Consolidated Statements of Earnings - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Net sales	$ 643,705	$ 643,679	$ 594,790
Cost of sales	432,338	439,427	405,781
Gross margin	211,367	204,252	189,009
Operating expenses:
Selling expenses	60,932	57,219	54,720
Research and development expenses	11,377	11,592	9,305
General and administrative expenses	36,505	28,341	28,081
Total operating expenses	108,814	97,152	92,106
Earnings from operations	102,553	107,100	96,903
Other expenses:
Interest expense, net	5,959	7,611	7,532
Other, net	116	459	883
Total other expenses	6,075	8,070	8,415
Earnings before income tax expense	96,478	99,030	88,488
Income tax expense/(benefit)	16,807	20,457	(1,583)
Net earnings	$ 79,671	$ 78,573	$ 90,071
Basic net earnings per common share (in dollars per share)	$ 2.48	$ 2.45	$ 2.83
Diluted net earnings per common share (in dollars per share)	$ 2.45	$ 2.42	$ 2.79