NET INCOME (LOSS) PER SHARE - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Apr. 29, 2017	Apr. 23, 2016	Apr. 29, 2017	Apr. 23, 2016
Common Class A [Member]
Numerator:
Net income allocated, basic	$ 4,550	$ 4,455	$ 12,214	$ 12,563
Conversion of Class B to Class A shares	1,312	1,308	3,551	3,686
Effect of share-based compensation on allocated net income	0	0	15	0
Net income allocated, diluted	$ 5,862	$ 5,763	$ 15,780	$ 16,249
Denominator:
Weighted average shares outstanding, basic (in shares)	9,696	9,559	9,634	9,566
Conversion of Class B to Class A shares (in shares)	4,316	4,319	4,318	4,319
Dilutive effect of share-based compensation (in shares)	0	0	36	0
Weighted average shares outstanding, diluted (in shares)	14,012	13,878	13,988	13,885
Common Class B [Member]
Numerator:
Net income allocated, basic	$ 1,312	$ 1,308	$ 3,551	$ 3,686
Conversion of Class B to Class A shares	0	0	0	0
Effect of share-based compensation on allocated net income	0	0	(4)	0
Net income allocated, diluted	$ 1,312	$ 1,308	$ 3,547	$ 3,686
Denominator:
Weighted average shares outstanding, basic (in shares)	4,316	4,319	4,318	4,319
Conversion of Class B to Class A shares (in shares)	0	0	0	0
Dilutive effect of share-based compensation (in shares)	0	0	0	0
Weighted average shares outstanding, diluted (in shares)	4,316	4,319	4,318	4,319