Organization and Basis of Presentation (Details) $ / shares in Units, instrument in Thousands, $ in Billions		12 Months Ended
	Mar. 01, 2019 USD ($) $ / shares	Dec. 31, 2019 instrument country segment venue
Organization, Consolidation And Presentation Of Financial Statements [Line Items]
Number of financial instruments | instrument		25
Number of venues | venue		235
Number of countries in which entity operates | country		36
Company’s product offering in number of counties (over) | country		50
Number of operating segments | segment		2
Number of non-operating segments | segment		1
ITG
Organization, Consolidation And Presentation Of Financial Statements [Line Items]
Acquisition value (in dollars per share) | $ / shares	$ 30.30
Total cash consideration | $	$ 1.0
Virtu Financial
Organization, Consolidation And Presentation Of Financial Statements [Line Items]
Ownership interest		62.20%