Quarterly report pursuant to Section 13 or 15(d)

Derivative Instruments And Hedging Strategies (Recognized Gains (Losses) On Derivative Instruments Not Designated As Hedging Instruments) (Details)

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Derivative Instruments And Hedging Strategies (Recognized Gains (Losses) On Derivative Instruments Not Designated As Hedging Instruments) (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Derivative [Line Items]    
Derivative gains (losses), net $ 0 $ 2,830
Forward Currency Exchange, Option And Future Contracts [Member]    
Derivative [Line Items]    
Derivative gains (losses), net 0 202
Three Point Seven Five Percentage Convertible Notes [Member]    
Derivative [Line Items]    
Embedded Derivative, Gain on Embedded Derivative $ 0 $ 2,628