Unaudited: Quarterly Results of Operations, Common Stock Price and Dividends (Details) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2022 USD ($) Stockholder $ / shares	Sep. 30, 2022 USD ($) $ / shares	Jun. 30, 2022 USD ($) $ / shares	Mar. 31, 2022 USD ($) $ / shares	Dec. 31, 2021 USD ($) Stockholder $ / shares	Sep. 30, 2021 USD ($) $ / shares	Jun. 30, 2021 USD ($) $ / shares	Mar. 31, 2021 USD ($) $ / shares	Dec. 31, 2022 USD ($) Stockholder $ / shares	Dec. 31, 2021 USD ($) Stockholder $ / shares	Dec. 31, 2020 USD ($) $ / shares
Number of shareholders | Stockholder	560				557				560	557
Net sales | $	$ 147,324	$ 148,009	$ 137,833	$ 132,402	$ 135,748	$ 128,738	$ 122,869	$ 117,842	$ 565,568	$ 505,198	$ 425,544
Gross margin | $	56,965	57,522	54,760	50,723	54,835	51,184	50,102	49,362	219,970	205,484	168,249
Net earnings | $	$ 17,539	$ 17,933	$ 16,664	$ 14,360	$ 17,276	$ 15,855	$ 13,972	$ 13,781	$ 66,496	$ 60,884	$ 49,343
Earnings per share:
Basic	$ 0.60	$ 0.61	$ 0.57	$ 0.49	$ 0.59	$ 0.54	$ 0.48	$ 0.47	$ 2.28	$ 2.09	$ 1.70
Diluted	0.60	0.61	0.57	0.49	0.59	0.54	0.48	0.47	2.26	2.08	1.69
Dividends declared	0.23	0.23	0.20	0.20	0.20	0.20	0.18	0.18	0.85	0.76	$ 0.70
Stock price	109.03	92.39	80.89	99.71	105.64	101.14	98.12	93.07	109.03	105.64
High
Earnings per share:
Stock price	120.54	103.30	102.67	108.76	112.36	108.25	100.01	111.77	120.54	112.36
Low
Earnings per share:
Stock price	$ 88.16	$ 76.88	$ 73.20	$ 85.55	$ 99.13	$ 93.88	$ 89.29	$ 88.98	$ 88.16	$ 99.13