Real Estate - Text (Detail) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | |||
|---|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
Sep. 30, 2025 |
|
| Real Estate Properties [Line Items] | |||||
| Real estate | $ 2,711.5 | $ 2,711.5 | $ 2,645.1 | ||
| Payments to Acquire Residential Real Estate | 214.8 | ||||
| Payments to Develop Real Estate Assets | 791.2 | ||||
| Asset, Impairment Loss | 0.0 | $ 0.0 | |||
| Loss on Contract Termination | 0.8 | $ 1.9 | 8.0 | $ 3.9 | |
| Developed and under development projects | |||||
| Real Estate Properties [Line Items] | |||||
| Real estate | 2,557.5 | 2,557.5 | 2,465.1 | ||
| Land held for future development | |||||
| Real Estate Properties [Line Items] | |||||
| Real estate | $ 154.0 | $ 154.0 | $ 180.0 | ||
| D.R. Horton, Inc. [Member] | Minimum | |||||
| Real Estate Properties [Line Items] | |||||
| Related Party Transaction, Rate | 12.00% | ||||
| D.R. Horton, Inc. [Member] | Maximum | |||||
| Real Estate Properties [Line Items] | |||||
| Related Party Transaction, Rate | 16.00% | ||||