Net Income (loss) Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2019
Net income per common share:
Denominator for diluted earnings per share (adjusted weighted average shares)	8,123,848	8,035,929	8,110,435	8,044,159	8,044,159
Basic net income per share	$ 1.16	$ 0.14	$ 3.41	$ 0.26	$ 0.26
Diluted net income per share	$ 1.14	$ 0.14	$ 3.36	$ 0.26	$ 0.26
Net income	$ 9,264	$ 1,146	$ 27,237	$ 2,076	$ 2,076
Denominator for basic net income per share (weighted-average shares which exclude shares in the treasury, 509,242 at July 31, 2020 and 471.289 for July 31, 2019	7,979,902	8,004,640	7,976,228	8,013,383
Effect of dilutive securities from restricted stock plan	143,946	31,289	134,207	30,776