Amount of revenue recognized that was previously reported as deferred or unearned revenue.

No definition available.

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- Definition

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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- Definition

Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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- Definition

Indicates line item in statement of income or comprehensive income that includes operating lease income.

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Amount of operating lease income from lease payments and variable lease payments paid and payable to lessor. Includes, but is not limited to, variable lease payments not included in measurement of lease receivable.

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Contract Revenue and Pass-through and Other Revenue - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Disaggregation Of Revenue [Line Items]
Deferred revenue recognized	$ 1.3		$ 3.7		$ 11.4	$ 3.0
Lease revenue	$ 0.2	$ 29.5	$ 26.1	$ 98.1	$ 123.0	$ 144.7	$ 158.4
Operating Lease, Lease Income, Statement of Income or Comprehensive Income [Extensible Enumeration]			Revenue from Contract with Customer, Excluding Assessed Tax		Revenue from Contract with Customer, Excluding Assessed Tax	Revenue from Contract with Customer, Excluding Assessed Tax	Revenue from Contract with Customer, Excluding Assessed Tax
CRJ-700
Disaggregation Of Revenue [Line Items]
Operating lease, term of contract					9 years