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, 2023	Oct. 31, 2022
Earnings Per Share [Line Items]
Net income	$ 47,241	$ 39,441
Denominator for basic income per share for both Class A and Class B	48,505	49,868
Plus: Effect of dilutive equity awards	306	222
Denominator for diluted income per share for both Class A and Class B	48,811	50,090
Class A Nonvoting Common Stock
Earnings Per Share [Line Items]
Basic	$ 0.97	$ 0.79
Diluted	$ 0.97	$ 0.79
Class B Voting Common Stock
Earnings Per Share [Line Items]
Preferential dividends	$ (748)	$ (769)
Preferential dividends on dilutive stock options	(5)	(4)
Numerator for basic and diluted income per Class B Voting Common Share	$ 46,488	$ 38,668
Basic	$ 0.96	$ 0.78
Diluted	$ 0.95	$ 0.77