Net Income per Common Share - Reconciliation of Numerator and Denominator of Basic and Diluted Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2023	Jan. 31, 2022	Jan. 31, 2023	Jan. 31, 2022
Earnings Per Share [Line Items]
Net income	$ 37,986	$ 33,815	$ 77,427	$ 68,861
Denominator for basic income per share for both Class A and Class B	49,745	51,800	49,806	51,887
Plus: Effect of dilutive equity awards	264	362	243	412
Denominator for diluted income per share for both Class A and Class B	50,009	52,162	50,049	52,299
Class A Nonvoting Common Stock
Earnings Per Share [Line Items]
Basic	$ 0.76	$ 0.65	$ 1.55	$ 1.33
Diluted	$ 0.76	$ 0.65	$ 1.55	$ 1.32
Class B Voting Common Stock
Earnings Per Share [Line Items]
Preferential dividends	$ 0	$ 0	$ 769	$ 803
Preferential dividends on dilutive stock options	0	0	4	(8)
Numerator for basic and diluted income per Class B Voting Common Share	$ 37,986	$ 33,815	$ 76,654	$ 68,050
Basic	$ 0.76	$ 0.65	$ 1.54	$ 1.31
Diluted	$ 0.76	$ 0.65	$ 1.53	$ 1.30