Description of the Business, Basis of Presentation and Summary of Significant Accounting Policies (Details) - Schedule Of Share Based Payment Award Stock Options Valuation Assumptions (USD $) In Millions, unless otherwise specified	12 Months Ended
	May 31, 2013	May 31, 2012	May 31, 2011
Schedule Of Share Based Payment Award Stock Options Valuation Assumptions [Abstract]
Estimated fair value of stock options granted (in Dollars)	$ 9.77	$ 9.30	$ 8.15
Assumptions:
Expected dividend yield	1.60%	1.40%	1.30%
Expected stock price volatility	37.50%	36.70%	37.30%
Risk-free interest rate	0.90%	1.60%	2.00%
Expected life of options	6 years	7 years	6 years