Leases (Additional Information) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Lessee, Lease, Description [Line Items]
Weighted average remaining lease term (in years)		6 years
Weighted average discount rate (in percentage)		3.78%
Operating lease minimum payments, executed leases that have not commenced		$ 159.0
Rent expense	$ 15.0		$ 45.5
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term (in years)		1 year
Lease renewal term (in years)		1 year
Optional termination period (in years)		1 year
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term (in years)		70 years
Lease renewal term (in years)		10 years
Optional termination period (in years)		11 years