Statement Of Consolidated Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Statement Of Consolidated Comprehensive Income [Abstract]
Net income	$ 18,600	$ 18,642
Other comprehensive income, before tax and net of reclassification adjustments:
Foreign currency translation adjustment	(2,924)	4,316
Unrealized (loss) gain on securities available-for-sale	(442)	1,293
Unrealized gain on derivative instruments	2,078	3,884
Other comprehensive income (loss), before tax	(1,288)	9,493
Tax provision related to items of other comprehensive income	1,162	2,025
Other comprehensive (loss) income, net of tax	(2,450)	7,468
Comprehensive income	$ 16,150	$ 26,110