QUARTERLY FINANCIAL DATA (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]
Sales	$ 166,847	$ 176,611	$ 174,939	$ 108,323	$ 100,915	$ 102,964	$ 92,560	$ 99,082	$ 626,720	$ 395,521	$ 362,745
Cost of sales	114,094	119,525	118,112	76,024	69,184	79,802	71,858	75,871	427,755	296,715	286,213
Gross profit	52,753	57,086	56,827	32,299	31,731	23,162	20,702	23,211	198,965	98,806	76,532
Advertising and promotion expenses	6,210	5,664	3,371	853	878	552	475	807	16,098	2,712	2,827
SG&A expenses	17,552	18,538	25,793	10,946	15,310	8,958	8,889	8,696	72,829	41,853	26,463
Insurance recoveries	(16,325)	0	0	0					(16,325)	0	0
Operating income	45,316	32,884	27,663	20,500	15,543	13,652	11,338	13,708	126,363	54,241	47,242
Interest expense	(1,329)	(1,116)	(1,104)	(488)	(566)	(594)	(628)	(479)	(4,037)	(2,267)	(1,305)
Other income (loss), net	(751)	(421)	(88)	30	275	185	330	(163)	(1,230)	627	0
Income before income taxes	43,236	31,347	26,471	20,042	15,252	13,243	11,040	13,066	121,096	52,601	45,937
Income tax expense (benefit)	11,578	7,674	6,412	4,615	3,620	2,862	2,550	3,224	30,279	12,256	7,144
Net income	$ 31,658	$ 23,673	$ 20,059	$ 15,427	$ 11,632	$ 10,381	$ 8,490	$ 9,842	$ 90,817	$ 40,345	$ 38,793
Basic EPS data (in dollars per share)	$ 1.44	$ 1.08	$ 0.91	$ 0.90	$ 0.69	$ 0.61	$ 0.50	$ 0.57	$ 4.37	$ 2.37	$ 2.27
Diluted EPS data (in dollars per share)	$ 1.40	$ 1.08	$ 0.91	$ 0.90	$ 0.69	$ 0.61	$ 0.50	$ 0.57	$ 4.34	$ 2.37	$ 2.27