Supplementary Information For Oil And Gas Producing Activities (Principal Sources Of Change In The Standardized Measure Of Discounted Future Net Cash Flows) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Supplementary Information For Oil And Gas Producing Activities Unaudited [Abstract]
Standardized Measure of Discounted Future Net Cash Flows at Beginning of Year	$ 2,353,572	$ 1,222,470	$ 1,736,319
Sales, Net of Production Costs	(1,572,402)	(626,132)	(290,975)
Net Changes in Prices, Net of Production Costs	4,132,889	1,478,995	(1,109,101)
Extensions and Discoveries	1,355,257	462,040	4,236
Changes in Estimated Future Development Costs	(32,160)	48,247	99,884
Purchases of Minerals in Place	0	0	170,363
Sales of Minerals in Place	(311,308)	0	0
Previously Estimated Development Costs Incurred	154,253	81,239	219,938
Net Change in Income Taxes at Applicable Statutory Rate	(1,180,349)	(415,993)	248,182
Revisions of Previous Quantity Estimates	3,316	(52,383)	(28,337)
Accretion of Discount and Other	545,262	155,089	171,961
Standardized Measure of Discounted Future Net Cash Flows at End of Year	$ 5,448,330	$ 2,353,572	$ 1,222,470