Goodwill and Other Intangibles (Details) - Schedule of other intangible assets subject to amortization (USD $) In Millions, unless otherwise specified	12 Months Ended
	May 31, 2013	May 31, 2012	May 31, 2011
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 2.5	$ 6.5	$ 1.4
Total other intangibles subject to amortization	12.6	14.7
Trademarks and other	2.0	2.0
Total other intangibles not subject to amortization	2.0	2.0
Total other intangibles	14.6	16.7
Customer Lists [Member]
Finite-Lived Intangible Assets [Line Items]
Begining balance	4.3	0.7
Additions due to acquisition	0.1	3.8
Amortization expense	(1.0)	(0.2)
Foreign currency translation	0	0
Total other intangibles subject to amortization	3.4	4.3
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Begining balance	10.4	17.3
Additions due to acquisition	0.2
Impairment charge		(5.4)
Amortization expense	(1.5)	(1.4)
Other	0.1	(0.1)
Total other intangibles subject to amortization	$ 9.2	$ 10.4