Supplemental Information on Oil and Natural Gas Producing Activities (Unaudited) - Summary of Changes in Estimated Oil and Natural Gas Reserves (Unaudited) (Details) Mcf in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2020 MBoe MBbls Mcf	Dec. 31, 2020 MBoe Mcf MBbls	Dec. 31, 2019 MBoe Mcf MBbls
Proved Developed and Undeveloped Reserves (in MBbls for Oil and NGLs/MMcf for Natural Gas)
Proved developed and undeveloped reserves, Beginning balance (MBoe) | MBoe		89,885	160,176
Revisions of previous estimates (MBoe) | MBoe	(9,000.0)	(44,800)	(58,514)
Acquisitions of new reserves (MBoe) | MBoe		1,076
Extensions and discoveries (MBoe) | MBoe			1,084
Sales of reserves in place (MBoe) | MBoe		(579)	(905)
Production (MBoe) | MBoe		(8,703)	(11,956)
Proved developed and undeveloped reserves, Ending balance (MBoe) | MBoe	36,879	36,879	89,885
Proved developed reserves (MBoe) | MBoe	36,879	36,879	62,086
Proved undeveloped reserves (MBoe) | MBoe	0	0	27,799
Oil
Proved Developed and Undeveloped Reserves (in MBbls for Oil and NGLs/MMcf for Natural Gas)
Proved developed and undeveloped reserves, beginning balance		35,308	64,019
Revisions of previous estimates		(24,650)	(25,530)
Acquisitions of new reserves		74
Extensions and discoveries			635
Sales of reserves in place		(163)	(297)
Production		(2,084)	(3,519)
Proved developed and undeveloped reserves, ending balance	8,485	8,485	35,308
Proved developed reserves (in MBbls for Oil and NGLs/MMcf for Natural Gas)	8,485	8,485	14,078
Proved undeveloped reserves (in MBbls for Oil and NGLs/MMcf for Natural Gas)	0	0	21,230
NGL
Proved Developed and Undeveloped Reserves (in MBbls for Oil and NGLs/MMcf for Natural Gas)
Proved developed and undeveloped reserves, beginning balance		15,859	28,175
Revisions of previous estimates		(2,246)	(9,277)
Acquisitions of new reserves		437
Extensions and discoveries			94
Sales of reserves in place		(111)	(223)
Production		(2,694)	(2,910)
Proved developed and undeveloped reserves, ending balance	11,245	11,245	15,859
Proved developed reserves (in MBbls for Oil and NGLs/MMcf for Natural Gas)	11,245	11,245	14,532
Proved undeveloped reserves (in MBbls for Oil and NGLs/MMcf for Natural Gas)	0	0	1,327
Natural gas
Proved Developed and Undeveloped Reserves (in MBbls for Oil and NGLs/MMcf for Natural Gas)
Proved developed and undeveloped reserves, beginning balance | Mcf		232,307	407,891
Revisions of previous estimates | Mcf		(107,426)	(142,239)
Acquisitions of new reserves | Mcf		3,391
Extensions and discoveries | Mcf			2,127
Sales of reserves in place | Mcf		(1,827)	(2,308)
Production | Mcf		(23,552)	(33,164)
Proved developed and undeveloped reserves, ending balance | Mcf	102,893	102,893	232,307
Proved developed reserves (in MBbls for Oil and NGLs/MMcf for Natural Gas) | Mcf	102,893	102,893	200,853
Proved undeveloped reserves (in MBbls for Oil and NGLs/MMcf for Natural Gas) | Mcf	0	0	31,454