Consolidated Statements of Stockholders’ Equity (Unaudited) (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, December 31, 2012 at Dec. 31, 2012	$ 165	$ 96,587	$ 257	$ 309,053	$ 406,062
Comprehensive income:
Net income				12,513	12,513
Change in unrealized appreciation on available-for-sale securities, net of income taxes			(2,667)		(2,667)
Comprehensive income					9,846
Stock issued as bonus shares	1	228			229
Vesting bonus shares		687			687
Stock issued for employee stock purchase plan		126			126
Exercise of stock options		95			95
Stock granted under stock-based compensation plans		27			27
Repurchase of common stock	(3)	(8,316)			(8,319)
Cash Dividends				(6,903)	(6,903)
Balance at Jun. 30, 2013	163	89,434	(2,410)	314,663	401,850
Comprehensive income:
Net income				10,718	10,718
Change in unrealized appreciation on available-for-sale securities, net of income taxes			(592)		(592)
Comprehensive income					10,126
Vesting bonus shares		703			703
Exercise of stock options		509			509
Stock issued for employee stock purchase plan		(23)			(23)
Repurchase of common stock	(1)	(2,528)			(2,529)
Cash Dividends				(6,804)	(6,804)
Balance at Dec. 31, 2013	162	88,095	(3,002)	318,577	403,832
Comprehensive income:
Net income				14,261	14,261
Change in unrealized appreciation on available-for-sale securities, net of income taxes			1,593		1,593
Comprehensive income					15,854
Stock issued as bonus shares	1	441			442
Vesting bonus shares		655			655
Stock issued for employee stock purchase plan		118			118
Exercise of stock options		843			843
Stock issued for employee stock purchase plan		(142)			(142)
Cash Dividends				(7,467)	(7,467)
Balance at Jun. 30, 2014	$ 163	$ 90,010	$ (1,409)	$ 325,371	$ 414,135