Note 11 - Discontinued Operations (Details Textual) - USD ($) $ in Thousands	12 Months Ended
Dec. 30, 2017	Dec. 31, 2016	Dec. 26, 2015
Proceeds from Divestiture of Businesses			$ 4,881
Broadcast Microwave Services, Inc. (“BMS”) [Member]
Proceeds from Divestiture of Businesses			4,900
Disposal Group, Including Discontinued Operation, Contingent Consideration			$ 2,500

The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585

Name:	us-gaap_ProceedsFromDivestitureOfBusinesses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration