Leases - Narrative (Details) $ in Thousands	3 Months Ended
	Apr. 30, 2020 USD ($) ft²	Dec. 31, 2019 ft²	Oct. 31, 2019
Lessee, Lease, Description [Line Items]
Total minimum payments	$ 81,548
NY Office Lease
Lessee, Lease, Description [Line Items]
Rentable office space (in sqft) | ft²	106,230
Term of contract	12 years
Total minimum payments	$ 87,300
Financing lease renewal term	5 years
Area of leased space (in sq ft) | ft²	21,000
Operating lease, term of contract			5 years
Lease not yet commenced, estimated base rent payments	$ 8,400
Dublin Lease
Lessee, Lease, Description [Line Items]
Area of leased space (in sq ft) | ft²		40,000
Operating lease, term of contract	12 years
Operating lease renewal term	5 years
estimated aggregate base rent payments, excluding the renewal options	$ 27,000
Palo Alto
Lessee, Lease, Description [Line Items]
Area of leased space (in sq ft) | ft²	16,000
Operating lease, term of contract	8 years
Operating lease renewal term	5 years
Lease not yet commenced, estimated base rent payments	$ 14,200