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Joint Ventures and Variable Interest Entities - Schedule of Equity in Earnings of Unconsolidated Joint Ventures (Details) - USD ($) $ in Thousands | 12 Months Ended
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Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2023
Joint Ventures and Variable Interest Entities [Line Items] |  |  |
Total | $ 27,013 | $ 2,124 | $ (279,352)
Unconsolidated Joint Ventures |  |  |
Joint Ventures and Variable Interest Entities [Line Items] |  |  |
Total | 27,000 | 2,100 | (279,400)
Unconsolidated Joint Ventures | Pass-through joint ventures |  |  |
Joint Ventures and Variable Interest Entities [Line Items] |  |  |
Total | 27,600 | 29,000 | 24,500
Unconsolidated Joint Ventures | Other joint ventures |  |  |
Joint Ventures and Variable Interest Entities [Line Items] |  |  |
Total | $ (600) | $ (26,900) | $ (303,900)

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