Operating Segments and Geographic Information Income Statement (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Revenues	$ 224,992	$ 295,569	$ 330,942	$ 271,798	$ 203,713	$ 274,897	$ 295,585	$ 226,708	$ 1,123,301	$ 1,000,903	$ 789,695
Income from operations	(4,897)	40,014	71,261	39,796	6,415	37,068	64,774	28,248	146,174	131,079	78,123
Interest expense									837	853	657
Foreign currency transaction (gains) losses, net									2,500	(4,886)	(2,325)
Other income, net									(2,711)	(1,578)	(1,001)
Income before taxes									145,548	136,690	80,792
Depreciation and amortization									36,694	37,263	37,059
Americas [Member]
Segment Reporting Information [Line Items]
Revenues									495,852	448,077	374,873
Income from operations									85,538	70,532	64,099
Depreciation and amortization									9,849	9,203	8,935
Asia [Member]
Segment Reporting Information [Line Items]
Revenues									457,411	381,767	285,017
Income from operations									140,828	123,918	89,248
Depreciation and amortization									6,922	6,084	6,772
Europe [Member]
Segment Reporting Information [Line Items]
Revenues									169,464	170,868	127,686
Income from operations									21,678	37,106	22,258
Depreciation and amortization									3,116	2,584	2,018
Total Segment Revenues [Member]
Segment Reporting Information [Line Items]
Revenues									1,122,727	1,000,712	787,576
Total Segment Operating Income [Member]
Segment Reporting Information [Line Items]
Income from operations									248,044	231,556	175,605
Total Segment Depreciation And Amortization [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization									19,887	17,871	17,725
Other businesses [Member]
Segment Reporting Information [Line Items]
Revenues									574	191	2,119
Income from operations									(10,805)	(14,128)	(23,321)
Depreciation and amortization									7,003	11,657	13,351
Intersegment eliminations [Member]
Segment Reporting Information [Line Items]
Income from operations									60	66	1,360
Unallocated corporate and other [Member]
Segment Reporting Information [Line Items]
Income from operations									(91,125)	(86,415)	(75,522)
Depreciation and amortization									$ 9,804	$ 7,735	$ 5,983