Schedule of Weighted-average Number of Shares Used in the Calculation of Basic and Diluted Earnings Per Share (Details) - shares	3 Months Ended		6 Months Ended
	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2022	Jan. 31, 2021
Earnings Per Share [Abstract]
Basic weighted-average number of shares	25,652,000	25,362,000	25,609,000	25,448,000
Effect of dilutive securities: Stock options	715,000	9,000	711,000	4,000
Effect of dilutive securities: Non-vested restricted Class B common stock	175,000	342,000	260,000	335,000
Diluted weighted-average number of shares	26,542,000	25,713,000	26,580,000	25,787,000