Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Treasury Stock [Member]	Total
Beginning balance at Dec. 31, 2014	$ 3,757	$ 123,194	$ 119,638	$ 17,801	$ (12,353)	$ 252,037
Beginning balance (in shares) at Dec. 31, 2014	20,873				1,655
Acquisition of treasury shares					$ (2,532)	(2,532)
Acquisition of treasury shares (in shares)					221
Equity incentive plan activity		383				383
Shares issued under employee benefit plans, value		(97)			$ 755	658
Shares issued under employee benefit plans, shares					(100)
Net income (loss)			21,863			21,863
Other comprehensive income, net of tax				(10,383)		(10,383)
Ending balance at Dec. 31, 2015	$ 3,757	123,480	141,501	7,418	$ (14,130)	262,026
Ending balance (in shares) at Dec. 31, 2015	20,873				1,776
Acquisition of treasury shares					$ (6,117)	(6,117)
Acquisition of treasury shares (in shares)					562
Equity incentive plan activity		(118)				(118)
Shares issued under employee benefit plans, value		(196)			$ 662	466
Shares issued under employee benefit plans, shares					(77)
Net income (loss)			6,526			6,526
Other comprehensive income, net of tax				2,953		2,953
Ending balance at Dec. 31, 2016	$ 3,757	123,166	148,027	10,371	$ (19,585)	265,736
Ending balance (in shares) at Dec. 31, 2016	20,873				2,261
Acquisition of treasury shares					$ (5,308)	(5,308)
Acquisition of treasury shares (in shares)					484
Equity incentive plan activity		149				149
Shares issued under employee benefit plans, value		(135)			$ 366	231
Shares issued under employee benefit plans, shares					(41)
Net income (loss)			(11,553)			(11,553)
Other comprehensive income, net of tax				1,863		1,863
Ending balance at Dec. 31, 2017	$ 3,757	$ 123,180	$ 136,474	$ 12,234	$ (24,527)	$ 251,118
Ending balance (in shares) at Dec. 31, 2017	20,873				2,704