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, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017
Earnings Per Share [Abstract]
Basic weighted average common shares outstanding	12,093	12,082	12,090	12,080
Stock options	84	83	63	104
Unvested restricted stock	3	35	15	37
Total weighted average common share equivalents	87	118	78	141
Diluted weighted average common shares outstanding	12,180	12,200	12,168	12,221