Note 4 - Accounts Receivable, Transit Accounts Receivable and Transit Accounts Payable (Details Textual) - USD ($) $ in Thousands	Sep. 28, 2019	Dec. 29, 2018
Accounts Receivable, after Allowance for Credit Loss, Current, Total	$ 57,470	$ 52,335
Loss Contingency, Receivable, Ending Balance	12,200	8,900
Loss Contingency, Estimate of Possible Loss	10,300
Collectibility of Receivables [Member]
Loss Contingency, Estimate of Possible Loss	10,300
Transit Accounts Payable [Member]
Accounts Payable, Current, Total	4,500	2,500
Transit Accounts Receivable [Member]
Accounts Receivable, before Allowance for Credit Loss, Current	3,700	2,600
Accounts Receivable, after Allowance for Credit Loss, Current, Total	$ 800	$ 100