Other Postretirement Benefits - Schedule of Components of Net Periodic Postretirement Benefit Income (Details) - Other Postretirement Benefit Plans, Defined Benefit [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2015	Dec. 28, 2014	Dec. 29, 2013
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 588	$ 580	$ 1,089
Interest cost	2,794	3,722	4,101
Amortization and other costs	5,197	7,299	4,440
Amortization of prior service credit	(9,495)	(7,199)	(13,051)
Effect of curtailment	0	0	(49,122)
Net periodic postretirement benefit (income)/expense	$ (916)	$ 4,402	$ (52,543)