Accumulated Other Comprehensive Income (Loss) (Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss) - total			$ (1,299)
Unrealized gain on interest rate swaps, net	$ 261	$ (35)	1,389	$ (223)
Reclassification of loss into earnings from interest rate swaps, net	150	178	555	601
Reclassification of net actuarial gain into earnings from postretirement benefit plans, net	(7)	(5)	(22)	(15)
Reclassification of prior service credits into earnings from postretirement benefit plans, net	(1)	$ (1)	(3)	$ (2)
Accumulated other comprehensive income (loss) - total	620		620
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			(1,587)
Unrealized gain on interest rate swaps, net			1,389
Reclassification of loss into earnings from interest rate swaps, net			555
Accumulated other comprehensive income (loss) - total	357		357
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss) - total			288
Reclassification of net actuarial gain into earnings from postretirement benefit plans, net			(22)
Reclassification of prior service credits into earnings from postretirement benefit plans, net			(3)
Accumulated other comprehensive income (loss) - total	$ 263		$ 263