Intangible Assets, Goodwill and Acquisitions - Additional Information (Details) $ in Millions	12 Months Ended
	Sep. 30, 2022 USD ($) Company	Sep. 30, 2021 USD ($) Company	Sep. 30, 2020 USD ($)
Finite Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 51.5	$ 52.3	$ 55.8
Goodwill impairment	$ 0.0	$ 0.0	15.5
Number of unrelated maintenance services companies acquired | Company	8	8
Consideration paid, net of cash acquired	$ 93.1	$ 110.4	90.3
Net service revenues	$ 2,774.6	$ 2,553.6	$ 2,346.0
Unrelated Maintenance Services Companies
Finite Lived Intangible Assets [Line Items]
Acquisition of operations, Percentage	100.00%	100.00%
Consideration paid, net of cash acquired	$ 93.1
Business Acquisitions
Finite Lived Intangible Assets [Line Items]
Net service revenues	65.5
Customer Relationships and Non-compete Agreements
Finite Lived Intangible Assets [Line Items]
Identifiable assets acquired related to intangible assets		$ 28.6
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Identifiable assets acquired related to intangible assets	$ 25.4