CONSOLIDATED STATEMENT OF INCOME (USD $)	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
CONSOLIDATED STATEMENT OF INCOME [Abstract]
Net sales	$ 109,941,922	$ 100,161,392	$ 88,865,426
Cost of goods sold	72,154,899	64,792,385	56,587,326
Gross profit	37,787,023	35,369,007	32,278,100
Operating expenses
Selling	11,818,299	12,017,123	11,674,270
General and administrative	14,090,913	12,760,600	11,633,509
Total selling, general and administrative	25,909,212	24,777,723	23,307,779
Income from operations	11,877,811	10,591,284	8,970,321
Interest expense	(166,206)	(191,181)	(212,470)
Other income	154,076	434,207	362,046
Income before taxes	11,865,681	10,834,310	9,119,897
Provision for taxes	3,820,458	3,700,609	2,980,765
Net income	$ 8,045,223	$ 7,133,701	$ 6,139,132
Earnings per share
Basic (in dollars per share)	$ 0.55	$ 0.49	$ 0.42
Diluted (in dollars per share)	$ 0.55	$ 0.48	$ 0.42
Average number of common and common equivalent shares outstanding
Basic (in shares)	14,685,038	14,662,055	14,629,215
Diluted (in shares)	14,738,035	14,774,692	14,758,659