Stock-Based Compensation (Details) (USD $)	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Summary of activity under Option and Stock Plans
Beginning Balance Outstanding, Shares	817,186	675,724
Beginning Balance Outstanding, Weighted Average Exercise Price	$ 12.10	$ 11.29
Beginning Balance Outstanding, Weighted Average Remaining Contract Term	5 years 4 months 21 days	4 years 11 months 9 days	5 years 9 months 11 days
Beginning Balance, Weighted Average Fair Value, Outstanding	$ 5.68	$ 5.79
Granted, Shares	293,000	212,500
Granted, Weighted Average Exercise Price	$ 17.36	$ 13.92
Exercise of stock options, Shares	(153,962)	(55,038)
Exercised, Weighted Average Exercise Price	$ 9.33	$ 9.36
Forfeited, Shares	(30,000)	(16,000)
Forfeited, Weighted Average Exercise Price	$ 8.66	$ 11.36
Ending Balance Outstanding, Shares	926,224	817,186	675,724
Ending Balance Outstanding, Weighted Average Exercise Price	$ 14.34	$ 12.10	$ 11.29
Ending Balance Outstanding, Weighted Average Remaining Contract Term	5 years 4 months 21 days	4 years 11 months 9 days	5 years 9 months 11 days
Ending Balance, Weighted Average Fair Value, Outstanding	$ 5.93	$ 5.68	$ 5.79
Exercisable, Shares	633,224
Exercisable, Weighted Average Exercise Price	$ 12.94
Exercisable, Weighted Average Remaining Contract Term	4 years 4 months 13 days
Exercisable, Weighted Average Fair Value	$ 6.06