CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock Class A Common Stock	Common Stock Class B Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock Class A
Balance (in shares) at Jul. 26, 2014		10,147	4,361			454
Balance at Jul. 26, 2014	$ 233,136	$ 47,056	$ 708	$ 203,722	$ (12,465)	$ (5,885)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	30,620			30,620
Other comprehensive income (loss), net of tax	(4,409)				(4,409)
Dividends	(12,577)			(12,577)
Exercise of stock options	$ 2,392	$ 950				$ 1,442
Exercise of stock options (in shares)	(111)					(111)
Share-based compensation expense (in shares)		3
Share-based compensation expense	$ 3,169	$ 3,169
Tax (deficit) benefit from exercise of stock options and restricted share vesting	436	$ 436
Conversion of Class B shares to Class A shares (in shares)		42	(42)
Conversion of Class B shares to Class A shares	0	$ 7	$ (7)
Balance (in shares) at Jul. 25, 2015		10,192	4,319			343
Balance at Jul. 25, 2015	252,767	$ 51,618	$ 701	221,765	(16,874)	$ (4,443)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	25,044			25,044
Other comprehensive income (loss), net of tax	3,535				3,535
Dividends	(12,634)			(12,634)
Exercise of stock options	$ 813	$ 390				$ 423
Exercise of stock options (in shares)	(30)					(30)
Stock Issued During Period, Shares, Restricted Stock Award, Forfeited		(4)
Stock Granted, Value, Share-based Compensation, Forfeited		$ (55)
Share-based compensation expense (in shares)		2
Share-based compensation expense	$ 3,250	$ 3,250
Tax (deficit) benefit from exercise of stock options and restricted share vesting	(7)	$ (7)
Balance (in shares) at Jul. 30, 2016		10,190	4,319			353
Balance at Jul. 30, 2016	271,735	$ 55,196	$ 701	234,175	(13,339)	$ (4,998)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	22,921			22,921
Other comprehensive income (loss), net of tax	5,933				5,933
Dividends	(12,788)			(12,788)
Exercise of stock options	$ 812	$ 366				$ 446
Exercise of stock options (in shares)	(31)					(31)
Treasury stock purchases (in shares)						155
Treasury stock purchases	$ (4,081)					$ (4,081)
Stock Issued During Period, Shares, Restricted Stock Award, Forfeited		(5)
Stock Granted, Value, Share-based Compensation, Forfeited	(102)	$ (102)
Share-based compensation expense (in shares)		362
Share-based compensation expense	3,236	$ 3,236
Tax (deficit) benefit from exercise of stock options and restricted share vesting	(846)	$ (846)
Conversion of Class B shares to Class A shares (in shares)		15	(15)
Conversion of Class B shares to Class A shares		$ 2	$ (2)
Balance (in shares) at Jul. 29, 2017		10,562	4,304			477
Balance at Jul. 29, 2017	$ 286,820	$ 57,852	$ 699	$ 244,308	$ (7,406)	$ (8,633)