Credit Risk	12 Months Ended
Dec. 31, 2018
Tradeweb Markets LLC
Entity Information [Line Items]
Credit Risk	16. Credit Risk The Company may be exposed to credit risk regarding its receivables, which are primarily receivable from financial institutions, including investment managers and broker/dealers. At December 31, 2018 and December 31, 2017 the Company established an allowance for doubtful accounts of $1,169,000 and $928,000, respectively, with regard to these accounts receivable. In the normal course of business the Company, as agent, executes transactions with, and on behalf of, other brokers and dealers. If the agency transactions do not settle because of failure to perform by either counterparty, the Company may be obligated to discharge the obligation of the non-performing party and, as a result, may incur a loss if the market value of the security is different from the contract amount of the transaction. A substantial number of the Company's transactions are collateralized and executed with, and on behalf of, a limited number of brokers and dealers. The Company's exposure to credit risk associated with the nonperformance of these clients in fulfilling their contractual obligations pursuant to securities transactions can be directly impacted by volatile trading markets which may impair the clients' ability to satisfy their obligations to the Company. The Company does not expect nonperformance by counterparties in the above situations. However, the Company's policy is to monitor its market exposure and counterparty risk. In addition, the Company has a policy of reviewing, as considered necessary, the credit standing of each counterparty with which it conducts business.

16. Credit Risk

The Company may be exposed to credit risk regarding its receivables, which are primarily receivable from financial institutions, including investment managers and broker/dealers. At December 31, 2018 and December 31, 2017 the Company established an allowance for doubtful accounts of $1,169,000 and $928,000, respectively, with regard to these accounts receivable.

In the normal course of business the Company, as agent, executes transactions with, and on behalf of, other brokers and dealers. If the agency transactions do not settle because of failure to perform by either counterparty, the Company may be obligated to discharge the obligation of the non-performing party and, as a result, may incur a loss if the market value of the security is different from the contract amount of the transaction.

A substantial number of the Company's transactions are collateralized and executed with, and on behalf of, a limited number of brokers and dealers. The Company's exposure to credit risk associated with the nonperformance of these clients in fulfilling their contractual obligations pursuant to securities transactions can be directly impacted by volatile trading markets which may impair the clients' ability to satisfy their obligations to the Company.

The Company does not expect nonperformance by counterparties in the above situations. However, the Company's policy is to monitor its market exposure and counterparty risk. In addition, the Company has a policy of reviewing, as considered necessary, the credit standing of each counterparty with which it conducts business.