Commitment and Contingencies - Additional Information (Details) - USD ($) $ in Millions	Jun. 30, 2022	Sep. 30, 2021
Commitments And Contingencies [Line Items]
Reserve for unpaid and incurred but not reported claims, amount	$ 151.2	$ 154.7
Reserve for unpaid and incurred but not reported claims, classified in current liabilities	49.6	50.2
Reserve for unpaid and incurred but not reported claims, classified in non-current liabilities	101.6	104.5
Claims recoverable from third party insurance carriers	22.6	30.5
Other Current Assets
Commitments And Contingencies [Line Items]
Claims recoverable from third party insurance carriers	6.9	8.2
Other Assets
Commitments And Contingencies [Line Items]
Claims recoverable from third party insurance carriers	$ 15.7	$ 22.3