Supplementary Information For Oil And Gas Producing Activities (Capitalized Costs Relating To Oil And Gas Producing Activities) (Details) - USD ($) $ in Thousands		Sep. 30, 2022	Sep. 30, 2021
Supplementary Information For Oil And Gas Producing Activities Unaudited [Abstract]
Proved Properties	[1]	$ 5,915,807	$ 6,652,341
Unproved Properties		65,994	103,759
Capitalized Costs, Oil and Gas Producing Activities, Gross, Total		5,981,801	6,756,100
Less - Accumulated Depreciation, Depletion and Amortization		4,034,266	4,881,972
Capitalized Costs Oil And Gas Producing Activities Net		1,947,535	1,874,128
Asset retirement costs		$ 120,800	$ 152,800

[1] Includes asset retirement costs of $120.8 million and $152.8 million at September 30, 2022 and 2021, respectively.