Derivative Financial Instruments (Details) bbl in Thousands, BTU in Billions	Oct. 29, 2020 BTU $ / Barrels $ / EnergyContent bbl	Sep. 30, 2020 BTU $ / EnergyContent $ / Barrels bbl
NYMEX Oil Swap Contract Fourth Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		4,397
Derivative, Swap Type, Weighted-Average Contract Price | $ / Barrels		57.03
NYMEX Oil Swap Contract, 2021 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		17,115
Derivative, Swap Type, Weighted-Average Contract Price | $ / Barrels		40.38
NYMEX Oil Swap Contract, 2022
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		3,885
Derivative, Swap Type, Weighted-Average Contract Price | $ / Barrels		43.58
NYMEX Oil Swap Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		25,397
NYMEX Oil Collar Contract Fourth Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		610
Derivative, Weighted-Average Floor Price | $ / Barrels		55.00
Derivative, Weighted-Average Ceiling Price | $ / Barrels		61.90
NYMEX Oil Collar Contract, 2021 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		551
Derivative, Weighted-Average Floor Price | $ / Barrels		48.97
Derivative, Weighted-Average Ceiling Price | $ / Barrels		51.96
NYMEX Oil Collar Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		1,161
NYMEX Oil Calendar Month Average Roll Differential Fourth Quarter, 2020
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		2,503
Derivative, Roll Differential Swap Type, Weighted-Average Contract Price | $ / Barrels		(1.18)
NYMEX Oil Calendar Month Average Roll Differential Contract, 2021
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		6,058
Derivative, Roll Differential Swap Type, Weighted-Average Contract Price | $ / Barrels		(0.40)
NYMEX Oil Calendar Month Average Roll Differential Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		8,561
WTI Midland NYMEX WTI [Member] | Oil Basis Swap Contract Fourth Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		4,087
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price | $ / Barrels		(0.38)
WTI Midland NYMEX WTI [Member] | Oil Basis Swap Contract, 2021 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		13,975
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price | $ / Barrels		0.75
WTI Midland NYMEX WTI [Member] | Oil Basis Swap Contract, 2022 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		9,500
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price | $ / Barrels		1.15
WTI Midland NYMEX WTI [Member] | Oil Basis Swap [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		27,562
NYMEX WTI ICE Brent [Member] | Oil Basis Swap Contract Fourth Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		920
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price | $ / Barrels		(8.01)
NYMEX WTI ICE Brent [Member] | Oil Basis Swap Contract, 2021 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		3,650
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price | $ / Barrels		(7.86)
NYMEX WTI ICE Brent [Member] | Oil Basis Swap Contract, 2022 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		3,650
Derivative, Oil Basis Swap Type, Weighted-Average Contract Price | $ / Barrels		(7.78)
NYMEX WTI ICE Brent [Member] | Oil Basis Swap [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		8,220
IF HSC [Member] | Gas Swaps Contract Fourth Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent		2.39
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		9,327
IF HSC [Member] | Gas Swaps Contract, 2021 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent		2.42
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		47,800
IF HSC [Member] | Gas Swaps Contract, 2022 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent		2.23
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		6,104
IF HSC [Member] | Gas Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		63,231
WAHA [Member] | Gas Swaps Contract Fourth Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent		1.21
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		4,872
WAHA [Member] | Gas Swaps Contract, 2021 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent		1.67
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		25,155
WAHA [Member] | Gas Swaps Contract, 2022 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent		2.10
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		5,904
WAHA [Member] | Gas Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU		35,931
IF WAHA [Member]
Derivative Financial Instruments
Index percent of natural gas fixed swaps		64.00%
GD WAHA [Member]
Derivative Financial Instruments
Index percent of natural gas fixed swaps		36.00%
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Fourth Quarter, 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		466
Derivative, Swap Type, Weighted-Average Contract Price | $ / Barrels		22.29
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract, 2021 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		392
Derivative, Swap Type, Weighted-Average Contract Price | $ / Barrels		19.74
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		858
Subsequent Event [Member] | NYMEX Oil Swap Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume	300
Derivative, Swap Type, Weighted-Average Contract Price | $ / Barrels	42.53
Subsequent Event [Member] | IF HSC [Member] | Gas Swaps Contract, 2021 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent	2.62
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU	1,290
Subsequent Event [Member] | IF HSC [Member] | Gas Swaps Contract, 2022 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent	2.58
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU	15,015
Subsequent Event [Member] | GD WAHA [Member] | Gas Swaps Contract, 2021 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent	2.47
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU	924
Subsequent Event [Member] | GD WAHA [Member] | Gas Swaps Contract, 2022 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Weighted-Average Contract Price | $ / EnergyContent	2.46
Derivative, Nonmonetary Notional Amount, Energy Measure | BTU	2,911
Subsequent Event [Member] | OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume	900
Derivative, Swap Type, Weighted-Average Contract Price | $ / Barrels	20.93