Statement Of Consolidated 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 Consolidated Comprehensive Income [Abstract]
Net income	$ 24,340	$ 12,736	$ 69,423	$ 69,745
Other comprehensive income, before tax and net of reclassification adjustments:
Foreign currency translation adjustment	2,278	(8,589)	1,324	(1,165)
Unrealized (loss) gain on securities available-for-sale, net	(609)	(281)	91	(1,285)
Unrealized (loss) gain on derivative instruments, net	(1,646)	(4,195)	2,986	(1,040)
Other comprehensive income (loss), before tax	23	(13,065)	4,401	(3,490)
Tax provision related to items of other comprehensive income	652	621	(507)	97
Other comprehensive income (loss), net of tax	675	(12,444)	3,894	(3,393)
Comprehensive income	$ 25,015	$ 292	$ 73,317	$ 66,352