RETIREMENT PLANS - Components of Net Periodic Benefit Cost and Weighted Average Assumptions (Details) - Defined Benefit Pension Plan - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
International Plan
Components of net periodic benefit cost (income):
Interest cost	$ 6.2	$ 3.0	$ 2.6
Expected return on plan assets	(5.5)	(5.1)	(5.5)
Net amortization	2.0	1.3	1.3
Net periodic benefit cost (income)	$ 2.7	$ (0.8)	$ (1.6)
Weighted average assumptions used in development of net periodic benefit cost (income):
Weighted average discount rate - interest cost	5.29%	1.64%	1.26%
Expected return on plan assets	3.91%	2.37%	2.45%
U.S. Plan
Components of net periodic benefit cost (income):
Interest cost	$ 3.6	$ 1.7	$ 1.5
Expected return on plan assets	(2.5)	(2.8)	(3.4)
Net amortization	1.8	1.7	2.1
Net periodic benefit cost (income)	$ 2.9	$ 0.6	$ 0.2
Weighted average assumptions used in development of net periodic benefit cost (income):
Weighted average discount rate - interest cost	4.87%	1.74%	1.43%
Expected return on plan assets	4.50%	3.50%	4.25%