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Revenue Recognition (Schedule Of Sales By Type Of Product) (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 26, 2020 | Sep. 26, 2020 | Jun. 27, 2020 | Mar. 28, 2020 | Dec. 28, 2019 | Sep. 28, 2019 | Jun. 29, 2019 | Mar. 30, 2019 | Dec. 26, 2020 | Dec. 28, 2019 | Dec. 29, 2018
Disaggregation of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total net sales | $ 1,025,690 | $ 1,002,387 | $ 1,098,704 | $ 985,820 | $ 902,392 | $ 876,222 | $ 887,967 | $ 876,718 | $ 4,112,601 | $ 3,543,299 | $ 3,509,270
Revenue Benchmark [Member] | Product Concentration Risk [Member] |  |  |  |  |  |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Concentration percent |  |  |  |  |  |  |  |  | 100.00% | 100.00% | 100.00%
Grocery [Member] | Revenue Benchmark [Member] | Product Concentration Risk [Member] |  |  |  |  |  |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total net sales |  |  |  |  |  |  |  |  | $ 3,627,898 | $ 3,068,754 | $ 3,063,218
Concentration percent |  |  |  |  |  |  |  |  | 88.20% | 86.60% | 87.30%
Pharmacy [Member] | Revenue Benchmark [Member] | Product Concentration Risk [Member] |  |  |  |  |  |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total net sales |  |  |  |  |  |  |  |  | $ 356,630 | $ 337,233 | $ 314,584
Concentration percent |  |  |  |  |  |  |  |  | 8.70% | 9.50% | 9.00%
Fuel [Member] | Revenue Benchmark [Member] | Product Concentration Risk [Member] |  |  |  |  |  |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total net sales |  |  |  |  |  |  |  |  | $ 117,800 | $ 127,828 | $ 125,993
Concentration percent |  |  |  |  |  |  |  |  | 2.90% | 3.60% | 3.60%
Manufacturing [Member] | Revenue Benchmark [Member] | Product Concentration Risk [Member] |  |  |  |  |  |  |  |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total net sales |  |  |  |  |  |  |  |  | $ 10,273 | $ 9,484 | $ 5,475
Concentration percent |  |  |  |  |  |  |  |  | 0.20% | 0.30% | 0.10%

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