Summary of Significant Accounting Policies - Schedule of Other Accruals and Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Sep. 30, 2024
Accounting Policies [Abstract]
Accrued Capital Expenditures	$ 45,932	$ 47,344
Regulatory Liabilities	20,624	29,352
Liability for Royalty and Working Interests	28,076	15,007
Pennsylvania Impact Fee	14,923	9,972
Non-Qualified Benefit Plan Liability	11,567	14,135
Other	53,567	47,093
Other Accruals and Current Liabilities	$ 174,689	$ 162,903