Unaudited: Quarterly Results of Operations, Common Stock Price and Dividends (Details) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2023 USD ($) Stockholder $ / shares	Sep. 30, 2023 USD ($) $ / shares	Jun. 30, 2023 USD ($) $ / shares	Mar. 31, 2023 USD ($) $ / shares	Dec. 31, 2022 USD ($) Stockholder $ / shares	Sep. 30, 2022 USD ($) $ / shares	Jun. 30, 2022 USD ($) $ / shares	Mar. 31, 2022 USD ($) $ / shares	Dec. 31, 2023 USD ($) Stockholder $ / shares	Dec. 31, 2022 USD ($) Stockholder $ / shares	Dec. 31, 2021 USD ($) $ / shares
Number of shareholders | Stockholder	560				560				560	560
Net sales | $	$ 182,440	$ 186,193	$ 175,858	$ 159,101	$ 147,324	$ 148,009	$ 137,833	$ 132,402	$ 703,592	$ 565,568	$ 505,198
Gross margin | $	71,465	72,723	69,434	62,816	56,965	57,522	54,760	50,723	276,438	219,970	205,484
Net Income (Loss) | $	$ 24,721	$ 25,969	$ 22,493	$ 19,415	$ 17,539	$ 17,933	$ 16,664	$ 14,360	$ 92,598	$ 66,496	$ 60,884
Earnings per share:
Basic	$ 0.84	$ 0.89	$ 0.77	$ 0.66	$ 0.60	$ 0.61	$ 0.57	$ 0.49	$ 3.16	$ 2.28	$ 2.09
Diluted	0.84	0.88	0.76	0.66	0.60	0.61	0.57	0.49	3.14	2.26	2.08
Dividends declared	0.27	0.27	0.23	0.23	0.23	0.23	0.20	0.20	0.99	0.85	$ 0.76
Stock price	154.37	143.87	147.56	121.82	109.03	92.39	80.89	99.71	154.37	109.03
High
Earnings per share:
Stock price	158.47	170.86	156.15	124.35	120.54	103.3	102.67	108.76	158.47	120.54
Low
Earnings per share:
Stock price	$ 134.06	$ 138.71	$ 117.53	$ 103.93	$ 88.16	$ 76.88	$ 73.20	$ 85.55	$ 134.06	$ 88.16