Pension Benefits (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 25, 2012
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Service cost	$ 268,000	$ 217,000
Interest cost	879,000	986,000
Expected return on plan assets	26,000	10,000
Amortization of actuarial loss	389,000	57,000
Amortization of transition obligation	0	14,000
Amortization of prior service costs	1,000	1,000
Net periodic pension cost	1,563,000	1,285,000
Estimated employer contributions	5,100,000
Pension contributions	$ 1,400,000