Financial Instruments and Risk Management (Balance Sheet Classification and Fair Value of Derivative Instruments) (Details) - Forward Contracts [Member] - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Not Designated as Hedging Instrument [Member] | Prepaid Expenses And Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	$ 1,650	$ 2,146
Not Designated as Hedging Instrument [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	2,268	953
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Prepaid Expenses And Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	947	11,855
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative assets	1,126	4,159
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	7,573	1,313
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Other Long Term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value of derivative liabilities	$ 6,590	$ 768