CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jul. 31, 2018	Jul. 31, 2017
Class A Nonvoting Common Stock [Member]
Common stock, shares issued	51,261,487	51,261,487
Common Stock Aggregate Liquidation Preference	$ 42,803	$ 42,803
Treasury stock, shares	2,867,870	3,446,669
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