Derivatives and Hedging-Disclosures and Fair Value Measurements - Offsetting of Financial Assets (Liabilities) and Derivative Assets (Liabilities) (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Sep. 30, 2023
Fair Values Of Financial Assets And Liabilities Including Derivative Financial Instruments [Line Items]
Net Assets (Liabilities) Presented in the Statement of Financial Position	$ (2,189)	$ (118)
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	(2,189)	(118)
Net Assets (Liabilities) Presented in the Statement of Financial Position	(41)	(15)
Gross Assets Recognized	8,161	18,670
Gross Liabilities Offset in the Statement of Financial Position	(10,129)	(8,028)
Net Assets (Liabilities) Presented in the Statement of Financial Position	(1,968)	10,642
Gross Amounts Not Offset in the Statement of Financial Position, Net Amount	(1,968)	10,642
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	1,951	17,815
Gross Liabilities Offset in the Statement of Financial Position	(1,729)	(7,155)
Net Assets (Liabilities) Presented in the Statement of Financial Position	$ 222	$ 10,660
Derivative Asset, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Derivative Asset, Current	Derivative Asset, Current
Gross Amounts Not Offset in the Statement of Financial Position, Net Amount	$ 222	$ 10,660
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	124	567
Gross Liabilities Offset in the Statement of Financial Position	(84)	(452)
Net Assets (Liabilities) Presented in the Statement of Financial Position	$ 40	$ 115
Derivative Asset, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Derivative Asset, Current	Derivative Asset, Current
Gross Amounts Not Offset in the Statement of Financial Position, Net Amount	$ 40	$ 115
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	5,720	76
Gross Liabilities Offset in the Statement of Financial Position	(7,909)	(194)
Gross Amounts Not Offset in the Statement of Financial Position, Net Amount	(2,189)	(118)
Subject to an enforceable master netting arrangement | Other long-term liabilities, net
Fair Values Of Financial Assets And Liabilities Including Derivative Financial Instruments [Line Items]
Gross Assets Recognized	366	212
Gross Liabilities Offset in the Statement of Financial Position	(407)	(227)
Gross Amounts Not Offset in the Statement of Financial Position, Net Amount	$ (41)	$ (15)