SUPPLEMENTAL INFORMATION ON OIL AND NATURAL GAS OPERATIONS (Unaudited) - Average First Day of the Month Price for Oil, Natural Gas & Natural Gas Liquids (Details)	12 Months Ended
	Dec. 31, 2019 $ / Mcf $ / bbl	Dec. 31, 2018 $ / Mcf $ / bbl	Dec. 31, 2017 $ / Mcf $ / bbl
Oil
Oil and Gas, Delivery Commitment [Line Items]
Average sales prices (dollars per unit)	51.88	59.63	48.03
Natural Gas
Oil and Gas, Delivery Commitment [Line Items]
Average sales prices (dollars per unit) | $ / Mcf	0.18	1.47	2.06
Natural Gas Liquids
Oil and Gas, Delivery Commitment [Line Items]
Average sales prices (dollars per unit) | $ / bbl	15.65	24.43	20.79