Supplementary Information for Exploration and Production Activities - Capitalized Costs Relating to Exploration and Production Activities (Details) - USD ($) $ in Thousands		Sep. 30, 2024	Sep. 30, 2023
Supplementary Information for Exploration and Production Activities Unaudited [Abstract]
Proved Properties	[1]	$ 7,079,903	$ 6,555,088
Unproved Properties		200,986	161,097
Capitalized costs relating to exploration and production activities, gross		7,280,889	6,716,185
Less — Accumulated Depreciation, Depletion and Amortization		5,004,299	4,269,959
Capitalized costs relating to exploration and production activities, net		2,276,590	2,446,226
Asset retirement costs		$ 175,200	$ 129,200

[1] Includes asset retirement costs of $175.2 million and $129.2 million at September 30, 2024 and 2023, respectively.