Other Postretirement Benefits - Changes in the Benefit Obligation and Plan Assets and Other Amounts (Details) (Other Postretirement Benefit Plans, Defined Benefit [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 29, 2013	Dec. 30, 2012	Dec. 25, 2011
Other Postretirement Benefit Plans, Defined Benefit [Member]
Change in benefit obligation
Benefit obligation at beginning of year	$ 120,767	$ 113,803
Service cost	1,089	957	1,143
Interest cost	4,101	4,985	6,891
Plan participants’ contributions	4,861	4,383
Actuarial (gain)/loss	(13,501)	11,562
Plan amendments	(1,690)	0
Benefits paid	(14,695)	(15,881)
Medicare subsidies received	0	958
Benefit obligation at end of year	100,932	120,767	113,803
Change in plan assets
Fair value of plan assets at beginning of year	0	0
Employer contributions	9,834	10,540
Plan participants’ contributions	4,861	4,383
Medicare subsidies received	0	958
Benefits paid	(14,695)	(15,881)
Fair value of plan assets at end of year	0	0	0
Amount recognized in the Consolidated Balance Sheets
Current liabilities	(10,329)	(10,420)
Noncurrent liabilities	(90,603)	(110,347)
Net amount recognized	(100,932)	(120,767)
Amount recognized in accumulated other comprehensive loss
Actuarial loss	33,406	51,346
Prior service cost	(33,660)	(94,143)
Total amount recognized in accumulated other comprehensive loss	$ (254)	$ (42,797)