Consolidated Statements of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities
Net income (loss)		$ (103,705)	$ 620,192	$ 18,898
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization		65,644	61,154	47,327
Amortization of purchased intangibles and acquired capitalized software		70,595	26,123	15,447
Debt issue cost related to debt refinancing and prepayment		41,134	10,645	10,460
Amortization of debt issuance costs and deferred financing fees		11,720	10,419	5,822
Termination of office leases		66,452	23,357	3,671
Share based compensation		71,728	31,934	26,259
Reserve for legal matters		0	2,020	657
Write-down of assets		0	3,239	1,216
Connectivity early termination		0	2,000	0
Tax receivable agreement obligation reduction		0	0	(86,599)
Deferred taxes		(18,691)	4,131	102,973
Gain on sale of businesses		0	(335,211)	0
Other		880	418	(4,577)
Changes in operating assets and liabilities:
Securities borrowed	[1]	(515,897)	71,488	155,277
Securities purchased under agreements to resell	[1]	(127,557)	(15,475)	16,894
Receivables from broker-dealers and clearing organizations	[1]	110,977	(111,344)	26,145
Trading assets, at fair value	[1]	(125,246)	72,701	1,210,599
Receivables from customers	[1]	29,733	(18,087)	0
Other assets	[1]	25,133	125,272	44,494
Securities loaned	[1]	452,397	375,352	366,295
Securities sold under agreements to repurchase	[1]	58,881	(108,781)	(450,964)
Payables to broker-dealers and clearing organizations	[1]	107,266	(148,764)	(516,376)
Payables to customers	[1]	(37,560)	(28,875)	0
Trading liabilities, at fair value	[1]	22,552	90,797	(721,204)
Accounts payable, accrued expenses and other liabilities	[1]	(37,665)	(50,110)	17,860
Net cash provided by (used in) operating activities		168,771	714,595	290,574
Cash flows from investing activities
Development of capitalized software		(48,492)	(21,482)	(14,158)
Acquisition of property and equipment		(9,320)	(26,467)	(18,932)
Proceeds from sale of telecommunication assets		0	600	0
Investment in joint ventures		(6,250)	(23,669)	0
Acquisition of Teza Technologies		0	0	(5,594)
Net cash provided by (used in) investing activities		(899,643)	329,174	(838,016)
Cash flows from financing activities
Distribution from Virtu Financial to non-controlling interest		(99,221)	(206,903)	(89,563)
Dividends		(112,414)	(100,329)	(63,814)
Stock options exercised		931	76,754	0
Short-term borrowings, net		39,935	(15,000)	7,000
Proceeds from long-term borrowings		1,492,500	0	1,115,036
Repayment of long term borrowings		(500,000)	(500,000)	(256,473)
Repayment of KCG Notes		0	0	(480,987)
Tax receivable agreement obligations		0	(12,359)	(7,045)
Debt issuance costs		(35,702)	(2,261)	(56,505)
Issuance of common stock, net of offering costs		0	0	735,974
Issuance of common stock in connection with secondary offering, net of offering costs		(375)	(950)	0
Net cash provided by (used in) financing activities		769,580	(835,482)	889,797
Effect of exchange rate changes on cash and cash equivalents		(1,475)	(5,127)	9,117
Net increase (decrease) in cash and cash equivalents		37,233	203,160	351,472
Cash, cash equivalents, and restricted or segregated cash, beginning of period		736,047	532,887	181,415
Cash, cash equivalents, and restricted or segregated cash, end of period		773,280	736,047	532,887
Supplementary disclosure of cash flow information
Cash paid for interest		205,433	139,412	112,982
Cash paid for taxes		12,273	93,991	5,976
Non-cash investing activities
Share based compensation to developers relating to capitalized software		2,135	2,936	1,605
Non-cash financing activities
Tax receivable agreement described in Note 6		0	(991)	1,534
Discount on issuance of senior secured credit facility		0	0	1,438
Treasury Stock
Cash flows from financing activities
Repurchase of stock		(15,878)	(66,218)	(2,683)
Class A-2
Cash flows from financing activities
Repurchase of stock		0	0	(11,143)
Class C common stock
Cash flows from financing activities
Repurchase of stock		(196)	(8,216)	0
ITG
Cash flows from investing activities
Acquisition, net of cash acquired, described in Note 3		(835,581)	0
KCG
Cash flows from investing activities
Acquisition, net of cash acquired, described in Note 3		0	0	(799,632)
BondPoint
Cash flows from investing activities
Proceeds from sale of business		0	400,192	0
DMM Business
Cash flows from investing activities
Proceeds from sale of business		$ 0	$ 0	$ 300

[1] Net of ITG Acquisition; see Note 3