Consolidated Statements of Shareholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock [Member]	Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock [Member]
Balance at Dec. 31, 2011	$ 573,071	$ 313	$ 321,994	$ 354,439	$ (26,348)	$ (77,327)
Balance (shares) at Dec. 31, 2011		31,299
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under employee plans	8,910		(4,377)			13,287
Repurchase of treasury stock	(3,923)					(3,923)
Tax benefit arising from common stock issued under employee plans	1,052		1,052
Stock-based compensation	5,653		5,653
Dividends on common stock	(17,013)			(17,013)
Comprehensive income (loss):
Foreign currency translation adjustments					1,995
Pension liability (net of income tax expense/benefit)					875
Cash flow hedging gain (loss) (net of income tax expense/benefit)					(4,103)
Net income	40,481			40,481
Comprehensive income	39,248
Balance at Dec. 31, 2012	606,998	313	324,322	377,907	(27,581)	(67,963)
Balance (shares) at Dec. 31, 2012		31,299
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under employee plans	15,196		(4,576)			19,772
Repurchase of treasury stock	(50,556)					(50,556)
Tax benefit arising from common stock issued under employee plans	1,097		1,097
Stock-based compensation	5,593		5,593
Dividends on common stock	(17,957)			(17,957)
Comprehensive income (loss):
Foreign currency translation adjustments					(1,193)
Pension liability (net of income tax expense/benefit)					11,457
Cash flow hedging gain (loss) (net of income tax expense/benefit)					(255)
Net income	35,939			35,939
Comprehensive income	45,948
Balance at Dec. 31, 2013	606,319	313	326,436	395,889	(17,572)	(98,747)
Balance (shares) at Dec. 31, 2013		31,299
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under employee plans	(6,139)		(16,658)			10,519
Repurchase of treasury stock	(16,862)					(16,862)
Tax benefit arising from common stock issued under employee plans	644		644
Stock-based compensation	9,330		9,330
Dividends on common stock	(21,936)			(21,936)
Comprehensive income (loss):
Foreign currency translation adjustments					(15,069)
Pension liability (net of income tax expense/benefit)					(11,842)
Cash flow hedging gain (loss) (net of income tax expense/benefit)					4,661
Net income	32,192			32,192
Comprehensive income	9,942
Balance at Dec. 31, 2014	$ 581,298	$ 313	$ 319,752	$ 406,145	$ (39,822)	$ (105,090)
Balance (shares) at Dec. 31, 2014		31,299