Summary Of Significant Accounting Policies (Schedule Of Other Accruals And Current Liabilities) (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Sep. 30, 2023
Summary Of Significant Accounting Policies [Line Items]
Accrued Capital Expenditures	$ 52,620	$ 43,323
Regulatory Liabilities	27,538	38,105
Reserve for Gas Replacement	6,657	0
Liability for Royalty and Working Interests	17,670	17,679
Non-Qualified Benefit Plan Liability	13,052	13,052
Other	50,569	48,815
Other Accruals and Current Liabilities	169,133	160,974
Federal
Summary Of Significant Accounting Policies [Line Items]
Federal Income Taxes Payable	$ 1,027	$ 0