Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Millions	6 Months Ended
Mar. 31, 2022	Sep. 30, 2021
Property Plant And Equipment [Line Items]
Property and equipment	$ 756.3	$ 686.7
Less: Accumulated depreciation	455.0	422.3
Property and equipment, net	301.3	264.4
Land
Property Plant And Equipment [Line Items]
Property and equipment	43.3	42.2
Building and Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment	44.3	38.6
Operating Equipment
Property Plant And Equipment [Line Items]
Property and equipment	277.1	239.1
Transportation Vehicles
Property Plant And Equipment [Line Items]
Property and equipment	314.6	288.4
Office Equipment and Software
Property Plant And Equipment [Line Items]
Property and equipment	73.1	74.3
Construction in Progress
Property Plant And Equipment [Line Items]
Property and equipment	$ 3.9	$ 4.1
Minimum \| Building and Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, Useful Life	2 years
Minimum \| Operating Equipment
Property Plant And Equipment [Line Items]
Property and equipment, Useful Life	2 years
Minimum \| Transportation Vehicles
Property Plant And Equipment [Line Items]
Property and equipment, Useful Life	3 years
Minimum \| Office Equipment and Software
Property Plant And Equipment [Line Items]
Property and equipment, Useful Life	3 years
Maximum \| Building and Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, Useful Life	40 years
Maximum \| Operating Equipment
Property Plant And Equipment [Line Items]
Property and equipment, Useful Life	7 years
Maximum \| Transportation Vehicles
Property Plant And Equipment [Line Items]
Property and equipment, Useful Life	7 years
Maximum \| Office Equipment and Software
Property Plant And Equipment [Line Items]
Property and equipment, Useful Life	10 years

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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