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v3.25.2

Leases - Additional Information (Detail) $ in Thousands | 3 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | ---
Mar. 31, 2025 USD ($) AIRCRAFT | Mar. 31, 2024 USD ($) | Mar. 31, 2025 USD ($) AIRCRAFT | Mar. 31, 2024 USD ($) | Sep. 30, 2024 USD ($) AIRCRAFT | Sep. 30, 2023 USD ($) | Sep. 30, 2022 USD ($)
Lessee, Lease, Description [Line Items] |  |  |  |  |  |  |
Number of leased aircraft under finance lease | AIRCRAFT |  |  |  |  | 2 |  |
Finance lease obligations |  |  |  |  | $ 4,700 |  |
Operating lease, right-of-use assets | $ 7,050 |  | $ 7,050 |  | 7,231 | $ 9,709 |
Operating lease current liabilities | 1,535 |  | 1,535 |  | 1,681 | 3,510 |
Operating lease noncurrent liabilities | $ 6,890 |  | $ 6,890 |  | 6,863 | 8,077 |
Financing lease current |  |  |  |  | $ 1,800 |  |
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] |  |  |  |  | Current portion of long-term debt and finance leases |  |
Number of leased aircraft | AIRCRAFT | 23 |  | 23 |  | 32 |  |
Financing lease noncurrent liabilities |  |  |  |  | $ 2,900 |  |
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] |  |  |  |  | Long-term debt and finance leases, excluding current portion |  |
Operating lease payments in operating cash flows |  |  | $ 1,417 | $ 2,858 | $ 4,585 | 9,476 | $ 36,262
Aggregate rental expense under all operating aircraft, equipment and facility lease |  |  |  |  | 13,900 | 12,200 | $ 43,400
Financing lease payments in operating cash flows |  |  |  |  | 2,000 | 1,200 |
Financing lease payments in financing cash flows |  |  |  |  | 65,300 | 15,100 |
Aggregate rental expense under all operating aircraft, equipment and facility leases | $ 2,840 | $ 4,595 | $ 6,109 | $ 12,565 | $ 22,547 | $ 30,114 |
Weighted average remaining lease term Operating leases | 6 years 2 months 12 days |  | 6 years 2 months 12 days |  | 6 years 6 months |  |
Weighted average discount rate Operating leases | 5.40% |  | 5.40% |  | 6.00% |  |

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