Property, Plant and Equipment (Tables)

12 Months Ended

Sep. 30, 2021

Property, Plant and Equipment [Abstract]

Schedule of property, plant and equipment

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

Category	Estimated Useful Life
Land and improvements	Land, unlimited; improvements, 15-25 years
Mineral 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, 2021 and 2020 consisted of the following (in thousands):

	September 30,
	2021		2020
Construction equipment	$	333,966	$	253,157
Plants	143,172		102,392
Land and improvements	53,415		38,647
Mineral reserves	86,556		22,205
Buildings	27,163		18,307
Furniture and fixtures	6,426		5,648
Leasehold improvements	1,230		1,135
Total property, plant and equipment, gross	651,928		441,491
Accumulated depreciation, depletion and amortization	(250,803)		(209,532)
Construction in progress	3,707		5,271
Total property, plant and equipment, net	$	404,832	$	237,230