Consolidated Statements of Stockholders’ Equity (September 30, 2013 and 2012 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 at Dec. 31, 2011	$ 172	$ 112,436	$ 439	$ 294,864	$ 407,911
Comprehensive income:
Net income				19,651	19,651
Change in unrealized appreciation on available-for-sale securities, net of income taxes			143		143
Comprehensive income					19,794
Stock issued as bonus shares	1	191			192
Vesting bonus shares		998			998
Stock issued for employee stock purchase plan		132			132
Stock granted under stock-based compensation plans		67			67
Repurchase of common stock	(6)	(14,668)			(14,674)
Cash Dividends				(10,172)	(10,172)
Balance at Sep. 30, 2012	167	99,156	582	304,343	404,248
Comprehensive income:
Net income				8,033	8,033
Change in unrealized appreciation on available-for-sale securities, net of income taxes			(325)		(325)
Comprehensive income					7,708
Vesting bonus shares		307			307
Stock granted under stock-based compensation plans		16			16
Repurchase of common stock	(2)	(2,892)			(2,894)
Cash Dividends				(3,323)	(3,323)
Balance at Dec. 31, 2012	165	96,587	257	309,053	406,062
Comprehensive income:
Net income				19,445	19,445
Change in unrealized appreciation on available-for-sale securities, net of income taxes			(2,858)		(2,858)
Comprehensive income					16,587
Stock issued as bonus shares	1	228			229
Vesting bonus shares		1,012			1,012
Stock issued for employee stock purchase plan		126			126
Exercise of stock options – 6,000 shares		143			143
Stock granted under stock-based compensation plans		27			27
Repurchase of common stock	(4)	(10,844)			(10,848)
Cash Dividends				(10,304)	(10,304)
Balance at Sep. 30, 2013	$ 162	$ 87,279	$ (2,601)	$ 318,194	$ 403,034