Shareholders' Equity (Components of Accumulated Other Comprehensive Loss) (Details) $ in Thousands	6 Months Ended
	Jun. 27, 2018 USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance as of December 27, 2017	$ (2,316)
Amortization of net loss	56	[1]
Net change in fair value of derivatives	260
Reclassification of derivatives to interest expense, net	86	[2]
Income tax (expense) benefit related to items of other comprehensive loss	(103)
Balance as of June 27, 2018	(2,017)
Estimated reclassification from accumulated other comprehensive income to interest expense related to the interest rate swaps over the next 12 months	800
Pensions [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance as of December 27, 2017	(982)
Amortization of net loss	56	[1]
Income tax (expense) benefit related to items of other comprehensive loss	(13)
Balance as of June 27, 2018	(939)
Derivatives [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance as of December 27, 2017	(1,334)
Net change in fair value of derivatives	260
Reclassification of derivatives to interest expense, net	86	[2]
Income tax (expense) benefit related to items of other comprehensive loss	(90)
Balance as of June 27, 2018	$ (1,078)

[1] Before-tax amount related to our defined benefit plans that was reclassified from accumulated other comprehensive loss and included as a component of pension expense within general and administrative expenses in our Condensed Consolidated Statements of Income during the two quarters ended June 27, 2018.

[2] Amounts reclassified from accumulated other comprehensive loss into income represent payments either received from or made to the counterparty for the effective portions of the interest rate swaps. These amounts are included as a component of interest expense, net in our Condensed Consolidated Statements of Income. We expect to make payments to the counterparty and reclassify approximately $0.8 million from accumulated other comprehensive loss related to our interest rate swaps during the next twelve months. See Note 9 for additional details.