Goodwill and Other Intangibles - Schedule of other intangible assets subject to amortization (Details) - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Nov. 30, 2018	Nov. 30, 2017	May 31, 2018
Finite-lived Intangible Assets [Roll Forward]
Beginning balance other intangibles subject to amortization	$ 10.1	$ 9.0	$ 9.0
Additions	0.6	0.1	3.3
Amortization expense	(1.3)	(1.0)	(2.1)
Foreign currency translation	(0.1)	0.1	(0.1)
Total other intangibles subject to amortization, net of accumulated amortization of $24.8, $24.1 and $22.5, respectively	9.3	8.2	10.1
Accumulated amortization of intangible assets	25.4	22.9	24.1
Total other intangibles not subject to amortization	2.1	2.1	2.1
Total other intangibles	$ 11.4	$ 10.3	$ 12.2