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