Consolidated Statements of Changes in Stockholders' Equity (USD $) In Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Gain (Loss) [Member]	Employee Stock Ownership Plan [Member]	Treasury Stock [Member]	Common Stock Acquired by Deferred Compensation Plan [Member]	Deferred Compensation Plan Liability [Member]
Beginning Balance at Dec. 31, 2011	$ 216,849		$ 336	$ 262,812	$ 186,666	$ (2,468)	$ (4,193)	$ (226,304)	$ (871)	$ 871
Net income	11,020				11,020
Unrealized gain (loss) on securities (net of tax expense (benefit) $1,254 in 2012 and $(3,378) in 2013)	1,816					1,816
Tax expense of stock plans	(2)			(2)
Stock awards	362			362
Treasury stock allocated to restricted stock plan				(282)	42			240
Purchased shares of common stock (513,737 in 2012 and 314,961 in 2013)	(7,314)							(7,314)
Allocation of ESOP stock	241			97			144
Cash dividend $0.24 in 2012 and $0.24 in 2013 per share	(4,342)				(4,342)
Exercise of stock options	206				(9)			215
Sale of stock for the deferred compensation plan									187	(187)
Ending Balance at Jun. 30, 2012	218,836		336	262,987	193,377	(652)	(4,049)	(233,163)	(684)	684
Beginning Balance at Dec. 31, 2012	219,792		336	262,704	198,109	49	(3,904)	(237,502)	(647)	647
Net income	9,424				9,424
Unrealized gain (loss) on securities (net of tax expense (benefit) $1,254 in 2012 and $(3,378) in 2013)	(4,891)					(4,891)
Stock awards	328			328
Treasury stock allocated to restricted stock plan				(259)	4			255
Purchased shares of common stock (513,737 in 2012 and 314,961 in 2013)	(4,512)							(4,512)
Allocation of ESOP stock	242			98			144
Cash dividend $0.24 in 2012 and $0.24 in 2013 per share	(4,151)				(4,151)
Exercise of stock options	46				(6)			52
Sale of stock for the deferred compensation plan									(9)	9
Ending Balance at Jun. 30, 2013	$ 216,278		$ 336	$ 262,871	$ 203,380	$ (4,842)	$ (3,760)	$ (241,707)	$ (656)	$ 656