PROPERTY, PLANT AND EQUIPMENT - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023
Property, Plant and Equipment [Line Items]
Finance leases	$ 137.9	$ 136.9
Property, plant and equipment	717.2	704.7
Accumulated depreciation	(446.0)	(429.6)
Property, plant and equipment, net	271.2	275.1
Land, buildings and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	84.9	83.4
Machinery, equipment and other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	334.5	330.1
Computer software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	140.8	136.2
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 19.1	$ 18.1