Leases (Additional Information) (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 30, 2020	Jan. 31, 2020
Lessee, Lease, Description [Line Items]
Weighted average remaining lease term (in years)	7 years 4 months 24 days	7 years 6 months
Weighted average discount rate (in percentage)	3.36%	3.41%
Operating lease minimum payments, executed leases that have not commenced	$ 29.8
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)	10 years