Long-Term Debt (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018
Line of Credit Facility [Line Items]
Interest Expense, Debt	$ 10,000	$ 29,000	$ 43,000	$ 269,000
Revolving Credit Facility [Member] | Wells Fargo Bank, N.A. [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	30,000,000		30,000,000
Line of credit facility, discretionary amount available	70,000,000		70,000,000
Line of Credit Facility, Remaining Borrowing Capacity	18,500,000		18,500,000
Letters of Credit Outstanding, Amount	$ 11,500,000		$ 11,500,000