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Description of the Business, Basis of Presentation and Summary of Significant Accounting Policies (Details3) - $ / shares
12 Months Ended
May 31, 2017
May 31, 2016
May 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]      
Estimated fair value of stock options granted (in Dollars) $ 12.70 $ 14.78 $ 11.41
Assumptions:      
Expected dividend yield (percent) 1.50% 1.40% 1.80%
Expected stock price volatility (percent) 36.60% 38.20% 38.20%
Risk-free interest rate (percent) 1.50% 1.90% 2.20%
Expected life of options (in years) 6 years 6 years 6 years