Consolidated Statements Of Stockholders' Equity (USD $) In Thousands, except Share data	Total		Common Stock [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
BALANCE at Dec. 31, 2012	$ 549,088		$ 504,881	$ (293,149)	$ 338,979	$ (1,623)
BALANCE (in shares) at Dec. 31, 2012	28,626,323		28,626,323
Proceeds from exercise of options, net (in shares)			153,810
Proceeds from exercise of options, net	4,655		4,655
Adjustments related to tax withholding for share-based compensation (in shares)			(65,730)
Adjustments related to tax withholding for share-based compensation	(3,913)		(3,913)
Share-based payments expense (in shares)			283,058
Share-based payments expense	4,837		4,837
Tax benefit on share-based compensation expense	1,973		1,973
Repurchases of common stock (in shares)			(937,446)
Repurchases of common stock	(46,482)			(46,482)
Repurchase of convertible debt - conversion option, net of tax	(17,607)		(17,607)
Reclassification of debt feature to temporary equity	(8,273)		(8,273)
Net income	22,604				22,604
Foreign currency translation adjustment, net of tax	(1,914)	[1]				(1,914)
BALANCE at Mar. 31, 2013	$ 504,968		$ 486,553	$ (339,631)	$ 361,583	$ (3,537)
BALANCE (in shares) at Mar. 31, 2013	28,060,015		28,060,015

[1] Foreign currency translation adjustment has no tax effect for the three months ended March 31, 2013 and 2012, respectively.