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
Statement of Other Comprehensive Income [Abstract]
Net income	$ 37,710	$ 22,304	$ 98,619	$ 57,118
Unrealized gains on available-for-sale securities, net of tax	8,356	(3,393)	12,714	3,245
Unrealized gains on cash flow hedging instruments, net of tax	463	(8,513)	1,492	(10,105)
Foreign currency translation adjustment, net of tax	1,049	(2,283)	1,439	(1,277)
Total other comprehensive income	9,868	(14,189)	15,645	(8,137)
Comprehensive income	$ 47,578	$ 8,115	$ 114,264	$ 48,981