Accumulated Other Comprehensive Income (Loss) (Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jun. 25, 2016	Jul. 01, 2017	Jun. 25, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss) - total			$ (1,960)
Unrealized loss on interest rate swaps, net	$ (223)	$ (765)	(188)	$ (1,657)
Reclassification of loss into earnings from interest rate swaps, net	201	179	423	361
Reclassification of net actuarial gain into earnings from postretirement benefit plans, net	(5)	(6)	(10)	(12)
Reclassification of prior service credits into earnings from postretirement benefit plans, net	(1)	$ (1)	(1)	$ (1)
Accumulated other comprehensive income (loss) - total	(1,736)		(1,736)
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			(2,216)
Unrealized loss on interest rate swaps, net			(188)
Reclassification of loss into earnings from interest rate swaps, net			423
Accumulated other comprehensive income (loss) - total	(1,981)		(1,981)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss) - total			256
Reclassification of net actuarial gain into earnings from postretirement benefit plans, net			(10)
Reclassification of prior service credits into earnings from postretirement benefit plans, net			(1)
Accumulated other comprehensive income (loss) - total	$ 245		$ 245