QUARTERLY FINANCIAL INFORMATION (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 213,133	$ 197,869	$ 202,365	$ 185,656	$ 180,713	$ 175,140	$ 173,355	$ 174,436	$ 799,023	$ 703,644	$ 643,705
Gross margin	64,066	60,934	59,447	58,727	56,818	56,368	55,380	55,331	243,174	223,897	211,367
Earnings before income tax expense	33,146	32,085	30,019	29,983	28,047	27,907	25,973	24,490	125,233	106,417	96,478
Net earnings	$ 24,949	$ 25,013	$ 22,731	$ 23,411	$ 22,162	$ 21,568	$ 21,125	$ 19,768	$ 96,104	$ 84,623	$ 79,671
Basic net earnings per common share (in dollars per share)	$ 0.78	$ 0.78	$ 0.71	$ 0.73	$ 0.69	$ 0.67	$ 0.66	$ 0.62	$ 2.98	$ 2.63	$ 2.48
Diluted net earnings per common share (in dollars per share)	$ 0.76	$ 0.77	$ 0.70	$ 0.72	$ 0.68	$ 0.66	$ 0.65	$ 0.61	$ 2.94	$ 2.60	$ 2.45