NET INCOME 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, 2021	Jan. 25, 2020	Jan. 23, 2021	Jan. 25, 2020
Common Class A
Numerator:
Net income allocated, basic	$ 3,437	$ 1,521	$ 5,971	$ 3,461
Conversion of Class B to Class A shares	974	435	1,692	993
Effect of share-based compensation on allocated net income		(3)		(5)
Net income allocated, diluted	$ 4,411	$ 1,953	$ 7,663	$ 4,449
Denominator:
Weighted average shares outstanding, basic (in shares)	9,850	9,768	9,850	9,769
Conversion of Class B to Class A shares (in shares)	4,294	4,294	4,294	4,294
Weighted average shares outstanding, diluted (in shares)	14,144	14,062	14,144	14,063
Common Class B
Numerator:
Net income allocated, basic	$ 974	$ 435	$ 1,692	$ 993
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	$ 974	$ 434	$ 1,692	$ 991
Denominator:
Weighted average shares outstanding, basic (in shares)	4,294	4,294	4,294	4,294
Conversion of Class B to Class A shares (in shares)	0	0	0	0
Weighted average shares outstanding, diluted (in shares)	4,294	4,294	4,294	4,294