Significant Accounting Policies - Schedule of Disaggregated Revenues (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Net revenues	$ 1,443.5	$ 1,236.1	$ 1,037.2
Discontinued Operations, Held-for-sale
Disaggregation of Revenue [Line Items]
Net revenues associated with suspended operations	1,174.4	2,695.2	2,086.7
Oil changes and related fees
Disaggregation of Revenue [Line Items]
Net revenues	1,074.3	913.4	762.3
Non-oil changes and related fees
Disaggregation of Revenue [Line Items]
Net revenues	297.6	248.3	207.9
Franchise fees and other
Disaggregation of Revenue [Line Items]
Net revenues	71.6	74.4	67.0
Franchise fees and other | Discontinued Operations, Held-for-sale
Disaggregation of Revenue [Line Items]
Net revenues associated with suspended operations	$ 0.2	$ 11.6	$ 14.9