Pension And Other Postretirement Benefits (Schedule Of Net Benefit Cost Of Pension And Postretirement Benefit Plans) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 01, 2012	Mar. 27, 2011
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 678	$ 579
Interest cost	4,126	4,244
Expected return on plan assets	(5,043)	(4,901)
Net amortization and deferral	1,606	1,056
Net benefit cost	1,367	978
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	158	198
Interest cost	473	550
Net amortization and deferral	123	70
Net benefit cost	$ 754	$ 818