Condensed Consolidated Statements of Earnings - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Statement [Abstract]
Net sales	$ 202,365	$ 173,355	$ 388,021	$ 347,791
Cost of sales	142,918	117,975	269,847	237,080
Gross margin	59,447	55,380	118,174	110,711
Operating expenses:
Selling expenses	14,846	13,836	29,770	29,266
Research and development expenses	2,899	2,569	5,648	5,269
General and administrative expenses	11,109	12,058	21,588	22,981
Total operating expenses	28,854	28,463	57,006	57,516
Earnings from operations	30,593	26,917	61,168	53,195
Other expenses:
Interest expense, net	608	960	1,333	2,656
Other (income) expense, net	(34)	(16)	(167)	76
Total other expenses (income)	574	944	1,166	2,732
Earnings before income tax expense	30,019	25,973	60,002	50,463
Income tax expense	7,288	4,848	13,860	9,570
Net earnings	$ 22,731	$ 21,125	$ 46,142	$ 40,893
Net earnings per common share - basic (in dollars per share)	$ 0.71	$ 0.66	$ 1.43	$ 1.27
Net earnings per common share - diluted (in dollars per share)	$ 0.70	$ 0.65	$ 1.41	$ 1.26