Consolidated Balance Sheets (Parenthetical) (USD $)	Nov. 30, 2012	May 31, 2012
Consolidated Balance Sheets [Abstract]
Common stock, par value	$ 0.0277	$ 0.0277
Common stock, shares authorized	15,000,000	15,000,000
Common stock, shares issued	11,217,144	11,217,144
Treasury stock, shares	2,825,900	2,825,900