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, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Consolidated net income	$ 1,103,000	$ 1,019,000	$ 2,457,000	$ 2,323,000
Provision for income taxes	503,000	429,000	1,068,000	1,040,000
Operating Segments [Member]
Consolidated net income	2,499,000	2,610,000	6,853,000	6,825,000
Operating Segments [Member] | Building Supply [Member]
Consolidated net income	1,339,000	1,618,000	3,471,000	4,287,000
Operating Segments [Member] | Disposable Protective Apparel [Member]
Consolidated net income	764,000	617,000	1,977,000	1,327,000
Operating Segments [Member] | Infection Control [Member]
Consolidated net income	396,000	375,000	1,405,000	1,211,000
Corporate, Non-Segment [Member]
Consolidated net income	$ 893,000	$ 1,162,000	$ 3,328,000	$ 3,462,000