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, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Details
Net Sales	$ 12,333	$ 12,505	$ 12,866	$ 12,520	$ 13,575	$ 12,955	$ 13,428	$ 12,323	$ 12,914	$ 12,572	$ 12,604	$ 10,964	$ 50,224	$ 52,281	$ 49,054
Gross Profit	7,098	7,359	7,739	7,843	8,327	8,186	8,151	7,533	8,112	8,073	7,785	6,947	30,038	32,196	30,917
Net Income	$ 4,287	$ 3,935	$ 4,200	$ 4,214	$ 4,555	$ 4,280	$ 4,103	$ 3,534	$ 4,131	$ 4,206	$ 3,426	$ 3,024	$ 16,635	$ 16,473	$ 14,788
Earnings Per Share Diluted	$ 1.18	$ 1.08	$ 1.15	$ 1.16	$ 1.25	$ 1.18	$ 1.12	$ 0.96	$ 1.13	$ 1.15	$ 0.94	$ 0.83	$ 4.57	$ 4.52	$ 4.04