Condensed Consolidated Statements of Earnings - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Net sales	$ 185,656	$ 174,436
Cost of sales	126,929	119,105
Gross margin	58,727	55,331
Operating expenses:
Selling expenses	14,924	15,430
Research and development expenses	2,749	2,700
General and administrative expenses	10,479	10,923
Total operating expenses	28,152	29,053
Earnings from operations	30,575	26,278
Other expenses:
Interest expense, net	725	1,696
Other (income) expense, net	(133)	92
Total other expenses (income)	592	1,788
Earnings before income tax expense	29,983	24,490
Income tax expense	6,572	4,722
Net earnings	$ 23,411	$ 19,768
Net earnings per common share - basic (in dollars per share)	$ 0.73	$ 0.62
Net earnings per common share - diluted (in dollars per share)	$ 0.72	$ 0.61