Retirement Plans (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	$ 3,707,000	$ 3,421,000	$ 11,120,000	$ 10,263,000
Employer contributions			11,500,000
Estimated future employer contributions during 2014			2,800,000
SERP and OPEB Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	$ 200,000	$ 200,000	$ 600,000	$ 600,000