NET INCOME (LOSS) PER SHARE - Schedule of Earnings Per Share, Basic and Diluted (Details) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Apr. 27, 2019 USD ($) shares	Apr. 28, 2018 USD ($) shares	Apr. 27, 2019 USD ($) shares	Apr. 28, 2018 USD ($) shares
Class of Stock [Line Items]
Conversion of Stock, Conversion Ratio			1
Common Class A [Member]
Numerator:
Net income allocated, basic | $	$ 3,770	$ 4,935	$ 14,237	$ 14,387
Conversion of Class B to Class A shares | $	1,076	1,421	4,083	4,142
Effect of share-based compensation on allocated net income | $	5	0	0	0
Net income allocated, diluted | $	$ 4,851	$ 6,356	$ 18,320	$ 18,529
Denominator:
Weighted average shares outstanding, basic (in shares) | shares	9,756	9,709	9,737	9,715
Conversion of Class B to Class A shares (in shares) | shares	4,294	4,304	4,300	4,304
Dilutive effect of share-based compensation (in shares) | shares	17	0	0	0
Weighted average shares outstanding, diluted (in shares) | shares	14,067	14,013	14,037	14,019
Common Class B [Member]
Numerator:
Net income allocated, basic | $	$ 1,076	$ 1,421	$ 4,083	$ 4,142
Conversion of Class B to Class A shares | $	0	0	0	0
Effect of share-based compensation on allocated net income | $	(1)	0	(1)	0
Net income allocated, diluted | $	$ 1,075	$ 1,421	$ 4,082	$ 4,142
Denominator:
Weighted average shares outstanding, basic (in shares) | shares	4,294	4,304	4,300	4,304
Conversion of Class B to Class A shares (in shares) | shares	0	0	0	0
Dilutive effect of share-based compensation (in shares) | shares	0	0	0	0
Weighted average shares outstanding, diluted (in shares) | shares	4,294	4,304	4,300	4,304