Discontinued Operations and Disposal Groups - Statement of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Apr. 02, 2021	Mar. 10, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss from discontinued operations before income taxes	$ (18,738)	$ 0
Income tax expense	(59)	0
Loss on discontinued operations	(18,797)	$ 0
Kansas Properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration from discontinued operations				$ 3,500
Kansas Properties | Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration from discontinued operations			$ 3,500	$ 3,500
Consideration from discontinued operations including closing adjustments			$ 3,300
Total revenues	0
Lease operating expenses	115
Goodwill impairment	18,516
Total expenses	18,631
Other expense	107
Loss from discontinued operations before income taxes	(18,738)
Income tax expense	(59)
Loss on discontinued operations	(18,797)
Kansas Properties | Discontinued Operations, Disposed of by Sale | Oil and natural gas sales, net
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenues	$ 0