Retirement Plans (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 29, 2013	Jun. 30, 2012	Jun. 29, 2013	Jun. 30, 2012
Net Periodic Benefit Cost [Abstract]
Service cost	$ 0	$ 517,000	$ 0	$ 1,034,000
Interest cost	3,421,000	3,633,000	6,842,000	7,266,000
Expected return on plan assets	(4,618,000)	(4,258,000)	(9,236,000)	(8,516,000)
Net amortization and deferral	(2,000)	(1,000)	(4,000)	(2,000)
Actuarial (gain) loss	1,992,000	1,628,000	3,984,000	3,256,000
Net periodic cost	793,000	1,519,000	1,586,000	3,038,000
Employer contributions			6,900,000
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	9,200,000		9,200,000
Reconciliation of Benefit Obligation [Roll Forward]
Service cost	0	517,000	0	1,034,000
Interest cost	3,421,000	3,633,000	6,842,000	7,266,000
Other Postretirement Benefit Plans, Defined Benefit [Member]
Net Periodic Benefit Cost [Abstract]
Interest cost	200,000	200,000	400,000	400,000
Reconciliation of Benefit Obligation [Roll Forward]
Interest cost	$ 200,000	$ 200,000	$ 400,000	$ 400,000