Condensed Consolidated Statements of Income Unaudited - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Income Statement [Abstract]
Net sales	$ 67,795	$ 64,981	$ 149,976	$ 149,100
Costs of goods sold	43,484	41,771	93,864	93,701
Gross profit	24,311	23,210	56,112	55,399
Selling, general and administrative expenses	17,780	16,674	44,915	43,771
(Gain) loss on sale of property, plant & equipment	(1)	17	(2)	9
Operating income	6,532	6,519	11,199	11,619
Interest expense, net	326	379	1,076	1,129
Income before income taxes	6,206	6,140	10,123	10,490
Income tax (benefit) expense	(17,792)	137	(17,622)	214
Net income	$ 23,998	$ 6,003	$ 27,745	$ 10,276
Net income (loss) per common share:
Basic (usd per share)	$ 1.59	$ 0.40	$ 1.84	$ 0.69
Diluted (usd per share)	$ 1.57	$ 0.39	$ 1.83	$ 0.67
Weighted average shares outstanding:
Basic (shares)	15,128	14,971	15,047	14,895
Diluted (shares)	15,293	15,324	15,186	15,227