NET INCOME PER SHARE - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Oct. 24, 2020	Oct. 26, 2019
Common Class A [Member]
Numerator:
Net income allocated, basic	$ 2,526	$ 1,939
Conversion of Class B to Class A shares	716	558
Effect of share-based compensation on allocated net income		(2)
Net income allocated, diluted	$ 3,242	$ 2,495
Denominator:
Weighted average shares outstanding, basic (in shares)	9,850	9,770
Conversion of Class B to Class A shares (in shares)	4,294	4,294
Weighted average shares outstanding, diluted (in shares)	14,144	14,064
Common Class B [Member]
Numerator:
Net income allocated, basic	$ 716	$ 558
Conversion of Class B to Class A shares	0	0
Effect of share-based compensation on allocated net income		(1)
Net income allocated, diluted	$ 716	$ 557
Denominator:
Weighted average shares outstanding, basic (in shares)	4,294	4,294
Conversion of Class B to Class A shares (in shares)	0	0
Weighted average shares outstanding, diluted (in shares)	4,294	4,294