Revenue by Geographic Area (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
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 195,016	$ 162,258	$ 380,361	$ 320,305
UNITED STATES
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	66,467	48,404	130,062	97,510
JAPAN
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	29,619	25,503	59,174	52,428
GERMANY
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	19,912	17,006	40,453	33,966
CANADA
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	3,130	2,540	6,268	5,490
Other European
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	42,284	40,856	84,140	80,061
Other International
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 33,604	$ 27,949	$ 60,264	$ 50,850