XML 61 R53.htm IDEA: XBRL DOCUMENT
v3.19.2

Restricted Cash (Details) - Tradeweb Markets LLC - USD ($) | Dec. 31, 2018 | Sep. 30, 2018 | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | --- | --- | ---
Successor |  |  |  |
Entity Information [Line Items] |  |  |  |
Restricted cash | $ 1,200,000 |  |  |
Predecessor |  |  |  |
Entity Information [Line Items] |  |  |  |
Restricted cash |  | $ 1,200,000 | $ 1,200,000 | $ 1,000,000

X
- 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: | dei_EntityInformationLineItems
Namespace Prefix: | dei_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of cash restricted as to withdrawal or usage. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=98513485&loc=SL98516268-108586 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(1)(a)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(2)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
Name: | us-gaap_RestrictedCash
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | dei_LegalEntityAxis=tw_TradewebMarketsLlcMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementScenarioAxis=tw_AdjustedForRefinitivTransactionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementScenarioAxis=us-gaap_PredecessorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |