Note 15 - Activity of Business Segments - Consolidated Net Sales (Details) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Net sales	$ 46,665,000	$ 46,624,000
Building Supply [Member] \| Operating Segments [Member]
Net sales	26,576,000	26,035,000
Disposable Protective Apparel [Member] \| Operating Segments [Member]
Net sales	$ 20,089,000	$ 20,589,000

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

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