Revenues Based on the Domicile of the Company's Customers (Detail) (USD $) In Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2011		Jun. 30, 2010
Segment Reporting Information [Line Items]
Total revenues	$ 447,554		$ 430,887		$ 876,985		$ 844,350
United States
Segment Reporting Information [Line Items]
Total revenues	301,100		311,600		593,800		605,100
Europe
Segment Reporting Information [Line Items]
Total revenues	72,000	[1]	57,900	[1]	137,800	[1]	120,400	[1]
Canada
Segment Reporting Information [Line Items]
Total revenues	46,400		37,700		90,500		74,400
Japan
Segment Reporting Information [Line Items]
Total revenues	18,300	[1]	14,900	[1]	35,700	[1]	27,100	[1]
Mexico
Segment Reporting Information [Line Items]
Total revenues	2,100		1,700		4,000		3,500
Other
Segment Reporting Information [Line Items]
Total revenues	$ 7,700		$ 7,100		$ 15,200		$ 13,900

[1] Revenues are impacted by movements in foreign currency exchange rates. Refer to the discussion under "Revenues" in the Results of Operations.