SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Jul. 31, 2021	Jul. 25, 2020
Class A Common Stock
Numerator:
Net income allocated, basic	$ 15,095	$ 18,857
Conversion of Class B to Class A shares	4,273	5,363
Net income allocated, diluted	$ 19,368	$ 24,220
Denominator:
Weighted average shares outstanding, basic (in shares)	9,853	9,794
Conversion of Class B to Class A shares (in shares)	4,294	4,294
Weighted average shares outstanding, diluted (in shares)	14,147	14,088
Net income per share
Basic (in dollars per share)	$ 1.53	$ 1.93
Diluted (in dollars per share)	$ 1.37	$ 1.72
Class B Common Stock
Numerator:
Net income allocated, basic	$ 4,273	$ 5,363
Conversion of Class B to Class A shares	0	0
Net income allocated, diluted	$ 4,273	$ 5,363
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
Net income per share
Basic (in dollars per share)	$ 1.00	$ 1.25
Diluted (in dollars per share)	$ 1.00	$ 1.25