Revenue, Deferred Revenue and Remaining Performance Obligations (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jul. 31, 2019 USD ($)	Jul. 31, 2019 USD ($)
Contract with Customer, Liability [Line Items]
Revenue included in the contract liability balance	$ 89,600	$ 169,500
Changes in deferred revenue
Balance, beginning	315,212	290,067
Additions to deferred revenue	162,658	283,880
Recognition of deferred revenue	(108,108)	(204,185)
Balance, ending	369,762	369,762
Transaction price allocated to remaining performance obligations	$ 455,000	$ 455,000
Amortization over an estimated period of benefit for commissions, including referral fees paid to channel partner		4 years
Amortization over an estimated period of benefit for sales commissions associated with professional service contract		6 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-08-01
Changes in deferred revenue
Subscription term	12 months	12 months
Percentage of performance obligation expected to be recognized		72.00%
Minimum | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-08-01
Changes in deferred revenue
Subscription term	1 year	1 year
Maximum | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-08-01
Changes in deferred revenue
Subscription term	3 years	3 years