Long-Term Debt - Schedule of Long-Term Debt (Details) - USD ($) $ in Millions	Mar. 31, 2024	Sep. 30, 2023
Debt Instrument [Line Items]
Financing costs, net	$ (5.8)	$ (6.6)
Long-term debt, net	880.4	888.1
Series B Term Loan
Debt Instrument [Line Items]
Debt instruments net of original issue discount	732.2	731.7
Receivables Financing Agreement
Debt Instrument [Line Items]
Debt instruments net of original issue discount	$ 154.0	$ 163.0