RELATED PARTY INFORMATION - WAKEFERN (Details) - USD ($)			12 Months Ended
	Aug. 15, 2017	Feb. 15, 2014	Jul. 29, 2017	Jul. 30, 2016	Jul. 25, 2015
Related Party Transaction [Line Items]
Amortization of pension actuarial loss, net of tax			$ 794,000	$ 892,000	$ 768,000	[1]
Notes receivable from Wakefern			$ 44,680,000
Wakefern
Related Party Transaction [Line Items]
Ownership interest in Wakefern			12.90%
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			$ 406,000
Installment payments year one			292,000
Installment payments year two			114,000
Installment payments year three			0
Maximum per store investment			925,000
Per store investment increase			25,000	25,000
Additional investment			626,000	717,000
Vendor allowances and rebates			30,048,000	30,559,000	27,557,000
Support services incurred charges			32,135,000	33,526,000	33,306,000
Demand deposits invested at related party Wakefern			60,037,000	63,609,000
Interest income earned on investments related entity			$ 2,841,000	$ 2,506,000	$ 2,399,000
Wakefern | Related Party Note Receivable Maturing August 2017
Related Party Transaction [Line Items]
Related Party Transaction, Basis Spread on Variable Rate		0.25%
Percent of notes receivable		50.00%
Wakefern | Related Party Note Receivable Maturing February 2019
Related Party Transaction [Line Items]
Related Party Transaction, Basis Spread on Variable Rate		1.25%
Percent of notes receivable		50.00%
Insure-Rite Ltd. | Wakefern
Related Party Transaction [Line Items]
Investment in Insure-Rite, Ltd			8.00%
Subsequent Event [Member]
Related Party Transaction [Line Items]
Notes receivable from Wakefern	$ 22,000,000
Related Party Transaction, Basis Spread on Variable Rate	1.25%

[1] Amounts are net of tax of $549, $612 and $527 for 2017, 2016 and 2015, respectively.