CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	May 31, 2013	May 31, 2012
CONSOLIDATED BALANCE SHEETS
Preferred stock, par value (in dollars per share)	$ 1.00	$ 1.00
Preferred stock, authorized shares	250,000	250,000
Preferred stock, issued shares	0	0
Common stock, par value (in dollars per share)	$ 1.00	$ 1.00
Common stock, authorized shares	100,000,000	100,000,000
Common stock, issued shares	44,691,437	44,849,196
Treasury stock, shares	5,309,252	4,576,368