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v3.10.0.1

Variable Interest Entity - Additional Information (Detail) $ in Thousands | Jun. 30, 2018 USD ($)
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AdvisorEngine [Member] |
Variable Interest Entity [Line Items] |
Remaining commitment amount | $ 3,000

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_VariableInterestEntityLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition Notes and loans receivable remaining commitment amount. + References No definition available. + Details
Name: | wetf_NotesAndLoansReceivableRemainingCommitmentAmount
Namespace Prefix: | wetf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=wetf_AdvisorEngineMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |