Earnings per Share - Basic and Diluted Weighted Average Common Shares Used in Earnings Per Share Calculation (Detail) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2014	Jul. 31, 2013
Earnings Per Share [Abstract]
Basic weighted average common shares outstanding	12,671	12,742	12,710	12,766
Stock options	293	419	305	406
Unvested restricted stock	22	15	29	26
Total weighted average common share equivalents	315	434	334	432
Diluted weighted average common shares outstanding	12,986	13,176	13,044	13,198