Derivatives Not Designated as Hedging Relationships (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Other Income (Expense) [Member]
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Foreign exchange forward contracts	$ 3,636	$ (2,063)	$ 2,113	$ (3,805)
Interest Rate Cap [Member] | Interest Expense [Member]
Derivative Instruments Not Designated as Hedging Instruments [Abstract]
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	$ 95	$ (175)	$ 377	$ (301)