Earnings per Share - Basic and Diluted Weighted Average Common Shares Used in Earnings Per Share Calculation (Detail) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Earnings Per Share [Abstract]
Basic weighted average common shares outstanding	12,087	12,075	12,082	12,068
Stock options	35	8	81	6
Unvested restricted stock	28	37	34	46
Total weighted average common share equivalents	63	45	115	52
Diluted weighted average common shares outstanding	12,150	12,120	12,197	12,120