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The number of new awards issued in the modification of the share-based incentive plan.

No definition available.

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Equity compensation payable to employees.

No definition available.

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The weighted average fair value at conversion date for nonvested equity-based awards converted during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

No definition available.

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The weighted average fair value at issue date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

No definition available.

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Amount of member capital in limited liability company (LLC).

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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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.

No definition available.

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The number of employees affected by the modification of an equity-based compensation plan.

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Name:	dei_LegalEntityAxis=tw_TradewebMarketsLlcMember
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Balance Type:
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Name:	us-gaap_StatementScenarioAxis=tw_AdjustedForRefinitivTransactionMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	srt_RestatementAxis=srt_RestatementAdjustmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_AwardTypeAxis=tw_PerformanceSharesSettledWithEquityMember
Namespace Prefix:
Data Type:	na
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Name:	us-gaap_TypeOfArrangementAxis=tw_LimitedLiabilityCompanyAgreementRecapitalizationMember
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