Derivatives and Hedging - Gains (Losses) Associated with Fair Value and Cash Flow Hedges (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments, Gain (Loss)
After-Tax Amount of Gain (Loss) Recognized in OCI	$ 2,696	$ (3,761)
After-Tax Amount of Gain (Loss) Reclassified from AOCI into Earnings	(761)	(159)
Foreign currency contracts
Derivative Instruments, Gain (Loss)
After-Tax Amount of Gain (Loss) Recognized in OCI	2,696	(3,761)
Foreign currency contracts | Total cost of revenue
Derivative Instruments, Gain (Loss)
After-Tax Amount of Gain (Loss) Reclassified from AOCI into Earnings	(499)	103
Interest rate contracts
Derivative Instruments, Gain (Loss)
After-Tax Amount of Gain (Loss) Recognized in OCI	0	0
Interest rate contracts | Interest expense
Derivative Instruments, Gain (Loss)
After-Tax Amount of Gain (Loss) Reclassified from AOCI into Earnings	$ (262)	$ (262)