Goodwill and Other Intangibles - Schedule of other intangible assets subject to amortization (Details) - USD ($) $ in Millions	9 Months Ended		12 Months Ended
	Feb. 28, 2021	Feb. 29, 2020	May 31, 2020
Finite-lived Intangible Assets [Roll Forward]
Beginning balance other intangibles subject to amortization	$ 10.5	$ 12.2	$ 12.2
Additions	0.0	1.6	1.6
Adjustments	(0.5)	0.0	0.0
Amortization expense	(1.7)	(2.4)	(3.2)
Foreign currency translation	0.5	0.1	(0.1)
Total other intangibles subject to amortization, net of accumulated amortization of $24.8, $24.1 and $22.5, respectively	8.8	11.5	10.5
Accumulated amortization of intangible assets	31.8	29.3	30.1
Total other intangibles not subject to amortization	2.1	2.1	2.1
Total other intangibles	$ 10.9	$ 13.6	$ 12.6