Regulatory Requirement - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Virtu Financial Capital Markets LLC
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Minimum capital required to be maintained in connection with the operation of the company's DMM business	$ 1,000,000.0
Required amount under exchange rules	1,000,000
Required amount under exchange rules for every 0.1% NYSE transaction dollar volume	$ 75,000
Percentage of NYSE transaction dollar volume	0.10%
VAL
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Cash in special reserve bank accounts for the benefit of customers	$ 96,200,000	$ 22,300,000
Cash in reserve bank accounts for the benefit of proprietary accounts of brokers	$ 20,400,000	4,500,000
VITG
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Cash in special reserve bank accounts for the benefit of customers		7,400,000
Cash in reserve bank accounts for the benefit of proprietary accounts of brokers		$ 5,000,000.0