DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Derivative Instruments (Details) bbl in Thousands, MMBTU in Thousands, $ in Millions	9 Months Ended
	Sep. 30, 2021 USD ($) $ / MMBTU $ / bbl MMBTU Counterparty bbl
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of derivative counterparties | Counterparty	11
Fixed Price Swaps | October—December 2021 | Crude Oil | NYMEX WTI
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, nonmonetary notional amount (in Mbbls) | bbl	1,012
Derivative weighted average fixed price (USD per bbl) | $ / bbl	58.59
Fixed Price Swaps | October—December 2021 | Crude Oil | Dated Brent
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, nonmonetary notional amount (in Mbbls) | bbl	828
Derivative weighted average fixed price (USD per bbl) | $ / bbl	61.44
Basis Swap | October—December 2021 | Crude Oil | Midland-WTI/Cushing-WTI
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, nonmonetary notional amount (in Mbbls) | bbl	1,012
Weighted average price differential | $ / bbl	0.70
Basis Swap Purchased | October—December 2021 | Natural Gas | NYMEX Henry Hub/IF Waha
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, nonmonetary notional amount (in MMBtu) | MMBTU	11,050
Weighted average price differential | $ / MMBTU	(0.42)
Basis Swap Purchased | January—December 2022 | Natural Gas | NYMEX Henry Hub/IF Waha
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, nonmonetary notional amount (in MMBtu) | MMBTU	43,800
Weighted average price differential | $ / MMBTU	(0.45)
Basis Swap Purchased | January—December 2023 | Natural Gas | NYMEX Henry Hub/IF Waha
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, nonmonetary notional amount (in MMBtu) | MMBTU	29,200
Weighted average price differential | $ / MMBTU	(0.40)
Basis Swap Sold | October—December 2021 | Natural Gas | NYMEX Henry Hub/IF HSC
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, nonmonetary notional amount (in MMBtu) | MMBTU	11,050
Weighted average price differential | $ / MMBTU	(0.07)
Basis Swap Sold | January—December 2022 | Natural Gas | NYMEX Henry Hub/IF HSC
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, nonmonetary notional amount (in MMBtu) | MMBTU	43,800
Weighted average price differential | $ / MMBTU	(0.08)
Basis Swap Sold | January—December 2023 | Natural Gas | NYMEX Henry Hub/IF HSC
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, nonmonetary notional amount (in MMBtu) | MMBTU	29,200
Weighted average price differential | $ / MMBTU	0.02
Financial Contracts, Gas Daily Pricing
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Realized gain in connection with contracts | $	$ 147