Supplementary Information for Exploration and Production Activities - Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Supplementary Information for Exploration and Production Activities Unaudited [Abstract]
Future Cash Inflows	$ 8,514,126	$ 11,947,345	$ 19,209,099
Less:
Future Production Costs	3,672,901	3,538,389	3,138,226
Future Development Costs	1,191,708	1,095,096	781,847
Future Income Tax Expense at Applicable Statutory Rate	826,094	1,867,457	3,876,272
Future Net Cash Flows	2,823,423	5,446,403	11,412,754
Less:
10% Annual Discount for Estimated Timing of Cash Flows	1,486,968	2,874,295	5,964,424
Standardized Measure of Discounted Future Net Cash Flows	$ 1,336,455	$ 2,572,108	$ 5,448,330	$ 2,353,572