Note 10 - Activity of Business Segments - Consolidated Net Property and Equipment, Goodwill and Intangible Assets (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Consolidated assets	$ 4,348,000	$ 4,415,000
Operating Segments [Member]
Consolidated assets	3,184,000	3,238,000
Operating Segments [Member] | Building Supply [Member]
Consolidated assets	1,756,000	1,806,000
Operating Segments [Member] | Disposable Protective Apparel [Member]
Consolidated assets	1,428,000	1,432,000
Corporate, Non-Segment [Member]
Consolidated assets	$ 1,164,000	$ 1,177,000