Goodwill and Other Intangibles (Details) - Schedule of other intangible assets subject to amortization (USD $) In Millions, unless otherwise specified	12 Months Ended
	May 31, 2014	May 31, 2013	May 31, 2012
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ (2.4)	$ (2.5)	$ (6.5)
Total other intangibles subject to amortization	10.0	12.6
Trademarks and other	2.2	2.0
Total other intangibles not subject to amortization	2.2	2.0
Total other intangibles	12.2	14.6
Customer Lists [Member]
Finite-Lived Intangible Assets [Line Items]
Begining balance		3.4	4.3
Additions due to acquisition	0	0.1
Amortization expense	(1.0)	(1.0)
Foreign currency translation	0	0
Total other intangibles subject to amortization		2.4	3.4
Accumulated amortization	3.3	2.3
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Begining balance		9.2	10.4
Additions due to acquisition	0	0.2
Amortization expense	(1.4)	(1.5)
Other	(0.2)	0.1
Total other intangibles subject to amortization	7.6	9.2
Accumulated amortization	$ 13.4	$ 12.0