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, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Earnings Per Share [Abstract]
Basic weighted average common shares outstanding	12,313	12,158	12,223	12,135
Stock options	70	44	24	80
Unvested restricted stock	17	2	10	2
Total weighted average common share equivalents	87	46	34	82
Diluted weighted average common shares outstanding	12,400	12,204	12,257	12,217