Note 9 - Income Taxes (Details Textual) - USD ($) $ in Thousands	3 Months Ended
Mar. 27, 2021	Mar. 28, 2020
Effective Income Tax Rate Reconciliation, Percent, Total	11.50%	5.40%
Unrecognized Tax Benefits, Period Increase (Decrease), Total	$ 0	$ 0

Amount of increase (decrease) in unrecognized tax benefits attributable to uncertain tax positions taken in tax returns.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319

Name:	us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration