Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Millions	Dec. 31, 2025	Sep. 30, 2025
Property Plant And Equipment [Line Items]
Property and equipment	$ 1,106.1	$ 1,092.5
Less: Accumulated depreciation	571.7	550.9
Property and equipment, net	534.4	541.6
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	48.6	48.5
Operating Equipment
Property Plant And Equipment [Line Items]
Property and equipment	445.3	443.3
Transportation Vehicles
Property Plant And Equipment [Line Items]
Property and equipment	507.8	491.9
Office Equipment and Software
Property Plant And Equipment [Line Items]
Property and equipment	57.4	56.3
Construction in Progress
Property Plant And Equipment [Line Items]
Property and equipment	$ 4.1	$ 9.6
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