Intangible Assets, Goodwill and Acquisitions - Additional Information (Details) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2023 USD ($) Company	Jun. 30, 2022 USD ($) Company	Jun. 30, 2023 USD ($) Company	Jun. 30, 2022 USD ($) Company
Finite Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 10.8	$ 13.2	$ 33.7	$ 38.7
Net service revenues	$ 766.0	$ 747.4	$ 2,072.3	$ 2,051.2
Number of unrelated maintenance services companies acquired | Company	3	7	3	7
Consideration paid, net of cash acquired			$ 13.8	$ 89.4
Unrelated Maintenance Services Companies
Finite Lived Intangible Assets [Line Items]
Acquisition of operations, Percentage	100.00%	100.00%	100.00%	100.00%
Consideration paid, net of cash acquired			$ 13.8	$ 89.4
Business Acquisitions
Finite Lived Intangible Assets [Line Items]
Net service revenues			11.2
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Identifiable assets acquired related to intangible assets	$ 4.0	$ 27.4	$ 4.0	$ 27.4