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DERIVATIVES AND RISK MANAGEMENT ACTIVITIES Table 1 - Fair Values of Derivative Instruments (Details) - USD ($)
$ in Thousands
Mar. 31, 2018
Dec. 31, 2017
Derivatives, Fair Value    
Asset Derivatives $ 8,633 $ 742
Liability Derivatives (1,457) (11,608)
Designated as Hedging Instruments    
Derivatives, Fair Value    
Asset Derivatives 7,874 0
Liability Derivatives (454) (10,100)
Designated as Hedging Instruments | Commodity contracts | Accrued liabilities    
Derivatives, Fair Value    
Asset Derivatives 20 0
Liability Derivatives (33) (112)
Designated as Hedging Instruments | Interest rate swaps | Other current assets    
Derivatives, Fair Value    
Asset Derivatives 5,547 0
Liability Derivatives 0 0
Designated as Hedging Instruments | Interest rate swaps | Other long-term assets, net    
Derivatives, Fair Value    
Asset Derivatives 2,307 0
Liability Derivatives 0 0
Designated as Hedging Instruments | Interest rate swaps | Accrued liabilities    
Derivatives, Fair Value    
Asset Derivatives 0 0
Liability Derivatives (114) (5,394)
Designated as Hedging Instruments | Interest rate swaps | Other long-term liabilities    
Derivatives, Fair Value    
Asset Derivatives 0 0
Liability Derivatives (307) (4,594)
Not Designated as Hedging Instruments | Commodity contracts | Accrued liabilities    
Derivatives, Fair Value    
Asset Derivatives 759 742
Liability Derivatives $ (1,003) $ (1,508)