Note 10 - Activity of Business Segments - Reconciliation of Total Segment Income to Total Consolidated Net Income (Details) - USD ($)	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Consolidated net income	$ 1,671,000	$ 3,719,000	$ 6,220,000	$ 5,342,000	$ 5,390,000	$ 11,561,000
Provision (benefit) for income taxes	347,000		1,822,000		1,354,000	794,000
Operating Segments [Member]
Consolidated net income	3,544,000		9,707,000		9,845,000	15,570,000
Operating Segments [Member] | Building Supply [Member]
Consolidated net income	2,177,000		1,307,000		3,729,000	2,716,000
Operating Segments [Member] | Disposable Protective Apparel [Member]
Consolidated net income	1,367,000		8,400,000		6,116,000	12,854,000
Corporate, Non-Segment [Member]
Consolidated net income	$ 1,526,000		$ 1,665,000		$ 3,101,000	$ 3,215,000