Intangible assets and goodwill (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Software development costs incurred and expensed	$ 10,500	$ 6,200	$ 31,100	$ 13,800
Amortization expense	25,300	$ 15,700	73,500	23,600
Goodwill, adjustments	$ 7,000		$ 5,838	$ 0