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
	Oct. 31, 2022	Oct. 31, 2021
Earnings Per Share [Line Items]
Net income	$ 39,441	$ 35,046
Denominator for basic income per share for both Class A and Class B	49,868	51,973
Plus: Effect of dilutive equity awards	222	463
Denominator for diluted income per share for both Class A and Class B	50,090	52,436
Class A Nonvoting Common Stock
Earnings Per Share [Line Items]
Basic	$ 0.79	$ 0.67
Diluted	$ 0.79	$ 0.67
Class B Voting Common Stock
Earnings Per Share [Line Items]
Preferential dividends	$ (769)	$ (803)
Preferential dividends on dilutive stock options	(4)	(8)
Numerator for basic and diluted income per Class B Voting Common Share	$ 38,668	$ 34,235
Basic	$ 0.78	$ 0.66
Diluted	$ 0.77	$ 0.65