Stock-based Compensation (Narrative) (Details) - shares	May 31, 2019	May 31, 2018	May 28, 2010
Common Stock, Shares Authorized	500,000,000	500,000,000
2010 Stock Plan [Member]
Common Stock, Shares Authorized			10,294,500
2010 Stock Plan - Stock Options [Member]
Common Stock, Shares Authorized			5,147,250
2010 Stock Plan - Restricted Shares [Member]
Common Stock, Shares Authorized			5,147,250