Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Preferred Stock [Member]	Common Stock [Member]	Warrant [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Comprehensive Income [Member]	Total
Beginning balance at Dec. 31, 2013	$ 56,600	$ 253	$ 946	$ 242,990	$ 96,393	$ (3,319)	$ 393,863
Beginning balance (in Shares) at Dec. 31, 2013	56,600	25,885,863
Ending balance at Sep. 30, 2014	$ 56,600	$ 255	946	247,811	135,490	1,512	442,614
Ending balance (in Shares) at Sep. 30, 2014	56,600	26,022,307
Net Income					39,531		39,531
Net change in other comprehensive income, net of tax						4,831	4,831
Stock-based compensation				2,948			2,948
Issuance of common stock related to options exercised				1,089			$ 1,089
Issuance of common stock related to options exercised (in Shares)		64,926					64,926
Tax benefits related to non-qualified stock compensation				338			$ 338
Vesting of restricted stock awards issued at date of grant, net of shares withheld for payroll taxes		$ 2		(2)
Vesting of restricted stock awards issued at date of grant, net of shares withheld for payroll taxes (in Shares)		(21,858)
Restricted stock awards granted (in Shares)		78,947
Issuance of common stock related to employee stock purchase plan				448			448
Issuance of common stock related to employee stock purchase plan (in Shares)		14,429
Preferred stock dividends					(434)		(434)
Beginning balance at Dec. 31, 2014	$ 71,900	$ 296	946	394,933	150,037	2,647	620,759
Beginning balance (in Shares) at Dec. 31, 2014	71,900	30,139,396
Ending balance at Sep. 30, 2015	$ 71,900	$ 330	$ 946	500,334	211,318	1,241	786,069
Ending balance (in Shares) at Sep. 30, 2015	71,900	33,405,510
Net Income					61,819		61,819
Net change in other comprehensive income, net of tax						$ (1,406)	(1,406)
Stock-based compensation				3,660			3,660
Issuance of common stock related to options exercised		$ 4		4,636			$ 4,640
Issuance of common stock related to options exercised (in Shares)		373,027					377,357
Tax benefits related to non-qualified stock compensation				1,945			$ 1,945
Vesting of restricted stock awards issued at date of grant, net of shares withheld for payroll taxes		$ 2		(2)
Vesting of restricted stock awards issued at date of grant, net of shares withheld for payroll taxes (in Shares)		(17,877)
Restricted stock awards granted (in Shares)		78,070
Shares issued in public offering, net of issuance costs of $5,302		$ 28		94,605			94,633
Shares issued in public offering, net of issuance costs of $5,302 (in Shares)		2,816,900
Issuance of common stock related to employee stock purchase plan				561	1		562
Issuance of common stock related to employee stock purchase plan (in Shares)		15,994
Cash paid in lieu of fractional shares upon merger with Virginia Heritage				$ (4)			(4)
Preferred stock dividends					$ (539)		$ (539)