Derivative Instruments and Hedging Activities - Foreign Exchange Gain (Loss) Derivative Instruments (Details) - Derivatives not designated as hedging instruments - Foreign exchange forward contracts - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative [Line Items]
Gain recognized in other income and expense	$ 121
Loss recognized in other income and expense		$ (12,238)	$ (3,288)	$ (8,487)