Stock-based compensation (Summary of share based compensation recognized) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 11,479	$ 23,156	$ 30,313	$ 36,774
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	2,209	1,415	5,737	3,285
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	2,035	1,304	4,810	3,469
Technology and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	2,641	2,171	8,051	5,600
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	4,594	3,332	11,715	9,486
Merger Integration
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	0	1,220	0	1,220
Other expense, net
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 0	$ 13,714	$ 0	$ 13,714