Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Consolidated Statements Of Comprehensive Income [Abstract]
Net income	$ 25,155	$ 19,800	$ 43,303	$ 29,098
Other comprehensive income, before tax and net of reclassification adjustments:
Foreign currency translation adjustment	11,702	(6,191)	15,664	8,166
Unrealized gain on securities available-for-sale	34	211	26	549
Unrealized (loss) gain on derivative instruments	(3,522)	138	(6,334)	3,565
Other comprehensive (loss) gain, before tax	8,214	(5,842)	9,356	12,280
Tax (benefit) expense related to items of other comprehensive income	(1,186)	(1,436)	(2,146)	3,275
Other comprehensive (loss) gain, net of tax	9,400	(4,406)	11,502	9,005
Comprehensive income	$ 34,555	$ 15,394	$ 54,805	$ 38,103