STANDARDIZED MEASURE OF DISCOUNTED FUTURE NET CASH FLOWS RELATING TO PROVED OIL, NATURAL GAS AND NATURAL GAS LIQUIDS RESERVES (UNAUDITED) (Narrative) (Details)	12 Months Ended
	Dec. 31, 2019 $ / MMBTU $ / bbl	Dec. 31, 2018 $ / item $ / MMBTU	Dec. 31, 2017 $ / item $ / MMBTU
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves [Line Items]
Future net cash flows, annual discount rate	10.00%	10.00%	10.00%
Oil
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves [Line Items]
Prices utilized in calculating total estimated proved reserves	55.69	65.56	51.34
Natural Gas
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves [Line Items]
Prices utilized in calculating total estimated proved reserves	2.578	3.100	2.976