Basis of Presentation and Summary of Significant Accounting Policies - Deferred Commissions (Details)	3 Months Ended
	Apr. 30, 2018 USD ($)
Finite-Lived Intangible Assets [Line Items]
Remaining amortization period	3 years 1 month 6 days
Contract Assets
Beginning balance as of January 31, 2018 (as adjusted)	$ 87,313,000
Additions	15,421,000
Recognition of deferred commissions	16,690,000
Ending balance as of April 30, 2018	86,044,000
Impairment loss, capitalized commissions	$ 0
Servicing Contracts
Finite-Lived Intangible Assets [Line Items]
Remaining amortization period	6 years