Subsequent Event	6 Months Ended
	Mar. 31, 2022
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event    On May 1, 2022, the Company entered into a purchase and sale agreement to sell Seneca’s California oil and gas assets to Sentinel Peak Resources California LLC for total consideration between $280 million and $310 million, depending on oil prices. This consideration consists of $280 million in cash at closing, plus up to three annual contingent payments between calendar 2023 and 2025 that can total $30 million in aggregate. The transaction has an effective date of April 1, 2022 and is expected to close on June 30, 2022, subject to customary closing conditions (including waivers of certain transfer restrictions). The Company pursued this sale given the strong commodity price environment and the Company’s strategic focus in the Appalachian Basin. Under the full cost method of accounting for oil and natural gas properties, it is expected that substantially all of the sale proceeds received at closing will be accounted for as a reduction of capitalized costs since the disposition will not significantly alter the relationship between capitalized costs and proved reserves of oil and gas attributable to the cost center. A portion of the sales proceeds will be applied to assets that are not subject to the full cost method of accounting.