Discontinued Operations and Disposal Groups - Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Sep. 30, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total Current Assets Associated with Discontinued Operations	$ 103	$ 0
Total Non-Current Assets Associated with Discontinued Operations	5,066	0
Total Current Liabilities Associated with Discontinued Operations	95	0
Total Non-Current Liabilities Associated with Discontinued Operations	1,607	$ 0
Discontinued Operations, Disposed of by Sale | Kansas Properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accounts receivable	2
Prepaid expenses and other current assets	101
Total Current Assets Associated with Discontinued Operations	103
Oil and natural gas properties, net (successful efforts)	4,526
Goodwill	540
Total Non-Current Assets Associated with Discontinued Operations	5,066
Total Assets Associated with Discontinued Operations	5,169
Accounts Payable	63
Accrued liabilities	32
Total Current Liabilities Associated with Discontinued Operations	95
Asset retirement obligations	1,607
Total Non-Current Liabilities Associated with Discontinued Operations	1,607
Total Liabilities Associated with Discontinued Operations	$ 1,702