CONSOLIDATED STATEMENTS OF STOCKHOLDERS' INVESTMENT - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Value, Issued	$ 548	$ 548	$ 548
Beginning Balances	603,598
Net earnings	95,645	80,110	2,987
Other comprehensive loss, net of tax	10,063	(9,711)	(109,190)
Stock-based compensation expense	9,495	8,154	4,471
Stock Repurchased During Period, Value		(23,552)
Purchase of shares of Class A Common Stock	0	(23,552)	0
Ending Balances	700,140	603,598
Additional Paid-in Capital [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balances	317,001	314,403	311,811
Issuance of shares of Class A Common Stock under stock plan	(5,868)	(3,830)	(1,315)
Stockholder's equity, other	1,943	(10)	2,312
Tax benefit from exercise of stock options, vesting of RSUs, and deferred compensation distributions	37	(1,716)	(2,876)
Stock-based compensation expense	9,495	8,154	4,471
Ending Balances	322,608	317,001	314,403
Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balances	453,371	414,069	452,057
Net earnings	95,645	80,110	2,987
Payment of Ordinary Dividends, Common Stock Class A	(39,037)	(38,001)	(38,204)
Payment of Ordinary Dividends, Common Stock Class B	(2,843)	(2,807)	(2,771)
Ending Balances	507,136	453,371	414,069
Treasury Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balances	(108,714)	(93,234)	(93,337)
Issuance of shares of Class A Common Stock under stock plan	23,591	8,300	2,735
Stockholder's equity, other	(347)	(228)	(2,632)
Ending Balances	(85,470)	(108,714)	(93,234)
Accumulated Other Comprehensive Income (Loss) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balances	(54,745)	(45,034)	64,156
Other comprehensive loss, net of tax	10,063	(9,711)	(109,190)
Ending Balances	(44,682)	(54,745)	(45,034)
Other equity component [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balances	(3,863)	(3,064)	(2,159)
Stockholder's equity, other	3,863	(799)	(905)
Ending Balances	$ 0	$ (3,863)	$ (3,064)