Summary of Significant Accounting Policies Revenue Recognition (Details) - USD ($) $ in Thousands	Jul. 31, 2020	Jul. 31, 2019
Accounting Policies [Abstract]
Contract with Customer, Refund Liability	$ 6,295	$ 5,796

Amount of liability for consideration received or receivable from customer which is not included in transaction price, when consideration is expected to be refunded to customer.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 55
-Paragraph 27
-URI http://asc.fasb.org/extlink&oid=121551570&loc=SL49130611-203046-203046

Name:	us-gaap_ContractWithCustomerRefundLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant