Other Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 28, 2013	Dec. 29, 2012	Dec. 31, 2011
Unrealized gain (loss) on interest rate swaps:
Before income taxes	$ 381	$ (767)	$ (665)
Income taxes	145	(291)	(253)
Net of taxes	236	(476)	(412)
Reclassification of loss into earnings from interest rate swaps:
Before income taxes	284	158	433
Income taxes	108	60	165
Net of taxes	176	98	268
Amortization of unrealized loss on dedesignated interest rate swaps:
Before income taxes	158	467	150
Income taxes	60	178	57
Net of taxes	98	289	93
Unrecognized net actuarial gain on postretirement benefit plans:
Before income taxes	32	33	108
Income taxes	12	13	41
Net of taxes	20	20	67
Reclassification of net actuarial gain into earnings from postretirement benefit plans:
Before income taxes	(35)	(45)	(29)
Income taxes	(13)	(18)	(11)
Net of taxes	(22)	(27)	(18)
Reclassification of prior service credits into earnings from postretirement benefit plans:
Before income taxes	(88)	(88)	(88)
Income taxes	(34)	(34)	(33)
Net of taxes	(54)	(54)	(55)
Other comprehensive income (loss)	$ 454	$ (150)	$ (57)