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 [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balances at Jul. 31, 2019	$ 700,140	$ 548	$ 329,969	$ 637,843			$ (46,332)	$ (71,254)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	112,369
Other Comprehensive Income (Loss), Net of Tax	4,777							4,777
Issuance of shares of Class A Common Stock under stock plan			(7,184)				(3,630)
Adjustments to Additional Paid in Capital, Other			134
Stock-based compensation expense (Note 7)			8,843
Repurchase of shares of Class A Common Stock							64,514
Dividends, Common Stock, Cash					$ (42,736)	$ (3,020)
Ending Balances at Jul. 31, 2020	752,112	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)
Adjustments to Additional Paid in Capital, Other			32
Stock-based compensation expense (Note 7)			10,098
Repurchase of shares of Class A Common Stock							3,593
Dividends, Common Stock, Cash					(42,690)	(3,056)
Ending Balances at Jul. 31, 2021	963,028	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)
Adjustments to Additional Paid in Capital, Other			115
Stock-based compensation expense (Note 7)			10,504
Repurchase of shares of Class A Common Stock	(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)