DERIVATIVE INSTRUMENTS - Schedule of Derivative Instruments (Details) bbl in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) $ / bbl bbl
Derivative [Line Items]
Fair Value	$ (466,828)
Swap
Derivative [Line Items]
Weighted Average Strike Price (in usd per barrel) | $ / bbl	55.37
Remaining Volume (Barrels) | bbl	80
Fair Value	$ (23,200)
Swap
Derivative [Line Items]
Weighted Average Strike Price (in usd per barrel) | $ / bbl	81.59
Remaining Volume (Barrels) | bbl	80
Fair Value	$ (35,448)
Futures
Derivative [Line Items]
Weighted Average Strike Price (in usd per barrel) | $ / bbl	81.10
Remaining Volume (Barrels) | bbl	110
Fair Value	$ (408,180)