Quarterly report pursuant to Section 13 or 15(d)

Financial Instruments And Risk Management (Effect And Classification Of Derivative Instruments) (Details)

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Financial Instruments And Risk Management (Effect And Classification Of Derivative Instruments) (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Derivative Instruments Designated As Cash Flow Hedges [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (loss) recognized in other comprehensive income or loss $ (5,537) $ (787) $ (6,975) $ (7,925)
Cost Of Sales [Member] | Derivative Instruments Designated As Cash Flow Hedges [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (loss) reclassified from accumulated other comprehensive income or loss to income or loss for the effective portion 897 171 951 1,605
Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net 0 (81) 0 (81)
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net 492 540 1,286 962
Sales [Member] | Derivative Instruments Designated As Cash Flow Hedges [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (loss) reclassified from accumulated other comprehensive income or loss to income or loss for the effective portion 0 0 144 161
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net 2 1 5 5
Other Non-operating Income (Expense) [Member] | Derivative Instruments Not Designated As Cash Flow Hedges [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (loss) recognized in income or loss $ (1,723) $ (1,887) $ (3,411) $ (3,441)