Hedging Instruments (Derivatives Designated In Cash Flow Hedging Relationships) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Foreign Currency Fair Value Hedge Derivative [Line Items]
Cost of revenue	$ 299,183	$ 260,353	$ 824,179	$ 767,062
Foreign currency exchange contracts | Costs of revenue
Foreign Currency Fair Value Hedge Derivative [Line Items]
Amount of gain (loss) reclassified from accumulated other comprehensive income into income	$ (591)	$ 3,171	$ 2,562	$ 7,091