Financial Instruments And Risk Management (Balance Sheet Classification And Fair Value Of Derivative Instruments) (Details) - Currency Forward Contracts [Member] - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 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	$ 10,839	$ 11,855	$ 11,392
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	4,641	2,146	2,181
Other Noncurrent Assets [Member] | Derivative Instruments Designated As Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	6,775	4,159	6,776
Accrued Liabilities [Member] | Derivative Instruments Designated As Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	80	1,313	170
Accrued Liabilities [Member] | Derivative Instruments Not Designated As Cash Flow Hedges [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	524	953	1,920
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	$ 140