Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Cash flows from operating activities
Net Income	$ (39,990)	$ 33,023	$ (14,503)	$ 123,665	$ 158,340
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	15,602	7,158	29,157	22,685
Amortization of purchased intangibles and acquired capitalized software	6,440	53	6,546	159
Debt issue cost related to debt refinancing			9,351
Amortization of debt issuance costs and deferred financing fees			3,470	1,396
Share based compensation			10,924	9,440
Reserve for legal matter			(2,176)
Equipment writeoff			1,335	428
Deferred taxes			1,489	9,345
Other			(444)	(1,267)
Changes in operating assets and liabilities:
Securities borrowed			101,046	58,484
Securities purchased under agreements to resell			8,645	14,981
Receivables from broker dealers and clearing organizations			21,241	(36,756)
Trading assets, at fair value			1,020,821	(142,754)
Other Assets			26,248	1,705
Securities loaned			194,523	(42,656)
Securities sold under agreements to repurchase			(220,719)
Payables to broker dealers and clearing organizations			(393,564)	(181,348)
Payables to customers			7,967
Trading liabilities, at fair value			(569,911)	339,469
Accounts payable and accrued expenses and other liabilities			(25,675)	10,166
Net cash provided by operating activities			215,771	187,142
Cash flows from investing activities
Development of capitalized software			(7,929)	(6,044)
Acquisition of property and equipment			(13,932)	(8,933)
Investment in SBI Japannext				(38,754)
Acquisition of KCG Holdings described in Note 3			(799,303)
Acquisition of Teza Technologies			(5,594)
Proceeds from sale of DMM business			300
Net cash used in investing activities			(826,458)	(53,731)
Cash flows from financing activities
Distribution from Virtu Financial to non-controlling interest			(65,573)	(123,867)
Dividends			(42,013)	(28,117)
Purchase of treasury stock			(147)
Short-term borrowings, net			(10,000)	(27,400)
Payments on repurchase of non-voting common interest			(6,092)	(1,500)
Proceeds from long-term borrowings			1,115,036	33,078
Repayment of senior secured credit facility			(206,473)	(3,825)
Repayment of KCG Notes			(480,987)
Tax receivable agreement obligations			(7,045)
Debt issuance costs			(52,528)	(93)
Issuance of common stock, net of offering costs			735,973	16,677
Repurchase of Virtu Financial Units and corresponding number of Class A and C Common Stock				(17,383)
Net cash provided by (used in) financing activities			980,151	(152,430)
Effect of exchange rate changes on cash, cash equivalents, and restricted cash			8,300	1,783
Increase (decrease) in cash, cash equivalents, and restricted cash			377,764	(17,236)
Cash, cash equivalents, and restricted cash, beginning of period			181,415	163,235	163,235
Cash, cash equivalents, and restricted cash, end of period	$ 559,179	$ 145,999	559,179	145,999	$ 181,415
Supplementary disclosure of cash flow information
Cash paid for interest			59,524	43,827
Cash paid for taxes			5,744	15,008
Non-cash investing activities
Share based compensation of developers relating to software capitalized			$ 1,448	$ 5,187