Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Millions	Jun. 30, 2025	Sep. 30, 2024
Property Plant And Equipment [Line Items]
Property and equipment	$ 1,056.9	$ 934.5
Less: Accumulated depreciation	563.8	542.6
Property and equipment, net	493.1	391.9
Land
Property Plant And Equipment [Line Items]
Property and equipment	42.9	42.9
Buildings and Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment	48.0	46.7
Operating Equipment
Property Plant And Equipment [Line Items]
Property and equipment	426.3	388.3
Transportation Vehicles
Property Plant And Equipment [Line Items]
Property and equipment	477.2	403.1
Office Equipment and Software
Property Plant And Equipment [Line Items]
Property and equipment	55.8	48.6
Construction in Progress
Property Plant And Equipment [Line Items]
Property and equipment	$ 6.7	$ 4.9
Minimum | Buildings 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 | Buildings 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