Debt and Credit Arrangements - Effect of Derivatives on Financial Statements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Dec. 25, 2016
Debt and Credit Arrangements
Weighted average interest rates on debt, including the impact of interest rate swap agreements	3.90%	2.70%	2.10%
Interest paid, including payments made or received under the swaps	$ 23,500	$ 10,800	$ 7,100
Interest rate swap | Other current and long-term assets
Debt and Credit Arrangements
Interest rate swap assets	$ 4,900
Estimate of period of time over which portion of derivative liability would be reclassified into earnings	12 months
Portion of derivative asset that would be reclassified into earnings	$ 1,300
Interest expense | Interest rate swap
Debt and Credit Arrangements
Amount of Gain or (Loss) Recognized in AOCI/AOCL on Derivative	3,222	891	940
Amount of Gain or (Loss) Reclassified from AOCI/AOCL into Income	(22)	(421)	(1,161)
Total Interest Expense on Consolidated Statements of Operations	$ (25,306)	$ (11,283)	$ (7,397)