Description of the Business, Basis of Presentation and Summary of Significant Accounting Policies (Tables)

12 Months Ended

May 31, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of assumptions used in valuation of share-based compensation awards

The table set forth below provides the estimated fair value of options granted by the Company during fiscal years 2018, 2017 and 2016 and the significant weighted average assumptions used in determining such fair value under the Black-Scholes option-pricing model. The average expected life represents an estimate of the period of time stock options are expected to remain outstanding based on the historical exercise behavior of the option grantees. The risk-free interest rate was based on the U.S. Treasury yield curve corresponding to the expected life in effect at the time of the grant. The volatility was estimated based on historical volatility corresponding to the expected life.

	2018			2017			2016
Estimated fair value of stock options granted	$	10.45		$	12.70		$	14.78
Assumptions:
Expected dividend yield	1.5		%	1.5		%	1.4		%
Expected stock price volatility	29.8		%	36.6		%	38.2		%
Risk-free interest rate	2.1		%	1.5		%	1.9		%
Average expected life of options	6 years			6 years			6 years