Revenues Based on Domicile of Customers (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011
Segment Reporting Information [Line Items]
Total revenues	$ 462,651		$ 447,554		$ 923,813		$ 876,985
United States
Segment Reporting Information [Line Items]
Total revenues	303,800		301,100		609,300		593,800
Europe
Segment Reporting Information [Line Items]
Total revenues	73,900	[1]	72,000	[1]	146,800	[1]	137,800	[1]
Canada
Segment Reporting Information [Line Items]
Total revenues	51,000		46,400		101,800		90,500
Japan
Segment Reporting Information [Line Items]
Total revenues	19,500	[1]	18,300	[1]	37,900	[1]	35,700	[1]
Mexico
Segment Reporting Information [Line Items]
Total revenues	2,700		2,100		5,100		4,000
Other
Segment Reporting Information [Line Items]
Total revenues	$ 11,800	[1]	$ 7,700	[1]	$ 22,900	[1]	$ 15,200	[1]

[1] Revenues are impacted by movements in foreign currency exchange rates.