NET INCOME (LOSS) PER SHARE - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Apr. 25, 2020	Apr. 27, 2019	Apr. 25, 2020	Apr. 27, 2019
Common Class A [Member]
Numerator:
Net income allocated, basic	$ 8,431	$ 3,770	$ 11,892	$ 14,237
Conversion of Class B to Class A shares	2,398	1,076	3,390	4,083
Effect of share-based compensation on allocated net income	0	5	0	0
Net income allocated, diluted	$ 10,829	$ 4,851	$ 15,282	$ 18,320
Denominator:
Weighted average shares outstanding, basic (in shares)	9,789	9,756	9,775	9,737
Conversion of Class B to Class A shares (in shares)	4,294	4,294	4,294	4,300
Dilutive effect of share-based compensation (in shares)		17		0
Weighted average shares outstanding, diluted (in shares)	14,083	14,067	14,069	14,037
Common Class B [Member]
Numerator:
Net income allocated, basic	$ 2,398	$ 1,076	$ 3,390	$ 4,083
Conversion of Class B to Class A shares	0	0	0	0
Effect of share-based compensation on allocated net income	0	(1)	0	(1)
Net income allocated, diluted	$ 2,398	$ 1,075	$ 3,390	$ 4,082
Denominator:
Weighted average shares outstanding, basic (in shares)	4,294	4,294	4,294	4,300
Conversion of Class B to Class A shares (in shares)	0	0	0	0
Dilutive effect of share-based compensation (in shares)		0		0
Weighted average shares outstanding, diluted (in shares)	4,294	4,294	4,294	4,300