Supplementary Information for Oil and Gas Producing Activities - Costs Incurred in Oil and Gas Property Acquisition, Exploration and Development Activities (Details) - USD ($) $ in Thousands		12 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Property Acquisition Costs:
Proved		$ 33,190	$ 2,491	$ 1,801
Unproved		129,061	10,665	5,102
Exploration Costs	[1]	10,055	9,631	15,413
Development Costs	[2]	553,469	528,684	329,368
Asset Retirement Costs		8,363	9,768	20,194
Total Property Acquisition Costs		734,138	561,239	371,878
Capitalized interest included in exploration costs		0	0	100
Capitalized interest included in development costs		$ 100	$ 600	$ 400

[1] Amounts for 2023, 2022 and 2021 include capitalized interest of zero, zero and $0.1 million respectively.

[2] Amounts for 2023, 2022 and 2021 include capitalized interest of $0.1 million, $0.6 million and $0.4 million, respectively.