Financial Instruments - Schedule of Derivative Instruments in Statement of Financial Position, Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Assets
Net Financial Instruments	$ 381,991	$ 230,686
Liabilities
Net Financial Instruments	(4,129)	(5,269)
Designated As Hedges:
Assets
Gross / Net Financial Instruments	355,075	169,469
Liabilities
Gross / Net Financial Instruments	0	0
Designated As Hedges: | Deferred charges and other assets | Interest rate contracts
Assets
Gross / Net Financial Instruments	355,075	169,469
Designated As Hedges: | Deferred credits and other liabilities | Interest rate contracts
Liabilities
Gross / Net Financial Instruments	0	0
Not Designated As Hedges:
Assets
Gross / Net Financial Instruments	26,916	61,217
Liabilities
Gross / Net Financial Instruments	(4,129)	(5,269)
Not Designated As Hedges: | Other current assets | Commodity contracts
Assets
Gross / Net Financial Instruments	26,207	55,073
Not Designated As Hedges: | Other current liabilities | Commodity contracts
Liabilities
Gross / Net Financial Instruments	(3,000)	(5,269)
Not Designated As Hedges: | Deferred charges and other assets | Commodity contracts
Assets
Gross / Net Financial Instruments	709	6,144
Not Designated As Hedges: | Deferred credits and other liabilities | Commodity contracts
Liabilities
Gross / Net Financial Instruments	$ (1,129)	$ 0