XML 68 R56.htm IDEA: XBRL DOCUMENT
v3.19.2

Fair Value Measures - Additional Information (Detail) - USD ($) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Jul. 31, 2019 | Jul. 31, 2018 | Jul. 31, 2019 | Jul. 31, 2018
Fair Value Disclosures [Abstract] |  |  |  |
Write-down of long-term investments | $ 0 | $ 0 | $ 0 | $ 0

X
- References No definition available. + Details
Name: | us-gaap_FairValueDisclosuresAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 8A -URI http://asc.fasb.org/extlink&oid=109979856&loc=SL6284422-111562 + Details
Name: | us-gaap_ImpairmentOfInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration