Derivative Financial Instruments and Hedging Derivative Financial Instruments and Hedging Narrative (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Sep. 30, 2024 |
Sep. 30, 2023 |
Sep. 30, 2022 |
|
| Derivative [Line Items] | |||
| Financing portion of cash paid for rate-lock interest rate swaps | $ 0.0 | $ (43.5) | $ 0.0 |
| Not Designated as Hedging Instrument | Interest rate swap | |||
| Derivative [Line Items] | |||
| Derivative, Notional amount of terminated contracts | 400.0 | 200.0 | |
| Derivative, Cash Received for Termination | 5.2 | 6.7 | |
| Derivative, Notional Amount | $ 300.0 | 700.0 | |
| Not Designated as Hedging Instrument | Interest rate swap, rate lock swaps | |||
| Derivative [Line Items] | |||
| Derivative, Notional amount of terminated contracts | 849.3 | 700.0 | |
| Derivative, Cash Settlements paid, net | 55.1 | $ 17.0 | |
| Not Designated as Hedging Instrument | Interest rate swap, options | |||
| Derivative [Line Items] | |||
| Derivative, Notional amount of terminated contracts | 332.6 | ||
| Derivative, Cash Settlements paid, net | $ 2.1 | ||