Leases - Additional Information (Detail) $ in Millions	3 Months Ended	9 Months Ended
	Oct. 31, 2019 USD ($)	Oct. 31, 2019 USD ($)
Leases [Line Items]
Operating lease expense	$ 1.8	$ 5.0
Finance lease expense		1.0
Additional operating leasess, primarily for office leases, that have not yet commenced	$ 3.3	$ 3.3
Maximum
Leases [Line Items]
Operating leases, options to extend leases term	9 years	9 years
Finance leases, options to extend leases term	9 years	9 years
Additional operating leases that have not yet commenced, lease terms	5 years	5 years
Minimum
Leases [Line Items]
Additional operating leases that have not yet commenced, lease terms	1 year	1 year