Stockholders' Equity - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2020	Apr. 30, 2019	Aug. 01, 2019	Jul. 31, 2019	Jul. 31, 2018
Schedule Of Stockholders Equity [Line Items]
Accumulated other comprehensive loss	$ (92,242)		$ (92,242)			$ (71,254)	$ (56,401)
Beginning balance	899,924	$ 803,381	850,774	$ 752,112
Net income	13,633	34,781	84,684	94,645
Other comprehensive loss, net of tax	(19,752)	(7,881)	(20,988)	(12,045)
Issuance of shares of Class A Common Stock under stock plan	(426)	(2,982)	(2,620)	(18,119)
Tax benefit and withholdings from deferred compensation distributions			133
Adjustments to Additional Paid in Capital, Income Tax Deficiency from Share-based Compensation				209
Stock-based compensation expense	1,796	2,506	7,180	10,311
Purchase of shares of Class A Common Stock				(3,182)
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets					$ (2,137)
Cash dividends on Class A common stock	(10,542)	(10,473)	(32,197)	(31,291)
Cash dividends on Class B common stock	(770)	(752)	(2,251)	(2,197)
Ending balance	820,602	824,544	820,602	824,544
Treasury Stock, Value, Acquired, Cost Method	(64,113)		(64,113)
Common Stock
Schedule Of Stockholders Equity [Line Items]
Beginning balance	548	548	548	548
Ending balance	548	548	548	548
Additional Paid-in Capital
Schedule Of Stockholders Equity [Line Items]
Beginning balance	329,263	328,978	329,969	325,631
Issuance of shares of Class A Common Stock under stock plan	(91)	(1,433)	(6,314)	(6,100)
Tax benefit and withholdings from deferred compensation distributions			133	209
Stock-based compensation expense	1,796	2,506	7,180	10,311
Ending balance	330,968	330,051	330,968	330,051
Retained Earnings
Schedule Of Stockholders Equity [Line Items]
Beginning balance	685,758	588,918	637,843	553,454
Net income	13,633	34,781	84,684	94,645
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets					$ (2,137)
Cash dividends on Class A common stock	(10,542)	(10,473)	(32,197)	(31,291)
Cash dividends on Class B common stock	(770)	(752)	(2,251)	(2,197)
Ending balance	688,079	612,474	688,079	612,474
Treasury Stock
Schedule Of Stockholders Equity [Line Items]
Beginning balance	(43,155)	(54,498)	(46,332)	(71,120)
Issuance of shares of Class A Common Stock under stock plan	(517)	(4,415)	(3,694)	(24,219)
Adjustments to Additional Paid in Capital, Income Tax Deficiency from Share-based Compensation				0
Purchase of shares of Class A Common Stock				(3,182)
Ending balance	(106,751)	(50,083)	(106,751)	(50,083)
Treasury Stock, Value, Acquired, Cost Method	(64,113)		(64,113)
Accumulated Other Comprehensive Loss
Schedule Of Stockholders Equity [Line Items]
Accumulated other comprehensive loss		(68,446)		(68,446)
Beginning balance	(72,490)	(60,565)	(71,254)	(56,401)
Other comprehensive loss, net of tax	(19,752)	(7,881)	(20,988)	(12,045)
Ending balance	$ (92,242)	$ (68,446)	$ (92,242)	$ (68,446)