XML 75 R56.htm IDEA: XBRL DOCUMENT
v3.21.1

Fair Value Measurements - Summary of Categorization of Assets and Liabilities Measured at Fair Value (Parenthetical) (Detail) - Fair Value, Measurements, Nonrecurring [Member] - USD ($) $ in Thousands | Dec. 31, 2020 | Sep. 30, 2020 | Aug. 13, 2020 | Jun. 16, 2020 | May 04, 2020
--- | --- | --- | --- | --- | ---
Fair value of convertible notes | $ 170,191 |  | $ 24,344 | $ 145,847 |
Advisor Engine [Member] |  |  |  |  |
Fair value of financial interest disposed off |  |  |  |  | $ 9,592
Thesys Group, Inc [Member] |  |  |  |  |
Fair value of financial interest |  | $ 0 |  |  |

X
- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_InvestmentsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value portion of notes payable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19,20,22) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_NotesPayableFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value of financial interest. + References No definition available. + Details
Name: | wetf_FairValueOfFinancialInterest
Namespace Prefix: | wetf_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsNonrecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | wetf_FinancialInterestAxis=wetf_ThesysGroupIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |