Condensed Consolidated Statements of Income Unaudited - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2017	Jul. 31, 2016
Income Statement [Abstract]
Net sales	$ 72,636	$ 61,354	$ 95,871	$ 82,181
Costs of goods sold	45,953	37,616	60,761	50,380
Gross profit	26,683	23,738	35,110	31,801
Selling, general and administrative expenses	18,278	16,226	29,970	27,135
(Gain) Loss on sale of property, plant & equipment	(1)	0	(1)	(1)
Operating income	8,406	7,512	5,141	4,667
Interest expense, net	529	486	824	750
Income (loss) before income taxes	7,877	7,026	4,317	3,917
Income tax (benefit) expense	2,849	140	1,500	170
Net income (loss)	$ 5,028	$ 6,886	$ 2,817	$ 3,747
Net income (loss) per common share:
Basic (usd per share)	$ 0.33	$ 0.46	$ 0.19	$ 0.25
Diluted (usd per share)	$ 0.33	$ 0.45	$ 0.18	$ 0.25
Weighted average shares outstanding:
Basic (shares)	15,211	15,036	15,170	15,004
Diluted (shares)	15,285	15,147	15,233	15,100