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Amount of increase (decrease) in allowance for credit loss on right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

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Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time, classified as current.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-11

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479837/606-10-45-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479837/606-10-45-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-8

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-11

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479837/606-10-45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-8

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479837/606-10-45-2

Name:	us-gaap_ContractWithCustomerLiability
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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The fair value as of the balance sheet date of firm holdings in private equity, mezzanine, venture capital, merchant banking, real estate and special situations investments. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 940
-SubTopic 320
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479035/940-320-45-2

Name:	us-gaap_FinancialInstrumentsOwnedPrincipalInvestmentsAtFairValue
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Losses recognized in the current period on contracts which are expected to generate losses, which are probable and can be reasonably estimated, in a future period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 605
-SubTopic 35
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481187/605-35-45-1

Name:	us-gaap_LossOnContracts
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Amount of realized and unrealized gain (loss) resulting from the difference between acquisition price and selling price or fair value of trading assets and trading liabilities, and from the firm's direct investment activity, conducted separately from customer trading activities, including, but not limited to, investments in private equity, alternative investment products, real estate, and exchanges and memberships.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 940
-SubTopic 320
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479048/940-320-50-1

Name:	us-gaap_PrincipalTransactionsRevenue
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

Name:	us-gaap_RevenueRecognitionAbstract
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Data Type:	xbrli:stringItemType
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Amount of transaction price allocated to performance obligation that has not been recognized as revenue.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (a)
-SubTopic 10
-Topic 606
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-13

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of contract liabilities related to accrued expenses and other current liabilities.

No definition available.

Name:	wtf_ContractLiabilitiesAccruedExpensesAndOtherCurrentLiabilities
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of increase (decrease) in the obligation to transfer a good or service to a customer for which consideration has been received or is receivable.

No definition available.

Name:	wtf_ContractWithCustomerLiabilityPeriodIncreaseDecrease
Namespace Prefix:	wtf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The standard payment term of contracts, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	wtf_ContractWithCustomerPaymentTerm
Namespace Prefix:	wtf_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The number of performance obligations when accounting for revenue under the provisions of ASC 606.

No definition available.

Name:	wtf_NumberOfPerformanceObligations
Namespace Prefix:	wtf_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

The prepay percentage amount for SaaS contract.

No definition available.

Name:	wtf_PrepayPercentageAmountForSaaS
Namespace Prefix:	wtf_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

Residual percentage due term after initial set up, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	wtf_ResidualPercentageDueTermAfterInitialSetUp
Namespace Prefix:	wtf_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Typical SaaS contract term, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	wtf_TypicalSaaSContractTerm
Namespace Prefix:	wtf_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=us-gaap_RelatedPartyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=us-gaap_NonrelatedPartyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
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