Description of the Business, Basis of Presentation and Summary of Significant Accounting Policies - Stock-based Compensation (Details) - $ / shares	12 Months Ended
	May 31, 2020	May 31, 2019	May 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Estimated fair value of stock options granted (in Dollars)	$ 6.99	$ 11.97	$ 10.45
Assumptions:
Expected dividend yield (percent)	1.90%	1.40%	1.50%
Expected stock price volatility (percent)	27.40%	28.40%	29.80%
Risk-free interest rate (percent)	1.30%	3.00%	2.10%
Expected life of options (in years)	5 years	6 years	6 years