Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	May 31, 2013	May 31, 2012	May 31, 2011
Commitments and Contingencies Disclosure [Text Block]
Operating Leases, Rent Expense, Net	$ 32.9	$ 38.9	$ 47.2
Capital Leases, Income Statement, Amortization Expense	1.1	1.1	1.2
Capital Lease Imputed Interest Rate	7.90%
Letters of Credit Outstanding, Amount	$ 6.6	$ 6.6