Note 6 - Acquisitions (Details Textual) - USD ($) $ in Thousands	3 Months Ended
Mar. 30, 2019	Mar. 31, 2018
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	$ 9,600
Payment for Contingent Consideration Liability, Financing Activities	$ 244	$ 0

Amount of cash outflow, not made soon after acquisition date of business combination, to settle contingent consideration liability up to amount recognized at acquisition date, including, but not limited to, measurement period adjustment and less amount paid soon after acquisition date.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration