Debt (Details) - Schedule of debt (USD $) In Millions, unless otherwise specified	Aug. 31, 2013	May 31, 2013	Aug. 31, 2012
Debt (Details) - Schedule of debt [Line Items]
Debt Long Term And Short Term Outstanding, Carrying Value	$ 29.2	$ 2.0	$ 153.4
Debt Long Term And Short Term Outstanding, Fair Value	29.2	2.0	154.2
Less lines of credit, short-term debt and current portion of long-term debt	(29.2)	(2.0)	(0.6)
Less lines of credit, short-term debt and current portion of long-term debt	(29.2)	(2.0)	(0.6)
Total long-term debt			152.8
Total long-term debt			153.6
Line of Credit [Member]
Debt (Details) - Schedule of debt [Line Items]
Debt Long Term And Short Term Outstanding, Carrying Value	14.2	2.0	0.6
Debt Long Term And Short Term Outstanding, Fair Value	14.2	2.0	0.6
Revolving Loan [Member]
Debt (Details) - Schedule of debt [Line Items]
Debt Long Term And Short Term Outstanding, Carrying Value	15.0
Debt Long Term And Short Term Outstanding, Fair Value	15.0
Notes Due 2013 [Member]
Debt (Details) - Schedule of debt [Line Items]
Debt Long Term And Short Term Outstanding, Carrying Value			152.8
Debt Long Term And Short Term Outstanding, Fair Value			$ 153.6