Long-Term Debt - Schedule of Long-Term Debt (Details) - USD ($) $ in Millions	Jun. 30, 2025	Sep. 30, 2024
Debt Instrument [Line Items]
Financing costs, net	$ (5.8)	$ (6.5)
Total debt, net	790.7	802.5
Less: Current portion of long-term debt	0.0	0.0
Long-term debt, net	790.7	802.5
Series B Term Loan
Debt Instrument [Line Items]
Debt instruments net of original issue discount	733.7	732.8
Receivables Financing Agreement
Debt Instrument [Line Items]
Debt instruments net of original issue discount	$ 62.8	$ 76.2