Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 193,389	$ 241,840	$ 158,405
Foreign currency translation adjustments, net of tax of $12,705, $19,903 and $13,662	(22,983)	(35,230)	(25,306)
Unrealized gain on interest rate derivatives, net of tax of ($4,956), $0 and $0	8,086	0	0
Other comprehensive loss, net of tax	(14,897)	(35,230)	(25,306)
Comprehensive income	$ 178,492	$ 206,610	$ 133,099