Shareholders' Equity Shareholders' Equity (Components of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 26, 2018	Dec. 27, 2017	Dec. 28, 2016
AOCI Attributable To Parent, Net Of Tax [Roll Forward]
Accumulated other comprehensive loss, net of tax, beginning balance		$ (2,316)	$ (1,407)	$ (23,777)
Benefit obligation actuarial gain (loss)		96	(172)	(1,018)
Net gain		(96)	172	603
Amortization of net loss	[1]	112	92	85
Settlement loss recognized			21	24,297
Net change in fair value		(2,595)	(1,359)	1,693
Reclassification of derivatives to interest expense	[2]	307	(72)	(789)
Income tax benefit (expense), pension		(53)	22	(2,148)
Income tax benefit (expense)		250	581	(2,501)
Accumulated other comprehensive loss, net of tax, ending balance		(4,146)	(2,316)	(1,407)
Estimated reclassification from other comprehensive income to interest expense related to the interest rate swaps over the next 12 months		200
Pensions [Member]
AOCI Attributable To Parent, Net Of Tax [Roll Forward]
Accumulated other comprehensive loss, net of tax, beginning balance		(982)	(945)	(22,764)
Benefit obligation actuarial gain (loss)		96	(172)	(1,018)
Net gain				603
Amortization of net loss	[1]	112	92	85
Settlement loss recognized			21	24,297
Income tax benefit (expense), pension		(53)	22	(2,148)
Accumulated other comprehensive loss, net of tax, ending balance		(827)	(982)	(945)
Derivatives [Member]
AOCI Attributable To Parent, Net Of Tax [Roll Forward]
Accumulated other comprehensive loss, net of tax, beginning balance		(1,334)	(462)	(1,013)
Net change in fair value, derivatives		(2,595)	(1,359)	1,693
Reclassification of derivatives to interest expense, derivatives	[2]	307	(72)	(789)
Income tax benefit (expense), derivatives		303	559	(353)
Accumulated other comprehensive loss, net of tax, ending balance		$ (3,319)	$ (1,334)	$ (462)

[1] Before-tax amount that was reclassified from accumulated other comprehensive loss and included as a component of pension expense within general and administrative expenses in our Consolidated Statements of Income. See Note 13 for additional details.

[2] Amounts reclassified from accumulated other comprehensive loss into income represent payments made to the counterparty for the effective portions of the interest rate swaps. These amounts are included as a component of interest expense in our Consolidated Statements of Income. We expect to reclassify approximately $0.2 million from accumulated other comprehensive loss related to our interest rate swaps during the next twelve months. See Note 12 for additional details.