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Concentrations of Credit Risk - Additional Information (Detail) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 30, 2025 USD ($)	Jun. 30, 2024	Jun. 30, 2025 USD ($)	Jun. 30, 2024	Sep. 30, 2024 USD ($) Vendor	Sep. 30, 2023 USD ($)	Sep. 30, 2022
Concentration Risk [Line Items]
Restricted cash	$ 3,048		$ 3,048		$ 3,009	$ 3,132
Outstanding letters of credit to be collateralized by amounts on deposit	3,000		3,000		3,000	3,100
Allowance for doubtful accounts	$ 0		$ 0		$ 0	$ 0
Number of vendors represents more than ten percentage of purchases | Vendor					2
AAR {Member]
Concentration Risk [Line Items]
Percentage of purchases during year					18.00%
Standard Aero Holdings, Inc. [Member]
Concentration Risk [Line Items]
Percentage of purchases during year					11.00%
Sales Revenue, Net [Member] | American Airlines Inc. [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration risk, percentage					0.00%	23.00%	45.00%
Sales Revenue, Net [Member] | United Airlines Inc [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	98.00%	98.00%	98.00%	96.00%	97.00%	73.00%	48.00%

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Amount of allowance for credit loss on accounts receivable.

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Amount of cash restricted as to withdrawal or usage. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits.

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