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, 2009	$ 576,515	$ 313	$ 317,366	$ 325,370	$ (12,405)	$ (54,129)
Balance (shares) at Dec. 31, 2009		31,299
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under employee plans	1,719		(2,376)	(1,696)		5,791
Repurchase of treasury stock	(22,977)					(22,977)
Tax benefit arising from common stock issued under employee plans	227		227
Retirement of 2.50% convertible notes	(34)		(34)
Stock-based compensation	4,223		4,223
Comprehensive income (loss):
Foreign currency translation adjustments					65
Pension liability (net of income tax expense/benefit)					(2,200)
Cash flow hedging gain (loss) (net of income tax expense/benefit)					(1,321)
Net income	30,346			30,346
Comprehensive income (loss)	26,890
Balance at Dec. 31, 2010	586,563	313	319,406	354,020	(15,861)	(71,315)
Balance (shares) at Dec. 31, 2010		31,299
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under employee plans	4,827		(3,849)	(333)		9,009
Repurchase of treasury stock	(15,021)					(15,021)
Tax benefit arising from common stock issued under employee plans	1,197		1,197
Stock-based compensation	5,240		5,240
Comprehensive income (loss):
Foreign currency translation adjustments					(1,937)
Pension liability (net of income tax expense/benefit)					(12,768)
Cash flow hedging gain (loss) (net of income tax expense/benefit)					4,218
Net income	752			752
Comprehensive income (loss)	(9,735)
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 (loss)	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