CONDENSED STATEMENTS OF SHAREHOLDERS' EQUITY (Parentheticals) - $ / shares
3 Months Ended
Nov. 30, 2021
Aug. 31, 2021
May 31, 2021
Nov. 30, 2020
Aug. 31, 2020
May 31, 2020
Retained Earnings [Member]            
Dividends declared $ 0.1 $ 0.1 $ 0.1 $ 0.1 $ 0.06 $ 0.06