Deferred Commissions (Details) - USD ($)	3 Months Ended
Apr. 30, 2020	Apr. 30, 2019
Revenue from Contract with Customer [Abstract]
Sales commissions capitalized as contract costs	$ 11,900,000	$ 9,800,000
Amortization of contract costs	8,700,000	6,300,000
Impairment loss related to costs capitalized	$ 0	$ 0

Amount of amortization expense for asset recognized from cost incurred to obtain or fulfill contract with customer.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=68051541&loc=SL49131252-203054

Name:	us-gaap_CapitalizedContractCostAmortization
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration