Quarterly report pursuant to Section 13 or 15(d)

Financial Instruments And Risk Management (Gross Notional Amount Of Outstanding Derivative Instruments) (Details)

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Financial Instruments And Risk Management (Gross Notional Amount Of Outstanding Derivative Instruments) (Details) - Currency Forward Contracts [Member] - USD ($)
$ in Thousands
Jun. 30, 2017
Dec. 31, 2016
Jun. 30, 2016
Derivative Instruments Designated As Cash Flow Hedges [Member]      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Currency forward contracts $ 314,000 $ 206,000 $ 247,500
Derivative Instruments Not Designated As Cash Flow Hedges [Member]      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Currency forward contracts $ 166,476 $ 184,940 $ 79,930