Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Employee Stock Ownership Plan [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) Gain [Member]	Treasury Stock [Member]	Common Stock Acquired by Deferred Compensation Plan [Member]	Deferred Compensation Plan Liability [Member]
Beginning Balance at Dec. 31, 2013	$ 214,350	$ (3,616)	$ 336	$ 263,319	$ 206,201	$ (6,619)	$ (245,271)	$ (665)	$ 665
Net income	14,988				14,988
Other comprehensive income (loss), net of tax	(570)					(570)
Tax benefit of stock plans	57			57
Stock awards	678			678
Treasury stock allocated to restricted stock plan				678	(99)		(579)
Purchased 334,630 and 373,594 shares of common stock in 2014 and 2015 respectively	(5,562)						(5,562)
Allocation of ESOP stock	431	215		216
Cash dividend $0.36 and $0.39 per share for 2014 and 2015 respectively	(6,071)				(6,071)
Exercise of stock options	349				(67)		416
Sale/Purchase of stock for the deferred compensation plan								363	(363)
Ending Balance at Sep. 30, 2014	218,650	(3,401)	336	264,948	214,952	(7,189)	(250,996)	(302)	302
Beginning Balance at Dec. 31, 2014	218,259	(3,330)	336	265,260	217,714	(7,109)	(254,612)	(304)	304
Net income	15,093				15,093
Other comprehensive income (loss), net of tax	783					783
Tax benefit of stock plans	13			13
Stock awards	985			985
Treasury stock allocated to restricted stock plan				1,215	(142)		(1,073)
Issued 660,998 treasury shares to finance acquisition	11,818			1,633			10,185
Purchased 334,630 and 373,594 shares of common stock in 2014 and 2015 respectively	(6,457)						(6,457)
Allocation of ESOP stock	440	214		226
Cash dividend $0.36 and $0.39 per share for 2014 and 2015 respectively	(6,496)				(6,496)
Exercise of stock options	250				(54)		304
Sale/Purchase of stock for the deferred compensation plan								(7)	7
Ending Balance at Sep. 30, 2015	$ 234,688	$ (3,116)	$ 336	$ 269,332	$ 226,115	$ (6,326)	$ (251,653)	$ (311)	$ 311