Condensed Consolidating Statements of Cash Flows (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011 As Restated [Member]		Jun. 30, 2012 Parent [Member]	Jun. 30, 2011 Parent [Member] As Restated [Member]	Jun. 30, 2012 Guarantor Subsidiaries [Member]	Jun. 30, 2011 Guarantor Subsidiaries [Member] As Restated [Member]	Jun. 30, 2012 Non-Guarantor Subsidiaries [Member]	Jun. 30, 2011 Non-Guarantor Subsidiaries [Member] As Restated [Member]	Jun. 30, 2012 Consolidation, Eliminations [Member]	Jun. 30, 2011 Consolidation, Eliminations [Member] As Restated [Member]
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided by (Used in) Operating Activities	$ 77,724	$ 93,114	[1]	$ (1,053)	$ 106,127	$ 54,799	$ (17,167)	$ 23,978	$ 4,154	$ 0	$ 0
Investing Activities:
Change in restricted cash	5,409	(2,256)	[1]	0	(19)	5,401	(2,202)	8	(35)	0	0
Payment of direct costs related to acquisitions		0
Purchase of property and equipment	(4,836)	(4,815)	[1]	0	0	(2,728)	(4,196)	(2,108)	(619)	0	0
Proceeds from disposal of property and equipment	355	50	[1]	0	0	57	93	298	(43)	0	0
Net cash (used in) provided by investing activities	928	(7,021)	[1]	0	(19)	2,730	(6,305)	(1,802)	(697)	0	0
Financing Activities:
Issuance of common stock—equity plans	1,780	3,498	[1]	1,780	3,498	0	0	0	0	0	0
Purchase of treasury stock and other, net	(613)	(4,527)	[1]	(613)	(4,527)	0	0	0	0	0	0
Debt issuance costs	0	(1,701)	[1]		(1,701)		0		0		0
Change in intercompany receivable/payable	0	0		0	0	(217)	614	217	(614)	0	0
Net cash (used in) provided by financing activities	1,167	(2,059)	[1]	1,167	(2,059)	(217)	614	217	(614)	0	0
Effect of exchange rates on cash and cash equivalents	(2,901)	1,106	[1]	0	0	0	0	(2,901)	1,106	0	0
Net increase (decrease) in cash and cash equivalent	76,918	85,140	[1]	114	104,049	57,312	(22,858)	19,492	3,949	0	0
Cash and Cash Equivalents, Beginning of Period	285,512	171,618	[1]	150,171	46,012	93,285	87,619	42,056	37,987	0	0
Cash and Cash Equivalents, End of Period	$ 362,430	$ 256,758	[1]	$ 150,285	$ 150,061	$ 150,597	$ 64,761	$ 61,548	$ 41,936	$ 0	$ 0

[1] (1) As restated - See Note 14 “Restatement of Previously Issued Financial Statements” of Notes to Condensed Consolidated Financial Statements.See notes to Condensed Consolidated Financial Statements.