Consolidated Balance Sheets (Parenthetical) (USD $)	May 31, 2013	May 31, 2012
Common stock, par value (in USD per share)	$ 1	$ 1
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	28,572,000	27,996,000
Common stock, shares outstanding	28,572,000	27,996,000