PROPERTY, PLANT AND EQUIPMENT

12 Months Ended

Sep. 30, 2025

Property, Plant and Equipment [Abstract]

PROPERTY, PLANT AND EQUIPMENT

12. PROPERTY, PLANT AND EQUIPMENT

As of September 30, 2025 and September 30, 2024, property, plant and equipment at cost and accumulated depreciation were as follows:

(in thousands)	September 30, 2025		September 30, 2024
Land	$	29,766	$	29,401
Buildings and related improvements	217,894		192,569
Machinery and equipment	701,220		596,748
Leasehold improvements	22,116		22,814
Software	64,371		57,363
Construction in progress	107,758		248,128
Property, plant and equipment, at cost	1,143,125		1,147,023
Accumulated depreciation	(548,859)		(494,930)
Property, plant and equipment, net	$	594,266	$	652,093

Depreciation expense for fiscal years ended September 30, 2025, September 30, 2024 and September 30, 2023 was $82,609, $65,507 and $57,720, respectively.

During fiscal 2025, the Company recorded two non-cash impairment charges totaling $59,596 related to certain long-lived assets related to its HDPE pipe and conduit products, primarily fixed assets and definite-lived intangible assets. Impairment charges of $2,918 were recorded to buildings and related improvements, $32,463 were recorded to construction in progress, $1,548 was recorded to leasehold improvements and $22,667 was recorded to machinery and equipment. Refer to Note 14 “Fair Value Measurements” for further discussion of the Company’s impairment review. No impairment was recorded during the fiscal year ended September 30, 2024.

As a result of the asset impairment charges, the book basis of the HDPE fixed assets was adjusted to the new fair value. This resulted in the elimination of previously accumulated depreciation of $14,965, as well as an equivalent reduction in gross fixed assets.