Employee Benefit Plans - Schedule of net periodic costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Nov. 30, 2022	Nov. 30, 2021	Nov. 30, 2022	Nov. 30, 2021
Pension Plans | Foreign Plan
Components of net periodic benefit (credit) cost:
Interest cost	$ 0.2	$ 0.3	$ 0.5	$ 0.5
Expected return on assets	(0.3)	(0.3)	(0.6)	(0.6)
Net amortization of prior service credit	0.0	0.0	0.0	0.0
Amortization of (gain) loss	0.1	0.2	0.2	0.4
Net periodic benefit (credit) cost	0.0	0.2	0.1	0.3
Post-Retirement Benefits
Components of net periodic benefit (credit) cost:
Interest cost	0.1	0.0	0.2	0.1
Expected return on assets	0.0	0.0	0.0	0.0
Net amortization of prior service credit	(0.2)	(0.2)	(0.4)	(0.4)
Amortization of (gain) loss	0.0	(0.0)	0.0	0.0
Net periodic benefit (credit) cost	$ (0.1)	$ (0.2)	$ (0.2)	$ (0.3)