Earnings per Share - Basic and Diluted Weighted Average Common Shares Used in Earnings Per Share Calculation (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2017	Jul. 31, 2016
Earnings Per Share [Abstract]
Basic weighted average common shares outstanding	12,082	12,070	12,080	12,065
Stock options	83		104	5
Unvested restricted stock	35	49	37	51
Total weighted average common share equivalents	118	49	141	56
Diluted weighted average common shares outstanding	12,200	12,119	12,221	12,121