Consolidated Statements of Stockholders’ Equity (USD $) In Thousands, unless otherwise specified	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Total
Balance at Dec. 31, 2011	$ 172	$ 112,436	$ 439	$ 294,864	$ 407,911
Comprehensive income:
Net income				27,684	27,684
Change in unrealized appreciation on available-for-sale securities, net of income taxes			(182)		(182)
Comprehensive income					27,502
Stock issued as bonus shares		191			191
Vesting bonus shares		1,305			1,305
Stock issued for employee stock purchase plan		132			132
Stock granted under stock-based compensation plans		83			83
Repurchase of common stock	(7)	(17,560)			(17,567)
Cash Dividends				(13,495)	(13,495)
Balance at Dec. 31, 2012	165	96,587	257	309,053	406,062
Comprehensive income:
Net income				23,231	23,231
Change in unrealized appreciation on available-for-sale securities, net of income taxes			(3,259)		(3,259)
Comprehensive income					19,972
Stock issued as bonus shares	1	228			229
Vesting bonus shares		1,390			1,390
Stock issued for employee stock purchase plan		126			126
Exercise of stock options		604			604
Stock granted under stock-based compensation plans		27			27
Stock issued for employee stock purchase plan		(23)			(23)
Repurchase of common stock	(4)	(10,844)			(10,848)
Cash Dividends				(13,707)	(13,707)
Balance at Dec. 31, 2013	162	88,095	(3,002)	318,577	403,832
Comprehensive income:
Net income				35,688	35,688
Change in unrealized appreciation on available-for-sale securities, net of income taxes			1,666		1,666
Comprehensive income					37,354
Stock issued as bonus shares	1	441			442
Vesting bonus shares		1,423			1,423
Stock issued for employee stock purchase plan		118			118
Exercise of stock options	2	1,674			1,676
Stock issued for employee stock purchase plan		(213)			(213)
Stock issued for Delta Trust & Bank acquisition – 1,629,515 shares	16	65,030			65,046
Cash Dividends				(15,359)	(15,359)
Balance at Dec. 31, 2014	$ 181	$ 156,568	$ (1,336)	$ 338,906	$ 494,319