Long-Term Debt (Details) - USD ($)	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
Line of Credit Facility [Line Items]
Interest Expense, Debt	$ 18,000	$ 167,000
Revolving Credit Facility [Member] | Wells Fargo Bank, N.A. [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	50,000,000
Line of credit facility, discretionary amount available	50,000,000
Line of Credit Facility, Remaining Borrowing Capacity	$ 88,600,000
Debt Instrument, Maturity Date	Sep. 01, 2019
Letters of Credit Outstanding, Amount	$ 11,400,000