Leases - Narrative (Details) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 27, 2020	Jun. 28, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019	Dec. 31, 2019
Leases [Abstract]
Operating Lease, Liability	$ 27,916,000			$ 27,916,000		$ 17,973,000
Operating lease, right-of-use asset	24,942,000			24,942,000		17,522,000
Operating lease, liability, current	7,863,000			7,863,000		5,647,000
Operating lease, liability, noncurrent	20,053,000			20,053,000		$ 12,326,000
Operating lease, cost	2,047,000		$ 1,749,000	6,100,000	$ 4,976,000
Operating lease, payments	2,041,000		1,708,000	5,995,000	4,778,000
Lease, cost	$ 22,000		22,000	$ 84,000	255,000
Weighted average discount rate	4.10%			4.10%		4.60%
Weighted average remaining lease term	5 years 2 months 12 days			5 years 2 months 12 days		3 years 8 months 12 days
Operating lease asset impairment charges		$ 2,534,000		$ 2,534,000	0
Carrying value operating lease right-of-use assets impaired		$ 0
Rental income	$ 0		$ 76,000	$ 77,000	$ 234,000