SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details)	12 Months Ended
	Jul. 28, 2018 USD ($) store segment	Jul. 29, 2017 USD ($)
Accounting Policies [Abstract]
Number of stores | store	30
Number of operating segments | segment	1
Cash and Cash Equivalents [Abstract]
Credit and debit card receivables	$ 8,227,000	$ 7,641,000
Inventory Disclosure [Abstract]
Percentage of LIFO inventory	65.00%
LIFO reserve inventory	$ 14,234,000	14,410,000
Leases [Abstract]
Deferred rent obligation	13,259	6,790
Marketing and Advertising Expense [Abstract]
Advertising expense	11,514,000	11,824,000
Wakefern
Related Party Transaction [Line Items]
Demand deposits invested at related party Wakefern	$ 63,413,000	$ 60,037,000
Buildings
Property, Plant and Equipment [Line Items]
Useful life	30 years
Store fixtures and equipment
Property, Plant and Equipment [Line Items]
Useful life	10 years
Vehicles
Property, Plant and Equipment [Line Items]
Useful life	3 years