Note 9 - Line of Credit (Details Textual) - USD ($) $ in Thousands		9 Months Ended
	Sep. 25, 2020	Sep. 26, 2020	Sep. 28, 2019	Dec. 28, 2019	Oct. 18, 2019
Repayments of Subordinated Debt, Total		$ 2,230
Long-term Line of Credit, Noncurrent		$ 13,258		$ 34,761
Note Issued to Acquire Treasury Stock [Member]
Repayments of Subordinated Debt, Total	$ 2,200
Citizens Bank of Pennsylvania [Member] | Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity					$ 45,000
Debt Instrument, Interest Rate, Effective Percentage		2.90%	4.60%
Long-term Line of Credit, Noncurrent		$ 13,300		34,800
Letters of Credit Outstanding, Amount		1,700		$ 1,600
Line of Credit Facility, Remaining Borrowing Capacity		$ 30,000