Revenue Recognition (Schedule Of Sales By Type Of Product) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Disaggregation of Revenue [Line Items]
Total sales and other revenue	$ 876,106	$ 852,229
Sales Revenue, Net [Member] | Product Concentration Risk [Member]
Disaggregation of Revenue [Line Items]
Concentration percent	100.00%	100.00%
Grocery [Member]
Disaggregation of Revenue [Line Items]
Total sales and other revenue	$ 768,019	$ 749,561
Grocery [Member] | Sales Revenue, Net [Member] | Product Concentration Risk [Member]
Disaggregation of Revenue [Line Items]
Concentration percent	87.70%	88.00%
Pharmacy [Member]
Disaggregation of Revenue [Line Items]
Total sales and other revenue	$ 77,940	$ 76,250
Pharmacy [Member] | Sales Revenue, Net [Member] | Product Concentration Risk [Member]
Disaggregation of Revenue [Line Items]
Concentration percent	8.90%	8.90%
Fuel [Member]
Disaggregation of Revenue [Line Items]
Total sales and other revenue	$ 28,645	$ 24,450
Fuel [Member] | Sales Revenue, Net [Member] | Product Concentration Risk [Member]
Disaggregation of Revenue [Line Items]
Concentration percent	3.30%	2.90%
Manufacturing [Member]
Disaggregation of Revenue [Line Items]
Total sales and other revenue	$ 1,502	$ 1,967
Manufacturing [Member] | Sales Revenue, Net [Member] | Product Concentration Risk [Member]
Disaggregation of Revenue [Line Items]
Concentration percent	0.10%	0.20%