Statement Of Consolidated Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Statement Of Consolidated Comprehensive Income [Abstract]
Net income	$ 18,642	$ 30,461
Other comprehensive income, before tax and net of reclassification adjustments:
Foreign currency translation adjustment	3,382	5,275
Unrealized gain (loss) on securities available-for-sale, net	1,013	(424)
Unrealized gain on derivative instruments, net	3,885	2,846
Other comprehensive income, before tax	8,280	7,697
Tax provision related to items of other comprehensive income	(812)	(477)
Other comprehensive income, net of tax	7,468	7,220
Comprehensive income	$ 26,110	$ 37,681