Derivatives Instruments and Hedging Activities - Foreign Exchange Gain (Loss) Derivative Instruments (Details) - Derivatives not designated as hedging instruments - Foreign exchange forward contracts - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Loss recognized in other income expense	$ (14,648)
Gain recognized in other income and expense		$ 17,902