FAIR VALUE MEASUREMENTS - Level 3 Fair Value Measurements of Derivative Commodity Instruments (Details) - Discounted Cash Flow Valuation Technique - Level 3 $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) $ / bbl
Oil | WTI/WTI Basis Swaps | 2018
Fair Value, Option, Quantitative Disclosures [Line Items]
Net derivative asset (liability), at fair value | $	$ (11,374)
Oil | WTI/WTI Basis Swaps | 2019
Fair Value, Option, Quantitative Disclosures [Line Items]
Net derivative asset (liability), at fair value | $	(626)
Natural Gas Liquids | 2018
Fair Value, Option, Quantitative Disclosures [Line Items]
Net derivative asset (liability), at fair value | $	(16,764)
Natural Gas Liquids | 2019
Fair Value, Option, Quantitative Disclosures [Line Items]
Net derivative asset (liability), at fair value | $	$ (524)
Natural Gas Liquids | WTI/WTI Basis Swaps | 2019
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value inputs, derivative, nonmonetary notional amount, price per unit (usdperbbl)	0.68
Minimum | Oil | WTI/WTI Basis Swaps | 2018
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value inputs, derivative, nonmonetary notional amount, price per unit (usdperbbl)	(0.03)
Minimum | Oil | WTI/WTI Basis Swaps | 2019
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value inputs, derivative, nonmonetary notional amount, price per unit (usdperbbl)	(0.36)
Minimum | Natural Gas Liquids | WTI/WTI Basis Swaps | 2018
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value inputs, derivative, nonmonetary notional amount, price per unit (usdperbbl)	0.74
Maximum | Oil | WTI/WTI Basis Swaps | 2018
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value inputs, derivative, nonmonetary notional amount, price per unit (usdperbbl)	0.11
Maximum | Oil | WTI/WTI Basis Swaps | 2019
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value inputs, derivative, nonmonetary notional amount, price per unit (usdperbbl)	(0.24)
Maximum | Natural Gas Liquids | WTI/WTI Basis Swaps | 2018
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value inputs, derivative, nonmonetary notional amount, price per unit (usdperbbl)	0.78