DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Commodity Derivative Instruments Outstanding (Details) gal in Thousands	12 Months Ended
	Dec. 31, 2015 gal
Derivatives NOT Designated as Hedging Instruments | Current Derivative Contract | Physical fixed price derivative contracts
Derivative Instruments And Hedging Activities
Volume (in gallons)	13,741
Derivatives NOT Designated as Hedging Instruments | Current Derivative Contract | Physical index derivative contracts
Derivative Instruments And Hedging Activities
Volume (in gallons)	69,457
Derivatives NOT Designated as Hedging Instruments | Current Derivative Contract | Futures contracts for refined petroleum products | Futures Contracts
Derivative Instruments And Hedging Activities
Volume (in gallons)	13,587
Derivatives NOT Designated as Hedging Instruments | Long-term Derivative Contract | Physical fixed price derivative contracts
Derivative Instruments And Hedging Activities
Volume (in gallons)	1,659
Derivatives NOT Designated as Hedging Instruments | Long-term Derivative Contract | Physical index derivative contracts
Derivative Instruments And Hedging Activities
Volume (in gallons)	0
Derivatives NOT Designated as Hedging Instruments | Long-term Derivative Contract | Futures contracts for refined petroleum products | Futures Contracts
Derivative Instruments And Hedging Activities
Volume (in gallons)	2,562
Derivatives Designated as Hedging Instruments | Current Derivative Contract | Futures contracts for refined petroleum products | Futures Contracts | Fair Value Hedge
Derivative Instruments And Hedging Activities
Volume (in gallons)	136,458
Derivatives Designated as Hedging Instruments | Current Derivative Contract | Futures contracts for refined petroleum products | Futures Contracts | Cash Flow Hedge
Derivative Instruments And Hedging Activities
Volume (in gallons)	8,400
Derivatives Designated as Hedging Instruments | Long-term Derivative Contract | Futures contracts for refined petroleum products | Futures Contracts | Fair Value Hedge
Derivative Instruments And Hedging Activities
Volume (in gallons)	0
Derivatives Designated as Hedging Instruments | Long-term Derivative Contract | Futures contracts for refined petroleum products | Futures Contracts | Cash Flow Hedge
Derivative Instruments And Hedging Activities
Volume (in gallons)	0