Note 10 - Activity of Business Segments - Consolidated Net Sales (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Net sales	$ 23,161,000	$ 18,154,000
Building Supply [Member] | Operating Segments [Member]
Net sales	8,340,000	7,557,000
Disposable Protective Apparel [Member] | Operating Segments [Member]
Net sales	$ 14,821,000	$ 10,597,000