Comprehensive Income (Detail) (USD $) In Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net income	$ 67,637	$ 47,221	$ 163,676	$ 92,616
Other comprehensive income:
Foreign currency translation adjustments, net of tax benefit of $2,527 and $6,318 in 2011, and tax benefit of $383 and tax of $203 in 2010	(4,189)	6,667	4,390	2,356
Reclassification of unrealized loss on available for sale securities to the income statement		(387)		382
Unrealized loss on available for sale securities, net of tax		387
Unrealized (loss) gain on derivative instruments, net of tax of $7,063 and $5,105 in 2011 and tax benefit of $2,010 and tax of $256 in 2010	11,878	(3,335)	8,588	426
Comprehensive income	$ 75,326	$ 50,553	$ 176,654	$ 95,780