Pension and Other Retirement Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 28, 2014
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 692	$ 709	$ 463
Interest cost	82,724	81,815	82,109
Expected return on plans’ assets	(107,616)	(111,690)	(113,056)
Recognized actuarial (gain) loss	0	0	(159)
Amortization of prior service costs (credits)	90	0	0
Net periodic benefit (credit) cost	(24,110)	(29,166)	(30,643)
Other Postretirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0	81	328
Interest cost	320	451	1,466
Expected return on plans’ assets	0	0	0
Recognized actuarial (gain) loss	0	25	(22)
Amortization of prior service costs (credits)	(380)	(81)	0
Net periodic benefit (credit) cost	$ (60)	$ 476	$ 1,772