Retirement Plans (Details) (USD $)	3 Months Ended
	Mar. 29, 2014	Mar. 30, 2013
Net Periodic Benefit Cost [Abstract]
Service cost	$ 0	$ 0
Interest cost	3,707,000	3,421,000
Expected return on plan assets	(5,206,000)	(4,618,000)
Net amortization and deferral	0	(2,000)
Net amortization and deferral	794,000	1,992,000
Net periodic (benefit) expense	(705,000)	793,000
Employer contributions	3,300,000
Estimated future employer contributions during 2014	14,800,000
Other Postretirement Benefit Plans, Defined Benefit [Member]
Net Periodic Benefit Cost [Abstract]
Interest cost	$ 200,000	$ 200,000