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	12 Months Ended
	Jul. 31, 2024	Jul. 31, 2023	Jul. 31, 2022	Jul. 31, 2021
Earnings Per Share [Line Items]
Net income	$ 197,215	$ 174,857	$ 149,979	$ 129,659
Denominator for basic earnings per share for both Class A and Class B	48,119	49,591	51,321
Plus: Effect of dilutive stock options	377	278	330
Denominator for diluted earnings per share for both Class A and Class B	48,496	49,869	51,651
Class A Nonvoting Common Stock
Earnings Per Share [Line Items]
Basic	$ 4.10	$ 3.53	$ 2.92
Diluted	$ 4.07	$ 3.51	$ 2.90
Class B Voting Common Stock
Earnings Per Share [Line Items]
Net Income (Loss) Available to Common Stockholders, Basic	$ 196,462	$ 174,085	$ 149,168
Cash dividends on Common Stock	748	769	803
Preferential dividends on dilutive stock options	$ 5	$ 3	$ 8
Basic	$ 4.08	$ 3.51	$ 2.91
Diluted	$ 4.05	$ 3.49	$ 2.89