Goodwill and Other Intangibles - Schedule of other intangible assets subject to amortization (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended		12 Months Ended
	Nov. 30, 2022	Nov. 30, 2022	Nov. 30, 2021	May 31, 2022
Finite-lived Intangible Assets [Roll Forward]
Beginning balance other intangibles subject to amortization		$ 6.0	$ 8.4	$ 8.4
Additions	$ 4.1	4.1	0.0	0.0
Amortization expense		(1.1)	(1.0)	(2.0)
Foreign currency translation		(0.1)	(0.3)	(0.4)
Total other intangibles subject to amortization, net of accumulated amortization of $24.8, $24.1 and $22.5, respectively	8.9	8.9	7.1	6.0
Accumulated amortization of intangible assets	35.4	35.4	33.3	34.3
Total other intangibles not subject to amortization	2.1	2.1	2.1	2.1
Total other intangibles	$ 11.0	$ 11.0	$ 9.2	$ 8.1