Consolidated Stockholders' Equity Statements (USD $) In Thousands	Total	Common Stock [Member]	Paid-In Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss), Translation Component of Equity [Member]	Accumulated Other Comprehensive Income (Loss), Pension and Postretirement Liability [Member]
Beginning balance at Dec. 31, 2009	$ 551,048	$ 503	$ 591,917	$ 72,625	$ (128,611)	$ 58,060	$ (43,446)
Beginning balance, shares at Dec. 31, 2009		50,335			(3,675)
Net income	108,459			108,459
Foreign currency translation	(25,965)					(25,965)
Adjustments to pension and postretirement liability, net of $1.0 , $4.8 and $3.2 million tax benefit for year 2010, 2011 and 2012 respectively	2,432						2,432
Exercise of stock options, net of tax withholding forfeitures, shares					177
Exercise of stock options, net of tax withholding forfeitures	2,698		(1,322)		4,020
Conversion of restricted stock units into common stock, net of tax withholding forfeitures, shares					208
Conversion of restricted stock units into common stock, net of tax withholding forfeitures	(2,731)		(7,166)		4,435
Share-based compensation	12,067		12,067
Dividends ($0.20 per share)	(9,493)		23	(9,516)
Ending balance at Dec. 31, 2010	638,515	503	595,519	171,568	(120,156)	32,095	(41,014)
Ending balance, shares at Dec. 31, 2010		50,335			(3,290)
Net income	114,345			114,345
Foreign currency translation	(4,632)					(4,632)
Adjustments to pension and postretirement liability, net of $1.0 , $4.8 and $3.2 million tax benefit for year 2010, 2011 and 2012 respectively	(9,158)						(9,158)
Exercise of stock options, net of tax withholding forfeitures, shares					264
Exercise of stock options, net of tax withholding forfeitures	3,862		(2,214)		6,076
Conversion of restricted stock units into common stock, net of tax withholding forfeitures, shares					151
Conversion of restricted stock units into common stock, net of tax withholding forfeitures	(1,864)		(4,852)		2,988
Share repurchase program, shares					(1,635)
Share repurchase program	(50,000)				(50,000)
Share-based compensation	13,031		13,031
Dividends ($0.20 per share)	(9,550)			(9,550)
Ending balance at Dec. 31, 2011	694,549	503	601,484	276,363	(161,092)	27,463	(50,172)
Ending balance, shares at Dec. 31, 2011		50,335			(4,510)
Net income	194,490			194,490
Foreign currency translation	(1,414)					1,053
Adjustments to pension and postretirement liability, net of $1.0 , $4.8 and $3.2 million tax benefit for year 2010, 2011 and 2012 respectively	(8,909)						(8,909)
Exercise of stock options, net of tax withholding forfeitures, shares					243
Exercise of stock options, net of tax withholding forfeitures	737		(8,694)		9,431
Conversion of restricted stock units into common stock, net of tax withholding forfeitures, shares					172
Conversion of restricted stock units into common stock, net of tax withholding forfeitures	(2,456)		(11,103)		8,647
Share repurchase program, shares	2,100				(2,072)
Share repurchase program	(75,000)				(75,000)
Share-based compensation	16,493		16,493
Dividends ($0.20 per share)	(9,097)			(9,097)
Ending balance at Dec. 31, 2012	$ 811,860	$ 503	$ 598,180	$ 461,756	$ (218,014)	$ 28,516	$ (59,081)
Ending balance, shares at Dec. 31, 2012		50,335			(6,167)