- Schedule of other intangible assets subject to amortization (Details) - USD ($) $ in Millions	9 Months Ended		12 Months Ended
	Feb. 28, 2017	Feb. 29, 2016	May 31, 2016
Finite-lived Intangible Assets [Roll Forward]
Beginning balance other intangibles subject to amortization	$ 4.7	$ 4.7	$ 4.7
Additions	0.2	2.4	2.4
Amortization expense	(1.8)	(1.7)	(2.2)
Foreign currency translation	(0.2)	(0.1)	(0.2)
Total other intangibles subject to amortization, net of accumulated amortization of $21.3, $19.5 and $19.0, respectively	2.9	5.3	4.7
Accumulated amortization of intangible assets	21.3	19.0	19.5
Total other intangibles not subject to amortization	2.1	2.1	2.1
Total other intangibles	$ 5.0	$ 7.4	$ 6.8