Consolidated Statements of Stockholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Income
Balance at Dec. 31, 2010	$ 253,260	$ 1,187	$ 84,377	$ (426)	$ 166,589	$ 1,533
Balance (shares) at Dec. 31, 2010		11,830,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	32,687				32,687
Translation adjustment	(2,788)					(2,788)
Unrealized derivative gain, net of taxes	144					144
Net actuarial gain arising during period net of taxes	(4,512)					(4,512)
Tax effect of non-qualified stock options	63		63
Stock-based compensation	986		986
Exercise of stock options	281	3	278
Exercise of stock options, shares		30,000
Dividends paid	(2,845)				(2,845)
Balance at Dec. 31, 2011	277,276	1,190	85,704	(426)	196,431	(5,623)
Balance (shares) at Dec. 31, 2011		11,860,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	28,903				28,903
Translation adjustment	4,445					4,445
Unrealized derivative gain, net of taxes	0
Net actuarial gain arising during period net of taxes	(453)					(453)
Tax effect of non-qualified stock options	(102)		(102)
Stock-based compensation	940		940
Exercise of stock options	2,131	13	2,118
Exercise of stock options, shares		126,000
Dividends paid	(2,854)				(2,854)
Balance at Dec. 31, 2012	310,286	1,203	88,660	(426)	222,480	(1,631)
Balance (shares) at Dec. 31, 2012		11,986,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	36,094				36,094
Translation adjustment	479					479
Unrealized derivative gain, net of taxes	0
Net actuarial gain arising during period net of taxes	4,190					4,190
Tax effect of non-qualified stock options	0
Stock-based compensation	1,501		1,501
Exercise of stock options	1,286	8	1,278
Exercise of stock options, shares		85,000
Dividends paid	(3,371)				(3,371)
Balance at Dec. 31, 2013	$ 350,465	$ 1,211	$ 91,439	$ (426)	$ 255,203	$ 3,038
Balance (shares) at Dec. 31, 2013		12,071,000