Property and Equipment, net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	3 Months Ended
Dec. 31, 2018	Sep. 30, 2018
Property Plant And Equipment [Line Items]
Property and equipment	$ 556,942	$ 544,813
Less: Accumulated depreciation	301,512	288,007
Property and equipment, net	255,430	256,806
Land
Property Plant And Equipment [Line Items]
Property and equipment	52,696	51,490
Building and Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment	37,403	36,275
Operating Equipment
Property Plant And Equipment [Line Items]
Property and equipment	189,897	186,499
Transportation Vehicles
Property Plant And Equipment [Line Items]
Property and equipment	216,136	208,371
Office Equipment and Software
Property Plant And Equipment [Line Items]
Property and equipment	55,433	57,976
Construction in Progress
Property Plant And Equipment [Line Items]
Property and equipment	$ 5,377	$ 4,202
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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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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