DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Fair Value of Each Classification of Derivative Instrument (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Derivatives, Fair Value
Fair value	$ 47,234	$ 33,808
Netting balance sheet adjustment	0	0
Net Total
Derivatives, Fair Value
Fair value	47,234	33,808
Derivatives NOT Designated as Hedging Instruments
Derivatives, Fair Value
Fair value	(2,601)	(13,137)
Derivatives Designated as Hedging Instruments
Derivatives, Fair Value
Fair value	49,835	46,945
Total current derivative assets
Derivatives, Fair Value
Fair value	50,981	53,285
Netting balance sheet adjustment	(97)	(51,759)
Total current derivative assets | Physical fixed-price derivative contracts
Derivatives, Fair Value
Fair value	816	1,499
Netting balance sheet adjustment	(95)	(306)
Total current derivative assets | Physical index derivative contracts
Derivatives, Fair Value
Fair value	226	334
Netting balance sheet adjustment	(2)	(1)
Total current derivative assets | Interest rate derivatives
Derivatives, Fair Value
Fair value	49,939
Netting balance sheet adjustment	0
Total current derivative assets | Futures contracts for refined petroleum products
Derivatives, Fair Value
Fair value		51,452
Netting balance sheet adjustment		(51,452)
Total current derivative assets | Net Total
Derivatives, Fair Value
Fair value	50,884	1,526
Total current derivative assets | Net Total | Physical fixed-price derivative contracts
Derivatives, Fair Value
Fair value	721	1,193
Total current derivative assets | Net Total | Physical index derivative contracts
Derivatives, Fair Value
Fair value	224	333
Total current derivative assets | Net Total | Interest rate derivatives
Derivatives, Fair Value
Fair value	49,939
Total current derivative assets | Net Total | Futures contracts for refined petroleum products
Derivatives, Fair Value
Fair value		0
Total current derivative assets | Derivatives NOT Designated as Hedging Instruments
Derivatives, Fair Value
Fair value	1,042	53,264
Total current derivative assets | Derivatives NOT Designated as Hedging Instruments | Physical fixed-price derivative contracts
Derivatives, Fair Value
Fair value	816	1,499
Total current derivative assets | Derivatives NOT Designated as Hedging Instruments | Physical index derivative contracts
Derivatives, Fair Value
Fair value	226	334
Total current derivative assets | Derivatives NOT Designated as Hedging Instruments | Interest rate derivatives
Derivatives, Fair Value
Fair value	0
Total current derivative assets | Derivatives NOT Designated as Hedging Instruments | Futures contracts for refined petroleum products
Derivatives, Fair Value
Fair value		51,431
Total current derivative assets | Derivatives Designated as Hedging Instruments
Derivatives, Fair Value
Fair value	49,939	21
Total current derivative assets | Derivatives Designated as Hedging Instruments | Physical fixed-price derivative contracts
Derivatives, Fair Value
Fair value	0	0
Total current derivative assets | Derivatives Designated as Hedging Instruments | Physical index derivative contracts
Derivatives, Fair Value
Fair value	0	0
Total current derivative assets | Derivatives Designated as Hedging Instruments | Interest rate derivatives
Derivatives, Fair Value
Fair value	49,939
Total current derivative assets | Derivatives Designated as Hedging Instruments | Futures contracts for refined petroleum products
Derivatives, Fair Value
Fair value		21
Total non-current derivative assets
Derivatives, Fair Value
Fair value	2	62,999
Netting balance sheet adjustment	0	(231)
Total non-current derivative assets | Physical fixed-price derivative contracts
Derivatives, Fair Value
Fair value	2	164
Netting balance sheet adjustment	0	(5)
Total non-current derivative assets | Interest rate derivatives
Derivatives, Fair Value
Fair value		62,609
Netting balance sheet adjustment		0
Total non-current derivative assets | Futures contracts for refined petroleum products
Derivatives, Fair Value
Fair value		226
Netting balance sheet adjustment		(226)
Total non-current derivative assets | Net Total
Derivatives, Fair Value
Fair value	2	62,768
Total non-current derivative assets | Net Total | Physical fixed-price derivative contracts
Derivatives, Fair Value
Fair value	2	159
Total non-current derivative assets | Net Total | Interest rate derivatives
Derivatives, Fair Value
Fair value		62,609
Total non-current derivative assets | Net Total | Futures contracts for refined petroleum products
Derivatives, Fair Value
Fair value		0
Total non-current derivative assets | Derivatives NOT Designated as Hedging Instruments
Derivatives, Fair Value
Fair value	2	390
Total non-current derivative assets | Derivatives NOT Designated as Hedging Instruments | Physical fixed-price derivative contracts
Derivatives, Fair Value
Fair value	2	164
Total non-current derivative assets | Derivatives NOT Designated as Hedging Instruments | Interest rate derivatives
Derivatives, Fair Value
Fair value		0
Total non-current derivative assets | Derivatives NOT Designated as Hedging Instruments | Futures contracts for refined petroleum products
Derivatives, Fair Value
Fair value		226
Total non-current derivative assets | Derivatives Designated as Hedging Instruments
Derivatives, Fair Value
Fair value	0	62,609
Total non-current derivative assets | Derivatives Designated as Hedging Instruments | Physical fixed-price derivative contracts
Derivatives, Fair Value
Fair value	0	0
Total non-current derivative assets | Derivatives Designated as Hedging Instruments | Interest rate derivatives
Derivatives, Fair Value
Fair value		62,609
Total non-current derivative assets | Derivatives Designated as Hedging Instruments | Futures contracts for refined petroleum products
Derivatives, Fair Value
Fair value		0
Total current derivative liabilities
Derivatives, Fair Value
Fair value	(3,665)	(78,031)
Netting balance sheet adjustment	97	51,759
Total current derivative liabilities | Physical fixed-price derivative contracts
Derivatives, Fair Value
Fair value	(3,662)	(4,517)
Netting balance sheet adjustment	95	306
Total current derivative liabilities | Physical index derivative contracts
Derivatives, Fair Value
Fair value	(3)	(1)
Netting balance sheet adjustment	2	1
Total current derivative liabilities | Futures contracts for refined petroleum products
Derivatives, Fair Value
Fair value		(73,513)
Netting balance sheet adjustment		51,452
Total current derivative liabilities | Net Total
Derivatives, Fair Value
Fair value	(3,568)	(26,272)
Total current derivative liabilities | Net Total | Physical fixed-price derivative contracts
Derivatives, Fair Value
Fair value	(3,567)	(4,211)
Total current derivative liabilities | Net Total | Physical index derivative contracts
Derivatives, Fair Value
Fair value	(1)	0
Total current derivative liabilities | Net Total | Futures contracts for refined petroleum products
Derivatives, Fair Value
Fair value		(22,061)
Total current derivative liabilities | Derivatives NOT Designated as Hedging Instruments
Derivatives, Fair Value
Fair value	(3,561)	(62,346)
Total current derivative liabilities | Derivatives NOT Designated as Hedging Instruments | Physical fixed-price derivative contracts
Derivatives, Fair Value
Fair value	(3,558)	(4,517)
Total current derivative liabilities | Derivatives NOT Designated as Hedging Instruments | Physical index derivative contracts
Derivatives, Fair Value
Fair value	(3)	(1)
Total current derivative liabilities | Derivatives NOT Designated as Hedging Instruments | Futures contracts for refined petroleum products
Derivatives, Fair Value
Fair value		(57,828)
Total current derivative liabilities | Derivatives Designated as Hedging Instruments
Derivatives, Fair Value
Fair value	(104)	(15,685)
Total current derivative liabilities | Derivatives Designated as Hedging Instruments | Physical fixed-price derivative contracts
Derivatives, Fair Value
Fair value	(104)	0
Total current derivative liabilities | Derivatives Designated as Hedging Instruments | Physical index derivative contracts
Derivatives, Fair Value
Fair value	0	0
Total current derivative liabilities | Derivatives Designated as Hedging Instruments | Futures contracts for refined petroleum products
Derivatives, Fair Value
Fair value		(15,685)
Total non-current derivative liabilities
Derivatives, Fair Value
Fair value	(84)	(4,445)
Netting balance sheet adjustment	0	231
Total non-current derivative liabilities | Physical fixed-price derivative contracts
Derivatives, Fair Value
Fair value	(84)	(61)
Netting balance sheet adjustment	0	5
Total non-current derivative liabilities | Futures contracts for refined petroleum products
Derivatives, Fair Value
Fair value		(4,384)
Netting balance sheet adjustment		226
Total non-current derivative liabilities | Net Total
Derivatives, Fair Value
Fair value	(84)	(4,214)
Total non-current derivative liabilities | Net Total | Physical fixed-price derivative contracts
Derivatives, Fair Value
Fair value	(84)	(56)
Total non-current derivative liabilities | Net Total | Futures contracts for refined petroleum products
Derivatives, Fair Value
Fair value		(4,158)
Total non-current derivative liabilities | Derivatives NOT Designated as Hedging Instruments
Derivatives, Fair Value
Fair value	(84)	(4,445)
Total non-current derivative liabilities | Derivatives NOT Designated as Hedging Instruments | Physical fixed-price derivative contracts
Derivatives, Fair Value
Fair value	(84)	(61)
Total non-current derivative liabilities | Derivatives NOT Designated as Hedging Instruments | Futures contracts for refined petroleum products
Derivatives, Fair Value
Fair value		(4,384)
Total non-current derivative liabilities | Derivatives Designated as Hedging Instruments
Derivatives, Fair Value
Fair value	0	0
Total non-current derivative liabilities | Derivatives Designated as Hedging Instruments | Physical fixed-price derivative contracts
Derivatives, Fair Value
Fair value	$ 0	0
Total non-current derivative liabilities | Derivatives Designated as Hedging Instruments | Futures contracts for refined petroleum products
Derivatives, Fair Value
Fair value		$ 0