Hedging Instruments (Derivatives Designated in Cash Flow Hedging Relationships) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Foreign Currency Fair Value Hedge Derivative [Line Items]
Total cost of revenue	$ 1,041,359	$ 971,700	$ 871,676
Foreign currency exchange contracts | Cost of revenue
Foreign Currency Fair Value Hedge Derivative [Line Items]
Amount of gain (loss) reclassified from accumulated other comprehensive income into income	$ 10,628	$ (976)	$ 27