Capital Structure - Employee Exchanges (Details)	9 Months Ended
	Sep. 30, 2019 shares	Sep. 30, 2018 shares
Virtu Financial
Class of Stock [Line Items]
Ownership interest (as a percent)	62.10%
VFH
Class of Stock [Line Items]
Common stock exchange ratio	1
VFH | Class A
Class of Stock [Line Items]
Issuance of common stock in connection with employee exchanges (in shares)	823,456	3,508,217