Note 10 - Activity of Business Segments - Reconciliation of Total Segment Income to Total Consolidated Net Income (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Consolidated net income	$ 1,218,000	$ 508,000
Provision for income taxes	243,000	92,000
Operating Segments [Member]
Consolidated net income	2,331,000	2,017,000
Operating Segments [Member] | Building Supply [Member]
Consolidated net income	908,000	994,000
Operating Segments [Member] | Disposable Protective Apparel [Member]
Consolidated net income	1,423,000	1,023,000
Corporate, Non-Segment [Member]
Consolidated net income	$ 870,000	$ 1,417,000