Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 95,529	$ 81,888	$ 243,783	$ 141,018
Other comprehensive income, net of tax:
Foreign currency translation adjustments	1,804	10,606	(12,099)	41,042
Unrealized gain (loss) on derivative instruments	(2,111)	(167)	2,998	(1,208)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	66	0	196	0
Comprehensive income	$ 95,288	$ 92,327	$ 234,878	$ 180,852