Goodwill and Other Intangibles (Details) - Schedule of activity in goodwill (USD $) In Millions, unless otherwise specified	12 Months Ended
	May 31, 2014	May 31, 2013
Goodwill [Roll Forward]
Gross beginning balance	$ 178.7	$ 178.5
Accumulated impairment	(20.8)	(20.8)
Beginning balance	157.9	157.7
Goodwill impairment	(13.4)	0
Foreign currency translation	0	0
Other	0	0.2
Gross ending balance	178.7	178.7
Accumulated impairment	(34.2)	(20.8)
Ending balance	$ 144.5	$ 157.9