Debt - Effect of Derivatives on Financial Statements (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018
Debt and Credit Arrangements
Total interest expense on Consolidated Statements of Operations	$ (17,022)	$ (20,593)	$ (25,673)
Weighted average interest rates on debt, including the impact of interest rate swap agreements	3.80%	4.10%	3.90%
Interest paid, including payments made or received under the swaps	$ 15,800	$ 18,100	$ 23,500
Interest rate swap
Debt and Credit Arrangements
Portion of derivative liability that would be reclassified into earnings	13,500
Interest expense \| Interest rate swap
Debt and Credit Arrangements
Amount of Gain or (Loss) Recognized in AOCI/AOCL on Derivative	(5,788)	(8,303)	3,222
Amount of Gain or (Loss) Reclassified from AOCI/AOCL into Income	(5,068)	660	(22)
Total interest expense on Consolidated Statements of Operations	(17,022)	$ (20,593)	$ (25,673)
Portion of derivative liability that would be reclassified into earnings	$ 7,200
Estimate of period of time over which portion of derivative liability would be reclassified into earnings	12 months

The average effective interest rate during the reporting period.

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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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Amount of the cost of borrowed funds accounted for as interest expense.

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