Other Postretirement Benefits - Schedule of Effect of One Percentage-Point Change in Assumed Health Care Cost Trend Rates (Details) - Other Postretirement Benefit Plans, Defined Benefit [Member] $ in Thousands	12 Months Ended
	Dec. 25, 2016 USD ($)
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]
Effect on total service and interest cost (increase)	$ 56
Effect on accumulated postretirement benefit obligation ( increase)	2,352
Effect on total service and interest cost (decrease)	(51)
Effect on accumulated postretirement benefit obligation (decrease)	$ (2,061)