Acquisitions and Dispositions - Acquisitions (Details) stores in Thousands, $ in Millions	12 Months Ended
	Sep. 30, 2024 USD ($) numberOfFormerFranchiseCenters service_center_store stores	Sep. 30, 2023 USD ($) service_center_store	Sep. 30, 2022 USD ($) numberOfFormerFranchiseCenters service_center_store
Business Acquisition [Line Items]
Number of service center stores acquired	36	31	37
Number of former franchise service center stores acquired | numberOfFormerFranchiseCenters	5		4
Purchase price | $	$ 53.3
Number of stores | stores	2
Number of service center stores	950
Aggregate purchase price | $	$ 53.3	$ 36.3	$ 50.7
Express Care
Business Acquisition [Line Items]
Number of service center stores acquired	2		5