Income Taxes	9 Months Ended
Income Taxes	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company is subject to U.S. federal, state and local income tax at the rate applicable to corporations less the rate attributable to the noncontrolling interest in Virtu Financial. These noncontrolling interests are subject to U.S. taxation as partnerships. Accordingly, for the three months ended September 30, 2019 and 2018, the income attributable to these noncontrolling interests is reported in the condensed consolidated statements of comprehensive income, but the related U.S. income tax expense attributable to these noncontrolling interests is not reported by the Company as it is the obligation of the individual partners. The Company’s provisions for (benefits from) income taxes and effective tax rates were $(0.6) million and 9.9%, and $13.8 million and 46.9%, for the three months ended September 30, 2019 and 2018, respectively, and $(14.3) million and 16.0%, and $75.3 million and 13.8% for the nine months ended September 30, 2019 and 2018, respectively. Income tax expense is also affected by the differing effective tax rates in foreign, state and local jurisdictions where certain of the Company’s subsidiaries are subject to corporate taxation. Included in Other assets on the condensed consolidated statements of financial condition at September 30, 2019 and December 31, 2018 are current income tax receivables of $69.7 million and $41.1 million, respectively. The balances at September 30, 2019 and December 31, 2018 primarily comprise income tax benefits due to the Company from federal, state and local, and foreign tax jurisdictions based on income before taxes. Included in Accounts payable, accrued expenses and other liabilities on the condensed consolidated statements of financial condition at September 30, 2019 and December 31, 2018 are current tax liabilities of $9.8 million and $10.0 million, respectively. The balances at September 30, 2019 and December 31, 2018 primarily comprise income taxes owed to federal, state and local, and foreign tax jurisdictions based on income before taxes. Deferred income taxes arise primarily due to the amortization of the deferred tax assets recognized in connection with the IPO (see Note 6 “Tax Receivable Agreements”), the Acquisition of KCG and the ITG Acquisition (see Note 3 “ITG Acquisition”), differences in the valuation of financial assets and liabilities, and other temporary differences arising from the deductibility of compensation, depreciation, and other expenses in different time periods for book and income tax return purposes. There are no expiration dates on the deferred tax assets. The provisions of ASC 740 require that carrying amounts of deferred tax assets be reduced by a valuation allowance if, based on the available evidence, it is more likely than not that some portion or all of the deferred tax assets will not be realized. Accordingly, the need to establish valuation allowances for deferred tax assets is assessed periodically with appropriate consideration given to all positive and negative evidence related to the realization of the deferred tax assets. As a result of the Acquisition of KCG, the Company has non-U.S. net operating losses at September 30, 2019 and December 31, 2018 of $239.3 million and $239.3 million, respectively, and has recorded a related deferred tax asset of $44.9 million and $44.9 million, respectively. A full valuation allowance was also recorded against this deferred tax asset at September 30, 2019 and December 31, 2018 as it is more likely than not that this deferred tax asset will not be realized. No valuation allowance against the remaining deferred taxes was recorded as of September 30, 2019 and December 31, 2018 because it is more likely than not that these deferred tax assets will be fully realized. The Company is subject to taxation in U.S. federal, state, local and foreign jurisdictions. As of September 30, 2019, the Company’s tax years for 2013 through 2017 and 2010 through 2017 are subject to examination by U.S. and non-U.S. tax authorities, respectively. As a result of the ITG Acquisition and the Acquisition of KCG, the Company has assumed any ITG and KCG tax exposures. In addition, the Company is subject to state and local income tax examinations in various jurisdictions for the tax years 2013 through 2017. The final outcome of these examinations is not yet determinable. However, the Company anticipates that adjustments to the unrecognized tax benefits, if any, will not result in a material change to the financial condition, results of operations and cash flows. The Company’s policy for recording interest and penalties associated with audits is to record such items as a component of income or loss before income taxes and noncontrolling interest. Penalties, if any, are recorded in Operations and administrative expense and interest received or paid is recorded in Other, net or Operations and administrative expense in the condensed consolidated statement of comprehensive income. The Company had $9.3 million of unrecognized tax benefits as of September 30, 2019, all of which would affect the Company’s effective tax rate if recognized. The Company has determined that there are no uncertain tax positions that would have a material impact on the Company’s financial position as of September 30, 2019.