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Related Party Transactions - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended
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Aug. 31, 2024 | Aug. 31, 2023 | Aug. 31, 2022
Related Party Transaction [Line Items] |  |  |
Percentage of recognized revenue and margin from sale | 60.00% |  |
Percentage of deferred revenue and margin from sale | 40.00% |  |
Axis LLC |  |  |
Related Party Transaction [Line Items] |  |  |
Percentage of ownership in entity | 41.90% |  |
Greenbrier |  |  |
Related Party Transaction [Line Items] |  |  |
Percentage of ownership in entity | 40.00% |  |
Leasing Warehouse |  |  |
Related Party Transaction [Line Items] |  |  |
Revenue recognized with railcars sold out of leasing warehouse |  | $ 15.1 | $ 9.3
Railcar Components | Axis LLC |  |  |
Related Party Transaction [Line Items] |  |  |
Purchases of goods from related party | $ 8.8 | $ 8.7 | $ 11.5

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