Note 8. Employee Benefits (Details) - Components of net periodic employee benefits expense: (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 23, 2012	Sep. 30, 2013	Sep. 23, 2012
Pension Plan, Defined Benefit [Member]
Note 8. Employee Benefits (Details) - Components of net periodic employee benefits expense: [Line Items]
Interest cost	$ 4,736	$ 5,290	$ 14,208	$ 15,871
Expected return on plan assets	(5,737)	(5,926)	(17,212)	(17,778)
Amortization of net loss/(gain)	2,155	1,412	6,464	4,236
Net periodic benefit cost	1,154	776	3,460	2,329
Other Postretirement Benefit Plan, Defined Benefit [Member]
Note 8. Employee Benefits (Details) - Components of net periodic employee benefits expense: [Line Items]
Service cost	27	50	82	150
Interest cost	221	445	663	1,335
Amortization of prior-service cost	22	315	68	944
Amortization of net loss/(gain)	(210)	(205)	(632)	(615)
Net periodic benefit cost	$ 60	$ 605	$ 181	$ 1,814