Share Based Compensation - Outstanding stock options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Jan. 31, 2021	Jan. 31, 2020
Number of options
Outstanding, beginning of period (in shares)	214,260
Granted (in shares)	0	0
Exercised (in shares)	(93,475)
Forfeited (in shares)	(5,630)
Outstanding, end of period (in shares)	115,155	214,260
Number of options, outstanding exercisable, end of period	72,855
Share-based compensation arrangement by share-based payment award, options, vested and expected to vest, outstanding, number	115,155
Weighted average exercise price
Outstanding, beginning of period (in usd per share)	$ 25.03
Granted (in usd per share)	0
Exercised (in usd per share)	16.13
Forfeited (in usd per share)	32.5
Outstanding, end of period (in usd per share)	31.89	$ 25.03
Weighted average exercise price, Outstanding exercisable, end of period	31.44
Share-based compensation arrangement by share-based payment award, options, vested and expected to vest, outstanding, weighted average exercise price	$ 31.89
Aggregate intrinsic value, Outstanding, end of period	$ 192
Aggregate intrinsic value, Outstanding exercisable, end of period	$ 138
Weighted average remaining contractual term (years), Outstanding, end of period	1 year 6 months 29 days
Weighted average remaining contractual term (years), Outstanding exercisable, end of period	1 year 5 months 19 days
Share-based compensation arrangement by share-based payment award, options, vested and expected to Vest, outstanding, weighted average remaining contractual term	1 year 6 months 29 days