Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Other Comprehensive Income [Abstract]
Net income	$ 113,144	$ 94,345	$ 268,612	$ 224,246
Other comprehensive income, net of tax:
Foreign currency translation adjustments, net of tax benefit (expense) of $60 and $281 in 2013 and ($478) and ($348) in 2012	8,982	4,997	2,655	2,927
Unrealized gain (loss) on derivative instruments, net of tax benefit (expense) of $672 and ($1,124) in 2013 and $997 and $2,067 in 2012	(1,131)	(1,750)	1,889	(3,396)
Comprehensive income	$ 120,995	$ 97,592	$ 273,156	$ 223,777