Shareholders' Equity (Components of Accumulated Other Comprehensive Loss) (Details) $ in Thousands	3 Months Ended
	Mar. 28, 2018 USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance as of December 27, 2017	$ (2,316)
Amortization of net loss	28	[1]
Net change in fair value of derivatives	(4,058)
Reclassification of derivatives to interest expense, net	(140)	[2]
Income tax (expense) benefit related to items of other comprehensive loss	1,079
Balance as of March 28, 2018	(5,407)
Estimated reclassification from accumulated other comprehensive income to interest expense related to the interest rate swaps over the next 12 months	1,000
Pensions [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance as of December 27, 2017	(982)
Amortization of net loss	28	[1]
Income tax (expense) benefit related to items of other comprehensive loss	(6)
Balance as of March 28, 2018	(960)
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	(4,058)
Reclassification of derivatives to interest expense, net	(140)	[2]
Income tax (expense) benefit related to items of other comprehensive loss	1,085
Balance as of March 28, 2018	$ (4,447)

[1] Before-tax amount related to our Other 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 quarter ended March 28, 2018. See Note 10 for additional details.

[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 $1.0 million from accumulated other comprehensive loss related to our interest rate swaps during the next twelve months. See Note 9 for additional details.