Description of the Business, Basis of Presentation and Summary of Significant Accounting Policies (Details3) (USD $)	12 Months Ended
	May 31, 2014	May 31, 2013	May 31, 2012
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Estimated fair value of stock options granted (in Dollars)	$ 10.37	$ 9.77	$ 9.30
Assumptions:
Expected dividend yield (percent)	1.70%	1.60%	1.40%
Expected stock price volatility (percent)	38.60%	37.50%	36.70%
Risk-free interest rate (percent)	2.20%	0.90%	1.60%
Expected life of options (in years)	6 years	6 years	7 years