CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Retained Earnings [Member] Class A Nonvoting Common Stock	Retained Earnings [Member] Class B Voting Common Stock	Treasury Stock, Common	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balances at Jul. 31, 2020		$ 548	$ 331,762	$ 704,456			$ (107,216)	$ (66,477)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 129,659
Other Comprehensive Income (Loss), Net of Tax	10,524							10,524
Issuance of shares of Class A Common Stock under stock plan			(2,767)				(1,748)
Tax benefit and withholdings from deferred compensation distributions			32
Stock-based compensation expense (Note 7)			10,098
Repurchase of shares of Class A Common Stock, including excise taxes							3,593
Dividends, Common Stock, Cash					$ (42,690)	$ (3,056)
Ending Balances at Jul. 31, 2021		548	339,125	788,369			(109,061)	(55,953)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	149,979
Other Comprehensive Income (Loss), Net of Tax	(53,124)							(53,124)
Issuance of shares of Class A Common Stock under stock plan			(4,478)				(434)
Tax benefit and withholdings from deferred compensation distributions			115
Stock-based compensation expense (Note 7)			10,504
Repurchase of shares of Class A Common Stock, including excise taxes							109,229
Dividends, Common Stock, Cash					(42,805)	(3,126)
Ending Balances at Jul. 31, 2022	911,298	548	345,266	892,417			(217,856)	(109,077)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	174,857
Other Comprehensive Income (Loss), Net of Tax	16,016							16,016
Issuance of shares of Class A Common Stock under stock plan			(1,069)				(3,119)
Tax benefit and withholdings from deferred compensation distributions			66
Stock-based compensation expense (Note 7)			7,508
Repurchase of shares of Class A Common Stock, including excise taxes							(75,472)
Dividends, Common Stock, Cash					$ (42,207)	$ (3,197)
Ending Balances at Jul. 31, 2023	$ 990,919	$ 548	$ 351,771	$ 1,021,870			$ (290,209)	$ (93,061)