Goodwill and Other Intangibles - Schedule of other intangible assets subject to amortization (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Feb. 29, 2024	Nov. 30, 2023	Feb. 29, 2024	Feb. 28, 2023	May 31, 2023
Finite-lived Intangible Assets [Roll Forward]
Beginning balance other intangibles subject to amortization			$ 7.8	$ 6.0	$ 6.0
Additions	$ 0.2	$ 5.8	6.0	4.1	4.1
Amortization expense			(1.9)	(1.7)	(2.2)
Foreign currency translation			0.0	(0.1)	(0.1)
Total other intangibles subject to amortization, net of accumulated amortization of $24.8, $24.1 and $22.5, respectively	11.9		11.9	8.3	7.8
Accumulated amortization of intangible assets	38.4		38.4	36.0	36.5
Total other intangibles not subject to amortization	2.1		2.1	2.1	2.1
Total other intangibles	$ 14.0		$ 14.0	$ 10.4	$ 9.9