Employee Benefits (Details) (USD $)	3 Months Ended		6 Months Ended
	Jul. 02, 2011	Jun. 26, 2010	Jul. 02, 2011	Jun. 26, 2010
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Anticipated full year pension plan contribution	$ 1,500,000		$ 1,500,000
Pension plan contributions			800,000
Pension benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	207,000	199,000	461,000	298,000
Interest cost	2,530,000	2,196,000	4,685,000	4,411,000
Expected return on plan assets	(2,919,000)	(2,592,000)	(5,571,000)	(5,413,000)
Amortization of prior service cost	1,000	73,000	1,000	147,000
Amortization of net (gain) loss	599,000	506,000	1,173,000	905,000
Net periodic benefit cost	418,000	382,000	749,000	348,000
Other benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	82,000	69,000	151,000	134,000
Interest cost	301,000	329,000	619,000	635,000
Amortization of prior service cost	(2,000)	0	(1,000)	1,000
Amortization of net (gain) loss	(31,000)	40,000	(6,000)	78,000
Net periodic benefit cost	$ 350,000	$ 438,000	$ 763,000	$ 848,000