NET INCOME (LOSS) PER SHARE - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Oct. 28, 2017	Oct. 29, 2016
Common Class A [Member]
Numerator:
Net income allocated, basic	$ 2,277	$ 3,116
Conversion of Class B to Class A shares	655	912
Effect of share-based compensation on allocated net income	(1)	2
Net income allocated, diluted	$ 2,931	$ 4,030
Denominator:
Weighted average shares outstanding, basic (in shares)	9,722	9,592
Conversion of Class B to Class A shares (in shares)	4,304	4,319
Dilutive effect of share-based compensation (in shares)	0	49
Weighted average shares outstanding, diluted (in shares)	14,026	13,960
Common Class B [Member]
Numerator:
Net income allocated, basic	$ 655	$ 912
Conversion of Class B to Class A shares	0	0
Effect of share-based compensation on allocated net income	(1)	(1)
Net income allocated, diluted	$ 654	$ 911
Denominator:
Weighted average shares outstanding, basic (in shares)	4,304	4,319
Conversion of Class B to Class A shares (in shares)	0	0
Dilutive effect of share-based compensation (in shares)	0	0
Weighted average shares outstanding, diluted (in shares)	4,304	4,319