Revenue Recognition Contract Balances (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019	Dec. 28, 2019
Revenue Recognition and Deferred Revenue [Abstract]
Revenue, Remaining Performance Obligation, Amount	$ 5,300		$ 5,300
Accounts Receivable, after Allowance for Credit Loss, Current	128,334		128,334		$ 146,161
Contract with Customer, Liability, Revenue Recognized	3,800	$ 5,300	4,300	$ 5,800
Contract with Customer, Liability	$ 6,578		$ 6,578		$ 6,991