CONSOLIDATED STATEMENTS OF INCOME (unaudited) (USD $)	3 Months Ended		6 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2012	Jul. 31, 2011
CONSOLIDATED STATEMENTS OF INCOME (unaudited) [Abstract]
Net sales	$ 27,997,242	$ 23,089,343	$ 53,204,303	$ 46,519,246
Cost of goods sold	19,299,138	14,952,362	35,555,673	30,324,060
Gross profit	8,698,104	8,136,981	17,648,630	16,195,186
Operating expenses
Selling	3,029,372	2,924,062	6,088,953	5,840,188
General and administrative	3,248,591	2,990,426	7,392,680	6,049,529
Total selling, general and administrative expenses	6,277,963	5,914,488	13,481,633	11,889,717
Income from operations	2,420,141	2,222,493	4,166,997	4,305,469
Interest expense	(41,863)	(49,908)	(84,398)	(98,709)
Other income	49,747	85,344	95,672	191,330
Income before taxes	2,428,025	2,257,929	4,178,271	4,398,090
Provision for taxes	808,026	767,695	1,299,574	1,495,349
Net income	$ 1,619,999	$ 1,490,234	$ 2,878,697	$ 2,902,741
Earnings per share, basic (in dollars per share)	$ 0.11	$ 0.10	$ 0.20	$ 0.20
Earnings per share, diluted (in dollars per share)	$ 0.11	$ 0.10	$ 0.20	$ 0.20
Cash dividend per share - declared (in dollars per share)	$ 0.071	$ 0.066	$ 0.142	$ 0.132
Cash dividend per share - paid (in dollars per share)	$ 0.071	$ 0.066	$ 0.142	$ 0.132