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 Gain (Loss) [Member]	Treasury Stock [Member]	Common Stock Acquired by Deferred Compensation Plan [Member]	Deferred Compensation Plan Liability [Member]
Beginning Balance at Dec. 31, 2014	$ 218,259	$ (3,330)	$ 336	$ 265,260	$ 217,714	$ (7,109)	$ (254,612)	$ (304)	$ 304
Net income	5,262				5,262
Other comprehensive income (loss), net of tax	321					321
Tax benefit (expense) of stock plans	7			7
Stock awards	292			292
Treasury stock allocated to restricted stock plan				1,195	(139)		(1,056)
Purchased 110,143 shares of common stock	(1,881)						(1,881)
Allocation of ESOP stock	141	71		70
Cash dividend $0.13 per share	(2,146)				(2,146)
Exercise of stock options	47				(14)		61
Purchase of stock for the deferred compensation plan								(3)	3
Ending Balance at Mar. 31, 2015	220,302	(3,259)	336	266,824	220,677	(6,788)	(257,488)	(307)	307
Beginning Balance at Dec. 31, 2015	238,446	(3,045)	336	269,757	229,140	(6,241)	(251,501)	(314)	314
Net income	4,205				4,205
Other comprehensive income (loss), net of tax	318					318
Tax benefit (expense) of stock plans	(270)			(270)
Stock awards	330			330
Treasury stock allocated to restricted stock plan				1,108	(113)		(995)
Allocation of ESOP stock	149	71		78
Cash dividend $0.13 per share	(2,197)				(2,197)
Exercise of stock options	95				(19)		114
Purchase of stock for the deferred compensation plan								9	(9)
Ending Balance at Mar. 31, 2016	$ 241,076	$ (2,974)	$ 336	$ 271,003	$ 231,016	$ (5,923)	$ (252,382)	$ (305)	$ 305