Note 10 - Activity of Business Segments - Reconciliation of Total Segment Income to Total Consolidated Net Income (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Consolidated net income	$ 5,342,000	$ 1,218,000
Provision (benefit) for income taxes	(1,028,000)	243,000
Operating Segments [Member]
Consolidated net income	5,863,000	2,331,000
Operating Segments [Member] | Building Supply [Member]
Consolidated net income	1,410,000	908,000
Operating Segments [Member] | Disposable Protective Apparel [Member]
Consolidated net income	4,453,000	1,423,000
Corporate, Non-Segment [Member]
Consolidated net income	$ 1,549,000	$ 870,000