Condensed Consolidated Balance Sheets (Parenthetical)	Apr. 30, 2012	Jul. 31, 2011
Class A nonvoting common stock
Common stock, shares Issued	51,261,487	51,261,487
Common stock, shares outstanding	49,031,625	49,284,252
Treasury stock, shares	1,919,862	1,667,235
Class B common stock
Common stock, shares Issued	3,538,628	3,538,628
Common stock, shares outstanding	3,538,628	3,538,628