Note 10 - Activity of Business Segments - Reconciliation of Total Segment Income to Total Consolidated Net Income (Details) - USD ($)	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Consolidated net income	$ 766,000	$ 1,671,000	$ 3,719,000	$ 8,107,000	$ 6,220,000	$ 5,342,000	$ 6,156,000	$ 19,668,000
Provision for income taxes	196,000			2,490,000			1,550,000	3,284,000
Operating Segments [Member]
Consolidated net income	2,135,000			12,187,000			11,980,000	27,756,000
Operating Segments [Member] | Building Supply [Member]
Consolidated net income	1,901,000			1,307,000			5,629,000	4,023,000
Operating Segments [Member] | Disposable Protective Apparel [Member]
Consolidated net income	234,000			10,880,000			6,351,000	23,733,000
Corporate, Non-Segment [Member]
Consolidated net income	$ 1,173,000			$ 1,590,000			$ 4,274,000	$ 4,804,000