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, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Consolidated net income	$ 1,010,000	$ 959,000	$ 2,228,000	$ 1,467,000
Provision for income taxes	238,000	203,000	481,000	294,000
Operating Segments [Member]
Consolidated net income	1,778,000	2,351,000	4,110,000	4,369,000
Operating Segments [Member] | Building Supply [Member]
Consolidated net income	900,000	1,067,000	1,809,000	2,061,000
Operating Segments [Member] | Disposable Protective Apparel [Member]
Consolidated net income	878,000	1,284,000	2,301,000	2,308,000
Corporate, Non-Segment [Member]
Consolidated net income	$ 530,000	$ 1,189,000	$ 1,401,000	$ 2,608,000