Commitment and Contingencies - Additional Information (Details) $ in Millions		1 Months Ended	3 Months Ended	9 Months Ended
		Apr. 30, 2019 Complaint	Jun. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)
Commitments And Contingencies [Line Items]
Reserve for unpaid and incurred but not reported claims, amount			$ 154.5	$ 154.5	$ 124.5
Reserve for unpaid and incurred but not reported claims, classified in current liabilities			51.8	51.8	37.4
Reserve for unpaid and incurred but not reported claims, classified in non-current liabilities			102.7	102.7	87.1
Claims recoverable from third party insurance carriers			37.7	37.7	32.1
Charge related to changes in self-insured liability estimates	[1]		24.1	24.1
Number of purported class action complaints | Complaint		2
Other Current Assets
Commitments And Contingencies [Line Items]
Claims recoverable from third party insurance carriers			10.3	10.3	6.1
Other Assets
Commitments And Contingencies [Line Items]
Claims recoverable from third party insurance carriers			$ 27.4	$ 27.4	$ 26.0

[1] Represents expenses related to changes in estimates and actuarial assumptions associated with the Company’s self-insured liability amounts for workers’ compensation, general liability, auto liability, and employee health care insurance programs, to reflect uncertainties associated with the current environment, including the COVID-19 pandemic.