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		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) on Derivatives Recognized in Income			$ (2,038)	$ (2,092)
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	$ (640)	$ 0	(1,525)	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	$ (2)	$ (236)	$ (1,026)	$ (1,891)