RELATED PARTY INFORMATION - WAKEFERN (Details) - USD ($) $ in Thousands	12 Months Ended
	Jul. 25, 2020	Jul. 27, 2019
Related Party Transaction [Line Items]
Related party transaction amount	$ 303	$ 43
Maturity of notes receivable from Wakefern	$ 0	24,937
Wakefern
Related Party Transaction [Line Items]
Ownership interest in Wakefern	12.50%
Purchase obligation, as a percentage of merchandise requirements	85.00%
Purchase obligation period	10 years
Percentage of stockholders to request termination	75.00%
Indebtedness to Wakefern	$ 1,185
Vendor allowances and rebates	33,151	31,412
Support services incurred charges	33,303	33,581
Demand deposits invested at related party Wakefern	76,259	73,879
Interest income earned on investments related entity	3,992	$ 5,215
Wakefern | Related Party Note Receivable Maturing August 2022
Related Party Transaction [Line Items]
Notes receivable from Wakefern	$ 26,130
Basis spread on variable rate (as a percent)	1.25%
Wakefern | Related Party Note Receivable Maturing February 2024
Related Party Transaction [Line Items]
Notes receivable from Wakefern	$ 26,878
Basis spread on variable rate (as a percent)	0.75%
Wakefern | Insure-Rite Ltd.
Related Party Transaction [Line Items]
Investment in Insure-Rite, Ltd	7.80%
Stock Subscriptions Outstanding, Payments Due In 2021
Related Party Transaction [Line Items]
Related party transaction amount	$ 353
Stock Subscriptions Outstanding, Payments Due In 2022
Related Party Transaction [Line Items]
Related party transaction amount	188
Stock Subscriptions Outstanding, Payments Due In 2023
Related Party Transaction [Line Items]
Related party transaction amount	154
Stock Subscriptions Outstanding, Payments Due In 2024
Related Party Transaction [Line Items]
Related party transaction amount	154
Stock Subscriptions Outstanding, Payments Due After 2024
Related Party Transaction [Line Items]
Related party transaction amount	33
Per Store Investment, Maximum | Wakefern
Related Party Transaction [Line Items]
Related party transaction amount	$ 950