Stock-Based Compensation (Details) (USD $)
 3 Months Ended 12 Months Ended
Apr. 30, 2013
Jan. 31, 2013
Summary of activity under Option and Stock Plans    
Beginning Balance Outstanding, Shares 926,224  
Beginning Balance Outstanding, Weighted Average Exercise Price $ 14.34  
Beginning Balance Outstanding, Weighted Average Remaining Contract Term 5 years 7 months 17 days 5 years 4 months 21 days
Beginning Balance, Weighted Average Fair Value, Outstanding $ 5.93  
Granted, Shares 71,000  
Granted, Weighted Average Exercise Price $ 16.11  
Forfeited, Shares     
Forfeited, Weighted Average Exercise Price     
Exercise of stock options, Shares     
Exercised, Weighted Average Exercise Price     
Ending Balance Outstanding, Shares 997,224 926,224
Ending Balance Outstanding, Weighted Average Exercise Price $ 14.47 $ 14.34
Ending Balance Outstanding, Weighted Average Remaining Contract Term 5 years 7 months 17 days 5 years 4 months 21 days
Ending Balance, Weighted Average Fair Value, Outstanding $ 5.74 $ 5.93
Exercisable, Shares 700,724 537,724
Exercisable, Weighted Average Exercise Price $ 13.17 $ 12.16
Exercisable, Weighted Average Remaining Contract Term 4 years 9 months 11 days 4 years 5 months 16 days
Exercisable, Weighted Average Fair Value $ 5.94 $ 6.12