Accumulated Other Comprehensive Income (Loss) (Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Sep. 26, 2015	Sep. 27, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss) - total			$ (1,513)
Unrealized gain (loss) on interest rate swaps, net	$ (1,192)	$ (15)	(1,529)	$ (1,242)
Reclassification of loss into earnings from interest rate swaps, net	116	54	281	160
Reclassification of net actuarial gain into earnings from postretirement benefit plans, net	(5)	(6)	(16)	(18)
Reclassification of prior service credits into earnings from postretirement benefit plans, net	(13)	$ (14)	(38)	$ (41)
Accumulated other comprehensive income (loss) - total	(2,815)		(2,815)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss) - total			(1,841)
Unrealized gain (loss) on interest rate swaps, net			(1,529)
Reclassification of loss into earnings from interest rate swaps, net			281
Accumulated other comprehensive income (loss) - total	(3,089)		(3,089)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss) - total			328
Reclassification of net actuarial gain into earnings from postretirement benefit plans, net			(16)
Reclassification of prior service credits into earnings from postretirement benefit plans, net			(38)
Accumulated other comprehensive income (loss) - total	$ 274		$ 274