Property, Plant and Equipment (Tables)

12 Months Ended

Sep. 30, 2023

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, 2023 and 2022 consisted of the following (in thousands):

	September 30,
	2023		2022
Construction equipment	$	447,467	$	402,581
Plants	208,708		167,625
Land and improvements	76,396		59,454
Mineral reserves	69,405		91,992
Buildings	36,885		32,566
Furniture and fixtures	7,538		7,110
Leasehold improvements	1,268		1,230
Total property, plant and equipment, gross	847,667		762,558
Accumulated depreciation, depletion and amortization	(358,462)		(304,935)
Construction in progress	15,890		23,789
Total property, plant and equipment, net	$	505,095	$	481,412