Quarterly Financial Data - Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 123,018	$ 113,777	$ 84,197	$ 103,075	$ 115,040	$ 115,651	$ 120,684	$ 117,625	$ 424,066	$ 468,999	$ 470,483
Gross margin	42,691	36,906	26,567	32,899	38,700	37,057	41,204	40,615	139,063	157,575	164,973
Operating earnings	17,137	13,259	6,242	8,492	12,391	10,124	17,083	14,218	45,129	53,815	61,038
Net earnings	$ 14,947	$ 11,073	$ 4,857	$ 3,808	$ 10,062	$ 2,722	$ 11,943	$ 11,419	$ 34,686	$ 36,146	$ 46,532
Basic earnings per share	$ 0.46	$ 0.34	$ 0.15	$ 0.12	$ 0.31	$ 0.08	$ 0.36	$ 0.35	$ 1.07	$ 1.11	$ 1.41
Diluted earnings per share	$ 0.46	$ 0.34	$ 0.15	$ 0.12	$ 0.31	$ 0.08	$ 0.36	$ 0.34	$ 1.06	$ 1.09	$ 1.39