CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Preferred	Common Stock	Additional Paid in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2012		90,908	28,692,616
Beginning balance at Dec. 31, 2012	$ 552,236	$ 90,908	$ 3,587	$ 256,843	$ 206,397	$ (5,499)
Comprehensive income
Net income	44,530				44,530
Other comprehensive income (loss), net of tax	(911)					(911)
Cash dividends on common stock	(5,612)				(5,612)
Cash dividends on preferred stock under small business lending fund	(2,380)				(2,380)
Preferred stock redemption under small business lending fund (in shares)		(90,783)
Preferred stock redemption under small business lending fund	(90,783)	$ (90,783)
Issuance of common stock related to acquisition (in shares)			7,079,457
Issuance of common stock related to acquisition	135,642		$ 885	134,757
Share-based compensation (in shares)			116,978
Share-based compensation	1,773		$ 15	1,758
Stock Issued under employee benefit plans (in shares)			33,451
Stock issued under employee benefit plans	479		$ 4	475
Stock issued under dividend reinvestment and stock purchase plan (in shares)			18,449
Stock issued under dividend reinvestment and stock purchase plan	325		$ 2	323
Stock options exercised (in shares)			13,750
Stock options exercised	115		$ 2	113
Stock redeemed (in shares)			(32,940)
Stock redeemed	(491)		$ (5)	(486)
Ending balance (in shares) at Dec. 31, 2013		125	35,921,761
Ending balance at Dec. 31, 2013	634,923	$ 125	$ 4,490	393,783	242,935	(6,410)
Comprehensive income
Net income	60,162				60,162
Other comprehensive income (loss), net of tax	4,780					4,780
Cash dividends on common stock	(10,694)				(10,694)
Issuance of common stock related to acquisition (in shares)			1,574,298
Issuance of common stock related to acquisition	34,981		$ 197	34,784
Share-based compensation (in shares)			132,446
Share-based compensation	2,177		$ 17	2,160
Stock Issued under employee benefit plans (in shares)			26,547
Stock issued under employee benefit plans	478		$ 3	475
Stock issued under dividend reinvestment and stock purchase plan (in shares)			24,556
Stock issued under dividend reinvestment and stock purchase plan	523		$ 3	520
Stock options exercised (in shares)			41,249
Stock options exercised	564		$ 5	559
Stock redeemed (in shares)			(50,909)
Stock redeemed	(1,067)		$ (6)	(1,061)
Ending balance (in shares) at Dec. 31, 2014		125	37,669,948
Ending balance at Dec. 31, 2014	726,827	$ 125	$ 4,709	431,220	292,403	(1,630)
Comprehensive income
Net income	65,384				65,384
Other comprehensive income (loss), net of tax	268					268
Cash dividends on common stock	(15,654)				(15,654)
Issuance of common stock related to acquisition (in shares)			2,769,568
Issuance of common stock related to acquisition	70,402		$ 346	70,056
Share-based compensation (in shares)			149,577
Share-based compensation	2,270		$ 19	2,251
Stock Issued under employee benefit plans (in shares)			22,074
Stock issued under employee benefit plans	460		$ 3	457
Stock issued under dividend reinvestment and stock purchase plan (in shares)			26,375
Stock issued under dividend reinvestment and stock purchase plan	$ 661		$ 3	658
Stock options exercised (in shares)	96,066		96,066
Stock options exercised	$ 1,531		$ 12	1,519
Stock redeemed (in shares)			(69,349)
Stock redeemed	(1,640)		$ (9)	(1,631)
Ending balance (in shares) at Dec. 31, 2015		125	40,664,259
Ending balance at Dec. 31, 2015	$ 850,509	$ 125	$ 5,083	$ 504,530	$ 342,133	$ (1,362)