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Revenue Recognition (Schedule Of Sales By Type Of Product) (Details) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 29, 2018 USD ($) | Sep. 29, 2018 USD ($) | Jun. 30, 2018 USD ($) | Mar. 31, 2018 USD ($) | Dec. 30, 2017 USD ($) | Sep. 30, 2017 USD ($) | Jul. 01, 2017 USD ($) | Apr. 01, 2017 USD ($) | Dec. 29, 2018 USD ($) segment | Dec. 30, 2017 USD ($) | Dec. 31, 2016 USD ($)
Disaggregation of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of reportable segments | segment |  |  |  |  |  |  |  |  | 1 |  |
Total net sales | $ 892,988 | $ 869,076 | $ 871,100 | $ 876,106 | $ 883,748 | $ 854,261 | $ 876,569 | $ 852,229 | $ 3,509,270 | $ 3,466,807 | $ 3,136,720
Sales Revenue, Net [Member] | Product Concentration Risk [Member] |  |  |  |  |  |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total net sales |  |  |  |  |  |  |  |  | $ 3,509,270 | $ 3,466,807 | $ 3,136,720
Concentration percent |  |  |  |  |  |  |  |  | 100.00% | 100.00% | 100.00%
Grocery [Member] | Sales Revenue, Net [Member] | Product Concentration Risk [Member] |  |  |  |  |  |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total net sales |  |  |  |  |  |  |  |  | $ 3,063,218 | $ 3,041,481 | $ 2,736,596
Concentration percent |  |  |  |  |  |  |  |  | 87.30% | 87.70% | 87.30%
Pharmacy [Member] | Sales Revenue, Net [Member] | Product Concentration Risk [Member] |  |  |  |  |  |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total net sales |  |  |  |  |  |  |  |  | $ 314,584 | $ 309,079 | $ 298,875
Concentration percent |  |  |  |  |  |  |  |  | 9.00% | 8.90% | 9.50%
Fuel [Member] | Sales Revenue, Net [Member] | Product Concentration Risk [Member] |  |  |  |  |  |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total net sales |  |  |  |  |  |  |  |  | $ 125,993 | $ 109,467 | $ 94,907
Concentration percent |  |  |  |  |  |  |  |  | 3.60% | 3.20% | 3.00%
Manufacturing [Member] | Sales Revenue, Net [Member] | Product Concentration Risk [Member] |  |  |  |  |  |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total net sales |  |  |  |  |  |  |  |  | $ 5,475 | $ 6,780 | $ 6,342
Concentration percent |  |  |  |  |  |  |  |  | 0.10% | 0.20% | 0.20%

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