Financial Instruments - Schedule of Derivative Instruments in Statement of Financial Position, Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Sep. 30, 2025
Derivatives Fair Value [Line Items]
Gross/net financial instruments, assets	$ 6,850	$ 9,897
Gross/net financial instruments, liabilities	(2,822)	(6,485)
Not Designated As Hedges:
Derivatives Fair Value [Line Items]
Gross/net financial instruments, assets	6,850	9,897
Gross/net financial instruments, liabilities	(2,822)	(6,485)
Not Designated As Hedges: \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherAssetsCurrent \| Commodity contracts
Derivatives Fair Value [Line Items]
Gross/net financial instruments, assets	3,824	5,303
Not Designated As Hedges: \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherAssetsNoncurrent \| Commodity contracts
Derivatives Fair Value [Line Items]
Gross/net financial instruments, assets	3,026	4,594
Not Designated As Hedges: \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesCurrent \| Commodity contracts
Derivatives Fair Value [Line Items]
Gross/net financial instruments, liabilities	(2,822)	(6,339)
Not Designated As Hedges: \| Location, Statement of Financial Position, Balance [Axis]: us-gaap:OtherLiabilitiesNoncurrent \| Commodity contracts
Derivatives Fair Value [Line Items]
Gross/net financial instruments, liabilities	$ 0	$ (146)