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Nature of Operations and Significant Accounting Policies - Narrative (Details) mi in Thousands, $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 25, 2016 USD ($) state mi | Mar. 27, 2015 | Dec. 30, 2016 | Dec. 25, 2015 USD ($)
Background |  |  |  |
Total number of rail route miles | mi | 21 |  |  |
Number of states rail network serves | state | 23 |  |  |
Fiscal Year |  |  |  |
Number of days in fiscal year |  |  |  | 364 days
Number of days in fiscal quarter | 91 days | 91 days |  |
Number of days in fiscal quarter YTD | 91 days | 91 days |  |
Allowance for Doubtful Accounts |  |  |  |
Allowance for doubtful accounts | $ | $ 32 |  |  | $ 37
Scenario Forecast |  |  |  |
Fiscal Year |  |  |  |
Number of days in fiscal year |  |  | 371 days |

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