(39,000)
Income tax expense (benefit)	(2,000)	15,000
Net of tax	4,000	(24,000)
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	42,000	42,000
Income tax expense (benefit)	(16,000)	(16,000)
Net of tax	$ 26,000	$ 26,000

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Taxes [Line Items]
Effective tax rate	(16.60%)	33.50%
Income tax expense	$ (145,000)
Federal statutory income tax rate	34.00%	34.00%
Tennessee
Income Taxes [Line Items]
Excise tax rate	6.50%	6.50%

Commitments and Contingencies - Schedule of Financial Instruments Representing Credit Risk (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Commitments And Contingencies Disclosure [Abstract]
Unused commitments to extend credit	$ 542,542	$ 508,990
Standby letters of credit	11,401	10,886
Total	$ 553,943	$ 519,876

Derivatives - Additional Information (Details) - Designated as Hedging Instrument - Interest Rate Swaps - Cash Flow Hedges - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Notional amounts	$ 20,000,000	$ 20,000,000
Investment securities pledged collateral to counterparties	2,300,000
Investment securities pledged collateral from counterparties	$ 0

Derivatives - Summary of Interest-Rate Swaps Designated as Cash Flow Hedges (Details) - Designated as Hedging Instrument - Cash Flow Hedges - Interest Rate Swaps - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Notional amounts	$ 20,000,000	$ 20,000,000
Weighted average pay rates	3.54%	3.54%
Weighted average receive rates	Mar. 31, 2017: 3 month LIBOR and Dec. 31, 2016: 3 month LIBOR
Weighted average maturity	6 years 2 months 12 days	6 years 6 months
Fair value	$ (1,535,000)	$ (1,535,000)
Amount of unrealized loss recognized in accumulated other comprehensive income, net of tax	$ (947,000)	$ (947,000)

Derivatives - Summary of Customer Related Interest Rate Swaps (Details) - Interest Rate Swaps - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Interest rate swap, Notional amount	$ 83,406,000	$ 82,508,000
Pay fixed/receive variable swaps
Derivative [Line Items]
Interest rate swap, Notional amount	41,703,000	41,254,000
Interest rate swap, Estimated fair value	214,000	460,000
Pay variable/receive fixed swaps
Derivative [Line Items]
Interest rate swap, Notional amount	41,703,000	41,254,000
Interest rate swap, Estimated fair value	$ (214,000)	$ (460,000)

Stock Options and Restricted Shares - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost	$ 1.4
Total fair value of shares vested	$ 0.5	$ 0.2
Vesting period	3 years
Contractual term	10 years
Expected dividend yield	0.00%
Options granted	0
Unrecognized compensation cost	$ 0.1
Restricted Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Cost expected to be recognized over a weighted-average period	1 year 10 months 24 days
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Cost expected to be recognized over a weighted-average period	2 years 3 months 18 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	199,891

Stock Options and Restricted Shares - Summary of Company Recognized Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based compensation expense before income taxes	$ 236	$ 196
Less: deferred tax benefit	(90)	(75)
Reduction of net income	$ 146	$ 121

Stock Options and Restricted Shares - Summary of Changes in Company's Nonvested Restricted Shares (Details)	3 Months Ended
	Mar. 31, 2017 $ / shares shares
Restricted Shares, Abstract
Restricted Shares, Nonvested Beginning Balance \| shares	199,641
Restricted Shares, Granted \| shares	7,333
Restricted Shares, Vested \| shares	(43,002)
Restricted Shares, Forfeited \| shares	(1,500)
Restricted Shares, Nonvested Ending Balance \| shares	162,472
Weighted Average Grant Date Fair Value, Abstract
Weighted Average Grant Date Fair Value, Nonvested Beginning Balance \| $ / shares	$ 12.34
Weighted Average Grant Date Fair Value, Granted \| $ / shares	19.85
Weighted Average Grant Date Fair Value, Vested \| $ / shares	12.24
Weighted Average Grant Date Fair Value, Forfeited \| $ / shares	13.22
Weighted Average Grant Date Fair Value, Nonvested Ending Balance \| $ / shares	$ 12.70

Stock Options and Restricted Shares - Summary of Fair Value of Options Granted Using Weighted Average Assumptions (Details)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Expected dividend yield	0.00%
Expected term (in years)	0 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)	3 Months Ended
	Mar. 31, 2017 $ / shares shares
Shares, Abstract
Shares Outstanding, Beginning Balance	1,006,000
Shares Outstanding, Granted	0
Shares Outstanding, Exercised	(20,000)
Shares Outstanding, Ending Balance	986,000
Shares, Fully Vested and Expected to Vest	978,308
Shares, Exercisable at End of Period	931,000
Weighted Average Exercise Price, Abstract
Weighted Average Exercise Price Outstanding, Beginning Balance \| $ / shares	$ 10.48
Weighted Average Exercise Price Outstanding, Exercised \| $ / shares	10.00
Weighted Average Exercise Price Outstanding, Ending Balance \| $ / shares	10.49
Weighted Average Exercise Price, Fully vested and expected to vest \| $ / shares	10.47
Weighted Average Exercise Price, Exercisable at End of Period \| $ / shares	$ 10.39
Weighted Average Remaining Contractual Term (year), Abstract
Weighted Average Remaining Contractual Term Outstanding	2 years 10 months 24 days
Weighted Average Remaining Contractual Term, Fully Vested and Expected to Vest	2 years 10 months 24 days
Weighted Average Remaining Contractual Term, Exercisable at End of Period	2 years 7 months 6 days

Stock Options and Restricted Shares - Information Related to Stock Options (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Intrinsic value of options exercised	$ 193,800	$ 53,756
Cash received from option exercises	200,000	96,306
Tax benefit realized from option exercises	$ 74,206	$ 20,583
Weighted average fair value of options granted		$ 3.16

Regulatory Capital Requirements - Schedule of Capital Amounts and Ratios (Details) - USD ($)
$ in Thousands

Mar. 31, 2017

Dec. 31, 2016

CapStar Financial Holdings, Inc.

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

Total capital to risk-weighted assets, actual amount

$ 152,445

$ 149,616

Tier I capital to risk-weighted assets, actual amount

138,375

137,909

Tier I capital to average assets, actual amount

$ 138,375

$ 137,909

Total capital to risk-weighted assets, actual ratio

12.10%

12.60%

Tier I capital to risk-weighted assets, actual ratio

11.00%

11.60%

Tier I capital to average assets, actual ratio

10.40%

10.50%

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

^[1]

$ 100,502

$ 95,028

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

^[1]

75,377

71,271

Tier I capital to average assets, minimum capital requirement amount

^[1]

$ 53,396

$ 52,727

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

$ 129,685

$ 129,528

Tier I capital to risk-weighted assets, actual ratio

10.30%

10.90%

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

^[1]

$ 56,533

$ 53,453

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

$ 129,571

$ 126,718

Tier I capital to risk-weighted assets, actual amount

115,501

115,011

Tier I capital to average assets, actual amount

$ 115,501

$ 115,011

Total capital to risk-weighted assets, actual ratio

10.30%

10.70%

Tier I capital to risk-weighted assets, actual ratio

9.20%

9.70%

Tier I capital to average assets, actual ratio

8.70%

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

^[1]

$ 100,483

$ 95,028

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

^[1]

75,362

71,271

Tier I capital to average assets, minimum capital requirement amount

^[1]

$ 53,394

$ 52,727

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]

$ 125,604

$ 118,785

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

^[2]

100,483

95,028

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

^[2]

$ 66,742

$ 65,909

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

$ 99,311

$ 99,130

Tier I capital to risk-weighted assets, actual ratio

7.90%

8.30%

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

^[1]

$ 56,522

$ 53,453

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]

$ 81,643

$ 77,210

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

^[2]

6.50%

[1]	For the calendar year 2017, the Company must maintain a capital conservation buffer of Tier 1 common equity capital in excess of minimum risk-based capital ratios by at least 1.25% 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.

Regulatory Capital Requirements - Schedule of Capital Amounts and Ratios (Parenthetical) (Details)	Mar. 31, 2017
Banking And Thrift [Abstract]
Minimum risk based capital ratios	1.25%

Earning Per Share - Summary of Basic and Diluted Earnings Per Share (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Basic net income per share calculation:
Numerator – Net income	$ 332,058	$ 1,583,846
Denominator – Average common shares outstanding	11,210,948	8,628,683
Basic net income per share of common stock	$ 0.03	$ 0.18
Diluted net income per share calculation:
Numerator – Net income	$ 332,058	$ 1,583,846
Denominator – Average common shares outstanding	11,210,948	8,628,683
Dilutive shares contingently issuable	1,573,169	1,943,510
Average diluted common shares outstanding	12,784,117	10,572,193
Diluted net income per share of common stock	$ 0.03	$ 0.15

Fair Value - Additional Information (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Other real estate owned	$ 0	$ 0
Loans held for sale carried at fair value	$ 0	$ 0

Fair Value - Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Assets:
Total securities available for sale	$ 188,516,087	$ 182,354,987
Obligations of States and Political Subdivisions
Assets:
Total securities available for sale	27,340,000	27,913,000
Asset-backed securities
Assets:
Total securities available for sale	20,724,000	20,473,000
Fair Value Measurements Recurring Basis
Assets:
Total securities available for sale	188,516,000	182,355,000
Liabilities:
Total derivatives	(1,863,000)	(1,995,000)
Fair Value Measurements Recurring Basis \| U.S. Government-sponsored Agencies
Assets:
Total securities available for sale	11,314,000	9,374,000
Fair Value Measurements Recurring Basis \| Obligations of States and Political Subdivisions
Assets:
Total securities available for sale	27,340,000	27,913,000
Fair Value Measurements Recurring Basis \| Mortgage-backed Securities-residential
Assets:
Total securities available for sale	129,138,000	124,595,000
Fair Value Measurements Recurring Basis \| Asset-backed securities
Assets:
Total securities available for sale	20,724,000	20,473,000
Fair Value Measurements Recurring Basis \| Interest Rate Swaps - Customer Related
Assets:
Interest rate swaps - customer related	328,000	460,000
Liabilities:
Total derivatives	(328,000)	(460,000)
Fair Value Measurements Recurring Basis \| Interest Rate Swaps - Cash Flow Hedges
Liabilities:
Total derivatives	(1,535,000)	(1,535,000)
Fair Value Measurements Recurring Basis \| Significant Other Observable Inputs (Level 2)
Assets:
Total securities available for sale	188,516,000	182,355,000
Liabilities:
Total derivatives	(1,863,000)	(1,995,000)
Fair Value Measurements Recurring Basis \| Significant Other Observable Inputs (Level 2) \| U.S. Government-sponsored Agencies
Assets:
Total securities available for sale	11,314,000	9,374,000
Fair Value Measurements Recurring Basis \| Significant Other Observable Inputs (Level 2) \| Obligations of States and Political Subdivisions
Assets:
Total securities available for sale	27,340,000	27,913,000
Fair Value Measurements Recurring Basis \| Significant Other Observable Inputs (Level 2) \| Mortgage-backed Securities-residential
Assets:
Total securities available for sale	129,138,000	124,595,000
Fair Value Measurements Recurring Basis \| Significant Other Observable Inputs (Level 2) \| Asset-backed securities
Assets:
Total securities available for sale	20,724,000	20,473,000
Fair Value Measurements Recurring Basis \| Significant Other Observable Inputs (Level 2) \| Interest Rate Swaps - Customer Related
Assets:
Interest rate swaps - customer related	328,000	460,000
Liabilities:
Total derivatives	(328,000)	(460,000)
Fair Value Measurements Recurring Basis \| Significant Other Observable Inputs (Level 2) \| Interest Rate Swaps - Cash Flow Hedges
Liabilities:
Total derivatives	$ (1,535,000)	$ (1,535,000)

Fair Value - Summary of Assets Measured at Fair Value on a Nonrecurring Basis (Details) - Fair Value, Measurements, Nonrecurring [Member] - Commercial and industrial - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Assets:
Impaired loans	$ 9,725	$ 1,809
Significant Unobservable Inputs (Level 3)
Assets:
Impaired loans	$ 9,725	$ 1,809

Fair Value - Summary of Quantitative Information About Level 3 Fair Value Measurements for Assets Measured at Fair Value on a Non-Recurring Basis (Details) - Fair Value, Measurements, Nonrecurring [Member] - Commercial and industrial - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impaired loans	$ 9,725	$ 1,809
Level 3 Fair Value Measurements
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impaired loans	$ 9,725	$ 1,809
Valuation Technique(s)	Mar. 31, 2017: Sales comparison approach and Dec. 31, 2016: Sales comparison approach
Unobservable Input(s)	Mar. 31, 2017: Appraisal discounts and Dec. 31, 2016: Appraisal discounts
Range (Weighted-Average)		25.00%
Level 3 Fair Value Measurements \| Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Range (Weighted-Average)	10.00%
Level 3 Fair Value Measurements \| Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Range (Weighted-Average)	25.00%

Fair Value - Summary of Carrying Value and Fair Values of the Bank's Financial Instruments (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Financial assets:
Securities available for sale	$ 188,516,087	$ 182,354,987
Securities held to maturity, fair value	49,769,285	49,731,169
Loans held for sale	0	0
Carrying amount
Financial assets:
Restricted equity securities	6,544,000	6,032,000
Carrying amount \| Level 1
Financial assets:
Cash and due from banks, interest-bearing deposits in financial institutions	58,629,000	63,456,000
Federal funds sold	1,410,000	16,654,000
Carrying amount \| Level 2
Financial assets:
Securities available for sale	188,516,000	182,355,000
Securities held to maturity, fair value	46,855,000	46,864,000
Loans held for sale	35,371,000	42,111,000
Accrued interest receivable	4,012,000	3,942,000
Bank owned life insurance	22,044,000	21,900,000
Other assets	328,000	460,000
Financial liabilities:
Federal Home Loan Bank advances	75,000,000	55,000,000
Accrued interest payable	236,000	212,000
Carrying amount \| Level 3 Fair Value Measurements
Financial assets:
Loans, net	1,003,434,000	935,251,000
Financial liabilities:
Deposits	1,157,995,000	1,128,722,000
Other liabilities	3,789,000	5,349,000
Fair value \| Level 1
Financial assets:
Cash and due from banks, interest-bearing deposits in financial institutions	58,629,000	63,456,000
Federal funds sold	1,410,000	16,654,000
Fair value \| Level 2
Financial assets:
Securities available for sale	188,516,000	182,355,000
Securities held to maturity, fair value	49,769,000	49,731,000
Loans held for sale	35,410,000	42,302,000
Accrued interest receivable	4,012,000	3,942,000
Bank owned life insurance	22,044,000	21,900,000
Other assets	328,000	460,000
Financial liabilities:
Federal Home Loan Bank advances	74,993,000	54,989,000
Accrued interest payable	236,000	212,000
Fair value \| Level 3 Fair Value Measurements
Financial assets:
Loans, net	1,002,131,000	934,628,000
Financial liabilities:
Deposits	1,116,924,000	1,088,758,000
Other liabilities	$ 3,789,000	$ 5,349,000