PROPERTY, PLANT AND EQUIPMENT - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Millions	Jun. 30, 2024	Sep. 30, 2023
Property, Plant and Equipment [Line Items]
Finance leases	$ 139.2	$ 136.9
Property, plant and equipment	733.2	704.7
Accumulated depreciation	(466.7)	(429.6)
Property, plant and equipment, net	266.5	275.1
Land, buildings and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	85.9	83.4
Machinery, equipment and other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	340.3	330.1
Computer software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	139.2	136.2
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 28.6	$ 18.1