Leases Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Leases [Abstract]
Operating Lease, Weighted Average Discount Rate, Percent	3.56%		3.56%
Operating Lease, Cost	$ 2,287	$ 2,250	$ 6,932	$ 6,539
Variable Lease, Cost	823	828	2,827	2,965
Lease, Cost	$ 3,110	$ 3,078	$ 9,759	$ 9,504
Operating Lease, Weighted Average Remaining Lease Term	8 years 6 months		8 years 6 months