Significant Accounting Policies (Tables)

12 Months Ended

Sep. 30, 2019

Accounting Policies [Abstract]

Schedule of customer concentration risk

Two customers accounted for more than 10% of consolidated revenues for the fiscal years ended September 30, 2019 and 2018, as follows:

	% of Consolidated Revenues for the Fiscal Year Ended September 30,
	2019		2018
Alabama Department of Transportation	13.8	%	15.1	%
North Carolina Department of Transportation	13.1	%	13.3	%

Schedule of Revenue by Major Customers by Reporting Segments

The following table reflects, for the periods presented, (i) revenues generated from public infrastructure construction projects and the sale of construction materials to public customers and (ii) revenues generated from private infrastructure construction projects and the sale of construction materials to private customers.

	% of Consolidated Revenues for the Fiscal Year Ended September 30,
	2019	2018
Private	30.7%	28.6%
Public	69.3%	71.4%

Schedule of useful lives of property, plant and equipment

The useful lives of property, plant and equipment categories are as follows:

Category	Estimated Useful Life
Land and improvements	Land, unlimited; improvements, 15-25 years
Quarry reserves	Based on depletion
Buildings	5 - 39 years
Plants	3 - 20 years
Construction equipment	3 - 10 years
Furniture and fixtures	5 - 10 years
Leasehold improvements	The shorter of 15 years or the remaining lease term

Property, plant and equipment at September 30, 2019 and 2018 consisted of the following (in thousands):

	September 30,
	2019		2018
Construction equipment	$	214,500	$	190,420
Plants	92,279		79,563
Land and improvements	34,365		29,624
Quarry reserves	20,678		20,908
Buildings	15,458		12,416
Furniture and fixtures	4,864		4,422
Leasehold improvements	1,135		765
Total property, plant and equipment, gross	383,279		338,118
Accumulated depreciation, depletion and amortization	(177,927)		(160,795)
Construction in progress	518		1,369
Total property, plant and equipment, net	$	205,870	$	178,692