Financial Instruments And Risk Management (Gross Notional Amount Of Outstanding Derivative Instruments) (Details) - Currency Forward Contracts [Member] - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Derivative Instruments Designated As Cash Flow Hedges [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Currency forward contracts	$ 419,402	$ 471,822	$ 412,041
Derivative Instruments Not Designated As Cash Flow Hedges [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Currency forward contracts	$ 224,573	$ 214,086	$ 235,945