Tax Receivable Agreement (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2020	Dec. 31, 2019
Tax Receivable Agreement
Percentage of amount of U.S. federal, state and local income or franchise tax savings	50.00%
Tax receivable agreement liability	$ 372,953	$ 240,817

The percentage of amount of U.S. federal, state and local income or franchise tax savings under the tax receivable agreement.

No definition available.

Name:	tw_TaxReceivableAgreementPercentageOfAmountOfFederalStateAndLocalIncomeOrFranchiseTaxSavings
Namespace Prefix:	tw_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration