Quarterly report pursuant to Section 13 or 15(d)

Schedule of Derivative Instruments in Statement of Financial Position, Fair Value (Details)

v3.7.0.1
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value (Details) - USD ($)
$ in Thousands
Jun. 30, 2017
Dec. 31, 2016
Derivatives, Fair Value    
Derivative Assets $ 5,130 $ 4,419
Derivative Liabilities 662 719
Forward Contracts | Commodity Contracts    
Derivatives, Fair Value    
Derivative Asset, Fair Value, Amount Not Offset Against Collateral 0 30
Derivative Liability, Fair Value, Amount Not Offset Against Collateral 662 719
Forward Contracts | Fair Value Hedge    
Derivatives, Fair Value    
Derivative Asset, Fair Value, Amount Not Offset Against Collateral 5,130 4,389
Not Designated as Hedging Instrument, Economic Hedge    
Derivatives, Fair Value    
Derivative Asset, Fair Value, Amount Not Offset Against Collateral 0 30
Derivative Liability, Fair Value, Amount Not Offset Against Collateral 662 719
Not Designated as Hedging Instrument, Economic Hedge | Accounts Receivable | Forward Contracts | Commodity Contracts    
Derivatives, Fair Value    
Derivative Asset, Fair Value, Amount Not Offset Against Collateral   30
Not Designated as Hedging Instrument, Economic Hedge | Accrued Liabilities | Forward Contracts | Commodity Contracts    
Derivatives, Fair Value    
Derivative Liability, Fair Value, Amount Not Offset Against Collateral 662 719
Designated as Hedging Instrument    
Derivatives, Fair Value    
Derivative Asset, Fair Value, Amount Not Offset Against Collateral 5,130 4,389
Derivative Liability, Fair Value, Amount Not Offset Against Collateral 0 0
Designated as Hedging Instrument | Other Assets | Forward Contracts | Fair Value Hedge    
Derivatives, Fair Value    
Derivative Asset, Fair Value, Amount Not Offset Against Collateral $ 5,130 $ 4,389