DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Commodity Derivative Instruments (Details) gal in Thousands	3 Months Ended
	Mar. 31, 2016 gal
Derivatives NOT Designated as Hedging Instruments | Physical fixed price derivative contracts | Current
Derivative Instruments And Hedging Activities
Volume (in gallons)	191
Derivatives NOT Designated as Hedging Instruments | Physical fixed price derivative contracts | Long-Term
Derivative Instruments And Hedging Activities
Volume (in gallons)	1,721
Derivatives NOT Designated as Hedging Instruments | Physical index derivative contracts | Current
Derivative Instruments And Hedging Activities
Volume (in gallons)	58,199
Derivatives NOT Designated as Hedging Instruments | Physical index derivative contracts | Long-Term
Derivative Instruments And Hedging Activities
Volume (in gallons)	0
Derivatives NOT Designated as Hedging Instruments | Futures contracts for refined petroleum products | Current
Derivative Instruments And Hedging Activities
Volume (in gallons)	2,342
Derivatives NOT Designated as Hedging Instruments | Futures contracts for refined petroleum products | Long-Term
Derivative Instruments And Hedging Activities
Volume (in gallons)	2,730
Derivatives Designated as Hedging Instruments | Fair Value Hedge | Futures contracts for refined petroleum products | Current
Derivative Instruments And Hedging Activities
Volume (in gallons)	124,278
Derivatives Designated as Hedging Instruments | Fair Value Hedge | Futures contracts for refined petroleum products | Long-Term
Derivative Instruments And Hedging Activities
Volume (in gallons)	0