Asset Retirement Obligation (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Asset Retirement Obligation [Line Items]
Liabilities Incurred	$ 2,401	$ 7,035	$ 61,246
Liabilities Settled	71,171	$ 14,270	7,268
California Asset Sale [Member]
Asset Retirement Obligation [Line Items]
Liabilities Settled	$ 50,100
Shell Acquisition [Member]
Asset Retirement Obligation [Line Items]
Liabilities Incurred			$ 57,200