Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net Income	$ 312,310	$ 227,575	$ 147,138
Other comprehensive income:
Foreign currency translation adjustments, net of tax (expense) benefit of ($182), $6,782, and ($222)	4,124	2,554	3,131
Unrealized (loss) gain on derivative instruments, net of tax benefit (expense) of $2,325, ($2,125), and $256	(3,909)	3,571	(439)
Unrealized gain on available for sale securities, net of tax benefit of $0, $0, and $230			382
Comprehensive income	$ 312,525	$ 233,700	$ 150,212