Consolidated Statements Of Changes In Shareholders' Equity (USD $) In Thousands	Common Stock [Member]	Capital Surplus[Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balances, beginning value at Dec. 31, 2009	$ 46,249	$ 102,917	$ 253,167	$ (90,877)	$ (2,554)	$ 308,902
Comprehensive income/(loss):
Net income			20,028			20,028
Other comprehensive gain, net of deferred income taxes
Unrealized gain (loss) on available-for-sale securities, net of taxes					5,242	5,242
Net unrealized loss on interest rate floors, net of taxes					(1,738)	(1,738)
Total comprehensive income						23,532
Cash dividends declared ($0.68 per share)			(10,685)			(10,685)
Issuance of stock awards, net		(192)		682		490
Exercise of stock options		(12)		58		46
Purchase of treasury shares				(9,710)		(9,710)
Balances, Ending Value at Jun. 30, 2010	46,249	102,713	262,510	(99,847)	950	312,575
Balances, beginning value at Dec. 31, 2010	46,249	103,057	270,905	(102,853)	(2,497)	314,861
Comprehensive income/(loss):
Net income			19,445			19,445
Other comprehensive gain, net of deferred income taxes
Unrealized gain (loss) on available-for-sale securities, net of taxes					954	954
Net unrealized loss on interest rate floors, net of taxes					(295)	(295)
Total comprehensive income						20,104
Cash dividends declared ($0.68 per share)			(10,319)			(10,319)
Issuance of stock awards, net		(119)		784		665
Exercise of stock options				153		153
Purchase of treasury shares				(15,085)		(15,085)
Balances, Ending Value at Jun. 30, 2011	$ 46,249	$ 102,938	$ 280,031	$ (117,001)	$ (1,838)	$ 310,379