Condensed Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Sales	$ 102,964	$ 90,685	$ 294,606	$ 270,282
Cost of sales	79,802	71,895	227,531	215,310
Gross profit	23,162	18,790	67,075	54,972
Selling, general and administrative expenses	9,510	7,186	28,377	23,981
Operating income	13,652	11,604	38,698	30,991
Interest expense, net and other	(409)	(364)	(1,349)	(937)
Income before income taxes	13,243	11,240	37,349	30,054
Income tax expense	2,862	3,025	8,636	4,208
Net income	10,381	8,215	28,713	25,846
Income attributable to participating securities	69	54	192	171
Net income attributable to common shareholders and used in earnings per share calculation	$ 10,312	$ 8,161	$ 28,521	$ 25,675
Share information:
Basic and diluted weighted average common shares (in shares)	16,916,675	17,027,068	16,943,130	17,006,226
Basic and diluted earnings per common share (in dollars per share)	$ 0.61	$ 0.48	$ 1.68	$ 1.51