Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 241,840	$ 158,405	$ 143,202
Foreign currency translation adjustments, net of tax of $19,903, $13,662 and $(5,605)	(35,230)	(25,306)	9,145
Reclassification of a cash flow hedge into earnings, net of tax of $0, $0 and $1,349			(2,201)
Unrealized gain on cash flow hedges, net of tax of $0, $0 and $(2,444)			3,987
Other comprehensive income (loss), net of tax	(35,230)	(25,306)	10,931
Comprehensive income	$ 206,610	$ 133,099	$ 154,133