Derivative Financial Instruments (Details)	Sep. 30, 2020 USD ($) bbl $ / bbl
Open costless collar contracts
Summary of contracts for oil and natural gas
Fair Value of Asset (Liability) | $	$ 4,333,000
Open Swap Contracts
Summary of contracts for oil and natural gas
Fair Value of Asset (Liability) | $	(26,724,000)
Open Basis Swap Contracts
Summary of contracts for oil and natural gas
Fair Value of Asset (Liability) | $	$ 9,239,000
Derivative Contract, Calculation Period One | Open costless collar contracts | Oil
Summary of contracts for oil and natural gas
Notional Quantity (Bbl or MMBtu) | bbl	879,000
Weighted Average Price Floor ($/Bbl or $/MMBtu)	48.03
Weighted Average Price Ceiling ($/Bbl or $/MMBtu)	66.05
Fair Value of Asset (Liability) | $	$ 6,752,000
Derivative Contract, Calculation Period One | Open Swap Contracts | Oil
Summary of contracts for oil and natural gas
Notional Quantity (Bbl or MMBtu) | bbl	2,160,000
Fair Value of Asset (Liability) | $	$ (12,061,000)
Derivative, Swap Type, Average Fixed Price	35.00
Derivative Contract, Calculation Period One | Open Basis Swap Contracts | Oil Basis
Summary of contracts for oil and natural gas
Notional Quantity (Bbl or MMBtu) | bbl	2,448,000
Fair Value of Asset (Liability) | $	$ 1,373,000
Derivative, Swap Type, Average Fixed Price	0.61
Derivative Contract, Calculation Period Two | Open costless collar contracts | Natural Gas
Summary of contracts for oil and natural gas
Notional Quantity (Bbl or MMBtu) | bbl	7,200,000
Weighted Average Price Floor ($/Bbl or $/MMBtu)	2.45
Weighted Average Price Ceiling ($/Bbl or $/MMBtu)	3.82
Fair Value of Asset (Liability) | $	$ 393,000
Derivative Contract, Calculation Period Three | Open costless collar contracts | Natural Gas
Summary of contracts for oil and natural gas
Notional Quantity (Bbl or MMBtu) | bbl	36,600,000
Weighted Average Price Floor ($/Bbl or $/MMBtu)	2.44
Weighted Average Price Ceiling ($/Bbl or $/MMBtu)	3.71
Fair Value of Asset (Liability) | $	$ (1,684,000)
Derivative Contract, Calculation Period Four | Open costless collar contracts | Oil
Summary of contracts for oil and natural gas
Notional Quantity (Bbl or MMBtu) | bbl	4,200,000
Weighted Average Price Floor ($/Bbl or $/MMBtu)	36.07
Weighted Average Price Ceiling ($/Bbl or $/MMBtu)	47.33
Fair Value of Asset (Liability) | $	$ (1,128,000)
Derivative Contract, Calculation Period Four | Open Swap Contracts | Oil
Summary of contracts for oil and natural gas
Notional Quantity (Bbl or MMBtu) | bbl	2,040,000
Fair Value of Asset (Liability) | $	$ (14,663,000)
Derivative, Swap Type, Average Fixed Price	35.26
Derivative Contract, Calculation Period Four | Open Basis Swap Contracts | Oil Basis
Summary of contracts for oil and natural gas
Notional Quantity (Bbl or MMBtu) | bbl	8,400,000
Fair Value of Asset (Liability) | $	$ 5,341,000
Derivative, Swap Type, Average Fixed Price	0.87
Derivative Contract, Calculation Period Five | Open Basis Swap Contracts | Oil Basis
Summary of contracts for oil and natural gas
Notional Quantity (Bbl or MMBtu) | bbl	5,520,000
Fair Value of Asset (Liability) | $	$ 2,525,000
Derivative, Swap Type, Average Fixed Price	0.95