Supplemental Financial Information - Disaggregation of Sales by Timing of Revenue Recognized and Revenue by Category (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2025	Mar. 31, 2024
Disaggregation of Revenue [Line Items]
Net revenues	$ 403.2	$ 388.7	$ 817.5	$ 762.1
Oil changes and related fees
Disaggregation of Revenue [Line Items]
Net revenues	291.0	283.2	592.7	560.7
Non-oil changes and related fees
Disaggregation of Revenue [Line Items]
Net revenues	89.9	86.8	181.3	165.0
Franchise fees and other
Disaggregation of Revenue [Line Items]
Net revenues	22.3	18.7	43.5	36.4
Net revenues transferred at a point in time
Disaggregation of Revenue [Line Items]
Net revenues	381.7	370.1	775.8	726.0
Franchised revenues transferred over time
Disaggregation of Revenue [Line Items]
Net revenues	$ 21.5	$ 18.6	$ 41.7	$ 36.1