Property and Equipment, net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Millions	3 Months Ended
Dec. 31, 2019	Sep. 30, 2019
Property Plant And Equipment [Line Items]
Property and equipment	$ 603.2	$ 602.0
Less: Accumulated depreciation	334.6	329.6
Property and equipment, net	268.6	272.4
Land
Property Plant And Equipment [Line Items]
Property and equipment	54.1	54.1
Building and Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment	42.0	40.1
Operating Equipment
Property Plant And Equipment [Line Items]
Property and equipment	197.1	199.8
Transportation Vehicles
Property Plant And Equipment [Line Items]
Property and equipment	240.3	236.5
Office Equipment and Software
Property Plant And Equipment [Line Items]
Property and equipment	61.4	63.3
Construction in Progress
Property Plant And Equipment [Line Items]
Property and equipment	$ 8.3	$ 8.2
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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