Debt (Details) - USD ($) $ in Millions	Jun. 30, 2025	Sep. 30, 2024
Debt Instrument [Line Items]
Total	$ 1,380.0	$ 1,284.0
Long-term debt	1,372.7	1,275.0
Notes payable	23.2	24.5
Unamortized debt issuance costs	$ 7.3	$ 9.0
Short-Term Debt, Weighted Average Interest Rate, at Point in Time	3.70%	3.80%
Senior notes | Senior Notes, Due 2028
Debt Instrument [Line Items]
Total	$ 750.0	$ 750.0
Unamortized debt issuance costs	4.3	5.4
Senior notes | Senior Notes, Due 2029
Debt Instrument [Line Items]
Total	500.0	500.0
Unamortized debt issuance costs	$ 3.0
Revolving credit facility
Debt Instrument [Line Items]
Total		$ 34.0