Significant Accounting Policies - Schedule of Disaggregated Revenues (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Net revenues	$ 1,619.0	$ 1,443.5	$ 1,236.1
Discontinued Operations, Held-for-sale
Disaggregation of Revenue [Line Items]
Net revenues associated with suspended operations	0.0	1,174.4	2,695.2
Oil changes and related fees
Disaggregation of Revenue [Line Items]
Net revenues	1,188.7	1,074.3	913.4
Non-oil changes and related fees
Disaggregation of Revenue [Line Items]
Net revenues	350.1	297.6	248.3
Franchise fees and other
Disaggregation of Revenue [Line Items]
Net revenues	$ 80.2	71.6	74.4
Franchise fees and other | Discontinued Operations, Held-for-sale
Disaggregation of Revenue [Line Items]
Net revenues associated with suspended operations		$ 0.2	$ 11.6