Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 81,888	$ 32,312	$ 141,018	$ 150,367
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments, net of tax benefit (expense) of ($20) and ($455) in 2017 and $13 and $41 in 2016	10,606	1,528	41,042	490
Unrealized gain (loss) on derivative instruments, net of tax benefit (expense) of $99 and $748 in 2017 and ($1,570) and $2,748 in 2016	(167)	2,638	(1,208)	(4,621)
Comprehensive income	$ 92,327	$ 36,478	$ 180,852	$ 146,236