Summary of Significant Accounting Policies (Details Textual) $ in Thousands			3 Months Ended						9 Months Ended
	Oct. 08, 2021 USD ($) shares	Oct. 01, 2021 USD ($) shares	Sep. 30, 2021 USD ($) bbl MMBTU $ / MMBTU $ / Boe shares	Jun. 30, 2021 shares	Mar. 31, 2021 shares	Sep. 30, 2020 USD ($) shares	Jun. 30, 2020 shares	Mar. 31, 2020 shares	Sep. 30, 2021 USD ($) bbl MMBTU $ / MMBTU $ / Boe shares	Sep. 30, 2020 USD ($) shares	Nov. 04, 2021 bbl MMBTU $ / MMBTU $ / Boe	Aug. 13, 2021 USD ($)	Dec. 31, 2020 USD ($)
Summary of Significant Accounting Policies
Brent Spot Price			78	77	64				78
WTI Spot Price			75	74	59				75
Stock Issued During Period, Shares, Acquisitions | shares			516,675
Acquisition of oil and gas properties | $									$ 13,219	$ 3,441
Total capitalized internal costs | $			$ 1,200			$ 800			3,500	2,800
Proved oil and gas properties | $			1,445,818						1,445,818				$ 1,310,008
Unproved oil and gas properties | $			24,988						24,988				28,090
Furniture, fixtures, and other equipment | $			5,780						5,780				5,275
Less - Accumulated depreciation, depletion, and amortization | $			(846,822)						(846,822)				(801,279)
Net Furniture, Fixtures and other equipment | $			629,764						629,764				542,094
Write-down of oil and gas properties | $			0			0			0	355,948
Allowance for doubtful accounts receivable, current | $			100						100				100
Accounts receivable, gross | $			41,800						41,800				18,800
Accounts receivable related to joint interest owners | $			800						800				4,000
Severance tax receivable | $			1,200						1,200				2,400
Other receivables | $			400						$ 400				700
Percentage of working interest in wells									100.00%
Total amount of supervision fees charged to wells | $			1,300			1,100			$ 3,600	3,200
Provision (Benefit) for Income Taxes | $			(408)			(572)			(408)	20,607
Oil and gas sales | $			99,249			$ 45,699			255,850	$ 123,921
Trade accounts payable | $			8,423						8,423				15,930
Accrued operating expenses | $			3,585						3,585				2,491
Accrued payroll costs | $			3,955						3,955				3,771
Asset retirement obligation - current portion | $			492						492				441
Accrued non-income based taxes | $			6,141						6,141				1,819
Accrued corporate and legal fees | $			132						132				150
Payables for Settled Derivatives | $			13,621						13,621				829
Other payables | $			1,651						1,651				1,560
Accounts payable and accrued liabilities | $			$ 38,000						$ 38,000				$ 26,991
Purchase of treasury stock (shares) | shares			440	13,969	60,177	958	1,098	26,675	74,586	28,731
ATM Program , Maximum Proceeds | $												$ 40,000
Stock Issued During Period, Shares, New Issues | shares			669,600
Stock Issued During Period, Value, New Issues | $			$ 12,756
Oil sales [Member]
Summary of Significant Accounting Policies
Oil and gas sales | $			25,230			$ 17,665			$ 58,587	$ 40,979
Natural gas sales [Member]
Summary of Significant Accounting Policies
Oil and gas sales | $			62,529			23,595			172,234	73,170
NGL sales [Member]
Summary of Significant Accounting Policies
Oil and gas sales | $			$ 11,489			$ 4,439			$ 25,030	$ 9,772
Subsequent Event [Member] | Post Oak Acquisition
Summary of Significant Accounting Policies
Working Interest Acquired		1
Net Oil Weighted Acres Acquired		15,000
Net Gas Weighted Acres Acquired		26,000
Stock Issued During Period, Shares, Acquisitions | shares		1,341,990
Asset Acquisition, Consideration Transferred | $		$ 35,600
Subsequent Event [Member] | Teal Acquisition
Summary of Significant Accounting Policies
Net Oil Weighted Acres Acquired	17,000
Asset Acquisition, Consideration Transferred | $	$ 75,000
Acquisition of oil and gas properties | $	$ 45,000
Wells Purchased	62
Asset Acquisition, Percentage of Liquids Production Acquired	0.71
Asset Acquisition, Percentage of Oil Production Acquired	0.46
Subsequent Event [Member] | Teal Acquisition | Asset Acquisition, Shares Issuable
Summary of Significant Accounting Policies
Stock Issued During Period, Shares, Acquisitions | shares	1,351,961
Subsequent Event [Member] | Teal Acquisition | Asset Acquisition, Share Value Issuable
Summary of Significant Accounting Policies
Asset Acquisition, Consideration Transferred, Contingent Consideration | $	$ 25,000
Swap [Member] | Fourth Quarter 2021 [Member] | Oil Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl			272,662						272,662
Derivative, Swap Type, Fixed Price | $ / Boe			57.50						57.50
Swap [Member] | Fourth Quarter 2021 [Member] | Natural Gas Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | MMBTU			1,530,000						1,530,000
Derivative, Swap Type, Fixed Price			3.60						3.60
Swap [Member] | Fourth Quarter 2021 [Member] | NGL Derivative
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl			192,324						192,324
Derivative, Swap Type, Fixed Price			24.26						24.26
Swap [Member] | First Quarter 2022 | Oil Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl			223,455						223,455
Derivative, Swap Type, Fixed Price | $ / Boe			49.32						49.32
Swap [Member] | First Quarter 2022 | Natural Gas Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | MMBTU			232,500						232,500
Derivative, Swap Type, Fixed Price			4.00						4.00
Swap [Member] | First Quarter 2022 | NGL Derivative
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl			135,000						135,000
Derivative, Swap Type, Fixed Price			25.75						25.75
Swap [Member] | First Quarter 2022 | NGL Derivative | Subsequent Event [Member]
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl											45,000
Derivative, Swap Type, Fixed Price											39.25
Swap [Member] | Second Quarter 2022 | Oil Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl			136,500						136,500
Derivative, Swap Type, Fixed Price | $ / Boe			56.66						56.66
Swap [Member] | Second Quarter 2022 | Natural Gas Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | MMBTU			3,795,000						3,795,000
Derivative, Swap Type, Fixed Price			2.99						2.99
Swap [Member] | Second Quarter 2022 | NGL Derivative
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl			91,000						91,000
Derivative, Swap Type, Fixed Price			26.87						26.87
Swap [Member] | Second Quarter 2022 | NGL Derivative | Subsequent Event [Member]
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl											45,500
Derivative, Swap Type, Fixed Price											32.82
Swap [Member] | Third Quarter 2022 | Oil Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl			246,100						246,100
Derivative, Swap Type, Fixed Price | $ / Boe			49.63						49.63
Swap [Member] | Third Quarter 2022 | Natural Gas Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | MMBTU			4,142,100						4,142,100
Derivative, Swap Type, Fixed Price			3.02						3.02
Swap [Member] | Third Quarter 2022 | NGL Derivative
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl			92,000						92,000
Derivative, Swap Type, Fixed Price			26.87						26.87
Swap [Member] | Third Quarter 2022 | NGL Derivative | Subsequent Event [Member]
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl											46,000
Derivative, Swap Type, Fixed Price											31.29
Swap [Member] | Fourth Quarter 2022 | Oil Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl			184,000						184,000
Derivative, Swap Type, Fixed Price | $ / Boe			54.84						54.84
Swap [Member] | Fourth Quarter 2022 | Natural Gas Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | MMBTU			2,760,000						2,760,000
Derivative, Swap Type, Fixed Price			3.14						3.14
Swap [Member] | Fourth Quarter 2022 | NGL Derivative
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl			92,000						92,000
Derivative, Swap Type, Fixed Price			26.87						26.87
Swap [Member] | Fourth Quarter 2022 | NGL Derivative | Subsequent Event [Member]
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl											46,000
Derivative, Swap Type, Fixed Price											31.09
Swap [Member] | First Quarter 2023 | Oil Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl			81,900						81,900
Derivative, Swap Type, Fixed Price | $ / Boe			55.70						55.70
Swap [Member] | First Quarter 2023 | Oil Derivative Swaps | Subsequent Event [Member]
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl											275
Derivative, Swap Type, Fixed Price | $ / Boe											69.40
Swap [Member] | Second Quarter 2023 | Oil Derivative Swaps | Subsequent Event [Member]
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl											575
Derivative, Swap Type, Fixed Price | $ / Boe											68.40
Swap [Member] | Third Quarter 2023 | Oil Derivative Swaps | Subsequent Event [Member]
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl											53,980
Derivative, Swap Type, Fixed Price | $ / Boe											66.55
Collar Contracts [Member] | Fourth Quarter 2021 [Member] | Oil Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | MMBTU			84,640						84,640
Derivative, Average Floor Price			34.70						34.70
Derivative, Average Cap Price			41.01						41.01
Collar Contracts [Member] | Fourth Quarter 2021 [Member] | Natural Gas Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | MMBTU			9,301,000						9,301,000
Derivative, Average Floor Price			2.73						2.73
Derivative, Average Cap Price			3.15						3.15
Collar Contracts [Member] | Fourth Quarter 2021 [Member] | Natural Gas Derivative Swaps | Subsequent Event [Member]
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | MMBTU											310,000
Derivative, Average Floor Price											6.00
Derivative, Average Cap Price											7.45
Collar Contracts [Member] | First Quarter 2022 | Oil Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | MMBTU			40,500						40,500
Derivative, Average Floor Price			40.00						40.00
Derivative, Average Cap Price			45.55						45.55
Collar Contracts [Member] | First Quarter 2022 | Oil Derivative Swaps | Subsequent Event [Member]
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl											45,000
Derivative, Average Floor Price											73.00
Derivative, Average Cap Price											79.75
Collar Contracts [Member] | First Quarter 2022 | Natural Gas Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | MMBTU			9,055,000						9,055,000
Derivative, Average Floor Price			2.87						2.87
Derivative, Average Cap Price			3.55						3.55
Collar Contracts [Member] | First Quarter 2022 | Natural Gas Derivative Swaps | Subsequent Event [Member]
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | MMBTU											590,000
Derivative, Average Floor Price											6.00
Derivative, Average Cap Price											7.45
Collar Contracts [Member] | Second Quarter 2022 | Oil Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | MMBTU			115,850						115,850
Derivative, Average Floor Price			39.25						39.25
Derivative, Average Cap Price			46.20						46.20
Collar Contracts [Member] | Second Quarter 2022 | Oil Derivative Swaps | Subsequent Event [Member]
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl											45,500
Derivative, Average Floor Price											71.00
Derivative, Average Cap Price											78.00
Collar Contracts [Member] | Second Quarter 2022 | Natural Gas Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | MMBTU			6,156,500						6,156,500
Derivative, Average Floor Price			2.29						2.29
Derivative, Average Cap Price			2.74						2.74
Collar Contracts [Member] | Third Quarter 2022 | Oil Derivative Swaps | Subsequent Event [Member]
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl											46,000
Derivative, Average Floor Price											70.00
Derivative, Average Cap Price											75.40
Collar Contracts [Member] | Third Quarter 2022 | Natural Gas Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | MMBTU			6,739,000						6,739,000
Derivative, Average Floor Price			2.60						2.60
Derivative, Average Cap Price			2.98						2.98
Collar Contracts [Member] | Fourth Quarter 2022 | Oil Derivative Swaps | Subsequent Event [Member]
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl											46,000
Derivative, Average Floor Price											68.00
Derivative, Average Cap Price											73.60
Collar Contracts [Member] | Fourth Quarter 2022 | Natural Gas Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | MMBTU			7,765,076						7,765,076
Derivative, Average Floor Price			2.69						2.69
Derivative, Average Cap Price			3.20						3.20
Collar Contracts [Member] | First Quarter 2023 | Oil Derivative Swaps | Subsequent Event [Member]
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl											45,000
Derivative, Average Floor Price											65.00
Derivative, Average Cap Price											72.80
Collar Contracts [Member] | First Quarter 2023 | Natural Gas Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | MMBTU			8,347,000						8,347,000
Derivative, Average Floor Price			2.89						2.89
Derivative, Average Cap Price			3.52						3.52
Collar Contracts [Member] | Second Quarter 2023 | Oil Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | MMBTU			65,975						65,975
Derivative, Average Floor Price			56.00						56.00
Derivative, Average Cap Price			63.20						63.20
Collar Contracts [Member] | Second Quarter 2023 | Oil Derivative Swaps | Subsequent Event [Member]
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl											45,500
Derivative, Average Floor Price											64.00
Derivative, Average Cap Price											70.85
Collar Contracts [Member] | Second Quarter 2023 | Natural Gas Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | MMBTU			4,125,000						4,125,000
Derivative, Average Floor Price			2.49						2.49
Derivative, Average Cap Price			2.92						2.92
Collar Contracts [Member] | Third Quarter 2023 | Oil Derivative Swaps | Subsequent Event [Member]
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl											46,000
Derivative, Average Floor Price											63.00
Derivative, Average Cap Price											69.10
Collar Contracts [Member] | Third Quarter 2023 | Natural Gas Derivative Swaps
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | MMBTU			1,380,000						1,380,000
Derivative, Average Floor Price			2.60						2.60
Derivative, Average Cap Price			3.13						3.13
Collar Contracts [Member] | Fourth Quarter 2023 | Oil Derivative Swaps | Subsequent Event [Member]
Summary of Significant Accounting Policies
Oil and Gas Production Hedged Volumes | bbl											46,000
Derivative, Average Floor Price											62.00
Derivative, Average Cap Price											67.55
Minimum [Member]
Summary of Significant Accounting Policies
Estimated useful lives of property									2 years
Maximum [Member]
Summary of Significant Accounting Policies
Estimated useful lives of property									20 years