Financial Instruments And Risk Management (Balance Sheet Classification And Fair Value Of Derivative Instruments) (Details) - Currency Forward Contracts [Member] - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Prepaid Expenses And Other Current Assets [Member] | Derivative Instruments Designated As Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	$ 18,945	$ 11,855	$ 14,366
Prepaid Expenses And Other Current Assets [Member] | Derivative Instruments Not Designated As Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	4,449	2,146	971
Other Noncurrent Assets [Member] | Derivative Instruments Designated As Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	10,520	4,159	10,014
Accrued Liabilities [Member] | Derivative Instruments Designated As Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	231	1,313	149
Accrued Liabilities [Member] | Derivative Instruments Not Designated As Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	978	953	349
Other Long Term Liabilities [Member] | Derivative Instruments Designated As Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	$ 0	$ 768	$ 0