NET INCOME (LOSS) PER SHARE - Schedule of Earnings Per Share, Basic and Diluted (Details) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 25, 2020 USD ($) shares	Jan. 26, 2019 USD ($) shares	Jan. 25, 2020 USD ($) shares	Jan. 26, 2019 USD ($) shares
Class of Stock [Line Items]
Conversion of Stock, Conversion Ratio			1
Common Class A [Member]
Numerator:
Net income allocated, basic	$ 1,521	$ 5,727	$ 3,461	$ 10,466
Conversion of Class B to Class A shares	435	1,646	993	3,007
Effect of share-based compensation on allocated net income	(3)		(5)
Net income allocated, diluted	$ 1,953	$ 7,373	$ 4,449	$ 13,473
Denominator:
Weighted average shares outstanding, basic (in shares) | shares	9,768	9,723	9,769	9,727
Conversion of Class B to Class A shares (in shares) | shares	4,294	4,304	4,294	4,304
Weighted average shares outstanding, diluted (in shares) | shares	14,062	14,027	14,063	14,031
Common Class B [Member]
Numerator:
Net income allocated, basic	$ 435	$ 1,646	$ 993	$ 3,007
Conversion of Class B to Class A shares	0	0	0	0
Effect of share-based compensation on allocated net income	(1)		(2)
Net income allocated, diluted	$ 434	$ 1,646	$ 991	$ 3,007
Denominator:
Weighted average shares outstanding, basic (in shares) | shares	4,294	4,304	4,294	4,304
Conversion of Class B to Class A shares (in shares) | shares	0	0	0	0
Weighted average shares outstanding, diluted (in shares) | shares	4,294	4,304	4,294	4,304