Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 31,054	$ 25,155	$ 55,322	$ 43,303
Other comprehensive income, before tax and net of reclassification adjustments:
Foreign currency translation adjustment	(11,804)	11,702	(6,001)	15,664
Unrealized gain (loss) on securities available-for-sale	128	34	(557)	26
Unrealized gain (loss) on derivative instruments	12,032	(3,522)	8,262	(6,334)
Other comprehensive income, before tax	356	8,214	1,704	9,356
Tax expense (benefit) related to items of other comprehensive income	2,621	(1,186)	1,760	(2,146)
Other comprehensive (loss) income, net of tax	(2,265)	9,400	(56)	11,502
Comprehensive income	$ 28,789	$ 34,555	$ 55,266	$ 54,805