NET INCOME (LOSS) PER SHARE - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 23, 2016	Jan. 24, 2015	Jan. 23, 2016	Jan. 24, 2015
Common Class A [Member]
Numerator:
Net income allocated, basic	$ 4,755	$ 4,957	$ 8,108	$ 7,870
Conversion of Class B to Class A shares	1,395	1,492	2,379	2,370
Effect of share-based compensation on allocated net income	0	9	0	11
Net income allocated, diluted	$ 6,150	$ 6,458	$ 10,487	$ 10,251
Denominator:
Weighted average shares outstanding, basic (in shares)	9,561	9,409	9,569	9,409
Conversion of Class B to Class A shares (in shares)	4,319	4,361	4,319	4,361
Dilutive effect of share-based compensation (in shares)	0	25	0	22
Weighted average shares outstanding, diluted (in shares)	13,880	13,795	13,888	13,792
Common Class B [Member]
Numerator:
Net income allocated, basic	$ 1,395	$ 1,492	$ 2,379	$ 2,370
Conversion of Class B to Class A shares	0	0	0	0
Effect of share-based compensation on allocated net income	0	(2)	0	(2)
Net income allocated, diluted	$ 1,395	$ 1,490	$ 2,379	$ 2,368
Denominator:
Weighted average shares outstanding, basic (in shares)	4,319	4,361	4,319	4,361
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)	4,319	4,361	4,319	4,361