Note 7. Employee Benefits (Detail) - Net Periodic Employee Benefits (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 23, 2012	Sep. 25, 2011	Sep. 23, 2012	Sep. 25, 2011
Pension Plans, Defined Benefit [Member]
Interest cost	$ 5,290	$ 5,606	$ 15,871	$ 16,819
Expected return on plan assets	(5,926)	(5,999)	(17,778)	(17,997)
Amortization of net loss/(gain)	1,412	949	4,236	2,846
Net periodic benefit cost	776	556	2,329	1,668
Other Postretirement Benefit Plans, Defined Benefit [Member]
Service cost	50	57	150	170
Interest cost	445	477	1,335	1,432
Amortization of prior-service cost	315	430	944	1,291
Amortization of net loss/(gain)	(205)	(256)	(615)	(769)
Net periodic benefit cost	$ 605	$ 708	$ 1,814	$ 2,124