Net Income (loss) Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Apr. 30, 2020	Apr. 30, 2019
Numerator:
Net income	$ 8,634	$ (465)
Denominator:
Denominator for basic earnings per share (weighted-average shares which reflect shares in the treasury, 509,242 at April 30,2020 and 462,089 for April 30, 2019	7,972,423	8,013,840
Effect of dilutive securities from restricted stock plan and from dilutive effect of stock options	72,426	0
Denominator for diluted earnings per share (adjusted weighted average shares)	8,044,849	8,013,840
Basic earnings per share	$ 1.08	$ (0.06)
Diluted earnings per share	$ 1.07	$ (0.06)
Warrants and restricted stock awards excluded from the computation of diluted loss per share because the effect of inclusion would have been anti-dilutive	0	196,340