Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Consolidated Statements of Comprehensive Income (Unaudited) [Abstract]
Net income	$ 41,672	$ 56,872	$ 111,202	$ 104,901
Other comprehensive income, net of tax:
Foreign currency translation adjustment, net of taxes of $(3,054) and $(760) for the three months ended September 30, 2017 and 2016, respectively, and $(1,376) and $(2,324) for the nine months ended September 30, 2017 and 2016, respectively	5,497	2,463	15,273	4,413
Net unrealized gains/(losses) on foreign currency cash flow hedges, net of taxes of $15 and $147 for the three months ended September 30, 2017 and 2016, respectively, and $114 and $1,722 for the nine months ended September 30, 2017 and 2016, respectively	(27)	(266)	(207)	(3,126)
Reclassification adjustment for realized losses/(gains) in current earnings, net of taxes of $(22) and $(409) for the three months ended September 30, 2017 and 2016, respectively, and $97 and $(803) for the nine months ended September 30, 2017 and 2016, respectively	40	743	(177)	1,459
Total other comprehensive income	5,510	2,940	14,889	2,746
Comprehensive income	$ 47,182	$ 59,812	$ 126,091	$ 107,647