Real Estate - Text (Detail) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | |||
|---|---|---|---|---|---|
Jun. 30, 2023 |
Jun. 30, 2022 |
Jun. 30, 2023 |
Jun. 30, 2022 |
Sep. 30, 2022 |
|
| Real Estate Properties [Line Items] | |||||
| Real estate | $ 1,909.1 | $ 1,909.1 | $ 2,022.4 | ||
| Payments to Acquire Residential Real Estate | 71.0 | ||||
| Payments to Develop Real Estate Assets | 566.3 | ||||
| Asset Impairment Charges | 0.0 | 19.4 | $ 3.8 | ||
| Due Diligence Write-Offs | 0.9 | $ 1.0 | 4.2 | $ 3.2 | |
| Developed and under development projects | |||||
| Real Estate Properties [Line Items] | |||||
| Real estate | 1,867.0 | 1,867.0 | 1,932.6 | ||
| Land held for future development | |||||
| Real Estate Properties [Line Items] | |||||
| Real estate | $ 42.1 | $ 42.1 | $ 89.8 | ||
| D.R. Horton, Inc. [Member] | Maximum | |||||
| Real Estate Properties [Line Items] | |||||
| Related Party Transaction, Rate | 16.00% | ||||
| D.R. Horton, Inc. [Member] | Minimum | |||||
| Real Estate Properties [Line Items] | |||||
| Related Party Transaction, Rate | 12.00% | ||||