Long-Term Debt - Schedule of Long-Term Debt (Details) - USD ($) $ in Millions	Jun. 30, 2026	Sep. 30, 2025
Debt Instrument [Line Items]
Financing costs, net	$ (7.0)	$ (5.3)
Total debt, net	882.7	790.2
Less: Current portion of long-term debt	7.4	0.0
Long-term debt, net	875.3	790.2
Series B Term Loan
Debt Instrument [Line Items]
Debt instruments net of original issue discount	736.0	733.9
Receivables Financing Agreement
Debt Instrument [Line Items]
Debt instruments net of original issue discount	$ 153.7	$ 61.6