Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 100,943	$ 96,905	$ 189,506	$ 177,806
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments, net of tax benefit (expense) of $198 and $213 in 2015 and ($123) and ($139) in 2014	2,465	(1,459)	(27,691)	(152)
Unrealized gain (loss) on derivative instruments, net of tax benefit (expense) of $798 and ($137) in 2015 and $941 and $604 in 2014	(1,341)	(1,581)	231	(1,015)
Comprehensive income	$ 102,067	$ 93,865	$ 162,046	$ 176,639