Leases - Narrative (Details) $ in Millions	3 Months Ended
Oct. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Undiscounted cash flows	$ 7.9
Term of contract (in years)	12 years 4 months 24 days
Building
Lessee, Lease, Description [Line Items]
Additional lease obligation	$ 19.4

Term of lessee's operating lease not yet commenced, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980

Name:	us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant