LEASES - Components of Lease Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Operating lease cost	$ 26.3	$ 19.8	$ 15.6
Finance lease cost
Amortization of leased assets	10.5	11.3	11.8
Interest on lease liability	5.2	5.3	5.7
Variable lease cost	10.8	9.8	9.8
Total lease cost	$ 52.8	$ 46.2	$ 42.9