CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)	Apr. 30, 2013	Jul. 31, 2012
Class A nonvoting common stock [Member]
Common stock, shares issued	51,261,487	51,261,487
Common stock, shares outstanding	47,972,270	47,630,926
Treasury stock, shares	2,974,218	3,245,561
Class B voting common stock [Member]
Common stock, shares issued	3,538,628	3,538,628
Common stock, shares outstanding	3,538,628	3,538,628