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) - USD ($)
$ in Thousands
Mar. 31, 2016
Dec. 31, 2015
Mar. 31, 2015
Derivative Instruments Designated As Cash Flow Hedges [Member] | Currency Forward Contracts [Member]      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Currency forward contracts $ 228,500 $ 161,000 $ 106,500
Derivative Instruments Designated As Cash Flow Hedges [Member] | Foreign Exchange Option [Member]      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Currency forward contracts 0 0 7,000
Derivative Instruments Not Designated As Cash Flow Hedges [Member] | Currency Forward Contracts [Member]      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Currency forward contracts $ 60,785 $ 113,195 $ 75,000