Annual report pursuant to Section 13 and 15(d)

Derivative Financial Instruments, Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Details)

v3.6.0.2
Derivative Financial Instruments, Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Details) - Designated as Hedging Instrument - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Derivative Instruments, Gain (Loss)      
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net $ 220 $ (36,816) $ 64,622
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net (753) 41,610 (15,626)
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net 0 0 0
Swaps | Commodity Contracts      
Derivative Instruments, Gain (Loss)      
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net   (35,878) 65,860
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net   0 0
Swaps | Interest Rate Swaps      
Derivative Instruments, Gain (Loss)      
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net 220 (938) (1,238)
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net 0 0 0
Cost of Sales | Swaps | Commodity Contracts      
Derivative Instruments, Gain (Loss)      
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net   41,948 (15,572)
Interest Expense | Swaps | Interest Rate Swaps      
Derivative Instruments, Gain (Loss)      
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net $ (753) $ (338) $ (54)