Derivative Contracts - Effect of Derivative Instruments on Consolidated Statements of Operations for Derivatives not Designated as Hedging Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) on Derivatives Recognized in Income			$ (1,614)	$ (1,823)
Foreign exchange contracts | Cost of Revenues | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) on Derivatives Recognized in Income	$ (885)	$ 0	(885)	4
Interest rate swap agreement | Interest and Other Expense | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) on Derivatives Recognized in Income	$ (28)	$ (1,004)	$ (1,024)	$ (1,656)