Credit Risk	6 Months Ended
Credit Risk	Jun. 30, 2022
Risks and Uncertainties [Abstract]
Credit Risk	Credit Risk 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 will recognize a receivable from (and a matching payable to) brokers and dealers and clearing organizations for the proceeds from the unsettled transaction, until the failed transaction settles. 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. However, from time to time, the Company enters into repurchase and/or reverse repurchase agreements to facilitate the clearance of securities relating to fails to deliver or receive. We seek to manage credit exposure related to these agreements to repurchase (or reverse repurchase), including the risk related to a decline in market value of collateral (pledged or received), by entering into agreements to repurchase with overnight or short-term maturity dates and only entering into repurchase transactions with netting members of the Fixed Income Clearing Corporation (“FICC”). The FICC operates a continuous net settlement system, whereby as trades are submitted and compared, the FICC becomes the counterparty. A substantial number of the Company’s transactions are collateralized and executed with, and on behalf of, a limited number of broker-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. Allowance for Credit Losses The Company may be exposed to credit risk regarding its receivables, which are primarily receivables from financial institutions, including investment managers and broker-dealers. The Company maintains an allowance for credit losses based upon an estimate of the amount of potential credit losses in existing accounts receivable, as determined from a review of aging schedules, past due balances, historical collection experience and other specific account data. Careful analysis of the financial condition of the Company’s counterparties is also performed. Account balances are pooled based on the following risk characteristics: 1.Geographic location 2.Transaction fee type (billing type) 3.Legal entity Write-Offs Once determined uncollectible, aged balances are written off against the allowance for credit losses. This determination is based on careful analysis of individual receivables and aging schedules, which are disaggregated based on the risk characteristics described above. Based on current policy, this generally occurs when the receivable is 360 days past due. As of June 30, 2022 and December 31, 2021, the Company maintained an allowance for credit losses with regard to these receivables of $0.1 million and $0.3 million, respectively. For the three months ended June 30, 2022, credit loss expense was recognized totaling $49,000. For the three months ended June 30, 2021, recoveries resulted in a reversal of credit loss expense totaling $42,000. For the six months ended June 30, 2022 and 2021, recoveries resulted in a reversal of credit loss expense totaling $25,000 and $106,000, respectively.