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, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Consolidated net income	$ 959,000	$ 804,000	$ 1,467,000	$ 1,354,000
Provision for income taxes	203,000	342,000	294,000	564,000
Operating Segments [Member]
Consolidated net income	2,351,000	2,334,000	4,369,000	4,353,000
Operating Segments [Member] | Building Supply [Member]
Consolidated net income	1,067,000	1,170,000	2,061,000	2,132,000
Operating Segments [Member] | Disposable Protective Apparel [Member]
Consolidated net income	891,000	752,000	1,181,000	1,213,000
Operating Segments [Member] | Infection Control [Member]
Consolidated net income	393,000	412,000	1,127,000	1,008,000
Corporate, Non-Segment [Member]
Consolidated net income	$ 1,189,000	$ 1,188,000	$ 2,608,000	$ 2,435,000