PROPERTY, PLANT AND EQUIPMENT - Schedule of Property Plant and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Sep. 30, 2025
Property, Plant, and Equipment [Line Items]
Property plant and equipment gross	$ 500,889	$ 473,785
Accumulated depreciation	(296,198)	(277,835)
Total	204,691	195,950
Land, building and building improvements
Property, Plant, and Equipment [Line Items]
Property plant and equipment gross	102,629	100,415
Machinery and equipment
Property, Plant, and Equipment [Line Items]
Property plant and equipment gross	367,908	343,029
Leasehold improvements
Property, Plant, and Equipment [Line Items]
Property plant and equipment gross	30,352	30,341
Construction in Progress
Property, Plant, and Equipment [Line Items]
Machinery and equipment	$ 22,674	$ 31,078