Derivatives and Hedging-Disclosures and Fair Value Measurements - Offsetting of Financial Assets (Liabilities) and Derivative Assets (Liabilities) (Detail) - USD ($) $ in Thousands	Jun. 30, 2026	Sep. 30, 2025
Fair Values Of Financial Assets And Liabilities Including Derivative Financial Instruments [Line Items]
Net Assets (Liabilities) Presented in the Statement of Financial Position	$ 0	$ (1,398)
Subject to an enforceable master netting arrangement
Fair Values Of Financial Assets And Liabilities Including Derivative Financial Instruments [Line Items]
Net Assets (Liabilities) Presented in the Statement of Financial Position		(1,398)
Gross Assets Recognized	18,611	8,316
Gross Liabilities Offset in the Statement of Financial Position	(7,637)	(8,822)
Net Assets (Liabilities) Presented in the Statement of Financial Position	10,974	(506)
Gross Amounts Not Offset in the Statement of Financial Position, Net Amount	10,974	(506)
Subject to an enforceable master netting arrangement \| Fair asset value of derivative instruments
Fair Values Of Financial Assets And Liabilities Including Derivative Financial Instruments [Line Items]
Gross Assets Recognized	17,892	3,630
Gross Liabilities Offset in the Statement of Financial Position	(7,073)	(2,840)
Net Assets (Liabilities) Presented in the Statement of Financial Position	10,819	790
Gross Amounts Not Offset in the Statement of Financial Position, Net Amount	10,819	790
Subject to an enforceable master netting arrangement \| Other long-term assets, net
Fair Values Of Financial Assets And Liabilities Including Derivative Financial Instruments [Line Items]
Gross Assets Recognized	695	755
Gross Liabilities Offset in the Statement of Financial Position	(536)	(653)
Net Assets (Liabilities) Presented in the Statement of Financial Position	159	102
Gross Amounts Not Offset in the Statement of Financial Position, Net Amount	159	102
Subject to an enforceable master netting arrangement \| Fair liability value of derivative instruments
Fair Values Of Financial Assets And Liabilities Including Derivative Financial Instruments [Line Items]
Gross Assets Recognized		3,931
Gross Liabilities Offset in the Statement of Financial Position		(5,329)
Gross Amounts Not Offset in the Statement of Financial Position, Net Amount		$ (1,398)
Subject to an enforceable master netting arrangement \| Other long-term liabilities
Fair Values Of Financial Assets And Liabilities Including Derivative Financial Instruments [Line Items]
Gross Assets Recognized	24
Gross Liabilities Offset in the Statement of Financial Position	(28)
Net Assets (Liabilities) Presented in the Statement of Financial Position	(4)
Gross Amounts Not Offset in the Statement of Financial Position, Net Amount	$ (4)

Fair values of financial assets and liabilities including derivative financial instruments.

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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 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 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, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

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The net amount as of the balance sheet date of the fair value of derivative assets and derivative liabilities that in accordance with the entity's accounting policy were offset against collateral under a 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 elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value, after offset of derivative liability, of 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, before offset against an obligation to return collateral under a master netting arrangement. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value, after effect of master netting arrangement and deduction of obligation to return financial collateral not offset and financial instrument subject to master netting arrangement not offset, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and contract can be net settled by means outside contract or delivery of asset. Includes derivative not subject to master netting arrangement or similar agreement.

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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 elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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Fair value of the assets less the liabilities of a derivative or group of derivatives.

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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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