Long-Term Debt - Schedule of Long-Term Debt (Details) - USD ($) $ in Millions	Mar. 31, 2025	Sep. 30, 2024
Debt Instrument [Line Items]
Financing costs, net	$ (6.4)	$ (6.5)
Total debt, net	798.9	802.5
Less: Current portion of long-term debt	0.0	0.0
Long-term debt, net	798.9	802.5
Series B Term Loan
Debt Instrument [Line Items]
Debt instruments net of original issue discount	733.4	732.8
Receivables Financing Agreement
Debt Instrument [Line Items]
Debt instruments net of original issue discount	$ 71.9	$ 76.2