Note 3 - Quarterly Results of Operations (Unaudited): Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Details
Net Sales	$ 9,756	$ 10,390	$ 10,965	$ 10,887	$ 10,201	$ 10,125	$ 10,829	$ 10,259	$ 41,998	$ 41,414	$ 39,298
Gross Profit	6,106	6,294	6,984	6,922	6,470	6,496	6,893	6,535	26,306	26,395	23,690
Net Income (Loss)	$ 3,393	$ 6,762	$ 4,308	$ 4,092	$ (2,522)	$ 3,622	$ 3,870	$ 3,536	$ 18,555	$ 8,505	$ 12,128
Earnings (Loss) Per Common Share (Diluted)	$ 0.91	$ 1.80	$ 1.15	$ 1.09	$ (0.67)	$ 0.97	$ 1.04	$ 0.95	$ 4.95	$ 2.28	$ 3.22