Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2014	$ 3,757	$ 123,194	$ 119,638	$ 17,801	$ (12,353)
Acquisition of treasury stock					(1,910)
Shares issued under employee benefit plans					716
Equity based compensation		526
Shares issued under employee benefit plans (value)		(114)
Net income			18,417			$ 18,417
Additional minimum pension liability, net of tax				51
Unrealized holding (losses) gains arising during period, net of tax				(5,108)
Reclassification adjustment for (gains) losses included in net income, net of tax				(3,823)
Balance at Sep. 30, 2015	3,757	123,606	138,055	8,921	(13,547)	260,792
Balance at Jun. 30, 2015	3,757	123,618	131,357	15,956	(12,376)
Acquisition of treasury stock					(1,180)
Shares issued under employee benefit plans					9
Equity based compensation		(11)
Shares issued under employee benefit plans (value)		(1)
Net income			6,698			6,698
Additional minimum pension liability, net of tax				17
Unrealized holding (losses) gains arising during period, net of tax				(7,034)
Reclassification adjustment for (gains) losses included in net income, net of tax				(18)
Balance at Sep. 30, 2015	3,757	123,606	138,055	8,921	(13,547)	260,792
Balance at Dec. 31, 2015	3,757	123,480	141,501	7,418	(14,130)	262,026
Acquisition of treasury stock					(5,792)
Shares issued under employee benefit plans					662
Equity based compensation		(21)
Shares issued under employee benefit plans (value)		(196)
Net income			10,188			10,188
Additional minimum pension liability, net of tax				55
Unrealized holding (losses) gains arising during period, net of tax				5,049
Reclassification adjustment for (gains) losses included in net income, net of tax				(1,033)
Balance at Sep. 30, 2016	3,757	123,263	151,689	11,489	(19,260)	270,938
Balance at Jun. 30, 2016	3,757	123,650	146,641	10,864	(18,817)
Acquisition of treasury stock					(1,047)
Shares issued under employee benefit plans					604
Equity based compensation		(249)
Shares issued under employee benefit plans (value)		(138)
Net income			5,048			5,048
Additional minimum pension liability, net of tax				18
Unrealized holding (losses) gains arising during period, net of tax				1,325
Reclassification adjustment for (gains) losses included in net income, net of tax				(718)
Balance at Sep. 30, 2016	$ 3,757	$ 123,263	$ 151,689	$ 11,489	$ (19,260)	$ 270,938