Taxes - Schedule of provision for income taxes (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2022	May 31, 2021	May 31, 2020
Current
Federal	$ (2.1)	$ 2.3	$ (72.2)
State and local	0.6	(0.3)	(1.2)
Non-United States	3.0	6.0	2.1
Total Current	1.5	8.0	(71.3)
Deferred Income Taxes and Tax Credits [Abstract]
Federal	6.1	(10.9)	27.3
State and local	2.4	(1.3)	(0.9)
Non-United States	(1.3)	(3.1)	(1.1)
Total Deferred	7.2	(15.3)	25.3
Total provision (benefit) for income taxes	$ 8.7	$ (7.3)	$ (46.0)