Leases - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019	Jan. 31, 2020
Leases [Abstract]
Weighted average remaining lease term	7 years 1 month 6 days		7 years 1 month 6 days		7 years 10 months 24 days
Weighted average discount rate	5.60%		5.60%		5.70%
Cash payments included in the measurement of operating lease liabilities	$ 7.7	$ 6.1	$ 22.7	$ 10.9