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, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Consolidated net income	$ 804,000	$ 797,000	$ 1,354,000	$ 1,304,000
Provision for income taxes	342,000	386,000	564,000	612,000
Operating Segments [Member]
Consolidated net income	2,334,000	2,413,000	4,353,000	4,216,000
Operating Segments [Member] | Building Supply [Member]
Consolidated net income	1,170,000	1,657,000	2,132,000	2,670,000
Operating Segments [Member] | Disposable Protective Apparel [Member]
Consolidated net income	752,000	375,000	1,213,000	710,000
Operating Segments [Member] | Infection Control [Member]
Consolidated net income	412,000	381,000	1,008,000	836,000
Corporate, Non-Segment [Member]
Consolidated net income	$ 1,188,000	$ 1,230,000	$ 2,435,000	$ 2,300,000