Other Comprehensive Income (Loss) (Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 30, 2013	Mar. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Abstract]
Accumulated other comprehensive loss - interest rate swaps	$ (654)
Accumulated other comprehensive - postretirement liabilities	416
Accumulated other comprehensive loss - total	(238)
Unrealized gain (loss) on interest rate swaps	12	(81)
Reclassification of loss into earnings from interest rate swaps	22	23
Amortization of unrealized losses on dedesignated interest rate swaps	68	74
Reclassification of net actuarial gain into earnings from postretirement benefit plans	(6)	(6)
Reclassification of prior service credits into earnings from postretirement benefit plans	(14)	(13)
Accumulated other comprehensive loss - interest rate swaps	(552)
Accumulated other comprehensive - postretirement liabilities	396
Accumulated other comprehensive loss - total	(156)
Unrealized gain (loss) on interest rate swaps - income taxes	(8)	49
Reclassification of loss into earnings from interest rate swaps - income taxes	13	14
Amortization of unrealized loss on dedesignated interest rate swap - income taxes	42	45
Reclassification of net actuarial gain into earnings from postretirement benefit plans - income taxes	4	4
Reclassification of prior service credits into earnings from postretirement benefit plans - income taxes	$ 8	$ 9