BASIS OF PRESENTATION and ACCOUNTING POLICIES - Disaggregated Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Oct. 24, 2020	Oct. 26, 2019
Revenue from External Customer [Line Items]
Sales	$ 490,136	$ 407,402
Percentage of total sales	100.00%	100.00%
Center Store
Revenue from External Customer [Line Items]
Sales	$ 295,940	$ 248,057
Percentage of total sales	60.40%	60.90%
Fresh
Revenue from External Customer [Line Items]
Sales	$ 175,644	$ 140,680
Percentage of total sales	35.80%	34.50%
Pharmacy
Revenue from External Customer [Line Items]
Sales	$ 16,432	$ 17,524
Percentage of total sales	3.40%	4.30%
Other
Revenue from External Customer [Line Items]
Sales	$ 2,120	$ 1,141
Percentage of total sales	0.40%	0.30%