Debt (Details) - USD ($) $ in Millions	Mar. 31, 2023		Sep. 30, 2022
Debt Instrument [Line Items]
Total long-term debt	$ 1,426.0		$ 1,405.0
Long-term debt	1,413.6		1,391.4
Notes payable	21.5		19.0
Unamortized debt issuance costs	12.4	[1]	13.6
Senior notes | Senior Notes, Due 2028
Debt Instrument [Line Items]
Total long-term debt	750.0		750.0
Unamortized debt issuance costs	7.6		8.3
Senior notes | Senior Notes, Due 2029
Debt Instrument [Line Items]
Total long-term debt	500.0		500.0
Unamortized debt issuance costs	4.8		5.3
Revolving credit facility
Debt Instrument [Line Items]
Total long-term debt	$ 176.0	[2]	$ 155.0

[1] As of March 31, 2023, the balance for the Senior Notes due 2028 and the Senior Notes due 2029 are reflected net of debt issuance costs of $7.6 and $4.8, respectively. As of September 30, 2022, the balance for the Senior Notes due 2028 and the Senior Notes due 2029 are reflected net of debt issuance costs of $8.3 and $5.3, respectively.

[2] The U.S. revolving credit facility matures in April 2025.