Pension Benefits (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 23, 2012	Sep. 25, 2011	Sep. 23, 2012	Sep. 25, 2011
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Service cost	$ 207,000	$ 247,000	$ 637,000	$ 736,000
Interest cost	940,000	1,125,000	2,898,000	3,346,000
Expected return on plan assets	10,000	39,000	31,000	117,000
Amortization of actuarial loss	54,000	12,000	166,000	37,000
Amortization of transition obligation	13,000	33,000	42,000	98,000
Amortization of prior service costs	1,000	1,000	2,000	2,000
Net periodic pension cost	1,225,000	1,457,000	3,776,000	4,336,000
Estimated employer contributions	4,700,000		4,700,000
Pension contributions			$ 3,700,000