NET INCOME (LOSS) PER SHARE - Schedule of Earnings Per Share, Basic and Diluted (Details) shares in Thousands, $ in Thousands	3 Months Ended
	Oct. 27, 2018 USD ($) shares	Oct. 28, 2017 USD ($) shares
Class of Stock [Line Items]
Conversion of Stock, Conversion Ratio	1
Common Class A [Member]
Numerator:
Net income allocated, basic | $	$ 4,739	$ 2,277
Conversion of Class B to Class A shares | $	1,361	655
Effect of share-based compensation on allocated net income | $	0	(1)
Net income allocated, diluted | $	$ 6,100	$ 2,931
Denominator:
Weighted average shares outstanding, basic (in shares) | shares	9,732	9,722
Conversion of Class B to Class A shares (in shares) | shares	4,304	4,304
Dilutive effect of share-based compensation (in shares) | shares	0	0
Weighted average shares outstanding, diluted (in shares) | shares	14,036	14,026
Common Class B [Member]
Numerator:
Net income allocated, basic | $	$ 1,361	$ 655
Conversion of Class B to Class A shares | $	0	0
Effect of share-based compensation on allocated net income | $	0	(1)
Net income allocated, diluted | $	$ 1,361	$ 654
Denominator:
Weighted average shares outstanding, basic (in shares) | shares	4,304	4,304
Conversion of Class B to Class A shares (in shares) | shares	0	0
Dilutive effect of share-based compensation (in shares) | shares	0	0
Weighted average shares outstanding, diluted (in shares) | shares	4,304	4,304