Revenue Recognition Contract Balances (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019	Dec. 28, 2019
Revenue Recognition and Deferred Revenue [Abstract]
Revenue, Remaining Performance Obligation, Amount	$ 7,300		$ 7,300
Accounts Receivable, after Allowance for Credit Loss, Current	179,709		179,709		$ 146,161
Contract with Customer, Liability, Revenue Recognized	1,800	$ 1,700	4,600	$ 5,800
Contract with Customer, Liability	$ 12,063		$ 12,063		$ 6,991