Derivative Instruments - Statement Of Financial Position (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Derivative [Line Items]
Derivative asset, net, gross fair value	$ (50,970)	$ 21,921
Derivative assets, net, net fair value	(50,970)	21,921	$ 14,959
Current derivative assets
Derivative [Line Items]
Derivative asset, gross fair value	186	19,690
Derivative asset, amounts netted	(186)	(871)
Derivative assets, net fair value	0	18,819
Non-current derivative assets
Derivative [Line Items]
Derivative asset, gross fair value	228	4,651
Derivative asset, amounts netted	(122)	(1,549)
Derivative assets, net fair value	106	3,102
Current derivative liabilities
Derivative [Line Items]
Derivative liability, gross fair value	(42,330)	(871)
Derivative liability, amounts netted	186	871
Derivative liability, net fair value	(42,144)	0
Non-current derivative liabilities
Derivative [Line Items]
Derivative liability, gross fair value	(9,054)	(1,549)
Derivative liability, amounts netted	122	1,549
Derivative liability, net fair value	$ (8,932)	$ 0

Derivative Asset, Fair Value, Amount Not Offset Against Collateral Including Not Subject To Master Netting Arrangement

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Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and elected not to be offset.

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Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Fair value of asset associated with financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

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Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and elected not to be offset.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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