Income Per Share of Common Stock (Details) - shares
 3 Months Ended 9 Months Ended
Apr. 30, 2018
Apr. 30, 2017
Apr. 30, 2018
Apr. 30, 2017
Leases [Abstract]        
Average common shares outstanding 2,015,780 2,015,780 2,015,780 2,015,780