Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Net income	$ 48,231	$ 42,285	$ 135,697	$ 140,823
Other comprehensive income:
Foreign currency translation adjustments	3,770	(5,588)	740	(1,200)
Change in unrealized (loss) gain on investments, net	1,246	(6,517)	1,540	(3,840)
Income tax (expense) benefit related to unrealized gain (loss) on investments, net	(425)	2,507	(538)	1,482
Other comprehensive income (loss)	4,591	(9,598)	1,742	(3,558)
Comprehensive income	$ 52,822	$ 32,687	$ 137,439	$ 137,265