Cowen (COWN) 10-Q 12 Nov 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Nov. 11, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	Cowen Inc.
Entity Central Index Key	0001466538
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity Common Stock, Shares Outstanding		29,014,359

Consolidated Statements of Fina

Consolidated Statements of Financial Condition - USD ($) $ in Thousands		Sep. 30, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents		$ 260,994	$ 259,148
Cash collateral pledged		18,609	6,318
Segregated cash		128,782	176,647
Securities owned, at fair value		922,164	520,888
Receivable on derivative contracts, at fair value		39,754	25,125
Securities borrowed		1,228,036	407,795
Other investments ($131,740 and $123,241 at fair value, respectively)		204,168	181,407
Deposits with clearing organizations, brokers and banks		91,450	89,423
Receivable from brokers, dealers and clearing organizations, net of allowance of $719 and $472, respectively		717,634	786,113
Receivable from customers, net of allowance of $623 and $516, respectively		46,126	37,858
Fees receivable, net of allowance of $1,399 and $1,569, respectively		101,508	111,946
Due from related parties		27,849	33,870
Fixed assets, net of accumulated depreciation and amortization of $31,007 and $31,630, respectively		29,977	26,443
Operating right of use assets		96,664	0
Goodwill		137,728	60,678
Intangible assets, net of accumulated amortization of $47,878 and $38,093, respectively		37,358	24,943
Deferred tax asset, net		84,041	93,057
Other assets		76,916	79,014
Consolidated Funds
Cash and cash equivalents, Consolidated Funds		3,364	38,118
Securities owned, at fair value		369,191	187,633
Receivable on derivative contracts, at fair value		3,885	4,416
Other Investments, Consolidated Funds		171,186	186,395
Receivable from brokers, Consolidated Funds		17,907	8,328
Other assets, Consolidated Funds		1,463	740
Total Assets		4,816,754	3,346,303
Liabilities
Securities sold, not yet purchased, at fair value		364,742	195,307
Securities Sold under Agreements to Repurchase		23,772	0
Payable for derivative contracts, at fair value		32,755	16,082
Securities Loaned		1,339,647	414,852
Payables to brokers, dealers and clearing organizations		271,012	228,731
Payable to customers		525,064	525,153
Commission management payable		89,124	95,270
Compensation payable		157,125	226,971
Operating lease liabilities		100,934	0
Notes payable and other debt		343,286	262,965
Convertible debt	[1]	117,469	134,489
Fees payable		33,625	22,565
Due to related parties		919	571
Accounts payable, accrued expenses and other liabilities		142,026	110,423
Consolidated Funds
Due to related parties		615	0
Payable for derivative contracts, at fair value		7,778	1,663
Payable to brokers		15,166	23,521
Capital withdrawals payable		1,002	11,106
Accounts payable, accrued expenses and other liabilities		455	424
Total Liabilities		3,566,516	2,270,093
Commitments and Contingencies
Commitments and Contingencies (Note 17)		348,424	216,923
Stockholders' equity
Additional paid-in capital		1,103,941	1,062,877
(Accumulated deficit) retained earnings		(20,334)	(34,648)
Accumulated other comprehensive income (loss)		(5)	(5)
Less: Class A common stock held in treasury, at cost, 16,664,613 and 15,336,871 shares as of June 30, 2019 and December 31, 2018, respectively.		(266,882)	(234,142)
Total Cowen Inc. Stockholders' Equity		901,814	859,287
Nonredeemable non-controlling interests		84,759	64,880
Total Permanent Equity		817,055	794,407
Total Liabilities and Stockholders' Equity		4,816,754	3,346,303
Convertible Preferred Stock
Stockholders' equity
Preferred stock		1	1
Common Stock Class A
Stockholders' equity
Common stock		334	324
Less: Class A common stock held in treasury, at cost, 16,664,613 and 15,336,871 shares as of June 30, 2019 and December 31, 2018, respectively.		(266,882)	(234,142)
Total Cowen Inc. Stockholders' Equity		901,814	859,287
Common Stock Class B
Stockholders' equity
Common stock		$ 0	$ 0
[1]	The carrying amount of the convertible debt includes an unamortized discount of $16.0 million and $19.5 million as of September 30, 2019 and December 31, 2018, respectively.

Consolidated Statements of Fi_2

Consolidated Statements of Financial Condition (Parenthetical) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Security Owned and Pledged as Collateral, Fair Value	$ 132,555,000	$ 57,583,000
Allowance for receivable from customers	623,000	516,000
Allowance for fees receivable	1,399,000	1,569,000
Allowance for receivable from brokers	719,000	472,000
Assets
Fixed assets, accumulated depreciation and amortization (in dollars)	31,007,000	31,630,000
Intangible assets, accumulated amortization (in dollars)	$ 47,878,000	$ 38,093,000
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	120,750	120,750
Preferred stock, shares outstanding	120,750	120,750
Preferred Stock, Liquidation Preference, Value	$ 120,750,000	$ 120,750,000
Treasury Stock, Shares	17,462,976	15,336,871
Common Stock Class A
Stockholders' equity
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	62,500,000	62,500,000
Common stock, shares issued	46,476,113	43,774,371
Common stock, shares outstanding	29,013,137	28,437,860
Common stock, restricted shares	216,912	253,772
Treasury Stock, Shares	17,462,976	15,336,871
Common Stock Class B
Stockholders' equity
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	62,500,000	62,500,000
Common stock, shares issued	0	0
Common stock, shares outstanding	0	0

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues
Investment banking	$ 77,292,000	$ 81,923,000	$ 272,103,000	$ 264,737,000
Brokerage	93,995,000	92,035,000	302,840,000	301,053,000
Management fees	7,300,000	7,546,000	21,480,000	22,336,000
Incentive income	701,000	33,000	724,000	97,000
Interest and dividends	60,707,000	26,448,000	129,846,000	77,511,000
Reimbursement from affiliates	238,000	353,000	780,000	1,066,000
Aircraft lease revenue	0	375,000	0	1,509,000
Reinsurance premiums	8,146,000	8,378,000	29,068,000	26,251,000
Other revenues	1,237,000	1,634,000	3,228,000	3,846,000
Consolidated Funds
Interest and dividends	2,374,000	2,294,000	8,148,000	8,565,000
Other revenues	57,000	9,000	91,000	14,000
Total revenues	252,047,000	221,028,000	768,308,000	706,985,000
Interest and dividends expense	56,477,000	26,000,000	125,089,000	74,846,000
Total net revenues	195,570,000	195,028,000	643,219,000	632,139,000
Expenses
Employee compensation and benefits	120,320,000	128,483,000	388,611,000	397,543,000
Brokerage and trade execution costs	25,808,000	23,217,000	78,578,000	82,317,000
Underwriting expenses	2,846,000	4,412,000	12,383,000	13,260,000
Professional, advisory and other fees	15,535,000	7,698,000	39,396,000	20,541,000
Service fees	5,943,000	4,880,000	17,266,000	14,927,000
Communications	8,295,000	7,894,000	24,654,000	22,566,000
Occupancy and equipment	9,784,000	10,140,000	30,160,000	30,385,000
Depreciation and amortization	5,082,000	3,139,000	14,990,000	9,558,000
Client services and business development	10,364,000	6,671,000	33,549,000	22,767,000
Goodwill Impairment	0	0	4,100,000	0
Reinsurance claims, commissions and amortization of deferred acquisition costs	8,195,000	8,773,000	25,139,000	27,428,000
Other expenses	5,276,000	5,335,000	14,929,000	15,007,000
Consolidated Funds
Interest and dividends	1,153,000	1,270,000	3,376,000	5,660,000
Professional, advisory and other fees	857,000	191,000	1,375,000	748,000
Brokerage and trade execution costs	15,000	39,000	103,000	192,000
Other expenses	491,000	187,000	1,375,000	667,000
Total expenses	219,964,000	212,329,000	689,984,000	663,566,000
Other income (loss)
Net gains (losses) on securities, derivatives and other investments	18,446,000	32,040,000	61,440,000	64,728,000
Gain (loss) on debt extinguishment	0	0	0	(556,000)
Consolidated Funds
Net realized and unrealized gains (losses) on investments and other transactions	13,613,000	8,280,000	22,793,000	52,284,000
Net realized and unrealized gains (losses) on derivatives	293,000	1,664,000	(1,188,000)	6,258,000
Net gains (losses) on foreign currency transactions	(10,000)	(2,000)	(69,000)	250,000
Total other income (loss)	32,342,000	41,982,000	82,976,000	122,964,000
Income (loss) before income taxes	7,948,000	24,681,000	36,211,000	91,537,000
Income tax expense (benefit)	1,365,000	5,083,000	9,615,000	15,999,000
Net income (loss)	6,583,000	19,598,000	26,596,000	75,538,000
Net Income (Loss) Attributable to Noncontrolling Interest	2,770,000	4,110,000	7,188,000	37,798,000
Net income (loss) attributable to Cowen Inc.	3,813,000	15,488,000	19,408,000	37,740,000
Preferred stock dividends	1,698,000	1,698,000	5,094,000	5,094,000
Net income (loss) attributable to Cowen Inc. common stockholders	$ 2,115,000	$ 13,790,000	$ 14,314,000	$ 32,646,000
Weighted average common shares outstanding:
Basic (in shares)	29,529	29,610	29,687	29,662
Diluted (in shares)	31,264	30,844	31,381	30,613
Earnings (loss) per share:
Earnings Per Share, Basic (in dollars per share)	$ 0.07	$ 0.47	$ 0.48	$ 1.10
Earnings Per Share, Diluted (in dollars per share)	$ 0.07	$ 0.45	$ 0.46	$ 1.07

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 6,583	$ 19,598	$ 26,596	$ 75,538
Other comprehensive income (loss), net of tax:
Foreign currency translation	(2)	4	0	5
Total other comprehensive income (loss), net of tax	(2)	4	0	5
Comprehensive income (loss)	6,581	19,602	26,596	75,543
Net Income (Loss) Attributable to Noncontrolling Interest	2,770	4,110	7,188	37,798
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 3,811	$ 15,492	$ 19,408	$ 37,745

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Treasury Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings/(Accumulated deficit)	Nonredeemable Noncontrolling Interests [Member]	Permanent Equity [Member]	Redeemable Noncontrolling Interests [Member]	Common Stock Class A	Preferred Stock	Convertible Preferred StockRetained Earnings/(Accumulated deficit)
Total Stockholders' Equity	$ 748,019
Common stock									$ 324
Common stock, shares outstanding, start at Dec. 31, 2017									29,632,020
Balance, start at Dec. 31, 2017		$ (186,846)	$ 1,004,664	$ (8)	$ (70,116)				$ 853,607	$ 1
Preferred stock, shares outstanding, start at Dec. 31, 2017										120,750
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative Effect on Retained Earnings, Net of Tax	(559)						$ (559)
Net income (loss) attributable to Cowen Inc.	37,740				37,740		37,740
Noncontrolling Interest in Net Income (Loss) Other Noncontrolling Interests, Nonredeemable						$ 15,297	15,297
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and investment funds	22,501
Foreign currency translation	5			5
Capital contributions	17,648					7,887	7,887
Capital withdrawals	(243,807)					27,254	27,254
Deconsolidation of investment funds	(32,559)					32,559	32,559
Common stock issued during period, value, acquisitions	0
Restricted stock awards issued, shares									1,469,983
Purchase of treasury stock, at cost, shares									(1,959,456)
Purchase of treasury stock, at cost	(28,477)	(28,477)					28,477
Preferred stock dividends	(5,094)						5,094				$ (5,094)
Embedded Cash Conversion Option	28,974		28,974				28,974
Amortization of share based compensation	27,636		27,636				27,636
Common stock, shares outstanding, end at Sep. 30, 2018									29,142,547
Balance, end at Sep. 30, 2018		(215,323)	1,061,274	(3)	(38,029)				$ 877,203	$ 1
Preferred stock, shares outstanding, end at Sep. 30, 2018										120,750
Redeemable Non-controlling Interest, end at Sep. 30, 2018	131,358							$ 131,358
Total Stockholders' Equity	793,207
Common stock									$ 324
Stockholders' Equity Attributable to Noncontrolling Interest						67,407
Common stock, shares outstanding, start at Jun. 30, 2018									29,609,472
Balance, start at Jun. 30, 2018		(208,009)	1,052,717	(7)	(51,819)				$ 860,614	$ 1
Preferred stock, shares outstanding, start at Jun. 30, 2018										121,000
Redeemable Non-controlling Interest, start at Jun. 30, 2018	342,944
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to Cowen Inc.	15,488				15,488		15,488
Noncontrolling Interest in Net Income (Loss) Other Noncontrolling Interests, Nonredeemable						2,622	2,622
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and investment funds								1,487
Foreign currency translation	4			4			4
Capital contributions	5,659					382	382
Capital withdrawals	(218,732)					1,452	1,452
Restricted stock awards issued, shares									30,228
Purchase of treasury stock, at cost, shares									(497,153)
Purchase of treasury stock, at cost	(7,314)	(7,314)					7,314
Preferred stock dividends	(1,698)						1,698				(1,698)
Embedded Cash Conversion Option	1		1				1
Amortization of share based compensation	8,556		8,556				8,556
Common stock, shares outstanding, end at Sep. 30, 2018									29,142,547
Balance, end at Sep. 30, 2018		(215,323)	1,061,274	(3)	(38,029)				$ 877,203	$ 1
Preferred stock, shares outstanding, end at Sep. 30, 2018										120,750
Redeemable Non-controlling Interest, end at Sep. 30, 2018	131,358							131,358
Total Stockholders' Equity	808,244
Common stock									324
Stockholders' Equity Attributable to Noncontrolling Interest						68,959
Total Stockholders' Equity	794,407
Common stock									$ 324
Stockholders' Equity Attributable to Noncontrolling Interest	64,880					64,880
Common stock, shares outstanding, start at Dec. 31, 2018									28,437,860
Balance, start at Dec. 31, 2018	$ 859,287	(234,142)	1,062,877	(5)	(34,648)				$ 859,287	$ 1
Preferred stock, shares outstanding, start at Dec. 31, 2018	120,750									120,750
Redeemable Non-controlling Interest, start at Dec. 31, 2018								216,923
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to Cowen Inc.	$ 19,408				19,408		19,408
Noncontrolling Interest in Net Income (Loss) Other Noncontrolling Interests, Nonredeemable						11,375	11,375
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and investment funds	(4,187)
Foreign currency translation	0			0
Capital contributions	213,391					11,442	11,442
Capital withdrawals	(77,703)					2,938	2,938
Common stock issued during period, shares, acquisitions									1,033,350
Common stock issued during period, value, acquisitions	14,446		14,436				14,446		$ 10
Restricted stock awards issued, shares									1,668,032
Purchase of treasury stock, at cost, shares									(2,126,105)
Purchase of treasury stock, at cost	(32,740)	(32,740)					32,740
Preferred stock dividends	(5,094)						5,094				(5,094)
Embedded Cash Conversion Option	(596)		(596)				(596)
Amortization of share based compensation	27,224		27,224				27,224
Common stock, shares outstanding, end at Sep. 30, 2019									29,013,137
Balance, end at Sep. 30, 2019	$ 901,814	(266,882)	1,103,941	(5)	(20,334)				$ 901,814	$ 1
Preferred stock, shares outstanding, end at Sep. 30, 2019	120,750									120,750
Redeemable Non-controlling Interest, end at Sep. 30, 2019								348,424
Total Stockholders' Equity	$ 817,424
Common stock									$ 334
Stockholders' Equity Attributable to Noncontrolling Interest						75,923
Common stock, shares outstanding, start at Jun. 30, 2019									29,480,287
Balance, start at Jun. 30, 2019		(254,357)	1,093,898	(3)	(22,449)				$ 893,347	$ 1
Preferred stock, shares outstanding, start at Jun. 30, 2019										120,750
Redeemable Non-controlling Interest, start at Jun. 30, 2019								359,643
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to Cowen Inc.	3,813				3,813		3,813
Noncontrolling Interest in Net Income (Loss) Other Noncontrolling Interests, Nonredeemable						9,618	9,618
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and investment funds	(6,848)
Foreign currency translation	(2)			(2)			(2)
Capital contributions	21,905					332	332
Capital withdrawals	(26,276)					1,114	1,114
Restricted stock awards issued, shares									331,213
Purchase of treasury stock, at cost, shares									(798,363)
Purchase of treasury stock, at cost	(12,525)	(12,525)					12,525
Preferred stock dividends	(1,698)						1,698				$ (1,698)
Amortization of share based compensation	10,043		10,043				$ 10,043
Common stock, shares outstanding, end at Sep. 30, 2019									29,013,137
Balance, end at Sep. 30, 2019	$ 901,814	$ (266,882)	$ 1,103,941	$ (5)	$ (20,334)				$ 901,814	$ 1
Preferred stock, shares outstanding, end at Sep. 30, 2019	120,750									120,750
Redeemable Non-controlling Interest, end at Sep. 30, 2019								$ 348,424
Total Stockholders' Equity	$ 817,055
Common stock									$ 334
Stockholders' Equity Attributable to Noncontrolling Interest	$ 84,759					$ 84,759

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Cash flows from operating activities:
Net income (loss)	$ 6,583,000	$ 19,598,000	$ 26,596,000	$ 75,538,000
Adjustments to reconcile net income (loss) to net cash provided by / (used in) operating activities:
Depreciation and amortization	5,082,000	3,139,000	14,990,000	9,558,000
Amortization of debt issuance costs			804,000	990,000
Amortization of debt discount			3,511,000	4,177,000
Noncash lease expense			(2,607,000)	0
Gain / (loss) on extinguishment of debt			0	(652,000)
Share-based compensation			27,224,000	27,636,000
Change in deferred taxes			8,420,000	14,640,000
Deferred rent obligations			0	(2,532,000)
Net loss (gain) on disposal of fixed assets			367,000	(146,000)
Goodwill Impairment	0	0	4,100,000	0	$ 0
Purchases of securities owned, at fair value			(1,405,478,000)	(3,137,168,000)
Proceeds from sales of securities owned, at fair value			1,282,527,000	3,329,707,000
Proceeds from sales of securities sold, not yet purchased, at fair value			902,271,000	2,132,935,000
Payments to cover securities sold, not yet purchased, at fair value			(939,072,000)	(2,233,427,000)
Proceeds from other investments			19,693,000	7,313,000
Net (gains) losses on securities, derivatives and other investments			(57,808,000)	(61,927,000)
Consolidated Funds
Purchases of securities owned, at fair value			(2,016,225,000)	(457,293,000)
Proceeds from sales of securities owned, at fair value			1,880,160,000	491,427,000
Purchases of other investments			(2,798,000)	(1,414,000)
Proceeds from other investments			23,865,000	230,832,000
Net realized and unrealized (gains) losses on investments and other transactions			(51,925,000)	(58,523,000)
(Increase) decrease in operating assets:
Securities owned, at fair value, held at broker-dealer			(250,579,000)	(124,740,000)
Receivable on derivative contracts, at fair value			(14,629,000)	36,949,000
Securities borrowed			(820,241,000)	(270,140,000)
Deposits with clearing organizations, brokers and banks			(2,027,000)	(4,650,000)
Receivable from brokers, dealers and clearing organizations			68,479,000	(136,214,000)
Receivable from customers, net of allowance			(8,268,000)	16,651,000
Fees receivable, net of allowance			17,707,000	(6,211,000)
Due from related parties			6,020,000	2,765,000
Other assets			1,038,000	16,573,000
Consolidated Funds
Cash and cash equivalents			34,809,000	(130,000)
Receivable on derivative contracts, at fair value			531,000	609,000
Receivable from brokers			(9,579,000)	(5,373,000)
Other assets			10,000	(153,000)
Increase (decrease) in operating liabilities:
Securities sold, not yet purchased, at fair value, held at broker dealer			191,640,000	146,853,000
Payable for derivative contracts, at fair value			16,672,000	16,225,000
Securities loaned			924,795,000	91,798,000
Payable to brokers, dealers and clearing organizations			42,281,000	(41,827,000)
Payable to customers			(88,000)	118,009,000
Commission management payable			(6,146,000)	19,782,000
Compensation payable			(92,903,000)	33,395,000
Fees payable			11,060,000	14,211,000
Due to related parties			(4,402,000)	1,000
Accounts payable, accrued expenses and other liabilities			(2,679,000)	1,527,000
Consolidated Funds
Payable to brokers			(8,355,000)	1,185,000
Payable for derivative contracts, at fair value			6,115,000	(4,941,000)
Due To Related Parties, Consolidated Funds			615,000	0
Accounts payable, accrued expenses and other liabilities			(184,000)	205,000
Net Cash Provided by (Used in) Operating Activities			(156,655,000)	295,626,000
Cash flows from investing activities:
Purchases of other investments			(15,899,000)	(21,355,000)
Purchase of business			(48,581,000)	0
Proceeds from sales of other investments			18,103,000	15,730,000
Proceeds from loans held for investment			0	1,410,000
Purchase of fixed assets			(7,862,000)	(6,710,000)
Net Cash Provided by (Used in) Investing Activities			(54,239,000)	(10,925,000)
Cash flows from financing activities:
Proceeds from (Payments for) in Securities Sold under Agreements to Repurchase			23,772,000	0
Repayments on convertible debt			(20,860,000)	(13,500,000)
Deferred debt issuance cost			(1,480,000)	(3,985,000)
Borrowings on notes and other debt			84,640,000	102,382,000
Repayments on notes and other debt			(7,834,000)	(6,561,000)
Purchase of treasury stock			(10,153,000)	(16,763,000)
Contingent liability payment			(1,235,000)	(797,000)
Capital contributions by redeemable non-controlling interests in operating entities			11,110,000	941,000
Capital withdrawals to redeemable non-controlling interests in operating entities			(1,713,000)	(1,685,000)
Consolidated Funds
Capital contributions by redeemable non-controlling interests in Consolidated Funds			213,723,000	24,594,000
Capital withdrawals to redeemable non-controlling interests in Consolidated Funds			(89,032,000)	(270,186,000)
Net Cash Provided by (Used in) Financing Activities			177,166,000	(185,560,000)
Change in cash and cash equivalents			(33,728,000)	99,141,000
Total cash beginning of period			442,113,000	264,208,000	264,208,000
Cash and cash equivalents	260,994,000	193,066,000	260,994,000	193,066,000	259,148,000
Cash collateral pledged	18,609,000	16,092,000	18,609,000	16,092,000	6,318,000
Segregated cash	128,782,000	154,191,000	128,782,000	154,191,000	176,647,000
Total cash at end of period	408,385,000	363,349,000	408,385,000	363,349,000	442,113,000
Supplemental information
Cash paid during the year for interest			98,363,000	62,371,000
Cash paid during the year for taxes			3,815,000	4,862,000
Purchase of treasury stock, at cost, through net settlement			22,420,000	8,544,000
Preferred stock dividends	1,698,000	1,698,000	5,094,000	5,094,000
Net assets (liabilities) acquired upon acquisition (net of cash)			90,727,000	0
Operating right of use assets	96,664,000		96,664,000		0
Operating lease liabilities	$ 100,934,000		100,934,000		$ 0
Transfer of investment from consolidated funds, securities owned, fair value to securities owned, fair value			97,655,000	8,820,000
Net decrease in redeemable non-controlling interests in Consolidated Funds due to deconsolidation of consolidated fund				32,559,000
Separately recognized conversion option reclassification from a derivative liability to equity		$ 1,000	(596,000)	28,974,000
Common stock issuance upon close of acquisition			$ 14,446,000	$ 0

Organization and Business

Organization and Business	9 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Business	Organization and Business Cowen Inc., a Delaware corporation formed in 2009, is a diversified financial services firm that, together with its consolidated subsidiaries (collectively, "Cowen" or the "Company"), provides investment management, investment banking, research, sales and trading, prime brokerage, global clearing and commission management services through its two business segments: the Operating Company (“Op Co”) and the Asset Company (“Asset Co”). The Op Co segment consists of four divisions: the Investment Banking division, the Markets division, the Research division and the Cowen Investment Management (“CIM”) division. The Company refers to the Investment Banking division, the Markets division and the Research division combined as its investment banking businesses. Op Co's investment banking businesses offer investment banking, research, sales and trading, prime brokerage, global execution, clearing and commission management services to companies and primarily institutional investor clients. Sectors covered by Op Co's investment banking business include healthcare, technology, media and telecommunications, consumer, industrials, information and technology services, and energy. Op Co’s CIM division includes advisers to investment funds (including private equity structures and privately placed hedge funds) and registered funds. The Asset Co segment consists of certain of the Company’s private investments, private real estate investments and other legacy multi-sector long/short equity strategies. The focus of Asset Co is to drive future monetization of the invested capital of the segment. Change in Segments As noted in the prior reporting period, the Company continually monitors and reviews its segment reporting structure in accordance with authoritative guidance to determine whether any changes have occurred that would impact its reportable segments. Because of the change in the Chief Operating Decision Maker (“CODM”) of the Company at the end of 2017, the Company experienced a strategic shift to refocus the Company’s businesses on a set of differentiated products which are aligned to the content and insight within the Company’s domain of expertise. During the second quarter of 2019, the Company realigned the business and reportable segment information that the CODM regularly reviews to evaluate performance for operating decision-making purposes, including evaluation and allocation of resources. As a result, the Company changed its segment reporting structure based on the Company's domain expertise as a driver of balance sheet harmonization and repeatable revenues for its operating business versus the Company’s long-term monetization strategies. As a result of the change in segments, during the second quarter of 2019, the Company has the following business segments: • The Op Co segment consists of four divisions: Investment Banking, Markets, Research and Cowen Investment Management. Each of Op Co’s four divisions leverage the Research division’s core domain expertise to drive harmonized repeatable revenue for the segment. – The Investment Banking division includes public and private capital raising transactions and providing strategic advisory services. – The Markets division includes trading equity and equity-linked securities on behalf of institutional investors as well as a full-service suite of prime brokerage services, cross-asset trading, securities finance, global execution, clearing and commission management businesses. – The Research division provides the thought leadership and domain expertise that drives Cowen DNA. The research content that is created helps to facilitate brokerage revenue in the Markets division, drive deal flow in the Investment Banking division and facilitate investor relationships and investing within CIM’s innovative investment products and solutions. – The CIM division offers innovative investment products and solutions across the liquidity spectrum to institutional and private clients. CIM offers investors access to a number of strategies to meet their specific needs including merger arbitrage, activism, healthcare royalties, private healthcare investing and private sustainable investing which leverage the content and domain expertise that are aligned with the Company's core areas of expertise ("Cowen DNA"). • The Asset Co segment consists of certain of the Company’s private investments, private real estate investments and other legacy multi-strategy funds. While the Asset Co segment is not a reportable segment, the Company will provide segment level information for Asset Co.

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies a. Basis of Presentation These unaudited condensed consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America ("US GAAP") as promulgated by the Financial Accounting Standards Board ("FASB") through Accounting Standards Codification (the "Accounting Standards") as the source of authoritative accounting principles in the preparation of financial statements, and include the accounts of the Company, its operating and other subsidiaries, and entities in which the Company has a controlling financial interest or a general partner interest. All material intercompany transactions and balances have been eliminated in consolidation. Certain fund entities that are consolidated in these accompanying condensed consolidated financial statements, as further discussed below, are not subject to the consolidation provisions with respect to their own controlled investments pursuant to their specialized accounting. The Company serves as the managing member/general partner and/or investment manager to affiliated fund entities which it sponsors and manages. Funds in which the Company has a controlling financial interest are consolidated with the Company pursuant to US GAAP as described below. Consequently, the Company's condensed consolidated financial statements reflect the assets, liabilities, income and expenses of these funds on a gross basis. The ownership interests in these funds that are not owned by the Company are reflected as redeemable or non-redeemable non-controlling interests in consolidated subsidiaries in the accompanying condensed consolidated financial statements. The management fees and incentive income earned by the Company from these funds are eliminated in consolidation. In this Form 10-Q, nonredeemable non-controlling interests for the three and nine months ended September 30, 2019 and 2018, respectively, have been reclassified to be presented separately from redeemable non-controlling interests within the permanent equity section of the accompanying condensed consolidated statements of financial condition. The Company carried out an analysis to evaluate instances where non-controlling interest parties have the unilateral right to redeem their ownership interest for cash, which resulted in a change to the presentation of certain nonredeemable non-controlling interests into permanent equity. Accordingly, prior period amounts have been recast to reflect the change to the presentation of nonredeemable non-controlling interests, which has no impact on net income (loss) attributable to Cowen Inc. common stockholders, total assets or total liabilities. With respect to the Company’s private equity investment management strategies, a portion of the Company's carried interest is granted to employees through profit sharing awards designed to more closely align compensation with the overall realized performance of the Company. These arrangements enable certain employees to earn compensation based on performance revenue earned by the Company and are recorded within compensation payable in the accompanying condensed consolidated statements of financial condition and employee compensation and benefits expense in the accompanying condensed consolidated statements of operation based on the probable and estimable payments under the terms of the awards. Prior period amounts have been recast to reflect this accounting treatment. The year-end condensed balance sheet data was derived from the audited financial statements, but does not include all disclosures included in the audited financial statements. b. Principles of consolidation The Company consolidates all entities that it controls through a majority voting interest or otherwise, including those investment funds in which the Company either directly or indirectly has a controlling financial interest. In addition, the Company consolidates all variable interest entities for which it is the primary beneficiary. In accordance with these standards, the Company consolidates five investment funds for which it acts as the general partner and investment manager. As of September 30, 2019 , the Company consolidated the following investment funds: Ramius Enterprise LP (“Enterprise LP”), Ramius Merger Fund LLC (the "Merger Fund"), Cowen Private Investments LP ("Cowen Private"), Ramius Merger Arbitrage UCITS Fund ("UCITS Fund"), and Cowen Sustainable Investments I LP ("CSI I LP") (each a "Consolidated Fund" and collectively the "Consolidated Funds"). The Company determines whether it has a controlling financial interest in an entity by first evaluating whether the entity is a voting operating entity ("VOE") or a variable interest entity ("VIE") under US GAAP. Voting Operating Entities — VOEs are entities in which (i) the total equity investment at risk is sufficient to enable the entity to finance its activities independently, (ii) the equity holders at risk have the obligation to absorb losses, the right to receive residual returns and the right to direct the activities of the entity that most significantly impact the entity's economic performance and (iii) voting rights of equity holders are proportionate to their obligation to absorb losses or the right to receive returns. Under US GAAP, the usual condition for a controlling financial interest in a VOE is ownership of a majority voting interest. Accordingly, the Company consolidates all VOEs in which it owns a majority of the entity's voting shares or units. Variable Interest Entities— VIEs are entities that lack one or more of the characteristics of a VOE. In accordance with US GAAP, an enterprise must consolidate all VIEs of which it is the primary beneficiary. Under the US GAAP consolidation model for VIEs, an enterprise that (1) has the power to direct the activities of a VIE that most significantly impacts the VIE's economic performance, and (2) has an obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE, is considered to be the primary beneficiary of the VIE and thus is required to consolidate it. The Company reconsiders whether it is the primary beneficiary of a VIE by performing a periodic qualitative and/or quantitative analysis of the VIE that includes a review of, among other things, its capital structure, contractual agreements between the Company and the VIE, the economic interests that create or absorb variability, related party relationships and the design of the VIE. As of September 30, 2019 , the total assets and total liabilities of the consolidated VIEs were $656.4 million and $34.3 million , respectively. As of December 31, 2018 , the total assets and total liabilities of the consolidated VIEs were $468.0 million and $40.5 million , respectively. The increase is primarily related to other investors' subscriptions which increased overall VIEs net assets. The VIEs act as investment managers and/or investment companies that may be managed by the Company or the Company may have equity interest in those investment companies. The VIEs are financed through their operations and/or loan agreements with the Company. As of September 30, 2019 , the Company held a variable interest in Ramius Merger Master Fund Ltd ("Merger Master") (the “Unconsolidated Master Fund”) through the consolidated Merger Fund. As of December 31, 2018 , the Company held variable interests in Ramius Enterprise Master Fund Ltd (“Enterprise Master”) and Ramius Merger Master Fund Ltd ("Merger Master") (collectively the “Unconsolidated Master Funds”) through two Consolidated Funds. Investment companies, which account for their investments under the specialized industry accounting guidance for investment companies prescribed under US GAAP, are not subject to the consolidation provisions for their investments. Therefore, the Company has not consolidated the Unconsolidated Master Funds. In the ordinary course of business, the Company also sponsors various other entities that it has determined to be VIEs. These VIEs are primarily investment funds for which the Company serves as the general partner, managing member and/or investment manager with decision-making rights. The reason that the Company does not consolidate the Unconsolidated Master Fund or real estate funds that are VIEs is due to the Company's conclusion that it is not the primary beneficiary in each instance. Investment fund investors are entitled to all of the economics of these VIEs with the exception of the management fee and incentive income, if any, earned by the Company. The Company has equity interests in the funds as both GP and Limited partner. In these instances the Company has concluded that the variable interests are not potentially significant to the VIE. Although the Company may advance amounts and pay certain expenses on behalf of the investment funds that it considers to be VIEs, it does not provide, nor is it required to provide, any type of substantive financial support to these entities outside of regular investment management services (see Note 6 for additional disclosures on VIEs). Equity Method Investments — For operating entities over which the Company exercises significant influence but which do not meet the requirements for consolidation as outlined above, the Company uses the equity method of accounting. The Company's investments in equity method investees are recorded in other investments in the accompanying condensed consolidated statements of financial condition. The Company's share of earnings or losses from equity method investees is included in net gains (losses) on securities, derivatives and other investments in the accompanying condensed consolidated statements of operations. The Company evaluates its equity method investments for impairment whenever events or changes in circumstances indicate that the carrying amounts of such investments may not be recoverable. The difference between the carrying value of the equity method investment and its estimated fair value is recognized as an impairment charge when the loss in value is deemed other than temporary. Other — If the Company does not consolidate an entity or apply the equity method of accounting, the Company accounts for such entities (primarily, all securities of such entity which are bought and held principally for the purpose of selling them in the near term as trading securities) in accordance with US GAAP, at fair value with unrealized gains (losses) resulting from changes in fair value reflected within net gains (losses) on securities, derivatives and other investments in the accompanying condensed consolidated statements of operations. Retention of Specialized Accounting — The Consolidated Funds and certain other consolidated companies are investment companies and apply specialized industry accounting for investment companies. The Company has retained this specialized accounting for these investment funds pursuant to US GAAP. The Company reports its investments on the condensed consolidated statements of financial condition at their estimated fair value, with unrealized gains (losses) resulting from changes in fair value reflected within net realized and unrealized gains (losses) on investments and other transactions. Accordingly, the accompanying condensed consolidated financial statements reflect different accounting policies for investments depending on whether or not they are held through a consolidated investment company. In addition, the Company's broker-dealer subsidiaries , Cowen and Company, LLC ("Cowen and Company"), Cowen Execution Services LLC ("Cowen Execution"), Westminster Research Associates LLC ("Westminster"), Cowen Execution Services Limited ("Cowen Execution Ltd"), ATM Execution LLC ("ATM Execution"), Cowen International Limited ("Cowen International Ltd"), and Cowen Prime Services LLC ("Cowen Prime") apply the specialized industry accounting for brokers and dealers in securities also prescribed under US GAAP. The Company also retains specialized accounting upon consolidation. c. Use of estimates The preparation of the accompanying condensed consolidated financial statements in conformity with US GAAP requires the management of the Company to make estimates and assumptions that affect the fair value of securities and other investments, the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the accompanying condensed consolidated financial statements, the accounting for goodwill and identifiable intangible assets and the reported amounts of revenues and expenses during the reporting period. Actual results could materially differ from those estimates. d. Allowance for credit losses The allowance for credit losses is based on the Company’s assessment of the collectability of receivables related to securities transactions, prepaid research and other receivables. The Company considers factors such as historical experience, credit quality, age of balances and current economic conditions that may affect collectability in determining the allowance for credit losses. Specifically, for prepaid research, the Company reviews clients' historical, current and forecasted trading activity in determining the allowance for credit losses. The credit loss expense related to the allowance for credit losses as well as any recoveries of amounts previously charged is reflected in other expenses in the accompanying condensed consolidated statements of operations. e. Valuation of investments and derivative contracts US GAAP establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (level 1 measurements) and the lowest priority to unobservable inputs (level 3 measurements). The three levels of the fair value hierarchy are as follows: Level 1 Inputs that reflect unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date; Level 2 Inputs other than quoted prices that are observable for the asset or liability either directly or indirectly, including inputs in markets that are not considered to be active; and Level 3 Fair value is determined based on pricing inputs that are unobservable and includes situations where there is little, if any, market activity for the asset or liability. The determination of fair value for assets and liabilities in this category requires significant management judgment or estimation. Inputs are used in applying the various valuation techniques and broadly refer to the assumptions that market participants use to make valuation decisions, including assumptions about risk. Inputs may include price information, volatility statistics, specific and broad credit data, liquidity statistics, and other factors. A financial instrument's level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. However, the determination of what constitutes “observable” requires significant judgment by the Company. The Company considers observable data to be that market data which is readily available, regularly distributed or updated, reliable and verifiable, not proprietary, and provided by independent sources that are actively involved in the relevant market. The categorization of a financial instrument within the hierarchy is based upon the pricing transparency of the instrument and does not necessarily correspond to the Company's perceived risk of that instrument. The Company and its operating subsidiaries act as the manager for the Consolidated Funds. Both the Company and the Consolidated Funds hold certain investments which are valued by the Company, acting as the investment manager. The fair value of these investments is generally estimated based on proprietary models developed by the Company, which include discounted cash flow analysis, public market comparables, and other techniques and may be based, at least in part, on independently sourced market information. The material estimates and assumptions used in these models include the timing and expected amount of cash flows, the appropriateness of discount rates used, and, in some cases, the ability to execute, timing of, and estimated proceeds from expected financings. Significant judgment and estimation impact the selection of an appropriate valuation methodology as well as the assumptions used in these models, and the timing and actual values realized with respect to investments could be materially different from values derived based on the use of those estimates. The valuation methodologies applied impact the reported value of the Company's investments and the investments held by the Consolidated Funds in the condensed consolidated financial statements. Certain of the Company's investments are relatively illiquid or thinly traded and may not be immediately liquidated on demand if needed. Fair values assigned to these investments may differ significantly from the fair values that would have been used had a ready market for the investments existed and such differences could be material . The Company primarily uses the “market approach” to value its financial instruments measured at fair value. In determining an instrument's level within the hierarchy, the Company categorizes the Company's financial instruments into three categories: securities, derivative contracts and other investments. To the extent applicable, each of these categories can further be divided between those held long or sold short. The Company has the option to measure certain financial assets and financial liabilities at fair value with changes in fair value recognized in earnings each period. The election is made on an instrument by instrument basis at initial recognition of an asset or liability or upon an event that gives rise to a new basis of accounting for that instrument. The Company has elected the fair value option for certain of its investments held by its operating companies. This option has been elected because the Company believes that it is consistent with the manner in which the business is managed, as well as the way that financial instruments in other parts of the business are recorded. Securities — Securities with values based on quoted market prices in active markets for identical assets are classified within level 1 of the fair value hierarchy. These securities primarily include active listed equities, certain U.S. government and sovereign obligations, Exchange Traded Funds ("ETFs"), mutual funds and certain money market securities. The Company does not adjust the quoted price for such instruments, even in situations where the Company holds a large position and a sale could reasonably impact the quoted price. Certain positions for which trading activity may not be readily visible, consisting primarily of convertible debt, corporate debt and loans and restricted equities, are stated at fair value and classified within level 2 of the fair value hierarchy. The estimated fair values assigned by management are determined in good faith and are based on available information considering, trading activity, broker quotes, quotations provided by published pricing services, counterparties and other market participants, and pricing models using quoted inputs, and do not necessarily represent the amounts which might ultimately be realized. As level 2 investments include positions that are not always traded in active markets and/or are subject to transfer restrictions, valuations may be adjusted to reflect illiquidity and/or non-transferability. Derivative contracts — Derivative contracts can be exchange-traded or privately negotiated over-the-counter (“OTC”). Exchange-traded derivatives, such as futures contracts and exchange-traded option contracts, are typically classified within level 1 or level 2 of the fair value hierarchy depending on whether or not they are deemed to be actively traded. OTC derivatives, such as generic forwards, swaps and options, have inputs which can generally be corroborated by market data and are therefore classified within level 2. OTC derivatives, such as swaps and options where market data is not readily available or observable are classified as level 3. Other investments — Other investments consist primarily of investment funds, real estate investments, carried interest and equity method investments, which are valued as follows : i. Portfolio funds— Portfolio funds (“Portfolio Funds”) include equity interests in private investment partnerships, foreign investment companies and other collective investment vehicles which may be managed by the Company or its affiliates. The Company follows US GAAP regarding fair value measurements and disclosures relating to investments in certain entities that calculate net asset value (“NAV”) per share (or its equivalent). The Company applies the practical expedient provided by US GAAP that permits an entity holding investments in certain entities that (a) do not have readily determinable fair values, (b) are investments in an investment company within the scope of ASC 946 Financial Services - Investment Companies (“ASC 946”) and (c) whose NAV is calculated in a manner consistent with the measurement principles of ASC 946 as of the reporting date, to measure the fair value of such investments on the basis of that NAV per share, or its equivalent, without adjustment. The Company applies an accounting policy election to recognize incentive income allocated to the Company under an equity ownership model as other investments in the accompanying condensed consolidated statements of financial condition (see Note 6). Carried interest allocated to the Company from certain portfolio funds represents Cowen's general partner capital accounts from those funds. These balances are subject to change upon cash distributions, additional allocations or reallocations back to limited partners within the respective funds. Investments which are valued using NAV per share as a practical expedient are not categorized within the fair value hierarchy. ii. Real estate investments— Real estate debt and equity investments are valued at fair value. The fair value of real estate investments is estimated based on the price that would be received to sell an asset in an orderly transaction between marketplace participants at the measurement date. Real estate investments without a public market are valued based on assumptions and valuation techniques used by the Company. Such valuation techniques may include discounted cash flow analysis, prevailing market capitalization rates or earnings multiples applied to earnings from the investment, analysis of recent comparable sales transactions, actual sale negotiations and bona fide purchase offers received from third parties, consideration of the amount that currently would be required to replace the asset, as adjusted for obsolescence, as well as independent external appraisals. In general, the Company considers several valuation techniques when measuring the fair value of a real estate investment. However, in certain circumstances, a single valuation technique may be appropriate. Real estate investments are reviewed on a quarterly basis by the Company for significant changes at the property level or a significant change in the overall market which would impact the value of the real estate investment resulting in unrealized appreciation or depreciation. Real estate and capital markets are cyclical in nature. Property and investment values are affected by, among other things, the availability of capital, occupancy rates, rental rates and interest and inflation rates. In addition, the Company invests in real estate and real estate related investments for which no liquid market exists. The market prices for such investments may be volatile and may not be readily ascertainable. Amounts ultimately realized by the Company from investments sold may differ from the fair values presented, and the differences could be material. The Company's real estate investments are typically categorized as level 3 investments within the fair value hierarchy as management uses significant unobservable inputs in determining their estimated fair value. See Notes 6 and 7 for further information regarding the Company's investments, including equity method investments and fair value measurements. f. Fees receivable Fees related to security transactions are reported net of an allowance for credit losses. An allowance for credit losses is assessed on any commission receivables aged over 180 days. Corporate finance and syndicate receivables, include receivables relating to the Company’s investment banking and advisory engagements net of allowance for credit losses. The Company records this allowance for credit losses on these receivables on a specific identification basis. The future collectability of the receivables is reviewed on a monthly basis based on the following factors: aging (usually if outstanding greater than 90 days), known financial stability of the paying company, as well as any other factors that might impact the collection of the outstanding fees. Management and incentive fees are earned as the managing member, general partner and/or investment manager to the Company's investment funds and are recognized in accordance with appropriate revenue recognition guidance (see Note 2( m )). g. Securities financing arrangements Securities borrowed and securities loaned are carried at the amounts of cash collateral advanced or received on a gross basis. The related rebates are recorded in the accompanying condensed consolidated statements of operations as interest and dividends income and interest and dividends expense. Securities borrowed transactions require the Company to deposit cash collateral with the lender. With respect to securities loaned, the Company receives cash or securities as collateral from the borrower. When the Company receives securities as collateral, and has concluded it (i) is the transferor and (ii) can pledge the securities to third parties, the Company recognizes the securities received as collateral at fair value in Securities owned, at fair value with the corresponding obligation to return the securities received as collateral at fair value in Securities sold, not yet purchased, at fair value. Securities received as collateral are not recognized when the Company either (i) is not the transferor or (ii) cannot pledge the securities to third parties. The initial collateral advanced or received approximates or is greater than the market value of securities borrowed or loaned. The Company monitors the market value of securities borrowed and loaned on a daily basis, with additional collateral obtained or returned, as necessary. Securities borrowed and loaned may also result in credit exposures for the Company in an event that the counterparties are unable to fulfill their contractual obligations. The Company minimizes its credit risk by continuously monitoring its credit exposure and collateral values by demanding additional or returning excess collateral in accordance with the netting provisions available in the master securities lending contracts in place with the counterparties. Fees and interest received or paid are recorded in interest and dividends income and interest and dividends expense, respectively, on an accrual basis in the accompanying condensed consolidated statements of operations. In cases where the fair value basis of accounting is elected, any resulting change in fair value would be reported in net gains (losses) on securities, derivatives and other investments in the accompanying condensed consolidated statements of operations. Accrued interest income and expense are recorded in receivable from brokers, dealers and clearing organizations and payable to brokers, dealers and clearing organizations, respectively, on an accrual basis in the accompanying condensed consolidated statements of financial condition. At September 30, 2019 and December 31, 2018 , the Company did not have any securities lending transactions for which fair value basis of accounting was elected. h. Securities sold under agreements to repurchase Securities sold under agreements to repurchase ("repos") are accounted for as collateralized financing transactions and are recorded at their contracted repurchase amount plus accrued interest. A repo is a transaction in which a firm sells financial instruments to a buyer, typically in exchange for cash, and simultaneously enters into an agreement to repurchase the same or substantially the same financial instruments from such buyer at a stated price plus accrued interest at a future date. When the Company receives securities as collateral, and has concluded it (i) is the transferor and (ii) can pledge the securities to third parties, the Company recognizes the securities received as collateral at fair value in Securities owned, at fair value with the corresponding obligation to return the securities received as collateral at fair value in Securities sold, not yet purchased, at fair value. Securities received as collateral are not recognized when the Company either (i) is not the transferor or (ii) cannot pledge the securities to third parties. The initial collateral advanced approximates or is greater than the market value of securities sold in the transaction. The Company typically enters into repo transactions with counterparties that prefer repo transactions to securities loaned transactions. The Company has executed master repo agreements with such counterparties and utilizes such counterparties to finance its own positions, or replace a securities lending transaction with a repo for matched book purposes. The Company monitors the market value of repos on a daily basis, with additional collateral obtained or returned, as necessary. Repos may also result in credit exposures for the Company in an event that the counterparties are unable to fulfill their contractual obligations. The Company mitigates its credit risk by continuously monitoring its credit exposure and collateral values by demanding additional collateral or returning excess collateral in accordance with the netting provisions available in the master repo contracts in place with the counterparties. Interest paid is recorded in interest and dividends expense on an accrual basis in the accompanying condensed consolidated statements of operations. In cases where the fair value basis of accounting is elected, any resulting change in fair value would be reported in net gains (losses) on securities, derivatives and other investments in the accompanying condensed consolidated statements of operations. At September 30, 2019 and December 31, 2018, the Company did not have any repos for which fair value basis of accounting was elected. i. Fixed assets Fixed assets are stated at cost less accumulated depreciation or amortization. Leasehold improvements are amortized on a straight-line basis over the lesser of their useful life or lease term. When the Company commits to a plan to abandon fixed assets or leasehold improvements before the end of its original useful life, the estimated depreciation or amortization period is revised to reflect the shortened useful life of the asset. Other fixed assets are depreciated on a straight-line basis over their estimated useful lives. Asset Depreciable Lives Depreciation and/or Amortization Method Telephone and computer equipment 5 years Straight-line Computer software 4 years Straight-line Furniture and fixtures 5 years Straight-line Leasehold improvements Term of Lease Straight-line Finance lease right-of-use asset 5 years Straight-line j. Goodwill and intangible assets Goodwill Goodwill represents the excess of the purchase price consideration of acquired companies over the estimated fair value assigned to the individual assets acquired and liabilities assumed. Goodwill is allocated to the Company's reporting units at the date the goodwill is initially recorded. Once goodwill has been allocated to the reporting units, it generally no longer retains its identification with a particular acquisition but instead becomes identifiable with the reporting unit. As a result, all of the fair value of each reporting unit is available to support the value of goodwill allocated to the unit. In January 2017, the FASB issued guidance that simplifies the subsequent measurement of goodwill. The new guidance eliminated Step 2 from the goodwill impairment test w

Acquisition

Acquisition	9 Months Ended
	Sep. 30, 2019
Business Combinations [Abstract]
Acquisitions	Acquisition On January 2, 2019 (the "Acquisition Date"), the Company, together with its indirect wholly owned subsidiaries, Cowen International Ltd and Cowen QN Acquisition LLC, completed its previously announced acquisition (the "Acquisition") of Quarton International AG through the acquisition of all of the outstanding equity interest of Quarton International AG’s affiliated combining companies, Quarton Management AG, Quarton International Europe AG, Quarton Partners, LLC and Quarton Securities GP, LLC (which owns a formerly U.S. Securities Exchange Commission ("SEC") registered broker-dealer that was subsequently renamed to Cowen Securities L.P. ("Cowen Securities") (see Note 23 ), comprising the U.S. and European operations of the acquired combining companies (collectively "Quarton"). Quarton is a group of leading global financial advisory companies serving the middle market. Quarton's operations were primarily conducted through eight entities based in the United States, Switzerland, and Germany. The acquisition was accounted for under the acquisition method of accounting in accordance with US GAAP. As such, results of operations for Quarton are included in the accompanying condensed consolidated statements of operations since the date of acquisition, and the assets acquired and liabilities assumed were recorded at their fair value as of the acquisition date. Subsequent to the acquisition, the operations of Quarton were integrated within the Company's existing businesses. The aggregate estimated purchase price of the Acquisition was $103.0 million . On the Acquisition Date the Company paid upfront consideration of $75.3 million subject to certain net working capital and other customary adjustments, with additional maximum contingent consideration of $40.0 million that will become payable dependent on the achievement of certain milestones by Quarton in each of the first four years (five years if certain conditions are met) following the Acquisition Date subject to a $10 million maximum in each year and a $40.0 million cumulative maximum. The Company estimated the contingent consideration at $27.7 million using the Monte Carlo valuation model which requires the Company to make estimates and assumptions regarding the future cash flows and profits. The contingent consideration liability is included within accounts payable, accrued expenses and other liabilities on the condensed consolidated statements of financial condition. Changes in these estimates and assumptions could have a significant impact on the amounts recognized. A portion of the preliminary purchase price was deposited into escrow, in the amount of $0.6 million , as a reserve for any future claims against the sellers of Quarton. All consideration, including the upfront consideration and contingent consideration, consists of a combination of 80% cash and 20% shares of the Company’s Class A common stock. Shares issued on the Acquisition Date of 1,033,350 were valued based on the 30-trading day volume-weighted average price per share of $14.52 as of December 31, 2018. The fair value of the shares of Class A common stock issued was determined on the basis of the closing market price of the Company’s shares on the Acquisition Date. Any shares of Class A common stock issued in connection with any such contingent payments will be valued based on the 30-trading day volume-weighted average price per share as of the day immediately prior to the date on which such shares are to be issued. In addition, Quarton and the Company have established a retention bonus pool, for Quarton employees that remain employed at the end of each year there is a contingent payment which will be settled in a combination of 80% cash and 20% shares of the Company’s Class A common stock based on Quarton meeting certain economic performance hurdles. The bonus pool has an aggregate maximum of $10.0 million over a five -year period with $2.5 million maximum in each year. The Company is recognizing the retention bonus over each contingent payment period based upon the Company’s revenue projections for Quarton. The table below summarizes the purchase price allocation of net tangible and intangible assets acquired and liabilities assumed as of January 2, 2019: (dollars in thousands) Cash and cash equivalents $ 12,236 Fees receivable 7,269 Fixed assets 1,085 Operating lease right-of-use assets 3,200 Intangible assets 22,200 Other assets 667 Compensation payable (637 ) Operating lease liabilities (3,200 ) Due to related parties (4,750 ) Accounts payable, accrued expenses and other liabilities (16,257 ) Total identifiable net assets acquired and liabilities assumed 21,813 Goodwill 81,150 Total estimated purchase price $ 102,963 As of the acquisition date, the estimated fair value of the Company's intangible assets, as acquired through the Acquisition, was $22.2 million . The allocation of the intangible assets is shown within the following table: Estimated intangible assets acquired Estimated average remaining useful lives (dollars in thousands) (in years) Intangible asset class Trade name $ 900 3 Customer relationships 7,100 4 Backlog 12,600 2 Proprietary software 1,600 3 Total intangible assets $ 22,200 Amortization expense for the three and nine months ended September 30, 2019 was $2.2 million and $6.7 million , respectively, and is included in depreciation and amortization in the accompanying condensed consolidated statements of operations. The estimated amortization expense related to these intangible assets in future periods is as follows: (dollars in thousands) 2019 $ 2,227 2020 8,908 2021 2,608 2022 1,775 2023 — Thereafter — $ 15,518 In addition to the purchase price consideration, for the three and nine months ended September 30, 2019 , the Company has incurred acquisition related expenses of $0.1 million and $1.2 million , respectively, including financial advisory, legal and valuation services, which are included in professional, advisory and other fees in the accompanying condensed consolidated statements of operations. Included in the accompanying condensed consolidated statements of operations for the three and nine months ended September 30, 2019 are revenues of $14.1 million and $26.3 million , respectively, and net income of $3.2 million and $5.6 million , respectively, related to the results of operations of Quarton. Subsequent to the acquisition, Quarton's businesses were integrated within the Op Co segment of the Company and therefore they are included within their respective line items in the accompanying condensed consolidated statements of operations. The following table provides supplemental pro forma financial information for the three and nine months ended September 30, 2018 , as if the acquisition were completed as of January 1, 2018. This unaudited supplemental pro forma information has been prepared for comparative purposes only and is not intended to be indicative of what the Company's financial results would have been had the acquisition been completed on January 1, 2018, nor does it purport to be indicative of any future results. Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 (dollars in thousands, except per share data) Net revenues $ 206,797 $ 661,759 Net income (loss) attributable to Cowen Inc. common stockholders 15,728 35,616 Net income (loss) per common share: Basic $ 0.51 $ 1.16 Diluted 0.49 1.12

Cash Collateral Pledged

Cash Collateral Pledged	9 Months Ended
	Sep. 30, 2019
Cash and Cash Equivalents [Abstract]
Cash Collateral Pledged	Cash Collateral Pledged As of September 30, 2019 and December 31, 2018 , the Company pledged cash collateral in the amount of $4.7 million and $5.3 million , respectively, which relates to letters of credit issued to the landlords of the Company's premises in New York City, Boston, Stamford and San Francisco. The Company also has pledged collateral for reinsurance agreements which amounted to $13.9 million , as of September 30, 2019 , and $1.0 million , as of December 31, 2018 , which is released annually between March 2020 and March 2023 based on the policy periods covered by the reinsurance agreements (see Note 18 ).

Segregated Cash

Segregated Cash	9 Months Ended
	Sep. 30, 2019
Segregated Cash [Abstract]
Segregated Cash	Segregated Cash As of September 30, 2019 and December 31, 2018 , cash segregated in compliance with federal regulations and other restricted deposits of $128.8 million and $176.6 million , respectively, consisted of cash deposited in Special Reserve Accounts for the exclusive benefit of customers under SEC Rule 15c3-3 and cash held in accounts designated as Special Reserve Bank Accounts for Proprietary Accounts of Broker-Dealers ("PAB").

Investments of Operating Entiti

Investments of Operating Entities and Consolidated Funds	9 Months Ended
	Sep. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Investments of Operating Entities and Consolidated Funds	Investments of Operating Entities and Consolidated Funds a. Operating Entities Securities owned, at fair value Securities owned, at fair value are held by the Company and are considered held for trading. Substantially all equity securities, which are not part of the Company's self-clearing securities finance activities, are pledged to external clearing brokers under terms which permit the external clearing broker to sell or re-pledge the securities to others subject to certain limitations. As of September 30, 2019 and December 31, 2018 , securities owned, at fair value consisted of the following: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Common stock (*) $ 853,786 $ 472,299 Preferred stock (*) 16,585 5,617 Warrants and rights (*) 19,865 7,990 Government bonds (a) 2,905 13,398 Corporate bonds (c) 18,366 13,041 Convertible bonds (b) (*) 2,541 3,000 Term loan (*) 1,054 — Trade claims (*) 7,062 5,543 $ 922,164 $ 520,888 (a) As of September 30, 2019 , maturities range from October 2019 to March 2020 with an interest rate of 0% . As of December 31, 2018 , maturities ranged from April 2019 to August 2019 with an interest rate of 0% . (b) As of September 30, 2019 , maturities range from April 2020 to March 2022 with an interest rate of 8% . As of December 31, 2018 , the maturity was June 2020 with an interest rate of 8% . (c) As of September 30, 2019 , maturities ranged from December 2019 to August 2044 and interest rates ranged from 0.00% to 15.00% . As of December 31, 2018 , maturities ranged from April 2019 to April 2049 and interest rates ranged from 2% to 15.50% . * The Company has elected the fair value option for securities owned, at fair value with a fair value of $18.3 million and $9.4 million , respectively, at September 30, 2019 and December 31, 2018 . Receivable on and Payable for derivative contracts, at fair value The Company's direct involvement with derivative financial instruments includes total return swaps, futures, currency forwards, equity swaps, credit default swaps and options. The Company's derivatives trading activities exposes the Company to certain risks, such as price and interest rate fluctuations, volatility risk, credit risk, counterparty risk, foreign currency movements and changes in the liquidity of markets. The Company's long and short exposure to derivatives is as follows: Receivable on derivative contracts As of September 30, 2019 As of December 31, 2018 Number of contracts / Notional Value Fair value Number of contracts / Notional Value Fair value (dollars in thousands) Futures $ 33,474 $ 103 $ 42,288 $ 334 Currency forwards $ 79,804 640 $ 395 1 Swaps $ 103,591 4,242 $ 13,702 917 Options other (a) 349,434 34,769 654,506 23,130 Pay to hold $ — — $ — 743 $ 39,754 $ 25,125 (a) Includes index, equity, commodity future and cash conversion options. Payable for derivative contracts As of September 30, 2019 As of December 31, 2018 Number of contracts / Notional Value Fair value Number of contracts / Notional Value Fair value (dollars in thousands) Currency forwards $ 24,636 91 $ 96,406 709 Swaps $ 164,056 6,502 $ 52,905 2,162 Options other (a) 190,321 26,162 90,730 13,211 $ 32,755 $ 16,082 (a) Includes index, equity, commodity future and cash conversion options. The following tables present the gross and net derivative positions and the related offsetting amount, as of September 30, 2019 and December 31, 2018 . This table does not include the impact of over-collateralization. Gross amounts not offset in the Condensed Consolidated Statement of Financial Condition Gross amounts recognized Gross amounts offset on the Condensed Consolidated Statements of Financial Condition (a) Net amounts included on the Condensed Consolidated Statements of Financial Condition Financial instruments Cash Collateral pledged (b) Net amounts (dollars in thousands) As of September 30, 2019 Receivable on derivative contracts, at fair value $ 39,754 $ — $ 39,754 $ — $ 4,882 $ 34,872 Payable for derivative contracts, at fair value 32,755 — 32,755 — 6,592 26,163 As of December 31, 2018 Receivable on derivative contracts, at fair value $ 25,125 $ — $ 25,125 $ — $ 1,662 $ 23,463 Payable for derivative contracts, at fair value 16,082 — 16,082 — 2,871 13,211 (a) Includes financial instruments subject to enforceable master netting provisions that are permitted to be offset to the extent an event of default has occurred. (b) Includes the amount of collateral held or posted. The realized and unrealized gains/(losses) related to derivatives trading activities were $7.1 million and $(7.5) million for the three months ended September 30, 2019 and 2018 and $2.3 million and $6.4 million for the nine months ended September 30, 2019 and 2018 , respectively, and are included in other income in the accompanying condensed consolidated statements of operations. Pursuant to the various derivatives transactions discussed above, except for exchange traded derivatives and certain options, the Company is required to post/receive collateral. As of September 30, 2019 and December 31, 2018 , collateral consisting of $8.2 million and $11.2 million of cash is included in receivable from brokers, dealers and clearing organizations and payable to brokers, dealers and clearing organizations, respectively, on the accompanying condensed consolidated statements of financial condition. As of September 30, 2019 and December 31, 2018 , all derivative contracts were with multiple major financial institutions. Other investments As of September 30, 2019 and December 31, 2018 , other investments included the following: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Portfolio funds, at fair value (1) $ 131,740 $ 123,241 Carried interest (2) 25,186 17,995 Equity method investments (3) 47,242 40,171 $ 204,168 $ 181,407 (1) Portfolio Funds, at fair value The Portfolio Funds, at fair value as of September 30, 2019 and December 31, 2018 , included the following: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Starboard Value and Opportunity Fund LP (c)(*) $ 36,566 $ 32,579 Formation8 Partners Fund I, L.P. (f) 33,613 34,099 RCG Longview Debt Fund V, L.P. (g)(*) 1,909 4,394 RCG Longview II LP (g) (*) 3,734 4,400 Cowen Healthcare Investments II LP (i) (*) 18,036 14,939 Eclipse Ventures Fund I, L.P. (b) 4,901 4,412 HealthCare Royalty Partners LP (a)(*) 1,367 1,833 Lagunita Biosciences, LLC (d) 4,868 3,833 Starboard Leaders Fund LP (e)(*) 1,511 1,230 Eclipse SPV I, LP (j)(*) 1,446 1,447 RCG Longview Equity Fund, LP (g) (*) 713 802 RCG Longview Debt Fund VI, LP (g) (*) 1,895 1,586 RCG Park Liberty GP Member LLC (g) (*) 952 1,023 HealthCare Royalty Partners II LP (a)(*) 1,681 1,037 RCGL PE MPA, LLC (g)(*) — 618 RCG LPP2 PNW5 Co-Invest, L.P. (h)(*) 10 296 Difesa Partners, LP (c) (*) 500 — Other private investment (k)(*) 14,711 11,625 Other affiliated funds (l)(*) 3,327 3,088 $ 131,740 $ 123,241 * These Portfolio Funds are affiliates of the Company. The Company has no unfunded commitments regarding the Portfolio Funds held by the Company except as noted in Note 17 . (a) HealthCare Royalty Partners, L.P. and HealthCare Royalty Partners II, L.P. are private equity funds and therefore distributions will be made when cash flows are received from the underlying investments, typically on a quarterly basis. (b) Eclipse Ventures Fund I, L.P. is a private equity fund which invests in early stage and growth hardware companies. Distributions will be made when the underlying investments are liquidated. (c) Starboard Value and Opportunity Fund LP and Difesa Partners, LP permits quarterly withdrawals upon 90 days' notice. (d) Lagunita Biosciences, LLC, is a healthcare investment company that creates and grows early stage companies to commercialize impactful translational science that addresses significant clinical needs, is a private equity structure and therefore distributions will be made when the underlying investments are liquidated. (e) Starboard Leaders Fund LP does not permit withdrawals, but instead allows terminations with respect to capital commitments upon 30 days' prior written notice at any time following the first anniversary of an investor's initial capital contribution. (f) Formation8 Partners Fund I, L.P. is a private equity fund which invests in early stage and growth transformational information and energy technology companies. Distributions will be made when the underlying investments are liquidated. (g) RCG Longview Debt Fund V, L.P., RCG Longview II LP, RCG Park Liberty GP Member LLC, RCG Longview Equity Fund, LP, RCGL PE MPA, LLC and RCG Longview Debt Fund VI, LP are real estate private equity structures. The timing of distributions depends on the nature of the underlying investments and therefore will be made either quarterly or when the underlying investments are liquidated. (h) RCG LPP2 PNW5 Co-Invest, L.P. is a single purpose entity formed to participate in a joint venture which acquired five multi-unit residential rental properties located in the Pacific Northwest. RCG LPP2 PNW5 Co-Invest, L.P. is a private equity structure and therefore distributions will be made when the underlying investments are liquidated. (i) Cowen Healthcare Investments II LP are private equity funds. Distributions are made from these funds when cash flows or securities are received from the underlying investments. Investors do not have redemption rights. (j) Eclipse SPV I, L.P. is a co-investment vehicle organized to invest in a private company focused on software-driven automation projects. Distributions will be made when the underlying investments are liquidated. (k) Other private investment represents the Company's closed end investment in a Portfolio Fund that invests in a wireless broadband communication provider in Italy. (l) The majority of these investment funds are affiliates of the Company or are managed by the Company and the investors can redeem from these funds as investments are liquidated. (2) Carried interest The Company applies an accounting policy election to recognize incentive income allocated to the Company under an equity ownership model as other investments in the accompanying condensed consolidated statements of financial condition (see Note 2m ). Carried interest allocated to the Company from certain portfolio funds represents Cowen's general partner capital accounts from those funds. These balances are subject to change upon cash distributions, additional allocations or reallocations back to limited partners within the respective funds. A portion of the Company's carried interest is granted to employees through profit sharing awards designed to more closely align compensation with the overall realized performance of the Company. These arrangements enable certain employees to earn compensation based on performance revenue earned by the Company are recorded within compensation payable in the accompanying condensed consolidated statements of financial condition. The carried interest as of September 30, 2019 and December 31, 2018 , included the following: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Cowen Healthcare Investments II LP (*) 19,365 6,778 Other private investment (a) (*) 4,388 4,273 RCG IO Renergys Sarl 863 6,369 Ramius Multi-Strategy Fund LP (*) 570 575 $ 25,186 $ 17,995 (a) Other private investment represents the Company's closed end investment in a Portfolio Fund that invests in a wireless broadband communication provider in Italy. * These carried interest balances are earned from affiliates of the Company. (3) Equity method investments Equity method investments include investments held by the Company in several operating companies whose operations primarily include the day to day management of a number of real estate funds, including the portfolio management and administrative services related to the acquisition, disposition, and active monitoring of the real estate funds' underlying debt and equity investments. The Company's ownership interests in these equity method investments range from 1% to 56% . The Company holds a majority of the outstanding ownership interest (i.e., more than 50%) in RCG Longview Partners II, LLC and 40% in Surf House Ocean Views Holdings, LLC (which is a joint venture in a real estate development project). The operating agreement that governs the management of day-to-day operations and affairs of these entities stipulates that certain decisions require support and approval from other members in addition to the support and approval of the Company. As a result, all operating decisions made in these entities requires the support of both the Company and an affirmative vote of a majority of the other managing members who are not affiliates of the Company. As the Company does not possess control over any of these entities, the presumption of consolidation has been overcome pursuant to current Accounting Standards and the Company accounts for these investments under the equity method of accounting. Also included in equity method investments are the investments in (a) HealthCare Royalty Partners General Partners and (b) Starboard Value (and certain related parties) which serves as an operating company whose operations primarily include the day to day management (including portfolio management) of several activist investment funds and related managed accounts. The Company completed the sale of its interests in RCG Longview Management, the management company for certain real estate investment funds which the Company was invested. The Company also entered into a transaction to sell some of the real estate assets held by the Company for which an impairment charge was recognized at September 30, 2019. The transactions resulted in the recognition of a $0.2 million loss for the three and nine months ended September 30, 2019 . During the third quarter of 2018, the Company completed an assessment of the recoverability of the Company's equity method investments and determined that the carrying value of the investment in Surf House Ocean View Holdings, LLC exceeded the estimated fair value of the Company's interest, which was other than temporary. Accordingly, an impairment charge of $7.1 million was recognized to reduce the carrying value of the investment to fair value at September 30, 2018 . The Company elected to use the cumulative earnings approach for the distributions it receives from its equity method investments. Under the cumulative earnings approach, any distributions received up to the amount of cumulative earnings are treated as return on investment and classified in operating activities within the cash flows. Any excess distributions would be considered as return of investments and classified in investing activities. The following table summarizes equity method investments held by the Company: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Surf House Ocean Views Holdings, LLC $ 9,946 $ 7,589 Starboard Value LP 22,627 12,699 RCG Longview Debt Fund V Partners, LLC 3,827 11,000 RCG Longview Management, LLC 2,474 1,167 RCG Longview Debt Fund VI Partners LLC 449 1,254 HealthCare Royalty GP, LLC 111 149 HealthCare Royalty GP II, LLC 285 176 RCG Longview Debt Fund IV Management, LLC 331 331 HealthCare Royalty GP III, LLC 2,190 1,573 TriArtisan ES Partners LLC 1,026 1,500 TriArtisan PFC Partners LLC 999 — RCG Kennedy House, LLC 65 131 RCG Longview Equity Management, LLC 105 114 RCG LPP II GP, LLC 30 272 RCG Park Liberty GP Member Manager, LLC 1,014 1,248 HCR Stafford Fund GP, LLC 682 — Other 1,081 968 $ 47,242 $ 40,171 For the period ended September 30, 2019 , one equity method investment has met the significance criteria as defined under Regulation S-X Rule 4-08(g) of the SEC guidance ("Reg S-X 4-08(g)"). As such, the Company is presenting the following summarized financial information for the significant investee for the periods ended September 30, 2019 and December 31, 2018, and three and nine months ended September 30, 2019 and 2018, and such information is as follows: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Assets Cash $ 2,553 $ 37 Performance & management fee receivable 68,052 16,594 Investments 4,266 3,599 Liabilities — — Equity $ 74,871 $ 20,230 Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (dollars in thousands) Revenues $ 4,564 $ (1,843 ) $ 83,287 $ 24,083 Expenses — — — — Net realized and unrealized gains (losses) 55 29 717 271 Net Income $ 4,619 $ (1,814 ) $ 84,004 $ 24,354 As of September 30, 2019 and December 31, 2018 , the Company's share of losses in its equity method investment in RCG Longview Partners II, LLC has exceeded the carrying amount recorded in this investee. These amounts are included in accounts payable, accrued expenses and other liabilities in the accompanying condensed consolidated statements of financial condition. RCG Longview Partners II, LLC, as general partner to a real estate fund, has reversed previously recorded incentive income allocations and has recorded a current clawback obligation to the limited partners in such fund. This obligation is due to a change in unrealized value of the real estate fund on which there have previously been distributed carried interest realizations; however, the settlement of a potential obligation is not due until the end of the life of the respective real estate fund. As the Company is obligated to return previous distributions it received from RCG Longview Partners II, LLC, it has continued to record its share of gains/losses in the investee including reflecting its share of the clawback obligation in the amount of $6.5 million and $6.5 million as of September 30, 2019 and December 31, 2018 , respectively. The Company's income (loss) from equity method investments was $2.7 million and $(4.7) million for the three months ended September 30, 2019 and 2018 , and $23.1 million and $7.2 million for the nine months ended September 30, 2019 and 2018 , respectively, and is included in net gains (losses) on securities, derivatives and other investments on the accompanying condensed consolidated statements of operations. Securities sold, not yet purchased, at fair value Securities sold, not yet purchased, at fair value represent obligations of the Company to deliver a specified security at a contracted price and, thereby, create a liability to purchase that security at prevailing prices. The Company's liability for securities to be delivered is measured at their fair value as of the date of the condensed consolidated financial statements. However, these transactions result in off-balance sheet risk, as the Company's ultimate cost to satisfy the delivery of securities sold, not yet purchased, at fair value may exceed the amount reflected in the accompanying condensed consolidated statements of financial condition. Substantially all equity securities and options are pledged to the clearing broker under terms which permit the clearing broker to sell or re-pledge the securities to others subject to certain limitations. As of September 30, 2019 and December 31, 2018 , securities sold, not yet purchased, at fair value consisted of the following: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Common stock $ 349,408 $ 194,305 Corporate bonds (a) 1,281 750 Government bonds (b) 2,250 — Preferred stock 4,394 199 Warrants and rights 7,409 53 $ 364,742 $ 195,307 (a) As of September 30, 2019 , the maturities ranged from February 2024 to April 2037 and interest rates ranged from 5.00% to 5.50% . As of December 31, 2018 , the maturities ranged from October 2022 to January 2034 and interest rates ranged from 2.25% to 9.38% . (b) As of September 30, 2019 , the maturities ranged from October 2019 to March 2038 and interest rates ranged from 7.00% to 8.25% . Securities sold under agreements to repurchase and securities lending and borrowing transactions The following tables present the contractual gross and net securities borrowing and lending agreements and securities sold under agreements to repurchase and the related offsetting amount as of September 30, 2019 and December 31, 2018 . Gross amounts not offset on the Condensed Consolidated Statement of Financial Condition Gross amounts recognized Gross amounts offset on the Condensed Consolidated Statements of Financial Condition (a) Net amounts included on the Condensed Consolidated Statements of Financial Condition Additional Amounts Available Financial instruments Cash Collateral pledged (b) Net amounts (dollars in thousands) As of September 30, 2019 Securities borrowed $ 1,228,036 $ — $ 1,228,036 $ — $ 1,209,672 $ — $ 18,364 Securities loaned 1,339,647 — 1,339,647 — 1,282,340 — 57,307 Securities sold under agreements to repurchase 23,772 — 23,772 — 25,635 — (1,863 ) As of December 31, 2018 Securities borrowed $ 407,795 $ — $ 407,795 $ — $ 383,593 $ — $ 24,202 Securities loaned 414,852 — 414,852 — 391,310 — 23,542 (a) Includes financial instruments subject to enforceable master netting provisions that are permitted to be offset to the extent an event of default has occurred. (b) Includes the amount of cash collateral held/posted. The following tables present gross obligations for securities loaned and securities sold under agreements to repurchase by remaining contractual maturity and class of collateral pledged as of September 30, 2019 and December 31, 2018 : Open and Overnight Up to 30 days 31 - 90 days Greater than 90 days Total (dollars in thousands) As of September 30, 2019 Securities loaned Common stock $ 1,024,436 $ — $ — $ — $ 1,024,436 Corporate bonds 315,211 — — — 315,211 Securities sold under agreements to repurchase — 15,951 7,821 — 23,772 As of December 31, 2018 Securities loaned Common stock $ 414,852 $ — $ — $ — $ 414,852 Variable Interest Entities The total assets and liabilities of the variable interest entities for which the Company has concluded that it holds a variable interest, but for which it is not the primary beneficiary, are $5.6 billion and $258.5 million as of September 30, 2019 and $5.1 billion and $157.6 million as of December 31, 2018 , respectively. The carrying value of the Company's exposure to loss for these variable interest entities as of September 30, 2019 was $241.1 million , and as of December 31, 2018 was $301.4 million , all of which is included in other investments, at fair value in the accompanying condensed consolidated statements of financial condition. The exposure to loss primarily relates to the Consolidated Fund's investment in their Unconsolidated Master Fund and the Company's investment in unconsolidated investment companies. Additionally, the Company’s maximum exposure to loss for the variable interest entities noted above as of September 30, 2019 and December 31, 2018 , was $264.3 million and $332.4 million , respectively. The maximum exposure to loss often differs from the carrying value of exposure to loss of the variable interests. The maximum exposure to loss is dependent on the nature of the variable interests in the VIEs and is limited to the notional amounts of certain commitments and guarantees. b. Consolidated Funds Securities owned, at fair value As of September 30, 2019 and December 31, 2018 , securities owned, at fair value, held by the Consolidated Funds consisted of the following: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Preferred stock $ 46,268 $ 24,314 Common stock 202,017 95,565 Government bonds (a) 100,724 38,377 Corporate bonds (b) 14,717 24,098 Warrants and rights 5,465 5,279 $ 369,191 $ 187,633 (a) As of September 30, 2019 , maturities ranged from November 2019 to December 2019 and interest rates were 0% . As of December 31, 2018 , maturities ranged from January 2019 to April 2019 and interest rates were 0% . (b) As of September 30, 2019 , maturities ranged from May 2022 to May 2026 and interest rates ranged from 4.87% to 6.50% . As of December 31, 2018 , maturities ranged from August 2020 to March 2026 and interest rates ranged from 5.88% to 7.63% . Receivable on derivative contracts As of September 30, 2019 and December 31, 2018 , receivable on derivative contracts, at fair value, held by the Consolidated Funds are comprised of: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Currency forwards $ 31 $ 186 Equity swaps 1,296 2,477 Options 2,558 1,753 $ 3,885 $ 4,416 Payable for derivative contracts As of September 30, 2019 and December 31, 2018 , payable for derivative contracts, at fair value, held by the Consolidated Funds are comprised of: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Currency forwards $ 2,341 $ 96 Equity swaps 5,022 713 Options 415 854 $ 7,778 $ 1,663 Other investments, at fair value Investments in Portfolio Funds, at fair value As of September 30, 2019 and December 31, 2018 , investments in Portfolio Funds, at fair value, included the following: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Investments of Enterprise LP $ 96,308 $ 97,656 Investments of Merger Fund 74,878 88,739 $ 171,186 $ 186,395 Consolidated portfolio fund investments of Enterprise LP On May 12, 2010, the Company announced its intention to close Enterprise Master. Enterprise LP operated under a “master-feeder” structure up until January 1, 2019, when Enterprise Master distributed its capital to each feeder and was liquidated. As of September 30, 2019 , the consolidated investments in Portfolio Funds include Enterprise LP's investment in RCG Special Opportunities Fund, Ltd which is a portfolio fund that invests in a limited number of private equity investment directly as well as through affiliated portfolio funds. As of December 31, 2018, the consolidated investments in Portfolio Funds included Enterprise LP's investment of $97.7 million in Enterprise Master. Prior to liquidation, strategies utilized by Enterprise Master included merger arbitrage and activist investing, investments in distressed securities, convertible hedging, capital structure arbitrage, equity market neutral, investments in private placements of convertible securities, proprietary mortgages, structured credit investments, investments in mortgage backed securities and other structured finance products, investments in real estate and real property interests, structured private placements and other relative value strategies. Enterprise Master had broad investment powers and maximum flexibility in seeking to achieve its investment objective. Enterprise Master was permitted to invest in equity securities, debt instruments, options, futures, swaps, credit default swaps and other derivatives. There are no unfunded commitments at Enterprise LP. Consolidated portfolio fund investments of Merger Fund The Merger Fund operates under a “master-feeder” structure, whereby Ramius Merger Master Ltd.'s ("Merger Master") shareholders are Merger Fund and Ramius Merger Fund Ltd. The consolidated investments in Portfolio Funds include Merger Fund's investment of $74.9 million and $88.7 million in Merger Master as of September 30, 2019 and December 31, 2018 , respectively. The Merger Master’s investment objective is to achieve consistent absolute returns while emphasizing the preservation of investor capital. The Merger Master seeks to achieve these objectives by taking a fundamental, research-driven approach to investing, primarily in the securities of issuers engaged in, or subject to, announced (or unannounced but otherwise anticipated) extraordinary corporate transactions, which may include, but are not limited to, mergers, acquisitions, leveraged buyouts, tender offers, hostile takeover bids, sale processes, exchange offers, and recapitalizations. Merger Master invests in the securities of one or more issuers engaged in or subject to such extraordinary corporate transactions. Merger Master typically seeks to derive a profit by realizing the price differential, or “spread,” between the market price of securities purchased or sold short and the market price or value of securities realized in connection with the completion or termination of the extraordinary corporate transaction, or in connection with the adjustment of market prices in anticipation thereof, while seeking to minimize the market risk associated with the aforementioned investment activities. Merger Master will, depending on market conditions, generally focus the majority of its investment program on announced transactions. If the investment manager of Merger Master considers it necessary, it may either alone or as part of a group, also initiate shareholder actions seeking to maximize value. Such shareholder actions may include, but are not limited to, re-orienting management’s focus or initiating the sale of the company (or one or more of its divisions) to a third party. There are no unfunded commitments at Merger Fund. Indirect Concentration of the Underlying Investments Held by Consolidated Funds From time to time, either directly or indirectly through its investments in the Consolidated Funds, the Company may maintain exposure to a particular issue or issuer (both long and/or short) which may account for 5% or more of the Company's equity. Based on information that is available to the Company as of September 30, 2019 and December 31, 2018 , the Company assessed whether or not its interests in an issuer for which the Company's pro-rata share exceeds 5% of the Company's equity. There was one indirect concentration that exceeded 5% of the Company's equity as of September 30, 2019 and one at December 31, 2018 . Through its investments in a Consolidated Fund and combined with direct Company investments, the Company maintained exposure to a particular investment which accounted for 5% or more of the Company's equity. Investment's percentage of the Company's stockholders' equity Issuer Security Type Country Industry Percentage of Stockholders' Equity Market Value (dollars in thousands) As of September 30, 2019 Linkem Equity Italy Wireless Broadband 8.56 % $ 69,927 As of December 31, 2018 Linkem Equity Italy Wireless Broadband 8.36 % $ 66,439 Underlying Investments of Unconsolidated Funds Held by Consolidated Funds Enterprise Master and Merger Master At December 31, 2018 , Enterprise LP's investment in Enterprise Master represented Enterprise LP's proportionate share of Enterprise Master's net assets; as a result, the investment balances of Enterprise Master reflected below may exceed the net investment which Enterprise LP has recorded. Merger Fund's investment in Merger Master represents Merger Fund's proportionate share of Merger Master's net assets; as a result, the investment balances of Merger Master reflected below may exceed the net investment which Merger Fund has recorded. The following tables present summarized investment information for the underlying investments and derivatives held by Enterprise Master and Merger Master as of September 30, 2019 and December 31, 2018 : Securities owned by Enterprise Master, at fair value As of December 31, 2018 (dollars in thousands) Common stock $ 469 $ 469 Portfolio Funds, owned by Enterprise Master, at fair value As of December 31, 2018 Strategy (dollars in thousands) RCG Special Opportunities Fund, Ltd* Multi-Strategy $ 111,548 Other Private Investments Various 846 $ 112,394 * Affiliates of the Company. Merger Master As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Securities owned by Merger Master, at fair value Common stock $ 166,669 $ 162,811 Corporate bonds 10,343 116,488 $ 177,012 $ 279,299 Securities sold, not yet purchased, by Merger Master, at fair value Common stock $ 58,444 $ 9,610 $ 58,444 $ 9,610 Receivable on derivative contracts, at fair value, owned by Merger Master As of September 30, 2019 As of December 31, 2018 Description (dollars in thousands) Options $ 2,691 $ 3,450 Equity swaps 99 5,320 $ 2,790 $ 8,770 Payable for derivative contracts, at fair value, owned by Merger Master As of September 30, 2019 As of December 31, 2018 Description (dollars in thousands) Options $ 856 $ 1,430 Currency forwards 13,936 270 Equity swaps 49 28 $ 14,841 $ 1,728

Fair Value Measurements for Ope

Fair Value Measurements for Operating Entities and Consolidated Funds	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements for Operating Entities and Consolidated Funds	Fair Value Measurements for Operating Entities and Consolidated Funds The following table presents the assets and liabilities that are measured at fair value on a recurring basis on the accompanying condensed consolidated statements of financial condition by caption and by level within the valuation hierarchy as of September 30, 2019 and December 31, 2018 : Assets at Fair Value as of September 30, 2019 Level 1 Level 2 Level 3 Total (dollars in thousands) Operating Entities Securities owned, at fair value Government bonds $ 2,905 $ — $ — $ 2,905 Preferred stock 8,750 — 7,835 16,585 Common stock 840,473 — 13,313 853,786 Convertible bonds — — 2,541 2,541 Corporate bonds — 16,293 2,073 18,366 Trade claims — — 7,062 7,062 Term Loan — 1,054 — 1,054 Warrants and rights 19,281 — 584 19,865 Receivable on derivative contracts, at fair value Futures 103 — — 103 Currency forwards — 640 — 640 Swaps — 4,242 — 4,242 Options 34,769 — — 34,769 Consolidated Funds Securities owned, at fair value Government bonds 100,724 — — 100,724 Preferred stock 41,875 — 4,393 46,268 Common stock 202,017 — — 202,017 Corporate bonds — 14,717 — 14,717 Warrants and rights — — 5,465 5,465 Receivable on derivative contracts, at fair value Currency forwards — 31 — 31 Equity swaps — 1,296 — 1,296 Options 2,558 — — 2,558 $ 1,253,455 $ 38,273 $ 43,266 $ 1,334,994 Percentage of total assets measured at fair value on a recurring basis 93.9 % 2.9 % 3.2 % Portfolio Funds measured at net asset value (a) 131,740 Carried interest (a) 25,186 Consolidated Funds' Portfolio Funds measured at net asset value (a) 171,186 Equity method investments 47,242 Total investments $ 1,710,348 Liabilities at Fair Value as of September 30, 2019 Level 1 Level 2 Level 3 Total (dollars in thousands) Operating Entities Securities sold, not yet purchased, at fair value Government bonds $ — $ — $ 2,250 $ 2,250 Common stock 349,408 — — 349,408 Corporate bonds — 81 1,200 1,281 Preferred stock 4,394 — — 4,394 Warrants and rights 7,409 — — 7,409 Payable for derivative contracts, at fair value Currency forwards — 91 — 91 Swaps — 6,502 — 6,502 Options 23,662 — 2,500 26,162 Accounts payable, accrued expenses and other liabilities Contingent consideration liability (b) — — 29,834 29,834 Consolidated Funds Payable for derivative contracts, at fair value Currency forwards — 2,341 — 2,341 Options 415 — — 415 Equity swaps — 5,022 — 5,022 $ 385,288 $ 14,037 $ 35,784 $ 435,109 Percentage of total liabilities measured at fair value 88.5 % 3.2 % 8.2 % (a) In accordance with US GAAP, certain investments that are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient and carried interest in portfolio funds have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the condensed consolidated statement of financial condition. (b) In accordance with the terms of the purchase agreements for acquisitions that closed during the second quarter of 2016 and the first quarter of 2019, the Company is required to pay to the sellers a portion of future net income and/or revenues of the acquired businesses, if certain targets are achieved through the periods ended December 2019 and December 2023, respectively. For the acquisition that closed during 2016, the Company estimated the contingent consideration liability using the income approach (discounted cash flow method) which requires the Company to make estimates and assumptions regarding the future cash flows and profits. For the acquisition that closed during 2019, the Company estimated the contingent consideration liability using the present value of the monte carlo simulated revenue. Changes in these estimates and assumptions could have a significant impact on the amounts recognized. The undiscounted amounts as of September 30, 2019 can range from $1.6 million to $40.0 million . Assets at Fair Value as of December 31, 2018 Level 1 Level 2 Level 3 Total (dollars in thousands) Operating Entities Securities owned, at fair value Government bonds $ 13,398 $ — $ — $ 13,398 Preferred stock 449 — 5,168 5,617 Common stock 459,601 2,848 9,850 472,299 Convertible bonds — — 3,000 3,000 Corporate bonds — 13,041 — 13,041 Trade claims — — 5,543 5,543 Warrants and rights 6,324 — 1,666 7,990 Receivable on derivative contracts, at fair value Futures 334 — — 334 Currency forwards — 1 — 1 Swaps — 917 — 917 Options 23,130 — — 23,130 Pay to hold — 743 — 743 Consolidated Funds Securities owned, at fair value Government bonds 38,377 — — 38,377 Preferred stock — — 24,314 24,314 Common stock 95,471 — 94 95,565 Corporate bonds — 24,098 — 24,098 Warrants and rights — — 5,279 5,279 Receivable on derivative contracts, at fair value Currency forwards — 186 — 186 Equity swaps — 2,477 — 2,477 Options 1,753 — — 1,753 $ 638,837 $ 44,311 $ 54,914 $ 738,062 Percentage of total assets measured at fair value on a recurring basis 86.6 % 6.0 % 7.4 % Portfolio Funds measured at net asset value (a) 123,241 Carried interest (a) 17,995 Consolidated Funds' Portfolio Funds measured at net asset value (a) 186,395 Equity method investments 40,171 Total investments $ 1,105,864 Liabilities at Fair Value as of December 31, 2018 Level 1 Level 2 Level 3 Total (dollars in thousands) Operating Entities Securities sold, not yet purchased, at fair value Common stock $ 194,305 $ — $ — $ 194,305 Corporate bonds — 750 — 750 Preferred stock 199 — — 199 Warrants and rights 53 — — 53 Payable for derivative contracts, at fair value Currency forwards — 709 — 709 Swaps — 2,162 — 2,162 Options 11,115 — 2,096 13,211 Accounts payable, accrued expenses and other liabilities Contingent consideration liability (b) — — 3,070 3,070 Consolidated Funds Payable for derivative contracts, at fair value Currency forwards — 96 — 96 Options 854 — — 854 Equity swaps — 713 — 713 $ 206,526 $ 4,430 $ 5,166 $ 216,122 Percentage of total liabilities measured at fair value 95.6 % 2.0 % 2.4 % (a) In accordance with US GAAP, certain investments that are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient and carried interest in portfolio funds have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the condensed consolidated statement of financial condition. (b) In accordance with the terms of the purchase agreements for the acquisition that closed during the second quarter of 2016, the Company is required to pay to the sellers a portion of future net income and/or revenues of the acquired business, if certain targets are achieved through the periods ended December 2020. The Company estimated the contingent consideration liability using the income approach (discounted cash flow method) which requires the Company to make estimates and assumptions regarding the future cash flows and profits. Changes in these estimates and assumptions could have a significant impact on the amounts recognized. The undiscounted amounts as of December 31, 2018 can range from $2.8 million to $3.4 million . The following table includes a roll forward of the amounts for the three and nine months ended September 30, 2019 and 2018 for financial instruments classified within level 3. The classification of a financial instrument within level 3 is based upon the significance of the unobservable inputs to the overall fair value measurement. Three Months Ended September 30, 2019 Balance at June 30, 2019 Transfers in Transfers out Purchases/(covers) (Sales)/shorts Realized and Unrealized gains/losses Balance at September 30, 2019 Change in unrealized gains/losses relating to instruments still held (1) (dollars in thousands) Operating Entities Preferred stock $ 7,401 $ — $ (1,000 ) (e) $ — $ — $ 1,434 $ 7,835 $ 2,295 Common stock 11,006 — — 2,579 (480 ) 208 13,313 210 Convertible bonds 6,318 (2,801 ) (e) 1,049 (2,072 ) 47 2,541 4 Corporate bond 775 20 (d) — 1,117 — 161 2,073 161 Options, liability 2,779 — — — — (279 ) 2,500 (279 ) Warrants and rights 595 — — — (72 ) 61 584 (12 ) Trade claims 10,488 — — 1,871 (5,354 ) 57 7,062 57 Corporate bond, liability — 2,525 (d) — — — (1,325 ) 1,200 (1,325 ) Government bonds, liability — 4,681 (d) — — — (2,431 ) 2,250 (2,431 ) Contingent consideration liability 29,536 — — — — 298 29,834 298 Consolidated Funds Preferred stock 24,322 — (19,929 ) (e) — — — 4,393 — Common stock 1,017 — (94 ) (e) — (957 ) 34 — — Warrants and rights 6,274 — — — (670 ) (139 ) 5,465 (809 ) Three Months Ended September 30, 2018 Balance at June 30, 2018 Transfers in Transfers out Purchases/(covers) (Sales)/shorts Realized and Unrealized gains/losses Balance at September 30, 2018 Change in unrealized gains/losses relating to instruments still held (1) (dollars in thousands) Operating Entities Preferred stock $ 7,422 $ — $ (1,141 ) (b) $ — $ — $ (1,123 ) $ 5,158 $ (1,124 ) Common stock 5,848 — — — — (174 ) 5,674 (174 ) Options, liability 301 — — — — 2,246 2,547 2,246 Warrants and rights 1,544 — — — 38 1,582 38 Trade claims 5,699 — — 44 — 3 5,746 3 Lehman claim 295 — — — (234 ) (61 ) — — Contingent consideration liability 2,870 — — — (227 ) — 2,643 — Consolidated Funds Preferred stock 24,314 — — — — — 24,314 — Common stock 94 — — — — — 94 — Warrants and rights 4,738 — — — 110 4,848 110 Nine Months Ended September 30, 2019 Balance at December 31, 2018 Transfers in Transfers out Purchases/(covers) (Sales)/shorts Realized and Unrealized gains/losses Balance at September 30, 2019 Change in unrealized gains/losses relating to instruments still held (1) (dollars in thousands) Operating Entities Preferred stock $ 5,168 $ — $ (1,000 ) (e) $ 3,243 $ (1,000 ) $ 1,424 $ 7,835 $ 2,285 Common stock 9,850 — — 16,737 (12,952 ) (322 ) 13,313 (122 ) Convertible bonds 3,000 — (4,826 ) (b) (e) 16,021 (11,764 ) 110 2,541 41 Corporate bond — 20 (d) — 1,892 — 161 2,073 161 Options, liability 2,096 — — — (4 ) 408 2,500 408 Warrants and rights 1,666 — — — (188 ) (894 ) 584 20 Trade claims 5,543 — — 6,965 (5,506 ) 60 7,062 57 Corporate Bond, liability — 2,525 (d) — — — (1,325 ) 1,200 (1,325 ) Government bonds, liability — 4,681 (d) — — — (2,431 ) 2,250 (2,431 ) Contingent consideration liability 3,070 — — 27,700 (1,234 ) 298 29,834 298 Consolidated Funds Preferred stock 24,314 — (19,929 ) (e) — — 8 4,393 8 Common stock 94 — (94 ) (e) 407 (958 ) 551 — — Warrants and rights 5,279 — — — (1,758 ) 1,944 5,465 190 Nine Months Ended September 30, 2018 Balance at December 31, 2017 Transfers in Transfers out Purchases/(covers) (Sales)/shorts Realized and Unrealized gains/losses Balance at September 30, 2018 Change in unrealized gains/losses relating to instruments still held (1) (dollars in thousands) Operating Entities Preferred stock $ 8,115 $ — $ (1,141 ) (b) $ 1,415 $ (695 ) $ (2,536 ) $ 5,158 $ (2,301 ) Common stock 7,570 — — 531 (1,333 ) (1,094 ) 5,674 (1,128 ) Convertible bonds 282 — — — (307 ) 25 — — Options, asset 1,455 — — — (1,455 ) — — — Options, liability 22,401 — (28,973 ) (c) — (259 ) 9,378 2,547 9,378 Warrants and rights 2,517 — — — (143 ) (792 ) 1,582 (933 ) Trade claim 5,950 — — 44 (334 ) 86 5,746 23 Lehman claim 301 — — — (234 ) (67 ) — — Contingent consideration liability 3,440 — — — (797 ) — 2,643 — Consolidated Funds Preferred stock 50,445 — (38,552 ) (a) 3,066 — 9,355 24,314 9,355 Common stock 50 — — — — 44 94 44 Warrants and rights 3,568 — (20 ) (a) (1,340 ) — 2,640 4,848 1,300 (1) Unrealized gains/losses are reported in other income (loss) in the accompanying condensed consolidated statements of operations. (a) The Company deconsolidated an investment fund. (b) The investments were converted to common stock. (c) On June 26, 2018, the Company received shareholder approval which allows the Company to settle its convertible note (see Note 18 ) entirely in class A common shares. Upon receiving shareholder approval, the Company reclassified the embedded conversion option, associated with the convertible debt, to equity. (see Note 19 ). (d) The investments had a change of valuation methodology due to increased activity in foreign market. (e) The entity in which the Company is invested completed an initial public offering. All realized and unrealized gains (losses) in the table above are reflected in other income (loss) in the accompanying condensed consolidated statements of operations. Certain assets and liabilities are measured at fair value on a nonrecurring basis and therefore are not included in the tables above. The Company recognizes all transfers and the related unrealized gain (loss) at the beginning of the reporting period. Transfers between level 1 and 2 generally relate to whether the principal market for the security becomes active or inactive. Transfers between level 2 and 3 generally relate to whether significant relevant observable inputs are available for the fair value measurements or due to change in liquidity restrictions for the investments. During the nine months ended September 30, 2019 and 2018 , there were no transfers between level 1 and level 2 assets and liabilities. The following table includes quantitative information as of September 30, 2019 and December 31, 2018 for financial instruments classified within level 3. The table below quantifies information about the significant unobservable inputs used in the fair value measurement of the Company's level 3 financial instruments. Quantitative Information about Level 3 Fair Value Measurements Fair Value September 30, 2019 Valuation Techniques Unobservable Inputs Range Level 3 Assets (dollars in thousands) Common and preferred stocks $ 314 Discounted cash flows Discount rate 8% Trade claims 28 Discounted cash flows Discount rate 20% Warrants and rights 6,048 Model based Discounted cash flows Volatility Discount rate 30% 6% to 7% Corporate and convertible bonds 533 Discounted cash flows Recovery Discount rate Probability of recovery 20% Other level 3 assets (a) 36,343 Total level 3 assets $ 43,266 Level 3 Liabilities Options 2,500 Option pricing models Volatility 35% to 40% Contingent consideration liability 29,834 Discounted cash flows Monte Carlo simulation Discount rate Volatility 14%-23% 14%-20% Other level 3 liabilities (a) 3,450 Total level 3 liabilities $ 35,784 Quantitative Information about Level 3 Fair Value Measurements Fair Value at Valuation Techniques Unobservable Inputs Range Level 3 Assets (dollars in thousands) Common and preferred stocks $ 4,323 Guideline companies/Discounted cash flows Discount rate 8%-14% Trade claims 25 Discounted cash flows Discount rate 20% Warrants and rights 1,666 Model based Discounted cash flows Discount rate 7% to 9% Other level 3 assets (a) 48,900 Total level 3 assets $ 54,914 Level 3 Liabilities Options 2,096 Option pricing models Volatility 35% to 40% Contingent consideration liability 3,070 Discounted cash flows Projected cash flow and discount rate 23% Total level 3 liabilities $ 5,166 (a) The quantitative disclosures exclude financial instruments for which the determination of fair value is based on prices from recent transactions. The Company has established valuation policies and procedures and an internal control infrastructure over its fair value measurement of financial instruments which includes ongoing oversight by the valuation committee as well as periodic audits performed by the Company's internal audit group. The valuation committee is comprised of senior management, including non-investment professionals, who are responsible for overseeing and monitoring the pricing of the Company's investments, including the review of the results of the independent price verification process, approval of new trading asset classes and use of applicable pricing models and approaches. The US GAAP fair value leveling hierarchy is designated and monitored on an ongoing basis. In determining the designation, the Company takes into consideration a number of factors including the observability of inputs, liquidity of the investment and the significance of a particular input to the fair value measurement. Designations, models, pricing vendors, third party valuation providers and inputs used to derive fair market value are subject to review by the valuation committee and the internal audit group. The Company reviews its valuation policy guidelines on an ongoing basis and may adjust them in light of, improved valuation metrics and models, the availability of reliable inputs and information, and prevailing market conditions. The Company reviews a daily profit and loss report, as well as other periodic reports, and analyzes material changes from period-to-period in the valuation of its investments as part of its control procedures. The Company also performs back testing on a regular basis by comparing prices observed in executed transactions to previous valuations. The fair market value for level 3 securities may be highly sensitive to the use of industry standard models, unobservable inputs and subjective assumptions. The degree of fair market value sensitivity is also contingent upon the subjective weight given to specific inputs and valuation metrics. The Company holds various equity and debt instruments where different weight may be applied to industry standard models representing standard valuation metrics such as: discounted cash flows, market multiples, comparative transactions, capital rates, recovery rates and timing, and bid levels. Generally, changes in the weights ascribed to the various valuation metrics and the significant unobservable inputs in isolation may result in significantly lower or higher fair value measurements. Volatility levels for warrants and options are not readily observable and subject to interpretation. Changes in capital rates, discount rates and replacement costs could significantly increase or decrease the valuation of the real estate investments. The interrelationship between unobservable inputs may vary significantly amongst level 3 securities as they are generally highly idiosyncratic. Significant increases (decreases) in any of those inputs in isolation can result in a significantly lower (higher) fair value measurement. Other financial assets and liabilities The following table presents the carrying values and fair values, at September 30, 2019 and December 31, 2018 , of financial assets and liabilities and information on their classification within the fair value hierarchy which are not measured at fair value on a recurring basis. For additional information regarding the financial instruments within the scope of this disclosure, and the methods and significant assumptions used to estimate their fair value see Note 2 . September 30, 2019 December 31, 2018 Fair Value Hierarchy Carrying Amount Fair Value Carrying Amount Fair Value (dollars in thousands) Financial Assets Operating companies Cash and cash equivalents $ 260,994 $ 260,994 $ 259,148 $ 259,148 Level 1 Cash collateral pledged 18,609 18,609 6,318 6,318 Level 2 Segregated cash 128,782 128,782 176,647 176,647 Level 1 Securities borrowed 1,228,036 1,209,672 407,795 383,593 Level 2 Loans receivable 38,121 38,121 (d) 36,021 36,021 (d) Level 3 Consolidated Funds Cash and cash equivalents 3,364 3,364 38,118 38,118 Level 1 Financial Liabilities Securities sold under agreements to repurchase 23,772 25,635 — — Level 2 Securities loaned 1,339,647 1,282,340 414,852 391,310 Level 2 Convertible debt 117,469 (a) 148,509 (b) 134,489 (a) 157,433 (b) Level 2 Notes payable and other debt 343,286 363,777 (c) 262,965 258,546 (c) Level 2 (a) The carrying amount of the convertible debt includes an unamortized discount of $16.0 million and $19.5 million as of September 30, 2019 and December 31, 2018 , respectively. (b) The convertible debt includes the conversion option and is based on the last broker quote available. (c) Notes payable and other debt are based on the last broker quote available. (d) The fair market value of level 3 loans is calculated using discounted cash flows where applicable.

Deposits with Clearing Organiza

Deposits with Clearing Organizations, Brokers and Banks	9 Months Ended
	Sep. 30, 2019
Deposits with Clearing Organizations, Brokers and Banks [Abstract]
Deposits with Clearing Organizations, Brokers and Banks	Deposits with Clearing Organizations, Brokers and Banks Under the terms of agreements between the Company and some of its clearing organizations, brokers and banks, balances owed are collateralized by certain of the Company’s cash and securities balances. As of September 30, 2019 and December 31, 2018 , the Company had a total of $91.5 million and $89.4 million , respectively, in deposit accounts with clearing organizations, brokers and banks that could be used as collateral to offset losses incurred by the clearing organizations, brokers and banks, on behalf of the Company’s activities, if such losses were to occur.

Receivables from and payables t

Receivables from and payables to brokers, dealers and clearing organizations	9 Months Ended
	Sep. 30, 2019
Brokers and Dealers [Abstract]
Receivables From and Payables to Brokers, Dealers and Clearing Organizations	Receivable From and Payable To Brokers, Dealers and Clearing Organizations Receivable from and payable to brokers, dealers and clearing organizations includes cash held at the clearing brokers, amounts receivable or payable for unsettled transactions, monies borrowed and proceeds from short sales equal to the fair value of securities sold, not yet purchased, at fair value, which are restricted until the Company purchases the securities sold short. Pursuant to the master netting agreements the Company entered into with its brokers, dealers and clearing organizations, these balances are presented net (assets less liabilities) across balances with the same counterparty. The Company's receivable from and payable to brokers, dealers and clearing organizations balances are held at multiple financial institutions. As of September 30, 2019 and December 31, 2018 , amounts receivable from brokers, dealers and clearing organizations include: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Broker-dealers $ 676,674 $ 692,581 Securities failed to deliver 17,943 72,918 Clearing organizations 5,929 15,319 Securities borrowed interest receivable 17,088 5,295 $ 717,634 $ 786,113 As of September 30, 2019 and December 31, 2018 , amounts payable to brokers, dealers and clearing organizations include: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Broker-dealers $ 210,913 $ 159,443 Securities failed to receive 25,840 28,826 Clearing organizations 21,236 36,338 Securities loaned interest payable 13,023 4,124 $ 271,012 $ 228,731

Receivable from and Payable to

Receivable from and Payable to Customers	9 Months Ended
	Sep. 30, 2019
Receivables and Payable to Customers [Abstract]
Receivable from and Payables to Customers [Text Block]	Receivable From and Payable To Customers As of September 30, 2019 and December 31, 2018 , receivable from customers of $46.1 million and $37.9 million , respectively, consist of amounts owed by customers relating to securities transactions not completed on settlement date and receivables arising from the prepayment of Commission Sharing Agreements (“CSA”), net of an allowance for credit losses. A prepaid CSA is established for research-related disbursements in advance of anticipated customer commission volumes. As of September 30, 2019 and December 31, 2018 , payable to customers of $525.1 million and $525.2 million , respectively, include amounts due on cash and margin transactions to the Company's clients, some of which have their assets held by a Company omnibus account, which are included within receivables from brokers, dealers and clearing organizations in the accompanying condensed consolidated statements of financial condition. In the omnibus structure, positions that are owned by Cowen International Ltd are fully cross collateralized by client funds, meaning that the Company, for all intents and purposes, has no market risk. Additionally, Cowen International Ltd has no obligation to settle any trade that it deems inappropriate from a risk perspective, adding an important market and counterparty risk mitigating factor.

Goodwill and Intangibles

Goodwill and Intangibles	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangibles [Abstract]
Goodwill and Intangible Assets	Goodwill and intangible assets Goodwill Goodwill represents the excess of the purchase price consideration of acquired companies over the estimated fair value assigned to the individual assets acquired and liabilities assumed. Goodwill is allocated to the Company's reporting units at the date the goodwill is initially recorded. Once goodwill has been allocated to the reporting units, it generally no longer retains its identification with a particular acquisition but instead becomes identifiable with the reporting unit. As a result, all of the fair value of each reporting unit is available to support the value of goodwill allocated to the unit. In January 2017, the FASB issued guidance that simplifies the subsequent measurement of goodwill. The new guidance eliminated Step 2 from the goodwill impairment test which was required in computing the implied fair value of goodwill. Instead, under the new amendments, an entity should perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. The Company early adopted these amendments during the second quarter of 2019 in conjunction with a quantitative goodwill test performed due to the Company’s change in operating segments and restructuring of reporting units. See Note 11 for the impact of the goodwill impairment test. In accordance with US GAAP, inclusive of the newly adopted amendments, the Company tests goodwill for impairment on an annual basis or at an interim period if events or changed circumstances would more likely than not reduce the fair value of a reporting unit below its carrying amount. In testing for goodwill impairment, the Company has the option to first assess qualitative factors to determine whether the existence of events or circumstances led to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If, after assessing the totality of events and circumstances, the Company concludes that fair value exceeds its carrying amount, then performing a quantitative impairment test is not necessary. If the Company concludes otherwise, the Company is required to perform a quantitative impairment test that requires a comparison of the fair value of the reporting unit to its carrying value, including goodwill. If the fair value of the reporting unit exceeds its carrying value, the related goodwill is not considered impaired and no further analysis is required. If the carrying value of the reporting unit exceeds its fair value, then the Company recognizes an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value. See Note 11 for further discussion. Intangible assets Intangible assets with finite lives are amortized over their estimated average useful lives. The Company does not have any intangible assets deemed to have indefinite lives. Intangible assets are tested for potential impairment whenever events or changes in circumstances suggest that an asset or asset group's carrying value may not be fully recoverable. An impairment loss, calculated as the difference between the estimated fair value and the carrying value of an asset or asset group, is recognized in the accompanying consolidated statements of operations if the sum of the estimated undiscounted cash flows relating to the asset or asset group is less than the corresponding carrying value. Goodwill and Intangible Assets In accordance with US GAAP, the Company tests goodwill for impairment on an annual basis or at an interim period if events or changed circumstances would more likely than not reduce the fair value of a reporting unit below its carrying amount. Under US GAAP, the Company first assesses the qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amounts as a basis for determining if it is necessary to perform a quantitative impairment test. Periodically estimating the fair value of a reporting unit requires significant judgment and often involves the use of significant estimates and assumptions. These estimates and assumptions could have a significant effect on whether or not an impairment charge is recorded and the magnitude of such a charge. During the second quarter of 2019, the Company realigned its business segments to Op Co and Asset Co (See Note 1 ). Prior to the reorganization, our Investment Management segment was also a reporting unit for purposes of measuring and reporting goodwill. The goodwill that was previously attributable to the Investment Management reporting unit was reallocated to the CIM reporting unit within the Op Co segment and the Asset Co reporting unit based on the relative fair value of the respective portions that became attributable to those reporting units. The Asset Co segment is also a reporting unit for purposes of measuring and reporting goodwill. Based on the change in segments and restructuring of reporting units, the Company determined that it was necessary to perform a quantitative impairment test which involves estimates of future cash flows, discount rates, economic forecast and other assumptions which are then used in the market approach (earnings and / or transactions multiples) and / or income approach (discounted cash flow method). Based on the results of the impairment analysis, the Company recognized a goodwill impairment, during the second quarter of 2019, in the amount of $4.1 million within the Asset Co reporting unit. No impairment charges for goodwill were recognized during the year ended December 31, 2018. The following table presents the changes in the Company's goodwill balance, by reporting unit for the periods ended September 30, 2019 and December 31, 2018 : Investment Management Investment Bank Cowen Investment Management Asset Co Total (dollars in thousands) Beginning balance - December 31, 2017 Goodwill $ 29,026 $ 51,337 $ — $ — 80,363 Accumulated impairment charges (10,200 ) (9,485 ) — — (19,685 ) Net 18,826 41,852 — — 60,678 Activity: 2018 Recognized goodwill — — — — — Goodwill impairment charges — — — — — Ending balance: December 31, 2018 Goodwill 29,026 51,337 — — 80,363 Accumulated impairment charges (10,200 ) (9,485 ) — — (19,685 ) Net 18,826 41,852 — — 60,678 Activity: 2019 Recognized goodwill (See note 3) — 81,150 — — 81,150 Realignment of segment goodwill: Goodwill (29,026 ) — 22,705 6,321 — Accumulated impairment charges 10,200 — (7,979 ) (2,221 ) — Goodwill impairment charges — — — (4,100 ) (4,100 ) Ending balance: September 30, 2019 Goodwill — 132,487 22,705 6,321 161,513 Accumulated impairment charges — (9,485 ) (7,979 ) (6,321 ) (23,785 ) Net $ — $ 123,002 $ 14,726 $ — $ 137,728 In connection with the Quarton transaction (see Note 3 ), in January 2019, the Company recognized goodwill of $81.2 million and intangible assets (including customer relationships, trade name, backlog and proprietary software) with an estimated fair value of $22.2 million which are included within intangible assets, net in the condensed consolidated statements of financial condition with the expected useful lives ranging from 2 to 4 years with a weighted average useful life of 2.8 years . Amortization expense related to intangibles from the Quarton acquisition for the three and nine months ended September 30, 2019 is $2.2 million and $6.7 million , respectively. Goodwill, the excess of the purchase price over the fair value of net assets, primarily relates to expected synergies from combining operations and has been assigned to the Op Co segment of the Company. Tax deductible goodwill will differ from goodwill recognized by the Company in an amount equal to the difference between actual contingent consideration and estimated contingent consideration (see Note 3 ).

Commission Management Payable

Commission Management Payable	9 Months Ended
	Sep. 30, 2019
Commission Management Payable [Abstract]
Commission Management Payable	Commission Management Payable The Company receives a gross commission from various clearing brokers, which is then used to fund commission sharing and recapture arrangements, less the portion retained as income to the Company. Accrued commission sharing and commission recapture payable of $89.1 million and $95.3 million , as of September 30, 2019 and December 31, 2018 , respectively, are classified as commission management payable in the accompanying condensed consolidated statements of financial condition.

Redeemable Non-Controlling Inte

Redeemable Non-Controlling Interests in Consolidated Subsidiaries and Funds	9 Months Ended
	Sep. 30, 2019
Noncontrolling Interest [Abstract]
Redeemable Non-Controlling Interests in Consolidated Subsidiaries and Funds	Non-Controlling Interests in Consolidated Subsidiaries and Investment Funds Redeemable and non-redeemable non-controlling interests in consolidated subsidiaries and investment funds and the related net income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds are comprised as follows: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Redeemable non-controlling interests in consolidated subsidiaries and investment funds Consolidated Funds $ 348,424 $ 216,923 Nonredeemable non-controlling interests in consolidated subsidiaries and investment funds Operating companies 15,268 7,457 Consolidated Funds 69,491 57,423 $ 433,183 $ 281,803 Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (dollars in thousands) Income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds Operating companies $ (2,126 ) $ 1,306 $ (1,586 ) $ 2,805 Consolidated Funds 4,896 2,804 8,774 34,993 $ 2,770 $ 4,110 $ 7,188 $ 37,798

Reinsurance

Reinsurance	9 Months Ended
	Sep. 30, 2019
Reinsurance [Abstract]
Reinsurance	Reinsurance The Company’s wholly-owned Luxembourg subsidiary, Hollenfels Re SA (“Hollenfels”) provides reinsurance to third party insurance and reinsurance companies. Hollenfels’s share of incurred and paid claims, as well as claims incurred but not reported plus expected development on reported claims (“Claims IBNR”) were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (dollars in thousands) Incurred and paid claims $ 126 $ 1,911 $ 7,046 $ 9,640 Claims IBNR 833 665 11,724 9,076 Hollenfels utilizes several methods to determine its Claims IBNR. It generally employs an estimation methodology whereby historical average claims ratios over a period of up to 10 years are utilized, based on availability of data. In cases where current claims development contradicts historical results, Hollenfels employs a method to average claims ratios derived through different actuarial calculation methods. Also, if an event occurs that may give rise to significant future claims in excess of the amount calculated using the above-mentioned methodologies, the impact of such an event is calculated using existing claims data and actuarial estimation methods to adjust Hollenfels’s Claims IBNR. During the three and nine months ended September 30, 2019 , Hollenfels calculated its claim liability or claim adjustment expenses using the above-mentioned methods consistent with prior years. While Hollenfels typically settles its premiums and claim payments on a quarterly basis, the frequency of claims in the underlying policies is impractical for Hollenfels to obtain. Certain contracts Hollenfels has written are on a quota-share basis while the rest of the policies provide aggregate loss protection, rendering the collection of information for all underlying contracts impracticable. Hollenfels did not discount any of its reserves and did not cede any portion of its exposures during the three and nine months ended September 30, 2019 and 2018 .

Share-Based Compensation and Em

Share-Based Compensation and Employee Ownership Plans	9 Months Ended
	Sep. 30, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation and Employee Ownership Plans	Share-Based and Deferred Compensation and Employee Ownership Plans The Company issues share-based compensation under the 2006 Equity and Incentive Plan, the 2007 Equity and Incentive Plan (both established prior to the November 2009 transaction between Ramius Capital Group LLC and Cowen) and the 2010 Equity and Incentive Plan (collectively, the “Equity Plans”). The Equity Plans permit the grant of options, restricted shares, restricted stock units, stock appreciation rights ("SARs") and other equity-based awards to the Company's employees and directors. Stock options granted generally vest over two -to- five -year periods and expire seven years from the date of grant. Restricted shares and restricted share units issued may be immediately vested or may generally vest over a two -to- five -year period. SARs vest and expire after five years from grant date. Awards are subject to the risk of forfeiture. As of September 30, 2019 , there were 0.2 million shares available for future issuance under the Equity Plans. Under the 2010 Equity and Incentive Plan, the Company awarded $0.6 million and $42.7 million , respectively, of deferred cash awards to its employees during the three and nine months ended September 30, 2019 . These awards vest over a four -year period and accrue interest at 0.70% per year. As of September 30, 2019 , the Company had unrecognized compensation expense related to the 2010 Equity and Incentive Plan deferred cash awards of $67.6 million . The Company measures compensation cost for share based awards according to the equity method. In accordance with the expense recognition provisions of those standards, the Company amortizes unearned compensation associated with share-based awards on a straight-line basis over the vesting period of the option or award, net of estimated forfeitures. In relation to awards under the Equity Plans, the Company recognized compensation expense of $10.0 million and $8.5 million for the three months ended September 30, 2019 and 2018 , and $27.2 million and $27.6 million for the nine months ended September 30, 2019 and 2018 , respectively. The income tax effect recognized for the Equity Plans was a benefit of $2.6 million and $2.4 million for the three months ended September 30, 2019 and 2018 , and $6.8 million and $7.2 million for the nine months ended September 30, 2019 and 2018 , respectively. Restricted Stock Units Granted to Employees Restricted shares and restricted stock units are referred to collectively as restricted stock. The following table summarizes the Company's restricted share and restricted stock unit activity for the nine months ended September 30, 2019 and 2018 : Nine Months Ended September 30, 2019 Nine Months Ended September 30, 2018 Nonvested Restricted Class A Common Shares and Class A Common Restricted Stock Units Weighted-Average Nonvested Restricted Class A Common Shares and Class A Common Restricted Stock Units Weighted-Average Beginning balance outstanding 5,962,295 $ 15.73 5,579,293 $ 16.33 Granted 2,322,996 16.62 2,255,794 14.27 Vested (1,545,850 ) 16.26 (1,423,075 ) 16.08 Canceled (584,333 ) 11.49 — — Forfeited (156,528 ) 13.97 (61,997 ) 14.13 Ending balance outstanding 5,998,580 $ 16.40 6,350,015 $ 15.68 Included in the restricted share and restricted stock unit activity are performance linked restricted stock units of 481,438 which were awarded to employees of the Company in December 2013 and January 2014. An additional 700,000 performance linked restricted stock units were awarded in March 2016 and 333,333 in April of 2019. Of the awards granted, 130,438 have been forfeited and 584,333 have been canceled, as they did not meet the performance criteria, through September 30, 2019 . The remaining awards, included in the outstanding balance as of September 30, 2019 , vest between May 2019 and December 2021 and will be earned only to the extent that the Company attains specified market conditions relating to its volume-weighted average share price and total shareholder return in relation to certain benchmark indices and performance goals relating to aggregate net income and average return on shareholder equity. The actual number of RSUs ultimately earned could vary from zero , if performance goals are not met, to as much as 200% of the targeted award. Each RSU is equal to the one share of the Company’s Class A common stock. Compensation expense is recognized to the extent that it is probable that the Company will attain the performance goals. The fair value of restricted stock (excluding certain performance linked units which are valued using the Monte Carlo valuation model) is determined based on the number of shares granted and the quoted price of the Company's common stock on the date of grant. As of September 30, 2019 , there was $70.3 million of unrecognized compensation expense related to the Company's grant of nonvested restricted shares and restricted stock units to employees. Unrecognized compensation expense related to nonvested restricted shares and restricted stock units granted to employees is expected to be recognized over a weighted-average period of 2.23 years. Restricted Shares and Restricted Stock Units Granted to Non-employee Board Members There were no restricted stock units awarded during the three and nine months ended September 30, 2019 and 120,430 were delivered. As of September 30, 2019 there were 216,912 restricted stock units outstanding. There were 88,504 restricted stock units awarded during the three and nine months ended September 30, 2018 . As of December 31, 2018 there were 253,772 restricted stock units outstanding.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The taxable results of the Company’s U.S. operations are included in the consolidated income tax returns of Cowen, Inc. as well as stand-alone state and local tax returns. The Company has subsidiaries that are resident in foreign countries where tax filings have to be submitted on a stand‑alone basis. These subsidiaries are subject to tax in their respective countries and the Company is responsible for and, thus, reports all taxes incurred by these subsidiaries. The countries where the Company owns subsidiaries that file tax returns are United Kingdom, Luxembourg, Gibraltar, Germany, Switzerland, Canada, South Africa, and Hong Kong. The Company calculates its U.S. tax provision using the estimated annual effective tax rate methodology. The tax expense or benefit caused by an unusual or infrequent item is recorded in the quarter in which it occurs. To the extent that information is not available for the Company to fully determine the full year estimated impact of an item of income or tax adjustment, the Company calculates the tax impact of such item discretely. Accordingly, the Company uses the discrete methodology to calculate the income tax provision for its foreign subsidiaries and the tax impact of income attributable to non-controlling interests in consolidated subsidiaries and funds. Based on these methodologies, the Company’s effective income tax rate was 26.55% and 17.48% for the nine months ended September 30, 2019 and 2018 , respectively. During the nine months ended September 30, 2019 and 2018 , the unusual or infrequent items whose tax impact were recorded discretely related primarily to foreign taxes, as well as stock compensation. For the nine months ended September 30, 2019 , the effective tax rate differs from the statutory rate of 21% primarily due to income attributable to non-controlling interests in consolidated subsidiaries and funds, foreign taxes, goodwill impairment as well as other nondeductible expenses. For the nine months ended September 30, 2018 , the effective tax rate differs from the statutory rate of 21% primarily due to income attributable to non-controlling interests in consolidated subsidiaries and funds, stock compensation, state and foreign taxes, as well as other nondeductible expenses. The Company recorded an uncertain tax position liability of $0.3 million as of September 30, 2019 and December 31, 2018 related to New York State tax matters. The Company records deferred tax assets and liabilities for the future tax benefit or expense that will result from differences between the carrying value of its assets for income tax purposes and for financial reporting purposes, as well as for operating or capital loss and tax credit carryovers. A valuation allowance is recorded to bring the net deferred tax assets to a level that, in management's view, is more likely than not to be realized in the foreseeable future. This level will be estimated based on a number of factors, especially the amount of net deferred tax assets of the Company that are actually expected to be realized, for tax purposes, in the foreseeable future. As of September 30, 2019 , the Company recorded a valuation allowance against deferred tax assets related to its foreign tax credits and foreign net operating losses. The Company is subject to examination by the United States Internal Revenue Service as well as state, local and foreign tax authorities in jurisdictions where the Company has significant business operations, such as New York, United Kingdom, Luxembourg, Germany and Switzerland. Currently, the Company is under audit by New York State for the 2013 to 2017 tax years. Management is not expecting a material tax liability from these audits. The Company continues to permanently reinvest the capital and accumulated earnings of its subsidiaries in the United Kingdom, Germany, Switzerland, Canada, South Africa and Hong Kong.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Operating Lease Obligations The Company has entered into leases for real estate and other facilities. These leases contain rent escalation clauses and options to extend the lease term. The Company does not include renewal options in the lease term for calculating the Company’s lease liability as the renewal options allow the Company operational flexibility and the Company is not reasonably certain to exercise these renewal options at this time as such the company has not incorporated the effect of the renewal options into the determination of the lease term. The Company records the expenses related to occupancy and equipment on a straight-line basis over the lease term and are included in occupancy and equipment expense and client services and business development expense in the accompanying condensed consolidated statements of operations. For the three and nine months ended September 30, 2019 , quantitative information regarding the Company's operating lease obligations reflected in the accompanying condensed consolidated statement of operations were as follows: Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 (dollars in thousands) Lease Cost Operating lease cost $ 5,748 $ 17,690 Short-term lease cost 23 113 Variable lease cost 388 834 Sublease income (232 ) (739 ) Total lease costs $ 5,927 $ 17,898 The following table summarizes the supplemental cash flow information and certain other information related to operating leases for the nine months ended September 30, 2019 : Nine Months Ended September 30, 2019 (dollars in thousands) Other Information Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 19,103 Weighted average remaining lease term - operating leases (in Years) 5.52 Weighted average discount rate - operating leases 4.14 % As of September 30, 2019 , maturities of the outstanding operating lease liabilities for the Company were as follows: Equipment Leases (operating) (b) Real Estate and Other Facility Rental (a) (dollars in thousands) 2019 $ 94 $ 4,530 2020 364 24,350 2021 177 24,049 2022 61 20,586 2023 — 17,416 Thereafter — 25,958 Total Operating Leases 696 116,889 Less discount 114 16,424 Less short term leases — 113 Total Lease Liability $ 582 $ 100,352 (a) The Company has entered into various agreements to sublease certain of its premises. (b) In the third quarter of 2019, the Company recognized operating ROU assets and leases liabilities of $0.1 million for equipment leases. See Note 18 for further information on the finance lease minimum payments. Prior to the adoption of the new lease accounting guidance, the minimum rental commitments under non-cancelable operating leases at December 31, 2018 , were as follows: Equipment Leases (a) Service Payments Real Estate and other Facility Rental (b) (dollars in thousands) 2019 $ 2,434 $ 21,758 $ 24,584 2020 1,492 7,514 22,608 2021 1,382 1,877 22,321 2022 1,123 1,372 19,166 2023 374 735 16,204 Thereafter — 735 21,478 $ 6,805 $ 33,991 $ 126,361 (a) Equipment Leases includes the Company's commitments relating to operating and capital leases. See Note 18 for further information on the capital lease minimum payments which are included in the table. (b) The Company has entered into various agreements to sublease certain of its premises. The Company recorded sublease income related to these leases of $1.4 million , $1.1 million , and $2.2 million for the years ended December 31, 2018, 2017, and 2016 respectively. Other Commitments As of September 30, 2019 , future minimum annual service payments for the Company were as follows: Service Payments (dollars in thousands) 2019 $ 6,691 2020 15,210 2021 8,483 2022 5,971 2023 3,573 Thereafter 6,331 Total Operating Leases $ 46,259 Clawback Obligations For financial reporting purposes, the general partners of a real estate fund have recorded a liability for potential clawback obligations to the limited partners, due to changes in the unrealized value of the real estate fund's remaining investments and where the real estate fund's general partner has previously received carried interest distributions. The clawback liability, however, is not realized until the end of the real estate fund's life. The real estate fund is currently in a winding-up phase whereby the remaining assets of the real estate fund are being liquidated as promptly as possible so as to maximize value. However a final date for liquidation has not been set. The clawback obligations for the real estate fund were $6.5 million at September 30, 2019 and December 31, 2018 , which is included in accounts payable, accrued expenses and other liabilities in the accompanying condensed consolidated statements of financial condition. The Company serves as the general partner/managing member and/or investment manager to various affiliated and sponsored investment funds. As such, the Company is contingently liable for obligations for those entities. These amounts are not included above as the Company believes that the assets in these investment funds are sufficient to discharge any liabilities. Unfunded Commitments The following table summarizes unfunded commitments as of September 30, 2019 : Entity Unfunded Commitments Commitment term (dollars in thousands) HealthCare Royalty Partners funds (a) 5,867 2 years Eclipse Ventures Fund I, L.P. (formerly Formation8 Partners Hardware Fund I, L.P.) 98 5 years Lagunita Biosciences, LLC 500 4 years Eclipse Fund II, L.P. 225 6 years Eclipse Continuity Fund I, L.P. 175 7 years Cowen Healthcare Investments II LP 6,891 2 years Cowen Healthcare Investments III LP 10,000 7 years Cowen Sustainable Investments I LP 25,000 10 years (a) The Company is a limited partner of the HealthCare Royalty Partners funds (which are managed by Healthcare Royalty Management) and is a member of HealthCare Royalty Partners General Partners. The Company will make its pro-rata investment in the HealthCare Royalty Partners funds along with the other limited partners. Litigation In the ordinary course of business, the Company and its affiliates, subsidiaries and current and former officers, directors and employees (the "Company and Related Parties") are named as defendants in, or as parties to, various legal actions and proceedings. Certain of these actions and proceedings assert claims or seek relief in connection with alleged violations of securities, banking, anti-fraud, anti-money laundering, employment and other statutory and common laws. Certain of these actual or threatened legal actions and proceedings include claims for substantial or indeterminate compensatory or punitive damages, or for injunctive relief. In the ordinary course of business, the Company and Related Parties are also subject to governmental and regulatory examinations, information gathering requests (both formal and informal), certain of which may result in adverse judgments, settlements, fines, penalties, injunctions or other relief. Certain of the Company's affiliates and subsidiaries are registered broker-dealers, futures commission merchants, investment advisers or other regulated entities and, in those capacities, are subject to regulation by various U.S., state and foreign securities, commodity futures and other regulators. In connection with formal and informal inquiries by these regulators, we receive requests, and orders seeking documents and other information in connection with various aspects of the Company's regulated activities. Due to the global scope of the Company's operations, and its presence in countries around the world, the Company and Related Parties may be subject to litigation, governmental and regulatory examinations, information gathering requests, investigations and proceedings (both formal and informal), in multiple jurisdictions with legal and regulatory regimes that may differ substantially, and present substantially different risks, from those to which the Company and Related Parties are subject in the United States. The Company seeks to resolve all litigation and regulatory matters in the manner management believes is in the best interests of the Company and its shareholders, and contests liability, allegations of wrongdoing and, where applicable, the amount of damages or scope of any penalties or other relief sought as appropriate in each pending matter. In accordance with US GAAP, the Company establishes reserves for contingencies when the Company believes that it is probable that a loss has been incurred and the amount of loss can be reasonably estimated. The Company discloses a contingency if there is at least a reasonable possibility that a loss may have been incurred and there is no reserve for the loss because the conditions above are not met. The Company's disclosure includes an estimate of the reasonably possible loss or range of loss for those matters, for which an estimate can be made. Neither a reserve nor disclosure is required for losses that are deemed remote . The Company appropriately reserves for certain matters where, in the opinion of management, the likelihood of liability is probable and the extent of such liability is reasonably estimable. Such amounts are included within accounts payable, accrued expenses and other liabilities in the accompanying condensed consolidated statements of financial condition. Estimates, by their nature, are based on judgment and currently available information and involve a variety of factors, including, but not limited to, the type and nature of the litigation, claim or proceeding, the progress of the matter, the advice of legal counsel, the Company's defenses and its experience in similar cases or proceedings as well as its assessment of matters, including settlements, involving other defendants in similar or related cases or proceedings. The Company may increase or decrease its legal reserves in the future, on a matter-by-matter basis, to account for developments in such matters. The Company accrues legal fees as incurred. The following information reflects developments with respect to the Company’s legal proceedings that occurred during the quarter ended September 30, 2019 . On December 27, 2013, Landol Fletcher filed a putative class action lawsuit against Convergex Holdings, LLC, Convergex Group, LLC, Cowen Execution, Convergex Global Markets Limited and G-Trade Services LLC (collectively, “Convergex”) in the United States District Court for the Southern District of New York (Landol Fletcher and all others similarly situated v. Convergex Group LLC, Cowen Execution, Convergex Global Markets Ltd., Convergex Holdings LLC, G-Trade Services LLC, & Does 1-10, No. 1:13-CV-09150-LLS). The suit alleges breaches of fiduciary duty and prohibited transactions under ERISA and seeks to maintain a class action on behalf of all ERISA plan participants, beneficiaries and named fiduciaries whose plans were impacted by net trading by Convergex Global Markets Limited from October 2006 to December 2011. On April 11, 2014, Landol Fletcher and Frederick P. Potter Jr., filed an amended complaint raising materially similar allegations. This matter was assumed by the Company as a result of the Company’s previously announced acquisition of Convergex Group, which was completed on June 1, 2017. On February 17, 2016, the District Court granted Convergex’s motion to dismiss the amended complaint. Plaintiffs filed an appeal to the Second Circuit, and the AARP and Department of Labor filed amicus briefs on plaintiffs' behalf. The appeal was argued on December 12, 2016. On February 10, 2017, the Second Circuit Court of Appeals (1) reversed the District Court, finding that plaintiff has constitutional standing in a “representative” capacity to sue for damages to the ERISA defined benefit plan in which he is a participant, and (2) remanded to the District Court to reconsider, in light of the Circuit Court’s decision, the issue whether plaintiff has standing to pursue claims on behalf of ERISA plans in which plaintiff is not a participant. Convergex filed a petition for rehearing, and the Court of Appeals denied the petition. On June 30, 2017, the Company filed a notice of motion and memorandum of law in support of a motion to stay the proceedings in the District Court pending resolution of its petition for writ of certiorari, which the Company intended to file with the U.S. Supreme Court. On August 16, 2017, the District Court granted the Company’s motion to stay the proceedings in the District Court pending resolution of the Company’s petition for writ of certiorari. On September 1, 2017, the Company filed a petition with the United States Supreme Court for a writ of certiorari requesting review of the decision of the Court of Appeals. On January 8, 2018, the U.S. Supreme Court denied the Company’s petition for a writ of certiorari. The previously granted stay of the proceedings in the District Court was lifted, and the case proceeded in the District Court. Status conferences were held on April 6, 2018, October 12, 2018, and December 4, 2018. On March 15, 2019, the Company filed a motion to dismiss the plaintiff’s amended complaint. The District Court granted the Company’s motion on July 2, 2019. The plaintiffs did not appeal the District Court’s decision. Accordingly, the plaintiff’s complaint has been dismissed and the case has been resolved.

Convertible Debt and Notes Paya

Convertible Debt and Notes Payable	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Convertible Debt and Notes Payable	Convertible Debt and Notes Payable As of September 30, 2019 and December 31, 2018 , the Company's outstanding debt was as follows: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Convertible debt $ 117,469 $ 134,489 Notes payable 306,645 229,740 Term loan 32,180 28,200 Other notes payable 395 — Finance lease obligations 4,066 5,025 $ 460,755 $ 397,454 Convertible Debt December 2022 Convertible Notes The Company, on December 14, 2017, issued $135.0 million aggregate principal amount of 3.00% convertible senior notes due December 2022 (the “December 2022 Convertible Notes”). The December 2022 Convertible Notes are due on December 15, 2022 unless earlier repurchased by the Company or converted by the holder in accordance with their terms prior to such date. The interest on the December 2022 Convertible Notes is payable semi-annually on December 15 and June 15 of each year. The December 2022 Convertible Notes are senior unsecured obligations of Cowen. The December 2022 Convertible Notes may be converted into cash or shares of Class A common stock at the Company's election based on the current conversion price. The December 2022 Convertible Notes were issued with an initial conversion price of $17.375 per share of Cowen’s Class A common stock. The Company used the net proceeds, together with cash on hand, from the offering for general corporate purposes, including the repurchase or repayment of $115.1 million of the Company’s outstanding 3.0% cash convertible senior notes due March 2019 (the "March 2019 Convertible Notes") and the repurchase of approximately $19.5 million of the Company’s shares of its Class A common stock, which were consummated substantially concurrently with the closing of the offering. As of September 30, 2019 , the outstanding principal amount of the December 2022 Convertible Notes was $135.0 million . On June 26, 2018, the Company received shareholder approval for the Company to settle the December 2022 Convertible Notes entirely in Class A common stock. Upon receiving shareholder approval, the Company reclassified the separately recognized conversion option from a derivative liability to equity. The Company recorded interest expense of $1.0 million and $1.0 million for the three months ended September 30, 2019 and 2018 , and $3.0 million and $3.0 million for the nine months ended September 30, 2019 and 2018 , respectively. The Company recognized the embedded cash conversion option at issuance date fair value, which also represents the initial unamortized discount on the December 2022 Convertible Notes of $23.4 million and is shown net in convertible debt in the accompanying condensed consolidated statements of financial condition. Amortization on the discount, included within interest and dividends expense in the accompanying condensed consolidated statements of operations is $1.1 million and $1.0 million for the three months ended September 30, 2019 and 2018 , and $3.2 million and $3.0 million for the nine months ended September 30, 2019 and 2018 , respectively, based on an effective interest rate of 7.13% . The Company capitalized the debt issuance costs in the amount of $2.2 million , which is a direct deduction from the carrying value of the debt and will be amortized over the life of the December 2022 Convertible Notes. March 2019 Convertible Notes On March 10, 2014, the Company issued $149.5 million of 3.0% cash convertible senior notes (the "March 2019 Convertible Notes"). The March 2019 Convertible Notes matured on March 15, 2019 and were fully repaid by the Company. The Company recorded interest expense of $0.2 million for the three months ended September 30, 2018 , and $0.1 million and $0.9 million for the nine months ended September 30, 2019 and 2018 , respectively. Amortization on the discount, included within interest and dividends expense in the accompanying condensed consolidated statements of operations was $0.3 million for the three months ended September 30, 2018 , and $0.3 million and $1.2 million for the nine months ended September 30, 2019 and 2018 , respectively, based on an effective interest rate of 8.89% . Notes Payable May 2024 Notes On May 7, 2019, the Company completed its private placement of $53.0 million aggregate principal amount of 7.25% senior notes due May 2024 (the "May 2024 Notes") with certain institutional investors. On September 30, 2019, the Company issued an additional $25.0 million of the same series of notes. The additional May 2024 Notes were purchased at a premium of $0.5 million , which is shown net in notes payable in the accompanying condensed consolidated statement of financial condition. To date the May 2024 Notes have maintained their initial private rating, and the interest rate has remained unchanged. Interest on the May 2024 Notes is payable semi-annually in arrears on May 6 and November 6. The Company recorded interest expense of $0.9 million for the three months ended September 30, 2019, and $1.5 million for the nine months ended September 30, 2019. The Company capitalized debt issuance costs of approximately $1.5 million in May 2019 and $0.6 million in September 2019, which is a direct deduction from the carrying value of the debt and will be amortized over the life of the May 2024 Notes. June 2033 Notes On June 11, 2018, the Company completed its public offering of $90.0 million of 7.75% senior notes due June 2033 (the “June 2033 Notes”) and subsequently the underwriters exercised in full their option to purchase an additional $10.0 million principal amount of the June 2033 Notes. Interest on the June 2033 Notes is payable quarterly in arrears on March 15, June 15, September 15 and December 15. The Company recorded interest expense of $1.9 million and $1.9 million for the three months ended September 30, 2019 and 2018 , and $5.8 million and $2.3 million for the nine months ended September 30, 2019 and 2018 , respectively. The Company capitalized debt issuance costs of approximately $3.6 million which is a direct deduction from the carrying value of the debt and will be amortized over the life of the June 2033 Notes. December 2027 Notes On December 8, 2017, the Company completed its public offering of $120.0 million of 7.35% senior notes due December 2027 (the “December 2027 Notes”) and subsequently the underwriters exercised in full their option to purchase an additional $18.0 million principal amount of the December 2027 Notes. Interest on the December 2027 Notes is payable quarterly in arrears on March 15, June 15, September 15 and December 15. The Company recorded interest expense of $2.5 million and $2.5 million for the three months ended September 30, 2019 and 2018 , and $7.6 million and $7.6 million for the nine months ended September 30, 2019 and 2018 , respectively. The Company capitalized debt issuance costs of approximately $5.0 million w hich is a direct deduction from the carrying value of the debt and will be amortized over the life of the December 2027 Notes. The net proceeds of the offering, after deducting the underwriting discount and estimated offering expenses payable by the Company were used to redeem all of its 8.25% senior notes due October 2021 and for general corporate purposes. Term Loan On June 30, 2017, the Company borrowed $28.2 million to fund general corporate purposes. This term loan has an effective interest rate of LIBOR plus 3.75% with a lump sum payment of the entire principal amount due (as amended) on June 26, 2020. In July 2019, the Company borrowed an additional $4.0 million to fund general corporate purposes. The loan is secured by the value of the Company's limited partnership interests in two affiliated investment funds. The Company has provided a guarantee for this loan. The Company recorded interest expense of $0.5 million and $0.4 million for the three months ended September 30, 2019 and 2018 , and $1.4 million and $1.2 million for the nine months ended September 30, 2019 and 2018 , respectively. Other Notes Payable During January 2019, the Company borrowed $2.2 million to fund insurance premium payments. This note had an effective interest rate of 2.51% and was due on December 31, 2019, with monthly payment requirements of $0.2 million . As of September 30, 2019 , the outstanding balance on this note was $0.4 million . Interest expense for the three and nine months ended September 30, 2019 was insignificant. Finance Lease Obligations The Company has entered into various finance leases for computer equipment. The Company's finance lease right-of-use asset amounted to $6.0 million and is recorded in fixed assets in the accompanying condensed consolidated statements of financial condition. T hese finance lease obligations are included in notes payable and other debt in the accompanying condensed consolidated statements of financial condition, and have a weighted average lease term of 3.4 years and weighted average interest rate of 4.93% as of September 30, 2019 . As of September 30, 2019 and December 31, 2018, the remaining balance on these finance leases was $4.1 million and $5.0 million , respectively. For the three and nine months ended September 30, 2019 and 2018 , quantitative information regarding the Company's finance lease obligations reflected in the accompanying condensed consolidated statement of operations, the supplemental cash flow information and certain other information related to finance leases were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (dollars in thousands) Lease Cost Finance Lease Cost: Amortization of finance lease right-of-use assets $ 299 $ 409 $ 966 $ 1,124 Interest on lease liabilities 54 64 172 167 Other Information Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from finance leases 172 167 Financing cash flows from finance leases $ 951 $ 1,630 Annual scheduled maturities of debt and minimum payments (of principal and interest) for all debt outstanding as of September 30, 2019 , are as follows: Convertible Debt Notes Payable Term loan Other Notes Payable Finance Lease (dollars in thousands) 2019 $ 2,025 $ 7,301 $ 489 $ 405 $ 231 2020 4,050 23,548 33,126 — 1,356 2021 4,050 23,548 — — 1,356 2022 139,050 23,548 — — 1,125 2023 — 23,548 — — 374 Thereafter — 433,025 — — — Subtotal 149,175 534,518 33,615 405 4,442 Less (a) (31,706 ) (227,873 ) (1,435 ) (10 ) (376 ) Total $ 117,469 $ 306,645 $ 32,180 $ 395 $ 4,066 (a) Amount necessary to reduce net minimum payments to present value calculated at the Company's implicit rate at inception. This amount also includes capitalized debt costs and the unamortized discount on the convertible debt. Letters of Credit As of September 30, 2019 , the Company has the following seven irrevocable letters of credit, related to leased office space, for which there is cash collateral pledged, which the Company pays a fee on the stated amount of the letter of credit. The Company also has pledged collateral for reinsurance agreements which amounted to $13.9 million , as of September 30, 2019 , and $1.0 million , as of December 31, 2018 , which is released annually between March 2020 and March 2023 based on the policy periods covered by the reinsurance agreements . Location Amount Maturity (dollars in thousands) Boston $ 392 March 2020 New York $ 358 April 2020 New York $ 71 October 2019 New York $ 398 October 2019 New York $ 1,125 October 2019 New York $ 1,623 November 2019 San Francisco $ 713 October 2025 To the extent any letter of credit is drawn upon, interest will be assessed at the prime commercial lending rate . As of September 30, 2019 and December 31, 2018 , there were no amounts due related to these letters of credit .

Stockholder's Equity

Stockholder's Equity	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Stockholder's Equity	Stockholder's Equity Preferred Stock and Purchase of Capped Call Option On May 19, 2015, the Company completed its offering of 120,750 shares of the Company's 5.625% Series A cumulative perpetual convertible preferred stock ("Series A Convertible Preferred Stock") that provided $117.2 million of proceeds, net of underwriting fees and issuance costs of $3.6 million . Each share of the Series A Convertible Preferred Stock is entitled to dividends at a rate of 5.625% per annum which will be payable, when and if declared by the board of directors of the Company, quarterly, in arrears, on February 15, May 15, August 15 and November 15 of each year. The Company may, at its option, pay dividends in cash, common stock or a combination thereof . The Company declared and accrued a cash dividend of $1.7 million and $1.7 million for the three months ended September 30, 2019 and 2018 , and $5.1 million and $5.1 million for the nine months ended September 30, 2019 and 2018 , respectively. Each share of Series A Convertible Preferred Stock is non-voting and has a liquidity preference over the Company's Class A common stock and ranks senior to all classes or series of the Company's Class A common stock, but junior to all of the Company's existing and future indebtedness with respect to divided rights and rights upon the Company's involuntary liquidation, dissolution or winding down. Each share of Series A Convertible Preferred Stock is convertible, at the option of the holder, into a number of shares of the Company's Class A common stock equal to the liquidation preference of $1,000 divided by the conversion rate. The initial conversion rate (subsequent to the December 5, 2016 reverse stock split) is 38.0619 shares (which equates to $26.27 per share) of the Company's Class A common stock for each share of the Series A Convertible Preferred Stock. At any time on or after May 20, 2020, the Company may elect to convert all outstanding shares of the Series A Convertible Preferred Stock into shares of the Company’s Class A common stock, cash or a combination thereof, at the Company’s election, in each case, based on the then-applicable conversion rate, if the last reported sale price of the Company’s Class A common stock equals or exceeds 150% of the then-current conversion price on at least 20 trading days (whether or not consecutive) during the period of 30 consecutive trading days (including on the last trading day of such period) immediately prior to such election. At the time of conversion, the conversion rate may be adjusted based on certain events including but not limited to the issuance of cash dividends or Class A common stock as dividends to the Company's Class A common shareholders or a share split or combination. In connection with the issuance and sale of the Series A Convertible Preferred Stock, the Company entered into a capped call option transaction (the “Capped Call Option Transaction”) with Nomura Global Financial Products Inc. (the “option counterparty”) for $15.9 million . The Capped Call Option Transaction is expected generally to reduce the potential dilution to the Company’s Class A common stock (if the Company elects to convert to common shares) and/or offset any cash payments that the Company is required to make upon conversion of any Series A Convertible Preferred Stock. The Capped Call Option Transaction has an initial effective strike price of $26.27 per share, which matches the initial conversion price of the Series A Convertible Preferred Stock, and a cap price of $33.54 per share. However, to the extent that the market price of Class A common stock, as measured under the terms of the Capped Call Option Transaction, exceeds the cap price thereof, there would nevertheless be dilution and/or such cash payments would not be offset. As the Capped Call Option Transaction is a free standing derivative that is indexed to the Company's own stock price and the Company controls if it is settled in cash or stock it qualifies for equity classification as a reduction to additional paid in capital. Embedded Cash Conversion Option on the December 2022 Convertible Notes Upon issuance of the December 2022 Convertible Notes (see Note 18 ), the Company recognized the embedded cash conversion option at fair value of $23.4 million which was valued as of June 26, 2018 at $29.0 million . On June 26, 2018, the Company received shareholder approval for the Company to settle the December 2022 Convertible Notes entirely in Class A common stock. Upon receiving shareholder approval, the Company reclassified the separately recognized conversion option from a derivative liability to equity. Treasury Stock Treasury stock of $266.9 million as of September 30, 2019 , compared to $234.1 million as of December 31, 2018 , resulted from $10.2 million acquired through repurchases of shares to cover employee minimum tax withholding obligations related to stock compensation vesting events under the Company's Equity Plans or other similar transactions, $0.2 million received from an escrow account established to satisfy the Company’s indemnification claims arising under the terms of the purchase agreement entered into in connection with the Company’s acquisition of Convergex Group, LLC and $22.4 million purchased in connection with a share repurchase program. The following represents the activity relating to the treasury stock held by the Company during the nine months ended September 30, 2019 : Treasury stock shares Cost Average cost per share Balance outstanding at December 31, 2018 15,336,871 $ 234,142 $ 15.27 Shares purchased for minimum tax withholding under the Equity Plans or other similar transactions 674,792 10,153 15.05 Shares of stock received in respect of indemnification claims 10,917 167 15.34 Purchase of treasury stock 1,440,396 22,420 15.57 Balance outstanding at September 30, 2019 17,462,976 $ 266,882 $ 15.28

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2019
Accumulated Other Comprehensive Income / (Loss) [Abstract]
Accumulated other comprehensive income (loss)	Accumulated Other Comprehensive Income (Loss) Accumulated other comprehensive income includes the after tax change in unrealized gains and losses on foreign currency translation adjustments. During the periods presented, the Company did not have material reclassifications out of other comprehensive income. Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (dollars in thousands) Beginning Balance $ (3 ) $ (7 ) $ (5 ) $ (8 ) Foreign currency translation (2 ) 4 — 5 Ending Balance $ (5 ) $ (3 ) $ (5 ) $ (3 )

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The Company calculates its basic and diluted earnings per share in accordance with US GAAP. Basic earnings per share is calculated by dividing net income attributable to the Company's common stockholders by the weighted average number of common shares outstanding for the period. As of September 30, 2019 , there were 29,013,137 shares of Class A common stock outstanding. As of September 30, 2019 , the Company has included 216,912 fully vested, unissued restricted stock units in its calculation of basic earnings per share. As of December 31, 2018, there were 28,437,860 shares of Class A common stock outstanding. As of December 31, 2018, the Company has included 253,772 fully vested, unissued restricted stock units in its calculation of basic earnings per share. Diluted earnings per common share are calculated by adjusting the weighted average outstanding shares to assume conversion of all potentially dilutive items. The Company uses the treasury stock method to reflect the potential dilutive effect of the unvested restricted shares, restricted stock units, and SAR's. In calculating the number of dilutive shares outstanding, the shares of common stock underlying unvested restricted shares and restricted stock units are assumed to have been delivered, and options and warrants are assumed to have been exercised, for the entire period being presented. The number of performance-linked unvested restricted stock units that are included in the calculation are at the amount that could be earned using current payout rates. The assumed proceeds from the assumed vesting, delivery and exercising were calculated as the amount of compensation cost attributed to future services and not yet recognized. The Company can elect to settle the Series A Convertible Preferred Stock in shares, cash, or a combination of both. The Company's intent is to settle in cash and, based on current and projected liquidity needs, the Company has the ability to do so. The computation of earnings per share is as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (dollars in thousands, except share and per share data) Net income (loss) $ 6,583 $ 19,598 $ 26,596 $ 75,538 Net income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds 2,770 4,110 7,188 37,798 Net income (loss) attributable to Cowen Inc. 3,813 15,488 19,408 37,740 Preferred stock dividends 1,698 1,698 5,094 5,094 Net income (loss) attributable to Cowen Inc. common stockholders $ 2,115 $ 13,790 $ 14,314 $ 32,646 Shares for basic and diluted calculations: Weighted average shares used in basic computation 29,529 29,610 29,687 29,662 Restricted stock 1,735 1,234 1,694 951 Weighted average shares used in diluted computation 31,264 30,844 31,381 30,613 Earnings (loss) per share: Basic $ 0.07 $ 0.47 $ 0.48 $ 1.10 Diluted $ 0.07 $ 0.45 $ 0.46 $ 1.07

Segment Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting Change in Segments During the second quarter of 2019 the Company realigned the information that the Chief Operating Decision Maker regularly reviews to evaluate performance for operating decision-making purposes, including evaluation and allocation of resources. As a result of this change in segment reporting, the Company retrospectively revised prior period results, by segment, to conform to the current period presentation (see Note 1 ). This structure includes two business segments: Op Co and Asset Co. The structure is based on the Company's domain expertise as a driver of balance sheet harmonization and repeatable revenues for its operating business versus the Company’s long-term monetization strategies. The Op Co segment consists of Cowen Investment Management (“CIM”), Investment Banking, Markets and Research. The Asset Co segment consists of the Company’s private investments, private real estate investments and other legacy multi-sector long/short equity strategies. Performance Measures The performance measure for these segments is Economic Income (Loss), which management uses to evaluate the financial performance of and make operating decisions for the segments including determining appropriate compensation levels. Expenses not directly associated with specific segments are allocated based on the most relevant measures applicable, including headcount, square footage and other factors. In general, Economic Income (Loss) is a pre-tax measure that (i) eliminates the impact of consolidation for Consolidated Funds and excludes (ii) goodwill and intangible impairment (iii) certain other transaction-related adjustments and/or reorganization expenses and (iv) certain costs associated with debt. Economic Operating Income (Loss) represents Economic Income (Loss) before depreciation and amortization expenses. In addition, Economic Income (Loss) revenues include investment income that represents the income the Company has earned in investing its own capital, including realized and unrealized gains and losses, interest and dividends, net of associated investment related expenses. For US GAAP purposes, these items are included in each of their respective line items. Economic Income (Loss) revenues also include management fees, incentive income and investment income earned through the Company's investment as a general partner in certain real estate entities and the Company's investment in the activist business and certain investment funds. For US GAAP purposes, all of these items, are recorded in other income (loss). Economic Income (Loss) recognizes (a) incentive fees during periods when the fees are not yet crystallized for US GAAP reporting and (b) retainer fees, relating to investment banking activities, earned during the period that would otherwise be deferred until closing for US GAAP reporting. In addition, Economic Income (Loss) expenses are reduced by reimbursement from affiliates, which for US GAAP purposes is presented gross as part of revenue. As further stated below, one major difference between Economic Income (Loss) and US GAAP net income (loss) is that Economic Income (Loss) presents the segments' results of operations without the impact resulting from the full consolidation of any of the Consolidated Funds. The consolidation of these investment funds' results include the pro rata share of the income or loss attributable to other owners of such entities which is reflected in net income (loss) attributable to non-controlling interest in consolidated subsidiaries in the accompanying condensed consolidated statements of operations. This pro rata share has no effect on the overall financial performance for the segments, as ultimately, this income or loss is not income or loss for the segments themselves. Included in Economic Income (Loss) is the actual pro rata share of the income or loss attributable to the Company as an investor in such entities, which is relevant in management making operating decisions and evaluating financial performance. The Company does not disclose total asset information for its business segments as the information is not reviewed by the CODM. The following tables set forth operating results for the Company's Op Co and Asset Co segments and related adjustments necessary to reconcile the Company's Economic Income (Loss) measure to arrive at the Company's consolidated US GAAP net income (loss): Three Months Ended September 30, 2019 Adjustments Operating Company Asset Company Total Economic Income/(Loss) Funds Other US GAAP (dollars in thousands) Revenues Investment banking $ 70,022 $ — $ 70,022 $ — $ 7,270 (a) $ 77,292 Brokerage 105,860 — 105,860 — (11,865 ) (b) 93,995 Management fees 10,321 586 10,907 (574 ) (3,033 ) (c) 7,300 Incentive income (loss) 15,384 (1,007 ) 14,377 (13 ) (13,663 ) (c) 701 Investment income (loss) 15,231 822 16,053 — (16,053 ) (d) — Interest and dividends — — — — 60,707 (b)(d) 60,707 Reimbursement from affiliates — — — (27 ) 265 (e) 238 Reinsurance premiums — — — — 8,146 (f) 8,146 Other revenue (132 ) 6 (126 ) (26 ) 1,389 (f) 1,237 Consolidated Funds revenues — — — 2,431 — 2,431 Total revenues 216,686 407 217,093 1,791 33,163 252,047 Interest expense (Economic Income/(Loss)) / Interest and dividend expense (US GAAP) 5,758 1,389 7,147 — 49,330 (b)(d) 56,477 Total net revenues 210,928 (982 ) 209,946 1,791 (16,167 ) 195,570 Expenses Non interest expense 200,637 1,403 202,040 — 15,408 (a)(e)(h)(i) 217,448 Consolidated Funds expenses — — — 2,516 — 2,516 Total expenses 200,637 1,403 202,040 2,516 15,408 219,964 Total other income (loss) — — — 5,621 26,721 (c)(d)(i) 32,342 Income taxes expense / (benefit) — — — — 1,365 (h) 1,365 Income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds 661 — 661 4,896 (2,787 ) 2,770 Income (loss) attributable to Cowen Inc. 9,630 (2,385 ) 7,245 — (3,432 ) 3,813 Less: Preferred stock dividends 1,341 357 1,698 — — 1,698 Economic Income (Loss)/ Income (loss) attributable to Cowen Inc. common stockholders 8,289 (2,742 ) 5,547 $ — $ (3,432 ) $ 2,115 Add back: Depreciation and Amortization expense 5,073 9 5,082 Economic operating income (loss) $ 13,362 $ (2,733 ) $ 10,629 Three Months Ended September 30, 2018 Adjustments Operating Company Asset Company Total Funds Other US GAAP (dollars in thousands) Revenues Investment banking $ 77,510 $ — $ 77,510 $ — $ 4,413 (a) $ 81,923 Brokerage 101,672 — 101,672 — (9,637 ) (b) 92,035 Management fees 10,840 1,546 12,386 (381 ) (4,459 ) (c) 7,546 Incentive income (loss) 1,859 5,051 6,910 (20 ) (6,857 ) (c)(a) 33 Investment income (loss) 25,779 1,893 27,672 — (27,672 ) (d)(g) — Interest and dividends — — — — 26,448 (b)(d) 26,448 Reimbursement from affiliates — — — (65 ) 418 (e) 353 Aircraft lease revenue — — — — 375 (g) 375 Reinsurance premiums — — — — 8,378 (f) 8,378 Other revenue 4 79 83 — 1,551 (f) 1,634 Consolidated Funds revenues — — — 2,303 — 2,303 Total revenues 217,664 8,569 226,233 1,837 (7,042 ) 221,028 Interest expense (Economic Income/(Loss)) / Interest and dividend expense (US GAAP) 4,878 1,541 6,419 — 19,581 (b)(d) $ 26,000 Total net revenues 212,786 7,028 219,814 1,837 (26,623 ) 195,028 Expenses Non interest expense 189,516 6,672 196,188 — 14,454 (a)(e)(h)(i) 210,642 Consolidated Funds expenses — — — 1,687 — 1,687 Total expenses 189,516 6,672 196,188 1,687 14,454 212,329 Total other income (loss) — — — 2,654 39,328 (c)(d)(i)(j) 41,982 Income taxes expense / (benefit) — — — — 5,083 (h) 5,083 Income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds 898 44 942 2,804 364 4,110 Income (loss) attributable to Cowen Inc. 22,372 312 22,684 — (7,196 ) 15,488 Less: Preferred stock dividends 1,290 408 1,698 — — 1,698 Economic Income (Loss)/ Income (loss) attributable to Cowen Inc. common stockholders 21,082 (96 ) 20,986 $ — $ (7,196 ) $ 13,790 Add back: Depreciation and Amortization expense 2,865 43 2,908 Economic operating income (loss) $ 23,947 $ (53 ) $ 23,894 Nine Months Ended September 30, 2019 Adjustments Operating Company Asset Company Total Economic Income (Loss) Funds Consolidation Other Adjustments US GAAP Net Income (Loss) (dollars in thousands) Revenues Investment banking $ 257,234 $ — $ 257,234 $ — $ 14,869 (a) $ 272,103 Brokerage 331,689 — 331,689 — (28,849 ) (b) 302,840 Management fees 30,016 1,788 31,804 (1,640 ) (8,684 ) (c) 21,480 Incentive income (loss) 34,654 699 35,353 (557 ) (34,072 ) (c) 724 Investment income (loss) 28,233 5,289 33,522 — (33,522 ) (d) — Interest and dividends — — — — 129,846 (b)(d) 129,846 Reimbursement from affiliates — — — (94 ) 874 (e) 780 Reinsurance premiums — — — — 29,068 (f) 29,068 Other revenue 5,295 56 5,351 (14 ) (2,109 ) (f) 3,228 Consolidated Funds revenues — — — 8,239 — 8,239 Total revenues 687,121 7,832 694,953 5,934 67,421 768,308 Interest expense (Economic Income/(Loss)) / Interest and dividend expense (US GAAP) 16,371 4,046 20,417 — 104,672 (b)(d) 125,089 Total net revenues 670,750 3,786 674,536 5,934 (37,251 ) 643,219 Expenses Non interest expense 623,167 7,025 630,192 — 49,463 (a)(e)(h)(i) 679,655 Goodwill impairment — — — — 4,100 4,100 Consolidated Funds expenses — — — 6,229 — 6,229 Total expenses 623,167 7,025 630,192 6,229 53,563 689,984 Total other income (loss) — — — 9,069 73,907 (c)(d)(i) 82,976 Income taxes expense / (benefit) — — — — 9,615 (h) 9,615 Income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds 2,944 — 2,944 8,774 (4,530 ) 7,188 Income (loss) attributable to Cowen Inc. 44,639 (3,239 ) 41,400 — (21,992 ) $ 19,408 Less: Preferred stock dividends 4,058 1,036 5,094 — — 5,094 Economic Income (Loss)/ Income (loss) attributable to Cowen Inc. common stockholders 40,581 (4,275 ) 36,306 $ — $ (21,992 ) $ 14,314 Add back: Depreciation and Amortization expense 14,957 30 14,987 Economic operating income (loss) $ 55,538 $ (4,245 ) $ 51,293 Nine Months Ended September 30, 2018 Adjustments Operating Company Asset Company Total Economic Income (Loss) Funds Consolidation Other Adjustments US GAAP Net Income (Loss) (dollars in thousands) Revenues Investment banking $ 251,476 $ — $ 251,476 $ — $ 13,261 (a) $ 264,737 Brokerage 328,929 — 328,929 — (27,876 ) (b) 301,053 Management fees 33,057 4,941 37,998 (2,197 ) (13,465 ) (c) 22,336 Incentive income (loss) 17,219 4,251 21,470 (37 ) (21,336 ) (c) 97 Investment income (loss) 62,488 (561 ) 61,927 — (61,927 ) (d)(g) — Interest and dividends — — — — 77,511 (b)(d) 77,511 Reimbursement from affiliates — — — (198 ) 1,264 (e) 1,066 Aircraft lease revenue — — — — 1,509 (g) 1,509 Reinsurance premiums — — — — 26,251 (f) 26,251 Other revenue (143 ) 393 250 — 3,596 (f) 3,846 Consolidated Funds revenues — — — 8,579 — 8,579 Total revenues 693,026 9,024 702,050 6,147 (1,212 ) 706,985 Interest expense (Economic Income/(Loss)) / Interest and dividend expense (US GAAP) 12,539 3,961 16,500 — 58,346 (b)(d) 74,846 Total net revenues 680,487 5,063 685,550 6,147 (59,558 ) 632,139 Expenses Non interest expense 601,480 12,081 613,561 — 42,738 (a)(e)(h)(i) 656,299 Consolidated Funds expenses — — — 7,267 — 7,267 Total expenses 601,480 12,081 613,561 7,267 42,738 663,566 Total other income (loss) — — — 36,113 86,851 (c)(d)(i)(j) 122,964 Income taxes expense / (benefit) — — — — 15,999 (h) 15,999 Income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds 2,805 700 3,505 34,993 (700 ) 37,798 Income (loss) attributable to Cowen Inc. 76,202 (7,718 ) 68,484 — (30,744 ) 37,740 Less: Preferred stock dividends 3,871 1,223 5,094 — — 5,094 Economic Income (Loss)/ Income (loss) attributable to Cowen Inc. common stockholders 72,331 (8,941 ) 63,390 $ — $ (30,744 ) $ 32,646 Add back: Depreciation and Amortization expense 8,707 147 8,854 Economic operating income (loss) $ 81,038 $ (8,794 ) $ 72,244 The following is a summary of the adjustments made to US GAAP net income (loss) to arrive at Economic Income (Loss): Funds Consolidation: The impacts of consolidation and the related elimination entries of the Consolidated Funds are not included in Economic Income (Loss). Adjustments to reconcile to US GAAP net income (loss) included elimination of incentive income and management fees earned from the Consolidated Funds and addition of investment fund expenses excluding management fees paid, investment fund revenues and investment income (loss). Other Adjustments: (a) Economic Income (Loss) presents underwriting expenses net of investment banking revenues, expenses reimbursed from clients within their respective expense category. Economic Income (Loss) also records retainer fees, relating to investment banking activities, collectible during the period that would otherwise be deferred until closing for US GAAP reporting. (b) Economic Income (Loss) brokerage revenues included net securities borrowed and securities loaned activities which are shown gross in interest income and interest expense for US GAAP. (c) Economic Income (Loss) recognizes revenues (i) net of distribution fees paid to agents, (ii) records income from uncrystallized incentive fees and (iii) the Company's proportionate share of management and incentive fees of certain real estate operating entities, the healthcare royalty business and the activist business. (d) Economic Income (Loss) recognizes Company income from proprietary trading (including interest and dividends). (e) Reimbursement from affiliates is shown as a reduction of Economic Income expenses, but is included as a part of revenues under US GAAP. (f) Economic Income (Loss) recognizes underwriting income from the Company's insurance related activities, net of expenses, within other revenue. (g) Aircraft lease revenue is shown net of expenses in investment income for Economic Income (Loss). (h) Economic Income (Loss) excludes income taxes and acquisition related adjustments as management does not consider these items when evaluating the performance of the segment. (i) Economic Income (Loss) recognizes the Company's proportionate share of expenses, for certain real estate operating entities and the activist business, for which the investments are recorded under the equity method of accounting for investments. (j) Economic Income (Loss) excludes gain/(loss) on debt extinguishment. For the three and nine months ended September 30, 2019 and 2018 , there was no one investment fund or other customer which represented more than 10% of the Company's total revenues.

Regulatory Requirements

Regulatory Requirements	9 Months Ended
	Sep. 30, 2019
Brokers and Dealers [Abstract]
Regulatory Requirements	Regulatory Requirements As registered broker-dealers, Cowen and Company, Cowen Execution, ATM Execution, Cowen Prime and Westminster are subject to the SEC's Uniform Net Capital Rule 15c3-1 (“SEC Rule 15c3-1”), which requires the maintenance of minimum net capital. Each registered broker-dealer has elected to compute net capital under the alternative method permitted by the Rule. Under the alternative method, Cowen and Company's minimum net capital requirement, as defined in (a)(4) of the Rule, is $1.0 million . Cowen Execution, ATM Execution, Cowen Prime and Westminster are required to maintain minimum net capital, as defined in (a)(1)(ii) of the Rule, equal to the greater of $250,000 or 2% of aggregate debits arising from customer transactions. Advances to affiliates, repayment of borrowings, distributions, dividend payments and other equity withdrawals are subject to certain notification and other requirements of the Rule and other regulatory bodies. On February 7, 2019, FINRA approved the transfer of all of Cowen Securities’ business and personnel to Cowen and Company. Cowen Securities subsequently filed a Form BDW, pursuant to Section 15(b) of the Securities Exchange Act of 1934, with FINRA to withdraw its status as a broker-dealer given that it will no longer conduct a securities business. On May 21, 2019, Cowen Securities Form BDW was approved and officially deregistered with the SEC. Cowen Prime is also subject to Commodity Futures Trading Commission Regulation 1.17 (“Regulation 1.17”). Regulation 1.17 requires net capital equal to or in excess of $45,000 or the amount of net capital required by SEC Rule 15c3-1, whichever is greater. Cowen Execution is also subject to Options Clearing Corporation ("OCC") Rule 302. OCC Rule 302 requires maintenance of net capital equal to the greater of $2.0 million or 2% of aggregate debit items. At September 30, 2019 , Cowen Execution had $103.5 million of net capital in excess of this minimum requirement. Cowen International Ltd and Cowen Execution Ltd are subject to the capital requirements of the FCA, as defined, must exceed the minimum capital requirement set forth by the FCA. Effective June 1, 2018, the FCA approved Ramius UK’s application to cancel all of its FCA authorization permissions. Accordingly, Ramius UK is no longer an FCA regulated and authorized firm. Ramius UK sought the cancellation. In April 2019, Cowen Execution Ltd was formally approved to trade in a principal capacity. Cowen and Company (Asia) Limited (“Cowen Asia”), a previously established entity, was re-registered with regulatory approval on May 17, 2019. Cowen Asia is subject to the financial resources requirements of the Securities and Futures Commission (“SFC”) of Hong Kong. Financial Resources must exceed the Total Financial Resources requirement of the SFC. As of September 30, 2019 , these regulated broker-dealers had regulatory net capital or financial resources, regulatory net capital requirements or minimum FCA requirement and excess as follows : Subsidiary Net Capital Minimum Net Capital Requirement Excess Net Capital (dollars in thousands) Cowen and Company $ 88,162 $ 1,000 $ 87,162 Cowen Execution $ 104,559 $ 1,069 $ 103,490 ATM Execution $ 5,538 $ 250 $ 5,288 Cowen Prime $ 17,449 $ 250 $ 17,199 Westminster $ 24,048 $ 250 $ 23,798 Cowen International Ltd $ 14,475 $ 9,925 $ 4,550 Cowen Execution Ltd $ 4,957 $ 2,043 $ 2,914 Cowen Asia $ 1,088 $ 383 $ 705 The Company’s U.S. broker-dealers must also comply with SEC Rule 15c3-3 or claim an exemption pursuant to subparagraphs (k)(2)(i) or (k)(2)(ii) of that rule. Firms can rely on more than one exemption. Cowen and Company, Cowen Prime and ATM Execution claim the (k)(2)(ii) exemption with regards to some or all of their customer accounts and transactions that are introduced on a fully-disclosed basis to their clearing agents for clearing, settlement and custody. Cowen and Company, Cowen Prime and Westminster claim the (k)(2)(i) exemption with regards to customer transactions and balances that are cleared, settled and custodied in Special Bank Accounts. In accordance with the requirements of SEC Rule 15c3-3, Cowen Execution may be required to deposit in a Special Reserve Account cash or acceptable qualified securities for the exclusive benefit of customers. As of September 30, 2019 , Cowen Execution had segregated approximately $17.0 million of cash, while its required deposit was $6.3 million . As a clearing broker-dealer, Cowen Execution is required to compute a reserve requirement for proprietary accounts of broker-dealers (“PAB accounts”), as defined in SEC Rule 15c3-3. Cowen Execution conducts PAB reserve computations in order to determine the amount it is required to deposit in its PAB Reserve Bank Accounts pursuant to SEC Rule 15c3-3. This allows each correspondent firm that uses Cowen Execution as its clearing broker-dealer to classify its PAB account assets held at Cowen Execution as allowable assets in the correspondent's net capital calculation. At September 30, 2019 , Cowen Execution had $26.9 million of cash on deposit in PAB Reserve Bank Accounts, which was more than its required deposit of $20.3 million . Cowen and Company, ATM Execution, Cowen Prime and Cowen Execution also maintain certain assets in PAB accounts held at their respective clearing brokers. Each treats its assets held in those PAB accounts at the respective clearing brokers as allowable assets for net capital purposes. Cowen’s Luxembourg reinsurance companies, Vianden RCG Re SCA and Hollenfels, individually and their Luxembourg parent holding company, Ramius Enterprise Luxembourg Holdco S.à r.l., on a combined basis with the reinsurance companies, are required to maintain a solvency capital ratio as calculated by relevant European Commission directives and local regulatory rules in Luxembourg. Each reinsurance company’s individual solvency capital ratio as well as the combined solvency capital ratio of the holding and reinsurance companies calculated as of December 31 of each year must exceed a minimum requirement. As of the last testing date, December 31, 2018, all of these entities were in excess of this minimum requirement. The companies are currently, and Management expects they will be at the next testing date of December 31, 2019, in compliance with these requirements. Based on minimum capital and surplus requirements pursuant to the laws of the state of New York that apply to captive insurance companies, RCG Insurance Company, Cowen’s captive insurance company incorporated and licensed in the state of New York, was required to maintain capital and surplus of approximately $0.3 million as of September 30, 2019 . RCG Insurance Company’s capital and surplus as of September 30, 2019 totaled approximately $32.9 million .

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2019
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions The Company and its affiliated entities are the managing member, general partner and/or investment manager to the Company's investment funds and certain managed accounts. Management fees and incentive income are primarily earned from affiliated entities. As of September 30, 2019 and December 31, 2018 , $19.9 million and $19.4 million , respectively, included in fees receivable, are earned from related parties. The Company may, at its discretion, reimburse certain fees charged to the investment funds that it manages to avoid duplication of fees when such funds have an underlying investment in another affiliated investment fund. For the three and nine months ended September 30, 2019 and 2018, the amounts which the Company reimbursed the investment funds it manages were immaterial. Fees receivable and fees payable are recorded at carrying value, which approximates fair value. The Company may also make loans to employees or other affiliates, excluding executive officers of the Company. These loans are interest bearing and settle pursuant to the agreed-upon terms with such employees or affiliates, and are included in due from related parties in the accompanying condensed consolidated statements of financial condition. As of September 30, 2019 and December 31, 2018 , loans to employees of $14.2 million and $17.0 million , respectively, were included in due from related parties on the accompanying condensed consolidated statements of financial condition. Of these amounts $7.4 million and $8.8 million , respectively, are related to forgivable loans. These forgivable loans provide for a cash payment up-front to employees, with the amount due back to the Company forgiven over a vesting period. An employee that voluntarily ceases employment, or is terminated with cause, is generally required to pay back to the Company any unvested forgivable loans granted to them. The forgivable loans are recorded as an asset to the Company on the date of grant and payment, and then amortized to compensation expense on a straight-line basis over the vesting period. The vesting period on forgivable loans is generally one to three years. The Company recorded compensation expense of $1.0 million and $0.8 million for the three months ended September 30, 2019 and 2018 , and $2.8 million and $2.2 million for the nine months ended September 30, 2019 , and 2018 , respectively. This expense is included in employee compensation and benefits in the accompanying condensed consolidated statement of operations. For the three and nine months ended September 30, 2019 , the interest income was $0.1 million for these related party loans and advances, respectively, and are included in interest and dividends in the accompanying condensed consolidated statement of operations. For the three and nine months ended September 30, 2018 , the interest income was immaterial for these related party loans and advances, respectively, and are included in interest and dividends in the accompanying condensed consolidated statement of operations. As of September 30, 2019 and December 31, 2018 , included in due from related parties is $7.0 million and $7.7 million , respectively, related to the sales of portions of the Company's ownership interest in the activist business of Starboard Value to the Starboard principals. It is being financed through the profits of the relevant Starboard entities over a 5 year period and earns interest at 5% per annum. The interest income for the three months ended September 30, 2019 and 2018 was $0.1 million and $0.1 million , and for the nine months ended September 30, 2019 and 2018 , was $0.3 million and $0.3 million , respectively. The remaining balance included in due from related parties of $6.6 million and $8.9 million as of September 30, 2019 and December 31, 2018 , respectively, relates to amounts due to the Company from affiliated investment funds and real estate entities due to expenses paid on their behalf. Included in due to related parties is approximately $0.3 million and $0.6 million September 30, 2019 and December 31, 2018 , respectively, related to a subordination agreement with an investor in certain real estate funds. This total is based on a hypothetical liquidation of the real estate funds as of the balance sheet date. The remaining balance in due to related parties of $0.5 million as of September 30, 2019 , relates to amounts due to the certain Company employees. Employees and certain other related parties invest on a discretionary basis within consolidated entities. These investments generally are subject to preferential management fee and performance fee arrangements. As of September 30, 2019 and December 31, 2018 , such investments aggregated $ 34.9 million and $ 25.1 million , respectively, were included in non-controlling interests on the accompanying condensed consolidated statements of financial condition. Their share of the net income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds aggregated $3.6 million and $4.1 million for the three months ended September 30, 2019 and 2018 , and $ 4.7 million and $ 8.4 million , for the nine months ended September 30, 2019 and 2018 , respectively. The Company may, at times, have unfunded commitment amounts pertaining to related parties. See Note 17 "Commitments and Contingencies" for amounts committed as of September 30, 2019 and December 31, 2018 .

Guarantees and Off-Balance Shee

Guarantees and Off-Balance Sheet Arrangements	9 Months Ended
	Sep. 30, 2019
Guarantees and Off Balance Sheet Arrangements [Abstract]
Guarantees and Off-Balance Sheet Arrangements	Guarantees and Off-Balance Sheet Arrangements Guarantees US GAAP requires the Company to disclose information about its obligations under certain guarantee arrangements. Those standards define guarantees as contracts and indemnification agreements that contingently require a guarantor to make payments to the guaranteed party based on changes in an underlying security (such as an interest or foreign exchange rate, security or commodity price, an index or the occurrence or nonoccurrence of a specified event) related to an asset, liability or equity security of a guaranteed party. Those standards also define guarantees as contracts that contingently require the guarantor to make payments to the guaranteed party based on another entity's failure to perform under an agreement as well as indirect guarantees of the indebtedness of others. In the normal course of its operations, the Company enters into contracts that contain a variety of representations and warranties which provide general indemnifications. The Company's maximum exposure under these arrangements is unknown as this would involve future claims that may be made against the Company that have not yet occurred. However, based on experience, the Company expects the risk of loss to be remote. The Company indemnifies and guarantees certain service providers, such as clearing and custody agents, trustees and administrators, against specified potential losses in connection with their acting as an agent of, or providing services to, the Company or its affiliates. The Company also indemnifies some clients against potential losses incurred in the event specified third-party service providers, including sub-custodians and third-party brokers, improperly execute transactions. The maximum potential amount of future payments that the Company could be required to make under these indemnifications cannot be estimated. However, the Company believes that it is unlikely it will have to make significant payments under these arrangements and has not recorded any contingent liability in the condensed consolidated financial statements for these indemnifications. The Company also provides representations and warranties to counterparties in connection with a variety of commercial transactions and occasionally indemnifies them against potential losses caused by the breach of those representations and warranties. The Company may also provide standard indemnifications to some counterparties to protect them in the event additional taxes are owed or payments are withheld, due either to a change in or adverse application of certain tax laws. These indemnifications generally are standard contractual terms and are entered into in the normal course of business. The maximum potential amount of future payments that the Company could be required to make under these indemnifications cannot be estimated. However, the Company believes it is unlikely it will have to make material payments under these arrangements and has not recorded any contingent liability in the accompanying condensed consolidated financial statements for these indemnifications. The Company may maintain cash and cash equivalents at financial institutions in excess of federally insured limits. The Company has not experienced any material losses in such accounts and does not believe it is exposed to significant credit risks in relation to such accounts. Off-Balance Sheet Arrangements The Company has no material off-balance sheet arrangements, which have not been disclosed, as of September 30, 2019 and December 31, 2018 . Through indemnification provisions in clearing agreements with clients, customer activities may expose the Company to off-balance-sheet credit risk. Pursuant to the clearing agreement, the Company is required to reimburse the Company's clearing broker, without limit, for any losses incurred due to a counterparty's failure to satisfy its contractual obligations. However, these transactions are collateralized by the underlying security, thereby reducing the associated risk to changes in the market value of the security through the settlement date. The Company’s customer securities activities are transacted on a delivery versus payment, cash or margin basis. In delivery versus payment transactions, the Company is exposed to risk of loss in the event of the customers’ or brokers’ inability to meet the terms of their contracts. In margin transactions, the Company extends credit to clients collateralized by cash and securities in their account. In the event the customers or brokers fail to satisfy their obligations, the Company may be required to purchase or sell securities at prevailing market prices in order to fulfill the obligations. The Company’s exposure to credit risk can be directly impacted by volatile securities markets, which may impair the ability of counterparties to satisfy their contractual obligations. The Company seeks to control its credit risk through a variety of reporting and control procedures, including establishing credit limits based upon a review of the customers’ financial condition and credit ratings. The Company seeks to control the risk associated with its customer margin transactions by requiring customers to maintain margin collateral in compliance with various regulatory and internal guidelines. The Company also monitors required margin levels daily and, pursuant to its guidelines, requires customers to deposit additional collateral, or reduce positions, when necessary. In addition, during the normal course of business, the Company has exposure to a number of risks including market risk, currency risk, credit risk, operational risk, liquidity risk and legal risk. As part of the Company's risk management process, these risks are monitored on a regular basis throughout the course of the year. The Company enters into secured and unsecured borrowing agreements to obtain funding necessary to cover daily securities settlements with clearing corporations. At times, funding is required for unsettled customer delivery versus payment and riskless principal transactions, as well as to meet deposit requirements with clearing organizations. Secured arrangements are collateralized by the securities. The Company maintains uncommitted financing arrangements with large financial institutions, the details of which are summarized below as of September 30, 2019 . Lender Contractual Amount Available Amount Maturity Date Description Pledge Lines (dollars in thousands) Texas Capital Bank $ 75,000 $ 75,000 None Secured Depository Trust Company Pledge Line BMO Harris Bank 75,000 75,000 None Secured Tri-Party Pledge Facility BMO Harris Bank 150,000 150,000 None Secured Depository Trust Company Pledge Line Total 300,000 300,000 Revolving Credit Facility BMO Harris Bank Canadian Imperial Bank of Commerce Texas Capital Bank 70,000 70,000 August 21, 2020 (Syndicated) Unsecured liquidity facility to cover increases in National Securities Clearing Corporation margin deposit requirements Total Credit Lines $ 370,000 $ 370,000

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On October 23, 2019, the Company's Board of Directors approved a $17.8 million increase in the Company's share repurchase program (see Note 19) bringing the total remaining shares available for repurchase to $25.0 million . The Company has evaluated events that have occurred after the balance sheet date but before the financial statements are issued and has determined that there were no other subsequent events requiring adjustment or disclosure in the condensed consolidated financial statements.

Significant Accounting Polici_2

Significant Accounting Policies - Quarterly (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Earnings Per Share	Diluted earnings per common share are calculated by adjusting the weighted average outstanding shares to assume conversion of all potentially dilutive items. The Company uses the treasury stock method to reflect the potential dilutive effect of the unvested restricted shares, restricted stock units, and SAR's. In calculating the number of dilutive shares outstanding, the shares of common stock underlying unvested restricted shares and restricted stock units are assumed to have been delivered, and options and warrants are assumed to have been exercised, for the entire period being presented. The number of performance-linked unvested restricted stock units that are included in the calculation are at the amount that could be earned using current payout rates. The assumed proceeds from the assumed vesting, delivery and exercising were calculated as the amount of compensation cost attributed to future services and not yet recognized.
Significant Accounting Policies	Significant Accounting Policies a. Basis of Presentation These unaudited condensed consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America ("US GAAP") as promulgated by the Financial Accounting Standards Board ("FASB") through Accounting Standards Codification (the "Accounting Standards") as the source of authoritative accounting principles in the preparation of financial statements, and include the accounts of the Company, its operating and other subsidiaries, and entities in which the Company has a controlling financial interest or a general partner interest. All material intercompany transactions and balances have been eliminated in consolidation. Certain fund entities that are consolidated in these accompanying condensed consolidated financial statements, as further discussed below, are not subject to the consolidation provisions with respect to their own controlled investments pursuant to their specialized accounting. The Company serves as the managing member/general partner and/or investment manager to affiliated fund entities which it sponsors and manages. Funds in which the Company has a controlling financial interest are consolidated with the Company pursuant to US GAAP as described below. Consequently, the Company's condensed consolidated financial statements reflect the assets, liabilities, income and expenses of these funds on a gross basis. The ownership interests in these funds that are not owned by the Company are reflected as redeemable or non-redeemable non-controlling interests in consolidated subsidiaries in the accompanying condensed consolidated financial statements. The management fees and incentive income earned by the Company from these funds are eliminated in consolidation. In this Form 10-Q, nonredeemable non-controlling interests for the three and nine months ended September 30, 2019 and 2018, respectively, have been reclassified to be presented separately from redeemable non-controlling interests within the permanent equity section of the accompanying condensed consolidated statements of financial condition. The Company carried out an analysis to evaluate instances where non-controlling interest parties have the unilateral right to redeem their ownership interest for cash, which resulted in a change to the presentation of certain nonredeemable non-controlling interests into permanent equity. Accordingly, prior period amounts have been recast to reflect the change to the presentation of nonredeemable non-controlling interests, which has no impact on net income (loss) attributable to Cowen Inc. common stockholders, total assets or total liabilities. With respect to the Company’s private equity investment management strategies, a portion of the Company's carried interest is granted to employees through profit sharing awards designed to more closely align compensation with the overall realized performance of the Company. These arrangements enable certain employees to earn compensation based on performance revenue earned by the Company and are recorded within compensation payable in the accompanying condensed consolidated statements of financial condition and employee compensation and benefits expense in the accompanying condensed consolidated statements of operation based on the probable and estimable payments under the terms of the awards. Prior period amounts have been recast to reflect this accounting treatment. The year-end condensed balance sheet data was derived from the audited financial statements, but does not include all disclosures included in the audited financial statements. b. Principles of consolidation The Company consolidates all entities that it controls through a majority voting interest or otherwise, including those investment funds in which the Company either directly or indirectly has a controlling financial interest. In addition, the Company consolidates all variable interest entities for which it is the primary beneficiary. In accordance with these standards, the Company consolidates five investment funds for which it acts as the general partner and investment manager. As of September 30, 2019 , the Company consolidated the following investment funds: Ramius Enterprise LP (“Enterprise LP”), Ramius Merger Fund LLC (the "Merger Fund"), Cowen Private Investments LP ("Cowen Private"), Ramius Merger Arbitrage UCITS Fund ("UCITS Fund"), and Cowen Sustainable Investments I LP ("CSI I LP") (each a "Consolidated Fund" and collectively the "Consolidated Funds"). The Company determines whether it has a controlling financial interest in an entity by first evaluating whether the entity is a voting operating entity ("VOE") or a variable interest entity ("VIE") under US GAAP. Voting Operating Entities — VOEs are entities in which (i) the total equity investment at risk is sufficient to enable the entity to finance its activities independently, (ii) the equity holders at risk have the obligation to absorb losses, the right to receive residual returns and the right to direct the activities of the entity that most significantly impact the entity's economic performance and (iii) voting rights of equity holders are proportionate to their obligation to absorb losses or the right to receive returns. Under US GAAP, the usual condition for a controlling financial interest in a VOE is ownership of a majority voting interest. Accordingly, the Company consolidates all VOEs in which it owns a majority of the entity's voting shares or units. Variable Interest Entities— VIEs are entities that lack one or more of the characteristics of a VOE. In accordance with US GAAP, an enterprise must consolidate all VIEs of which it is the primary beneficiary. Under the US GAAP consolidation model for VIEs, an enterprise that (1) has the power to direct the activities of a VIE that most significantly impacts the VIE's economic performance, and (2) has an obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE, is considered to be the primary beneficiary of the VIE and thus is required to consolidate it. The Company reconsiders whether it is the primary beneficiary of a VIE by performing a periodic qualitative and/or quantitative analysis of the VIE that includes a review of, among other things, its capital structure, contractual agreements between the Company and the VIE, the economic interests that create or absorb variability, related party relationships and the design of the VIE. As of September 30, 2019 , the total assets and total liabilities of the consolidated VIEs were $656.4 million and $34.3 million , respectively. As of December 31, 2018 , the total assets and total liabilities of the consolidated VIEs were $468.0 million and $40.5 million , respectively. The increase is primarily related to other investors' subscriptions which increased overall VIEs net assets. The VIEs act as investment managers and/or investment companies that may be managed by the Company or the Company may have equity interest in those investment companies. The VIEs are financed through their operations and/or loan agreements with the Company. As of September 30, 2019 , the Company held a variable interest in Ramius Merger Master Fund Ltd ("Merger Master") (the “Unconsolidated Master Fund”) through the consolidated Merger Fund. As of December 31, 2018 , the Company held variable interests in Ramius Enterprise Master Fund Ltd (“Enterprise Master”) and Ramius Merger Master Fund Ltd ("Merger Master") (collectively the “Unconsolidated Master Funds”) through two Consolidated Funds. Investment companies, which account for their investments under the specialized industry accounting guidance for investment companies prescribed under US GAAP, are not subject to the consolidation provisions for their investments. Therefore, the Company has not consolidated the Unconsolidated Master Funds. In the ordinary course of business, the Company also sponsors various other entities that it has determined to be VIEs. These VIEs are primarily investment funds for which the Company serves as the general partner, managing member and/or investment manager with decision-making rights. The reason that the Company does not consolidate the Unconsolidated Master Fund or real estate funds that are VIEs is due to the Company's conclusion that it is not the primary beneficiary in each instance. Investment fund investors are entitled to all of the economics of these VIEs with the exception of the management fee and incentive income, if any, earned by the Company. The Company has equity interests in the funds as both GP and Limited partner. In these instances the Company has concluded that the variable interests are not potentially significant to the VIE. Although the Company may advance amounts and pay certain expenses on behalf of the investment funds that it considers to be VIEs, it does not provide, nor is it required to provide, any type of substantive financial support to these entities outside of regular investment management services (see Note 6 for additional disclosures on VIEs). Equity Method Investments — For operating entities over which the Company exercises significant influence but which do not meet the requirements for consolidation as outlined above, the Company uses the equity method of accounting. The Company's investments in equity method investees are recorded in other investments in the accompanying condensed consolidated statements of financial condition. The Company's share of earnings or losses from equity method investees is included in net gains (losses) on securities, derivatives and other investments in the accompanying condensed consolidated statements of operations. The Company evaluates its equity method investments for impairment whenever events or changes in circumstances indicate that the carrying amounts of such investments may not be recoverable. The difference between the carrying value of the equity method investment and its estimated fair value is recognized as an impairment charge when the loss in value is deemed other than temporary. Other — If the Company does not consolidate an entity or apply the equity method of accounting, the Company accounts for such entities (primarily, all securities of such entity which are bought and held principally for the purpose of selling them in the near term as trading securities) in accordance with US GAAP, at fair value with unrealized gains (losses) resulting from changes in fair value reflected within net gains (losses) on securities, derivatives and other investments in the accompanying condensed consolidated statements of operations. Retention of Specialized Accounting — The Consolidated Funds and certain other consolidated companies are investment companies and apply specialized industry accounting for investment companies. The Company has retained this specialized accounting for these investment funds pursuant to US GAAP. The Company reports its investments on the condensed consolidated statements of financial condition at their estimated fair value, with unrealized gains (losses) resulting from changes in fair value reflected within net realized and unrealized gains (losses) on investments and other transactions. Accordingly, the accompanying condensed consolidated financial statements reflect different accounting policies for investments depending on whether or not they are held through a consolidated investment company. In addition, the Company's broker-dealer subsidiaries , Cowen and Company, LLC ("Cowen and Company"), Cowen Execution Services LLC ("Cowen Execution"), Westminster Research Associates LLC ("Westminster"), Cowen Execution Services Limited ("Cowen Execution Ltd"), ATM Execution LLC ("ATM Execution"), Cowen International Limited ("Cowen International Ltd"), and Cowen Prime Services LLC ("Cowen Prime") apply the specialized industry accounting for brokers and dealers in securities also prescribed under US GAAP. The Company also retains specialized accounting upon consolidation. c. Use of estimates The preparation of the accompanying condensed consolidated financial statements in conformity with US GAAP requires the management of the Company to make estimates and assumptions that affect the fair value of securities and other investments, the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the accompanying condensed consolidated financial statements, the accounting for goodwill and identifiable intangible assets and the reported amounts of revenues and expenses during the reporting period. Actual results could materially differ from those estimates. d. Allowance for credit losses The allowance for credit losses is based on the Company’s assessment of the collectability of receivables related to securities transactions, prepaid research and other receivables. The Company considers factors such as historical experience, credit quality, age of balances and current economic conditions that may affect collectability in determining the allowance for credit losses. Specifically, for prepaid research, the Company reviews clients' historical, current and forecasted trading activity in determining the allowance for credit losses. The credit loss expense related to the allowance for credit losses as well as any recoveries of amounts previously charged is reflected in other expenses in the accompanying condensed consolidated statements of operations. e. Valuation of investments and derivative contracts US GAAP establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (level 1 measurements) and the lowest priority to unobservable inputs (level 3 measurements). The three levels of the fair value hierarchy are as follows: Level 1 Inputs that reflect unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date; Level 2 Inputs other than quoted prices that are observable for the asset or liability either directly or indirectly, including inputs in markets that are not considered to be active; and Level 3 Fair value is determined based on pricing inputs that are unobservable and includes situations where there is little, if any, market activity for the asset or liability. The determination of fair value for assets and liabilities in this category requires significant management judgment or estimation. Inputs are used in applying the various valuation techniques and broadly refer to the assumptions that market participants use to make valuation decisions, including assumptions about risk. Inputs may include price information, volatility statistics, specific and broad credit data, liquidity statistics, and other factors. A financial instrument's level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. However, the determination of what constitutes “observable” requires significant judgment by the Company. The Company considers observable data to be that market data which is readily available, regularly distributed or updated, reliable and verifiable, not proprietary, and provided by independent sources that are actively involved in the relevant market. The categorization of a financial instrument within the hierarchy is based upon the pricing transparency of the instrument and does not necessarily correspond to the Company's perceived risk of that instrument. The Company and its operating subsidiaries act as the manager for the Consolidated Funds. Both the Company and the Consolidated Funds hold certain investments which are valued by the Company, acting as the investment manager. The fair value of these investments is generally estimated based on proprietary models developed by the Company, which include discounted cash flow analysis, public market comparables, and other techniques and may be based, at least in part, on independently sourced market information. The material estimates and assumptions used in these models include the timing and expected amount of cash flows, the appropriateness of discount rates used, and, in some cases, the ability to execute, timing of, and estimated proceeds from expected financings. Significant judgment and estimation impact the selection of an appropriate valuation methodology as well as the assumptions used in these models, and the timing and actual values realized with respect to investments could be materially different from values derived based on the use of those estimates. The valuation methodologies applied impact the reported value of the Company's investments and the investments held by the Consolidated Funds in the condensed consolidated financial statements. Certain of the Company's investments are relatively illiquid or thinly traded and may not be immediately liquidated on demand if needed. Fair values assigned to these investments may differ significantly from the fair values that would have been used had a ready market for the investments existed and such differences could be material . The Company primarily uses the “market approach” to value its financial instruments measured at fair value. In determining an instrument's level within the hierarchy, the Company categorizes the Company's financial instruments into three categories: securities, derivative contracts and other investments. To the extent applicable, each of these categories can further be divided between those held long or sold short. The Company has the option to measure certain financial assets and financial liabilities at fair value with changes in fair value recognized in earnings each period. The election is made on an instrument by instrument basis at initial recognition of an asset or liability or upon an event that gives rise to a new basis of accounting for that instrument. The Company has elected the fair value option for certain of its investments held by its operating companies. This option has been elected because the Company believes that it is consistent with the manner in which the business is managed, as well as the way that financial instruments in other parts of the business are recorded. Securities — Securities with values based on quoted market prices in active markets for identical assets are classified within level 1 of the fair value hierarchy. These securities primarily include active listed equities, certain U.S. government and sovereign obligations, Exchange Traded Funds ("ETFs"), mutual funds and certain money market securities. The Company does not adjust the quoted price for such instruments, even in situations where the Company holds a large position and a sale could reasonably impact the quoted price. Certain positions for which trading activity may not be readily visible, consisting primarily of convertible debt, corporate debt and loans and restricted equities, are stated at fair value and classified within level 2 of the fair value hierarchy. The estimated fair values assigned by management are determined in good faith and are based on available information considering, trading activity, broker quotes, quotations provided by published pricing services, counterparties and other market participants, and pricing models using quoted inputs, and do not necessarily represent the amounts which might ultimately be realized. As level 2 investments include positions that are not always traded in active markets and/or are subject to transfer restrictions, valuations may be adjusted to reflect illiquidity and/or non-transferability. Derivative contracts — Derivative contracts can be exchange-traded or privately negotiated over-the-counter (“OTC”). Exchange-traded derivatives, such as futures contracts and exchange-traded option contracts, are typically classified within level 1 or level 2 of the fair value hierarchy depending on whether or not they are deemed to be actively traded. OTC derivatives, such as generic forwards, swaps and options, have inputs which can generally be corroborated by market data and are therefore classified within level 2. OTC derivatives, such as swaps and options where market data is not readily available or observable are classified as level 3. Other investments — Other investments consist primarily of investment funds, real estate investments, carried interest and equity method investments, which are valued as follows : i. Portfolio funds— Portfolio funds (“Portfolio Funds”) include equity interests in private investment partnerships, foreign investment companies and other collective investment vehicles which may be managed by the Company or its affiliates. The Company follows US GAAP regarding fair value measurements and disclosures relating to investments in certain entities that calculate net asset value (“NAV”) per share (or its equivalent). The Company applies the practical expedient provided by US GAAP that permits an entity holding investments in certain entities that (a) do not have readily determinable fair values, (b) are investments in an investment company within the scope of ASC 946 Financial Services - Investment Companies (“ASC 946”) and (c) whose NAV is calculated in a manner consistent with the measurement principles of ASC 946 as of the reporting date, to measure the fair value of such investments on the basis of that NAV per share, or its equivalent, without adjustment. The Company applies an accounting policy election to recognize incentive income allocated to the Company under an equity ownership model as other investments in the accompanying condensed consolidated statements of financial condition (see Note 6). Carried interest allocated to the Company from certain portfolio funds represents Cowen's general partner capital accounts from those funds. These balances are subject to change upon cash distributions, additional allocations or reallocations back to limited partners within the respective funds. Investments which are valued using NAV per share as a practical expedient are not categorized within the fair value hierarchy. ii. Real estate investments— Real estate debt and equity investments are valued at fair value. The fair value of real estate investments is estimated based on the price that would be received to sell an asset in an orderly transaction between marketplace participants at the measurement date. Real estate investments without a public market are valued based on assumptions and valuation techniques used by the Company. Such valuation techniques may include discounted cash flow analysis, prevailing market capitalization rates or earnings multiples applied to earnings from the investment, analysis of recent comparable sales transactions, actual sale negotiations and bona fide purchase offers received from third parties, consideration of the amount that currently would be required to replace the asset, as adjusted for obsolescence, as well as independent external appraisals. In general, the Company considers several valuation techniques when measuring the fair value of a real estate investment. However, in certain circumstances, a single valuation technique may be appropriate. Real estate investments are reviewed on a quarterly basis by the Company for significant changes at the property level or a significant change in the overall market which would impact the value of the real estate investment resulting in unrealized appreciation or depreciation. Real estate and capital markets are cyclical in nature. Property and investment values are affected by, among other things, the availability of capital, occupancy rates, rental rates and interest and inflation rates. In addition, the Company invests in real estate and real estate related investments for which no liquid market exists. The market prices for such investments may be volatile and may not be readily ascertainable. Amounts ultimately realized by the Company from investments sold may differ from the fair values presented, and the differences could be material. The Company's real estate investments are typically categorized as level 3 investments within the fair value hierarchy as management uses significant unobservable inputs in determining their estimated fair value. See Notes 6 and 7 for further information regarding the Company's investments, including equity method investments and fair value measurements. f. Fees receivable Fees related to security transactions are reported net of an allowance for credit losses. An allowance for credit losses is assessed on any commission receivables aged over 180 days. Corporate finance and syndicate receivables, include receivables relating to the Company’s investment banking and advisory engagements net of allowance for credit losses. The Company records this allowance for credit losses on these receivables on a specific identification basis. The future collectability of the receivables is reviewed on a monthly basis based on the following factors: aging (usually if outstanding greater than 90 days), known financial stability of the paying company, as well as any other factors that might impact the collection of the outstanding fees. Management and incentive fees are earned as the managing member, general partner and/or investment manager to the Company's investment funds and are recognized in accordance with appropriate revenue recognition guidance (see Note 2( m )). g. Securities financing arrangements Securities borrowed and securities loaned are carried at the amounts of cash collateral advanced or received on a gross basis. The related rebates are recorded in the accompanying condensed consolidated statements of operations as interest and dividends income and interest and dividends expense. Securities borrowed transactions require the Company to deposit cash collateral with the lender. With respect to securities loaned, the Company receives cash or securities as collateral from the borrower. When the Company receives securities as collateral, and has concluded it (i) is the transferor and (ii) can pledge the securities to third parties, the Company recognizes the securities received as collateral at fair value in Securities owned, at fair value with the corresponding obligation to return the securities received as collateral at fair value in Securities sold, not yet purchased, at fair value. Securities received as collateral are not recognized when the Company either (i) is not the transferor or (ii) cannot pledge the securities to third parties. The initial collateral advanced or received approximates or is greater than the market value of securities borrowed or loaned. The Company monitors the market value of securities borrowed and loaned on a daily basis, with additional collateral obtained or returned, as necessary. Securities borrowed and loaned may also result in credit exposures for the Company in an event that the counterparties are unable to fulfill their contractual obligations. The Company minimizes its credit risk by continuously monitoring its credit exposure and collateral values by demanding additional or returning excess collateral in accordance with the netting provisions available in the master securities lending contracts in place with the counterparties. Fees and interest received or paid are recorded in interest and dividends income and interest and dividends expense, respectively, on an accrual basis in the accompanying condensed consolidated statements of operations. In cases where the fair value basis of accounting is elected, any resulting change in fair value would be reported in net gains (losses) on securities, derivatives and other investments in the accompanying condensed consolidated statements of operations. Accrued interest income and expense are recorded in receivable from brokers, dealers and clearing organizations and payable to brokers, dealers and clearing organizations, respectively, on an accrual basis in the accompanying condensed consolidated statements of financial condition. At September 30, 2019 and December 31, 2018 , the Company did not have any securities lending transactions for which fair value basis of accounting was elected. h. Securities sold under agreements to repurchase Securities sold under agreements to repurchase ("repos") are accounted for as collateralized financing transactions and are recorded at their contracted repurchase amount plus accrued interest. A repo is a transaction in which a firm sells financial instruments to a buyer, typically in exchange for cash, and simultaneously enters into an agreement to repurchase the same or substantially the same financial instruments from such buyer at a stated price plus accrued interest at a future date. When the Company receives securities as collateral, and has concluded it (i) is the transferor and (ii) can pledge the securities to third parties, the Company recognizes the securities received as collateral at fair value in Securities owned, at fair value with the corresponding obligation to return the securities received as collateral at fair value in Securities sold, not yet purchased, at fair value. Securities received as collateral are not recognized when the Company either (i) is not the transferor or (ii) cannot pledge the securities to third parties. The initial collateral advanced approximates or is greater than the market value of securities sold in the transaction. The Company typically enters into repo transactions with counterparties that prefer repo transactions to securities loaned transactions. The Company has executed master repo agreements with such counterparties and utilizes such counterparties to finance its own positions, or replace a securities lending transaction with a repo for matched book purposes. The Company monitors the market value of repos on a daily basis, with additional collateral obtained or returned, as necessary. Repos may also result in credit exposures for the Company in an event that the counterparties are unable to fulfill their contractual obligations. The Company mitigates its credit risk by continuously monitoring its credit exposure and collateral values by demanding additional collateral or returning excess collateral in accordance with the netting provisions available in the master repo contracts in place with the counterparties. Interest paid is recorded in interest and dividends expense on an accrual basis in the accompanying condensed consolidated statements of operations. In cases where the fair value basis of accounting is elected, any resulting change in fair value would be reported in net gains (losses) on securities, derivatives and other investments in the accompanying condensed consolidated statements of operations. At September 30, 2019 and December 31, 2018, the Company did not have any repos for which fair value basis of accounting was elected. i. Fixed assets Fixed assets are stated at cost less accumulated depreciation or amortization. Leasehold improvements are amortized on a straight-line basis over the lesser of their useful life or lease term. When the Company commits to a plan to abandon fixed assets or leasehold improvements before the end of its original useful life, the estimated depreciation or amortization period is revised to reflect the shortened useful life of the asset. Other fixed assets are depreciated on a straight-line basis over their estimated useful lives. Asset Depreciable Lives Depreciation and/or Amortization Method Telephone and computer equipment 5 years Straight-line Computer software 4 years Straight-line Furniture and fixtures 5 years Straight-line Leasehold improvements Term of Lease Straight-line Finance lease right-of-use asset 5 years Straight-line j. Goodwill and intangible assets Goodwill Goodwill represents the excess of the purchase price consideration of acquired companies over the estimated fair value assigned to the individual assets acquired and liabilities assumed. Goodwill is allocated to the Company's reporting units at the date the goodwill is initially recorded. Once goodwill has been allocated to the reporting units, it generally no longer retains its identification with a particular acquisition but instead becomes identifiable with the reporting unit. As a result, all of the fair value of each reporting unit is available to support the value of goodwill allocated to the unit. In January 2017, the FASB issued guidance that simplifies the subsequent measurement of goodwill. The new guidance eliminated Step 2 from the goodwill impairment test w
Basis of presentation	Basis of Presentation These unaudited condensed consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America ("US GAAP") as promulgated by the Financial Accounting Standards Board ("FASB") through Accounting Standards Codification (the "Accounting Standards") as the source of authoritative accounting principles in the preparation of financial statements, and include the accounts of the Company, its operating and other subsidiaries, and entities in which the Company has a controlling financial interest or a general partner interest. All material intercompany transactions and balances have been eliminated in consolidation. Certain fund entities that are consolidated in these accompanying condensed consolidated financial statements, as further discussed below, are not subject to the consolidation provisions with respect to their own controlled investments pursuant to their specialized accounting. The Company serves as the managing member/general partner and/or investment manager to affiliated fund entities which it sponsors and manages. Funds in which the Company has a controlling financial interest are consolidated with the Company pursuant to US GAAP as described below. Consequently, the Company's condensed consolidated financial statements reflect the assets, liabilities, income and expenses of these funds on a gross basis. The ownership interests in these funds that are not owned by the Company are reflected as redeemable or non-redeemable non-controlling interests in consolidated subsidiaries in the accompanying condensed consolidated financial statements. The management fees and incentive income earned by the Company from these funds are eliminated in consolidation. In this Form 10-Q, nonredeemable non-controlling interests for the three and nine months ended September 30, 2019 and 2018, respectively, have been reclassified to be presented separately from redeemable non-controlling interests within the permanent equity section of the accompanying condensed consolidated statements of financial condition. The Company carried out an analysis to evaluate instances where non-controlling interest parties have the unilateral right to redeem their ownership interest for cash, which resulted in a change to the presentation of certain nonredeemable non-controlling interests into permanent equity. Accordingly, prior period amounts have been recast to reflect the change to the presentation of nonredeemable non-controlling interests, which has no impact on net income (loss) attributable to Cowen Inc. common stockholders, total assets or total liabilities. With respect to the Company’s private equity investment management strategies, a portion of the Company's carried interest is granted to employees through profit sharing awards designed to more closely align compensation with the overall realized performance of the Company. These arrangements enable certain employees to earn compensation based on performance revenue earned by the Company and are recorded within compensation payable in the accompanying condensed consolidated statements of financial condition and employee compensation and benefits expense in the accompanying condensed consolidated statements of operation based on the probable and estimable payments under the terms of the awards. Prior period amounts have been recast to reflect this accounting treatment. The year-end condensed balance sheet data was derived from the audited financial statements, but does not include all disclosures included in the audited financial statements.
Principles of consolidation	Principles of consolidation The Company consolidates all entities that it controls through a majority voting interest or otherwise, including those investment funds in which the Company either directly or indirectly has a controlling financial interest. In addition, the Company consolidates all variable interest entities for which it is the primary beneficiary. In accordance with these standards, the Company consolidates five investment funds for which it acts as the general partner and investment manager. As of September 30, 2019 , the Company consolidated the following investment funds: Ramius Enterprise LP (“Enterprise LP”), Ramius Merger Fund LLC (the "Merger Fund"), Cowen Private Investments LP ("Cowen Private"), Ramius Merger Arbitrage UCITS Fund ("UCITS Fund"), and Cowen Sustainable Investments I LP ("CSI I LP") (each a "Consolidated Fund" and collectively the "Consolidated Funds"). The Company determines whether it has a controlling financial interest in an entity by first evaluating whether the entity is a voting operating entity ("VOE") or a variable interest entity ("VIE") under US GAAP. Voting Operating Entities — VOEs are entities in which (i) the total equity investment at risk is sufficient to enable the entity to finance its activities independently, (ii) the equity holders at risk have the obligation to absorb losses, the right to receive residual returns and the right to direct the activities of the entity that most significantly impact the entity's economic performance and (iii) voting rights of equity holders are proportionate to their obligation to absorb losses or the right to receive returns. Under US GAAP, the usual condition for a controlling financial interest in a VOE is ownership of a majority voting interest. Accordingly, the Company consolidates all VOEs in which it owns a majority of the entity's voting shares or units. Variable Interest Entities— VIEs are entities that lack one or more of the characteristics of a VOE. In accordance with US GAAP, an enterprise must consolidate all VIEs of which it is the primary beneficiary. Under the US GAAP consolidation model for VIEs, an enterprise that (1) has the power to direct the activities of a VIE that most significantly impacts the VIE's economic performance, and (2) has an obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE, is considered to be the primary beneficiary of the VIE and thus is required to consolidate it. The Company reconsiders whether it is the primary beneficiary of a VIE by performing a periodic qualitative and/or quantitative analysis of the VIE that includes a review of, among other things, its capital structure, contractual agreements between the Company and the VIE, the economic interests that create or absorb variability, related party relationships and the design of the VIE. As of September 30, 2019 , the total assets and total liabilities of the consolidated VIEs were $656.4 million and $34.3 million , respectively. As of December 31, 2018 , the total assets and total liabilities of the consolidated VIEs were $468.0 million and $40.5 million , respectively. The increase is primarily related to other investors' subscriptions which increased overall VIEs net assets. The VIEs act as investment managers and/or investment companies that may be managed by the Company or the Company may have equity interest in those investment companies. The VIEs are financed through their operations and/or loan agreements with the Company. As of September 30, 2019 , the Company held a variable interest in Ramius Merger Master Fund Ltd ("Merger Master") (the “Unconsolidated Master Fund”) through the consolidated Merger Fund. As of December 31, 2018 , the Company held variable interests in Ramius Enterprise Master Fund Ltd (“Enterprise Master”) and Ramius Merger Master Fund Ltd ("Merger Master") (collectively the “Unconsolidated Master Funds”) through two Consolidated Funds. Investment companies, which account for their investments under the specialized industry accounting guidance for investment companies prescribed under US GAAP, are not subject to the consolidation provisions for their investments. Therefore, the Company has not consolidated the Unconsolidated Master Funds. In the ordinary course of business, the Company also sponsors various other entities that it has determined to be VIEs. These VIEs are primarily investment funds for which the Company serves as the general partner, managing member and/or investment manager with decision-making rights. The reason that the Company does not consolidate the Unconsolidated Master Fund or real estate funds that are VIEs is due to the Company's conclusion that it is not the primary beneficiary in each instance. Investment fund investors are entitled to all of the economics of these VIEs with the exception of the management fee and incentive income, if any, earned by the Company. The Company has equity interests in the funds as both GP and Limited partner. In these instances the Company has concluded that the variable interests are not potentially significant to the VIE. Although the Company may advance amounts and pay certain expenses on behalf of the investment funds that it considers to be VIEs, it does not provide, nor is it required to provide, any type of substantive financial support to these entities outside of regular investment management services (see Note 6 for additional disclosures on VIEs). Equity Method Investments — For operating entities over which the Company exercises significant influence but which do not meet the requirements for consolidation as outlined above, the Company uses the equity method of accounting. The Company's investments in equity method investees are recorded in other investments in the accompanying condensed consolidated statements of financial condition. The Company's share of earnings or losses from equity method investees is included in net gains (losses) on securities, derivatives and other investments in the accompanying condensed consolidated statements of operations. The Company evaluates its equity method investments for impairment whenever events or changes in circumstances indicate that the carrying amounts of such investments may not be recoverable. The difference between the carrying value of the equity method investment and its estimated fair value is recognized as an impairment charge when the loss in value is deemed other than temporary. Other — If the Company does not consolidate an entity or apply the equity method of accounting, the Company accounts for such entities (primarily, all securities of such entity which are bought and held principally for the purpose of selling them in the near term as trading securities) in accordance with US GAAP, at fair value with unrealized gains (losses) resulting from changes in fair value reflected within net gains (losses) on securities, derivatives and other investments in the accompanying condensed consolidated statements of operations. Retention of Specialized Accounting — The Consolidated Funds and certain other consolidated companies are investment companies and apply specialized industry accounting for investment companies. The Company has retained this specialized accounting for these investment funds pursuant to US GAAP. The Company reports its investments on the condensed consolidated statements of financial condition at their estimated fair value, with unrealized gains (losses) resulting from changes in fair value reflected within net realized and unrealized gains (losses) on investments and other transactions. Accordingly, the accompanying condensed consolidated financial statements reflect different accounting policies for investments depending on whether or not they are held through a consolidated investment company. In addition, the Company's broker-dealer subsidiaries , Cowen and Company, LLC ("Cowen and Company"), Cowen Execution Services LLC ("Cowen Execution"), Westminster Research Associates LLC ("Westminster"), Cowen Execution Services Limited ("Cowen Execution Ltd"), ATM Execution LLC ("ATM Execution"), Cowen International Limited ("Cowen International Ltd"), and Cowen Prime Services LLC ("Cowen Prime") apply the specialized industry accounting for brokers and dealers in securities also prescribed under US GAAP. The Company also retains specialized accounting upon consolidation.
Use of estimates	Use of estimates The preparation of the accompanying condensed consolidated financial statements in conformity with US GAAP requires the management of the Company to make estimates and assumptions that affect the fair value of securities and other investments, the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the accompanying condensed consolidated financial statements, the accounting for goodwill and identifiable intangible assets and the reported amounts of revenues and expenses during the reporting period. Actual results could materially differ from those estimates.
Allowance for doubtful accounts	Allowance for credit losses The allowance for credit losses is based on the Company’s assessment of the collectability of receivables related to securities transactions, prepaid research and other receivables. The Company considers factors such as historical experience, credit quality, age of balances and current economic conditions that may affect collectability in determining the allowance for credit losses. Specifically, for prepaid research, the Company reviews clients' historical, current and forecasted trading activity in determining the allowance for credit losses. The credit loss expense related to the allowance for credit losses as well as any recoveries of amounts previously charged is reflected in other expenses in the accompanying condensed consolidated statements of operations.
Valuation of investments and derivative contracts	Valuation of investments and derivative contracts US GAAP establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (level 1 measurements) and the lowest priority to unobservable inputs (level 3 measurements). The three levels of the fair value hierarchy are as follows: Level 1 Inputs that reflect unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date; Level 2 Inputs other than quoted prices that are observable for the asset or liability either directly or indirectly, including inputs in markets that are not considered to be active; and Level 3 Fair value is determined based on pricing inputs that are unobservable and includes situations where there is little, if any, market activity for the asset or liability. The determination of fair value for assets and liabilities in this category requires significant management judgment or estimation. Inputs are used in applying the various valuation techniques and broadly refer to the assumptions that market participants use to make valuation decisions, including assumptions about risk. Inputs may include price information, volatility statistics, specific and broad credit data, liquidity statistics, and other factors. A financial instrument's level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. However, the determination of what constitutes “observable” requires significant judgment by the Company. The Company considers observable data to be that market data which is readily available, regularly distributed or updated, reliable and verifiable, not proprietary, and provided by independent sources that are actively involved in the relevant market. The categorization of a financial instrument within the hierarchy is based upon the pricing transparency of the instrument and does not necessarily correspond to the Company's perceived risk of that instrument. The Company and its operating subsidiaries act as the manager for the Consolidated Funds. Both the Company and the Consolidated Funds hold certain investments which are valued by the Company, acting as the investment manager. The fair value of these investments is generally estimated based on proprietary models developed by the Company, which include discounted cash flow analysis, public market comparables, and other techniques and may be based, at least in part, on independently sourced market information. The material estimates and assumptions used in these models include the timing and expected amount of cash flows, the appropriateness of discount rates used, and, in some cases, the ability to execute, timing of, and estimated proceeds from expected financings. Significant judgment and estimation impact the selection of an appropriate valuation methodology as well as the assumptions used in these models, and the timing and actual values realized with respect to investments could be materially different from values derived based on the use of those estimates. The valuation methodologies applied impact the reported value of the Company's investments and the investments held by the Consolidated Funds in the condensed consolidated financial statements. Certain of the Company's investments are relatively illiquid or thinly traded and may not be immediately liquidated on demand if needed. Fair values assigned to these investments may differ significantly from the fair values that would have been used had a ready market for the investments existed and such differences could be material . The Company primarily uses the “market approach” to value its financial instruments measured at fair value. In determining an instrument's level within the hierarchy, the Company categorizes the Company's financial instruments into three categories: securities, derivative contracts and other investments. To the extent applicable, each of these categories can further be divided between those held long or sold short. The Company has the option to measure certain financial assets and financial liabilities at fair value with changes in fair value recognized in earnings each period. The election is made on an instrument by instrument basis at initial recognition of an asset or liability or upon an event that gives rise to a new basis of accounting for that instrument. The Company has elected the fair value option for certain of its investments held by its operating companies. This option has been elected because the Company believes that it is consistent with the manner in which the business is managed, as well as the way that financial instruments in other parts of the business are recorded. Securities — Securities with values based on quoted market prices in active markets for identical assets are classified within level 1 of the fair value hierarchy. These securities primarily include active listed equities, certain U.S. government and sovereign obligations, Exchange Traded Funds ("ETFs"), mutual funds and certain money market securities. The Company does not adjust the quoted price for such instruments, even in situations where the Company holds a large position and a sale could reasonably impact the quoted price. Certain positions for which trading activity may not be readily visible, consisting primarily of convertible debt, corporate debt and loans and restricted equities, are stated at fair value and classified within level 2 of the fair value hierarchy. The estimated fair values assigned by management are determined in good faith and are based on available information considering, trading activity, broker quotes, quotations provided by published pricing services, counterparties and other market participants, and pricing models using quoted inputs, and do not necessarily represent the amounts which might ultimately be realized. As level 2 investments include positions that are not always traded in active markets and/or are subject to transfer restrictions, valuations may be adjusted to reflect illiquidity and/or non-transferability. Derivative contracts — Derivative contracts can be exchange-traded or privately negotiated over-the-counter (“OTC”). Exchange-traded derivatives, such as futures contracts and exchange-traded option contracts, are typically classified within level 1 or level 2 of the fair value hierarchy depending on whether or not they are deemed to be actively traded. OTC derivatives, such as generic forwards, swaps and options, have inputs which can generally be corroborated by market data and are therefore classified within level 2. OTC derivatives, such as swaps and options where market data is not readily available or observable are classified as level 3. Other investments — Other investments consist primarily of investment funds, real estate investments, carried interest and equity method investments, which are valued as follows : i. Portfolio funds— Portfolio funds (“Portfolio Funds”) include equity interests in private investment partnerships, foreign investment companies and other collective investment vehicles which may be managed by the Company or its affiliates. The Company follows US GAAP regarding fair value measurements and disclosures relating to investments in certain entities that calculate net asset value (“NAV”) per share (or its equivalent). The Company applies the practical expedient provided by US GAAP that permits an entity holding investments in certain entities that (a) do not have readily determinable fair values, (b) are investments in an investment company within the scope of ASC 946 Financial Services - Investment Companies (“ASC 946”) and (c) whose NAV is calculated in a manner consistent with the measurement principles of ASC 946 as of the reporting date, to measure the fair value of such investments on the basis of that NAV per share, or its equivalent, without adjustment. The Company applies an accounting policy election to recognize incentive income allocated to the Company under an equity ownership model as other investments in the accompanying condensed consolidated statements of financial condition (see Note 6). Carried interest allocated to the Company from certain portfolio funds represents Cowen's general partner capital accounts from those funds. These balances are subject to change upon cash distributions, additional allocations or reallocations back to limited partners within the respective funds. Investments which are valued using NAV per share as a practical expedient are not categorized within the fair value hierarchy. ii. Real estate investments— Real estate debt and equity investments are valued at fair value. The fair value of real estate investments is estimated based on the price that would be received to sell an asset in an orderly transaction between marketplace participants at the measurement date. Real estate investments without a public market are valued based on assumptions and valuation techniques used by the Company. Such valuation techniques may include discounted cash flow analysis, prevailing market capitalization rates or earnings multiples applied to earnings from the investment, analysis of recent comparable sales transactions, actual sale negotiations and bona fide purchase offers received from third parties, consideration of the amount that currently would be required to replace the asset, as adjusted for obsolescence, as well as independent external appraisals. In general, the Company considers several valuation techniques when measuring the fair value of a real estate investment. However, in certain circumstances, a single valuation technique may be appropriate. Real estate investments are reviewed on a quarterly basis by the Company for significant changes at the property level or a significant change in the overall market which would impact the value of the real estate investment resulting in unrealized appreciation or depreciation. Real estate and capital markets are cyclical in nature. Property and investment values are affected by, among other things, the availability of capital, occupancy rates, rental rates and interest and inflation rates. In addition, the Company invests in real estate and real estate related investments for which no liquid market exists. The market prices for such investments may be volatile and may not be readily ascertainable. Amounts ultimately realized by the Company from investments sold may differ from the fair values presented, and the differences could be material. The Company's real estate investments are typically categorized as level 3 investments within the fair value hierarchy as management uses significant unobservable inputs in determining their estimated fair value. See Notes 6 and 7 for further information regarding the Company's investments, including equity method investments and fair value measurements.
Fees receivable	Fees receivable Fees related to security transactions are reported net of an allowance for credit losses. An allowance for credit losses is assessed on any commission receivables aged over 180 days. Corporate finance and syndicate receivables, include receivables relating to the Company’s investment banking and advisory engagements net of allowance for credit losses. The Company records this allowance for credit losses on these receivables on a specific identification basis. The future collectability of the receivables is reviewed on a monthly basis based on the following factors: aging (usually if outstanding greater than 90 days), known financial stability of the paying company, as well as any other factors that might impact the collection of the outstanding fees. Management and incentive fees are earned as the managing member, general partner and/or investment manager to the Company's investment funds and are recognized in accordance with appropriate revenue recognition guidance (see Note 2( m )).
Securities borrowed and securities loaned	Securities financing arrangements Securities borrowed and securities loaned are carried at the amounts of cash collateral advanced or received on a gross basis. The related rebates are recorded in the accompanying condensed consolidated statements of operations as interest and dividends income and interest and dividends expense. Securities borrowed transactions require the Company to deposit cash collateral with the lender. With respect to securities loaned, the Company receives cash or securities as collateral from the borrower. When the Company receives securities as collateral, and has concluded it (i) is the transferor and (ii) can pledge the securities to third parties, the Company recognizes the securities received as collateral at fair value in Securities owned, at fair value with the corresponding obligation to return the securities received as collateral at fair value in Securities sold, not yet purchased, at fair value. Securities received as collateral are not recognized when the Company either (i) is not the transferor or (ii) cannot pledge the securities to third parties. The initial collateral advanced or received approximates or is greater than the market value of securities borrowed or loaned. The Company monitors the market value of securities borrowed and loaned on a daily basis, with additional collateral obtained or returned, as necessary. Securities borrowed and loaned may also result in credit exposures for the Company in an event that the counterparties are unable to fulfill their contractual obligations. The Company minimizes its credit risk by continuously monitoring its credit exposure and collateral values by demanding additional or returning excess collateral in accordance with the netting provisions available in the master securities lending contracts in place with the counterparties. Fees and interest received or paid are recorded in interest and dividends income and interest and dividends expense, respectively, on an accrual basis in the accompanying condensed consolidated statements of operations. In cases where the fair value basis of accounting is elected, any resulting change in fair value would be reported in net gains (losses) on securities, derivatives and other investments in the accompanying condensed consolidated statements of operations. Accrued interest income and expense are recorded in receivable from brokers, dealers and clearing organizations and payable to brokers, dealers and clearing organizations, respectively, on an accrual basis in the accompanying condensed consolidated statements of financial condition. At September 30, 2019 and December 31, 2018 , the Company did not have any securities lending transactions for which fair value basis of accounting was elected.
Securities sold under agreements to repurchase	Securities sold under agreements to repurchase Securities sold under agreements to repurchase ("repos") are accounted for as collateralized financing transactions and are recorded at their contracted repurchase amount plus accrued interest. A repo is a transaction in which a firm sells financial instruments to a buyer, typically in exchange for cash, and simultaneously enters into an agreement to repurchase the same or substantially the same financial instruments from such buyer at a stated price plus accrued interest at a future date. When the Company receives securities as collateral, and has concluded it (i) is the transferor and (ii) can pledge the securities to third parties, the Company recognizes the securities received as collateral at fair value in Securities owned, at fair value with the corresponding obligation to return the securities received as collateral at fair value in Securities sold, not yet purchased, at fair value. Securities received as collateral are not recognized when the Company either (i) is not the transferor or (ii) cannot pledge the securities to third parties. The initial collateral advanced approximates or is greater than the market value of securities sold in the transaction. The Company typically enters into repo transactions with counterparties that prefer repo transactions to securities loaned transactions. The Company has executed master repo agreements with such counterparties and utilizes such counterparties to finance its own positions, or replace a securities lending transaction with a repo for matched book purposes. The Company monitors the market value of repos on a daily basis, with additional collateral obtained or returned, as necessary. Repos may also result in credit exposures for the Company in an event that the counterparties are unable to fulfill their contractual obligations. The Company mitigates its credit risk by continuously monitoring its credit exposure and collateral values by demanding additional collateral or returning excess collateral in accordance with the netting provisions available in the master repo contracts in place with the counterparties. Interest paid is recorded in interest and dividends expense on an accrual basis in the accompanying condensed consolidated statements of operations. In cases where the fair value basis of accounting is elected, any resulting change in fair value would be reported in net gains (losses) on securities, derivatives and other investments in the accompanying condensed consolidated statements of operations. At September 30, 2019 and December 31, 2018, the Company did not have any repos for which fair value basis of accounting was elected.
Fixed Assets	Fixed assets Fixed assets are stated at cost less accumulated depreciation or amortization. Leasehold improvements are amortized on a straight-line basis over the lesser of their useful life or lease term. When the Company commits to a plan to abandon fixed assets or leasehold improvements before the end of its original useful life, the estimated depreciation or amortization period is revised to reflect the shortened useful life of the asset. Other fixed assets are depreciated on a straight-line basis over their estimated useful lives. Asset Depreciable Lives Depreciation and/or Amortization Method Telephone and computer equipment 5 years Straight-line Computer software 4 years Straight-line Furniture and fixtures 5 years Straight-line Leasehold improvements Term of Lease Straight-line Finance lease right-of-use asset 5 years Straight-line
Goodwill and Intangible Assets	Goodwill and intangible assets Goodwill Goodwill represents the excess of the purchase price consideration of acquired companies over the estimated fair value assigned to the individual assets acquired and liabilities assumed. Goodwill is allocated to the Company's reporting units at the date the goodwill is initially recorded. Once goodwill has been allocated to the reporting units, it generally no longer retains its identification with a particular acquisition but instead becomes identifiable with the reporting unit. As a result, all of the fair value of each reporting unit is available to support the value of goodwill allocated to the unit. In January 2017, the FASB issued guidance that simplifies the subsequent measurement of goodwill. The new guidance eliminated Step 2 from the goodwill impairment test which was required in computing the implied fair value of goodwill. Instead, under the new amendments, an entity should perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. The Company early adopted these amendments during the second quarter of 2019 in conjunction with a quantitative goodwill test performed due to the Company’s change in operating segments and restructuring of reporting units. See Note 11 for the impact of the goodwill impairment test. In accordance with US GAAP, inclusive of the newly adopted amendments, the Company tests goodwill for impairment on an annual basis or at an interim period if events or changed circumstances would more likely than not reduce the fair value of a reporting unit below its carrying amount. In testing for goodwill impairment, the Company has the option to first assess qualitative factors to determine whether the existence of events or circumstances led to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If, after assessing the totality of events and circumstances, the Company concludes that fair value exceeds its carrying amount, then performing a quantitative impairment test is not necessary. If the Company concludes otherwise, the Company is required to perform a quantitative impairment test that requires a comparison of the fair value of the reporting unit to its carrying value, including goodwill. If the fair value of the reporting unit exceeds its carrying value, the related goodwill is not considered impaired and no further analysis is required. If the carrying value of the reporting unit exceeds its fair value, then the Company recognizes an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value. See Note 11 for further discussion. Intangible assets Intangible assets with finite lives are amortized over their estimated average useful lives. The Company does not have any intangible assets deemed to have indefinite lives. Intangible assets are tested for potential impairment whenever events or changes in circumstances suggest that an asset or asset group's carrying value may not be fully recoverable. An impairment loss, calculated as the difference between the estimated fair value and the carrying value of an asset or asset group, is recognized in the accompanying consolidated statements of operations if the sum of the estimated undiscounted cash flows relating to the asset or asset group is less than the corresponding carrying value. Goodwill and Intangible Assets In accordance with US GAAP, the Company tests goodwill for impairment on an annual basis or at an interim period if events or changed circumstances would more likely than not reduce the fair value of a reporting unit below its carrying amount. Under US GAAP, the Company first assesses the qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amounts as a basis for determining if it is necessary to perform a quantitative impairment test. Periodically estimating the fair value of a reporting unit requires significant judgment and often involves the use of significant estimates and assumptions. These estimates and assumptions could have a significant effect on whether or not an impairment charge is recorded and the magnitude of such a charge. During the second quarter of 2019, the Company realigned its business segments to Op Co and Asset Co (See Note 1 ). Prior to the reorganization, our Investment Management segment was also a reporting unit for purposes of measuring and reporting goodwill. The goodwill that was previously attributable to the Investment Management reporting unit was reallocated to the CIM reporting unit within the Op Co segment and the Asset Co reporting unit based on the relative fair value of the respective portions that became attributable to those reporting units. The Asset Co segment is also a reporting unit for purposes of measuring and reporting goodwill. Based on the change in segments and restructuring of reporting units, the Company determined that it was necessary to perform a quantitative impairment test which involves estimates of future cash flows, discount rates, economic forecast and other assumptions which are then used in the market approach (earnings and / or transactions multiples) and / or income approach (discounted cash flow method). Based on the results of the impairment analysis, the Company recognized a goodwill impairment, during the second quarter of 2019, in the amount of $4.1 million within the Asset Co reporting unit. No impairment charges for goodwill were recognized during the year ended December 31, 2018. The following table presents the changes in the Company's goodwill balance, by reporting unit for the periods ended September 30, 2019 and December 31, 2018 : Investment Management Investment Bank Cowen Investment Management Asset Co Total (dollars in thousands) Beginning balance - December 31, 2017 Goodwill $ 29,026 $ 51,337 $ — $ — 80,363 Accumulated impairment charges (10,200 ) (9,485 ) — — (19,685 ) Net 18,826 41,852 — — 60,678 Activity: 2018 Recognized goodwill — — — — — Goodwill impairment charges — — — — — Ending balance: December 31, 2018 Goodwill 29,026 51,337 — — 80,363 Accumulated impairment charges (10,200 ) (9,485 ) — — (19,685 ) Net 18,826 41,852 — — 60,678 Activity: 2019 Recognized goodwill (See note 3) — 81,150 — — 81,150 Realignment of segment goodwill: Goodwill (29,026 ) — 22,705 6,321 — Accumulated impairment charges 10,200 — (7,979 ) (2,221 ) — Goodwill impairment charges — — — (4,100 ) (4,100 ) Ending balance: September 30, 2019 Goodwill — 132,487 22,705 6,321 161,513 Accumulated impairment charges — (9,485 ) (7,979 ) (6,321 ) (23,785 ) Net $ — $ 123,002 $ 14,726 $ — $ 137,728 In connection with the Quarton transaction (see Note 3 ), in January 2019, the Company recognized goodwill of $81.2 million and intangible assets (including customer relationships, trade name, backlog and proprietary software) with an estimated fair value of $22.2 million which are included within intangible assets, net in the condensed consolidated statements of financial condition with the expected useful lives ranging from 2 to 4 years with a weighted average useful life of 2.8 years . Amortization expense related to intangibles from the Quarton acquisition for the three and nine months ended September 30, 2019 is $2.2 million and $6.7 million , respectively. Goodwill, the excess of the purchase price over the fair value of net assets, primarily relates to expected synergies from combining operations and has been assigned to the Op Co segment of the Company. Tax deductible goodwill will differ from goodwill recognized by the Company in an amount equal to the difference between actual contingent consideration and estimated contingent consideration (see Note 3 ).
Debt	Debt Long-term debt is carried at the principal amount borrowed net of any unamortized discount/premium. The discount is accreted to interest expense using the effective interest method over the remaining life of the underlying debt obligations. Accrued but unpaid coupon interest is included in accounts payable, accrued expenses and other liabilities in the accompanying condensed consolidated statements of financial condition.
Revenue recognition	Revenue recognition The Company recognizes revenue in accordance with ASC Topic 606, Revenue from Contracts with Customers ("ASC Topic 606"), which requires that an entity recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The Company follows a five-step model to (a) identify the contract(s) with a customer, (b) identify the performance obligations in the contract, (c) determine the transaction price, (d) allocate the transaction price to the performance obligations in the contract, and (e) recognize revenue when (or as) the entity satisfies a performance obligation. In determining the transaction price, the Company includes variable consideration only to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized would not occur when the uncertainty associated with the variable consideration is resolved. Significant judgments are required in the application of the five-step model including; when determining whether performance obligations are satisfied at a point in time or over time; how to allocate transaction prices where multiple performance obligations are identified; when to recognize revenue based on the appropriate measure of the Company’s progress under the contract; and whether constraints on variable consideration should be applied due to uncertain future events. The Company's principle sources of revenue are generated within two segments: Op Co and Asset Co as more fully described below. Revenue from contracts with customers includes management fees, incentive income, investment banking revenue and brokerage services revenue excluding principal transactions. ASC Topic 606 does not apply to revenue associated with financial instruments, interest income and expense, leasing and insurance contracts. The following is a description of principal activities, separated by business segments, from which the Company generates its revenue. For more detailed information about reportable segments, see Note 22 . Operating Company The Op Co segment generates revenue through five principle sources: investment banking revenue, brokerage revenue, management fees, incentive income and investment income from the Company's own capital. Investment income is excluded from ASC Topic 606. Investment Banking The Company earns investment banking revenue primarily from fees associated with public and private capital raising transactions and providing strategic advisory services. Investment banking revenues are derived primarily from public and private small- and mid-capitalization companies within the Company's Target Sectors. Investment banking revenue consists of underwriting fees, strategic/financial advisory fees, expenses reimbursed from clients and placement and sales agent fees. • Underwriting fees. The Company earns underwriting fees in securities offerings in which the Company acts as an underwriter, such as initial public offerings, follow-on equity offerings, debt offerings, and convertible securities offerings. Fee revenue relating to underwriting commitments is recorded at the point in time when all significant items relating to the underwriting process have been completed and the amount of the underwriting revenue has been determined. This generally is the point at which all of the following have occurred: (i) the issuer's registration statement has become effective with the SEC or the other offering documents are finalized; (ii) the Company has made a firm commitment for the purchase of securities from the issuer; (iii) the Company has been informed of the number of securities that it has been allotted; and (iv) the issuer obtains control and benefits of the offering; which generally occurs on trade date. Underwriting fees are recognized gross of transaction-related expenses, and such amounts are adjusted to reflect actual expenses in the period in which the Company receives the final settlement, typically within 90 days following the closing of the transaction. • Strategic/financial advisory fees. The Company's strategic advisory revenue includes success fees earned in connection with advising companies, principally in mergers, acquisitions and restructuring transactions. The Company also earns fees for related advisory work such as providing fairness opinions. A significant portion of the Company's advisory revenue (i.e., success related advisory fees) is considered variable consideration and recognized when it is probable that the variable consideration will not be reversed in a future period. The variable consideration is constrained until satisfaction of the performance obligation. The Company records strategic advisory revenues at the point in time, gross of related expenses, when the services for the transactions are completed or the contract is canceled under the terms of each assignment or engagement. • Placement and sales agent fees. The Company earns agency placement fees and sales agent commissions in non-underwritten transactions, such as private placements of loans and debt and equity securities, including, private investment in public equity transactions (“PIPEs”), and as sales agent in at-the-market offerings of equity securities. The Company records placement revenues (which may be in cash and/or securities) at the point in time when the services for the transactions are completed under the terms of each assignment or engagement. The Company records sales agent commissions on a trade-date basis. • Expense reimbursements from clients. Investment banking revenue includes expense reimbursements for transaction-related expenses, primarily consisting of legal, travel and other costs directly associated with the transaction. Expense reimbursements associated with investment banking engagements are recognized in revenue at the point in time when the Company is contractually entitled to reimbursement. The related expenses are presented gross within their respective expense category in the accompanying condensed consolidated statements of operations. Brokerage Brokerage revenue consists of commissions, principal transactions, equity and credit research fees and trade conversion revenue. • Commissions. Commission revenue includes fees from executing and clearing client transactions and commission sharing arrangements. Trade execution and clearing services, when provided together, represent a single performance obligation as the services are not separately identifiable in the context of the contract. Commission revenues associated with combined trade execution and clearing services on a standalone basis, are recognized at a point in time on trade-date. Commissions revenues are generally paid on settlement date and the Company records a receivable between trade-date and payment on settlement date. The Company permits institutional customers to allocate a portion of their commissions to pay for research products and other services provided by third parties. The amounts allocated for those purposes are commonly referred to as "soft dollar arrangements". The Company also offers institutional clients the ability to allocate a portion of their gross commissions incurred on trades executed with various brokers to pay for research products and other services provided by third parties by entering into commission sharing arrangements. The Company acts as an agent in the soft dollar and commission sharing arrangements as the customer controls the use of the soft dollars and directs payments to third-party service providers on its behalf. Accordingly, amounts allocated to soft dollar arrangements are netted against commission revenues and recorded on trade date. Commissions on soft dollar brokerage are recorded net of the related expenditures. The costs of commission sharing arrangements are recorded for each eligible trade and shown net of commission revenue. • Principal transactions. Principal transactions revenue includes net trading gains and losses from the Company's market-making activities in over-the-counter equity and fixed income securities, trading of convertible securities, and trading gains and losses on inventory and other Company positions, which include securities previously received as part of investment banking transactions. In certain cases, the Company provides liquidity to clients by buying or selling blocks of shares of listed stocks without previously identifying the other side of the trade at execution, which subjects the Company to market risk. These positions are typically held for a short duration. • Equity and credit research fees. Equity and credit research fees are paid to the Company for providing its equity and credit research. In the US, revenue is recognized once an arrangement exists, access to research has been provided and the customer has benefited from the research. As part of MiFID II, the Company’s international broker-dealers have executed equity and credit research contracts with its clients. The contracts either contain a fixed price for providing access to research or a price at the discretion of the customer with a contract minimum. Fixed equity and credit research fees are recognized over the contract period as the customer is benefiting from the research throughout the contracts term. When the equity and credit research fees are based on the customer’s discretion with a contract minimum, the Company recognizes the contract minimum over the life of the contract as the customer benefits from the research provided and adjusts the revenue when the Company can estimate the amount of equity and credit research fees over the contract minimum. Additionally, the Company earns variable consideration for attending client conferences and events. Revenue is recognized when the Company attends a client conference or event. • Trade conversion revenue. Trade conversion revenue includes fees earned from converting foreign securities into an American Depository Receipt (“ADR”) and fees earned from converting an ADR into foreign securities on behalf of customers, and margins earned from facilitating customer foreign exchange transactions. Trade conversion revenue is recognized on a trade-date basis. Management fees The Company earns management fees from investment funds and certain managed accounts for which it serves as the investment manager; such fees earned are typically based on committed and invested capital. The Company has determined that the primary drivers of management fees are committed and invested capital relating to private equity funds. The management fees are earned as the investment management services are provided and are not subject to reversals. The performance obligation related to the transfer of these services is satisfied over time because the customer is receiving and consuming the benefits as they are provided by the Company. Several investment managers and/or general partners of the investment funds are owned jointly by the Company and third parties. Accordingly, the management fees generated by these funds are split between the Company and these third parties based on the proportionate ownership of the management company. Pursuant to US GAAP, these fees received by the management companies are accounted for under the equity method of accounting and are reflected under net gains (losses) on securities, derivatives and other investments in the accompanying condensed consolidated statements of operations. Management fees are generally paid on a quarterly basis and are prorated for capital inflows (or commitments) and redemptions (or distributions) and are recognized as revenue at that time as they relate specifically to the services provided in that period, which are distinct from the services provided in other periods. While some investors may have separately negotiated fees, in general the management fees are as follows: • Private Equity Funds. Management fees for the Company's private equity or debt funds are generally charged at an annual rate of 1% to 2% of committed capital during the investment period (as defined in the relevant partnership agreement). After the investment period, management fees for these private equity funds are generally charged at an annual rate of 0.5% to 2% of the net asset value or the aggregate cost basis of the unrealized investments held by the private equity funds. For certain other private equity funds (and managed accounts), the management fees range from 0.2% to 1% and there is no adjustment based on the investment period. Management fees for the Company's private equity funds are generally paid on a quarterly basis. • Hedge Funds. Management fees for the Company's hedge funds are generally charged at an annual rate of up to 2% of utilized invested capital, committed capital or notional trading level. Management fees are generally calculated monthly at the end of each month. • Cowen Trading Strategies. Advisory fees for the Company's collateral management advisory business are typically paid quarterly based on utilized invested capital or committed capital, generally subject to a minimum fee. Incentive income The Company earns incentive income based on net profits (as defined in the respective investment management or partnership agreements) with respect to certain of the Company's investment funds and managed accounts. The incentive income is either allocated to the Company or is charged to the investment funds in accordance with their respective investment management or partnership agreements. For the hedge funds the Company offers, incentive income earned is typically up to 20% (in certain cases on performance in excess of a benchmark) of the net profits earned for the full year that are attributable to each fee-paying investor. For the private equity and debt fund products the Company offers, the carried interest earned is typically up to 20% of the distributions made to investors after return of their contributed capital and generally a preferred return. In relation to ASC Topic 606, the Company applies an accounting policy election to recognize incentive income allocated to the Company under an equity ownership model as net gains (losses) on securities, derivatives and other investments in the accompanying condensed consolidated statements of operations. The Company previously recognized these amounts as incentive income. Under the equity method of accounting the Company recognizes its allocations of incentive income or carried interest within net gains (losses) along with the allocations proportionate to the Company’s ownership interests in the investment funds. The Company recognizes incentive income charged to the Company's hedge funds based on the net profits of the hedge funds. The Company recognizes such incentive income when the fees are no longer subject to reversal or are crystalized. For a majority of the hedge funds, the incentive fee crystallizes annually when the high-water mark for such hedge funds is reset, which delays recognition of the incentive fee until year end. In periods following a period of a net loss attributable to an investor, the Company generally does not earn incentive income on any future profits attributable to such investor until the accumulated net loss from prior periods is recovered, an arrangement commonly referred to as a “high-water mark.” Generally, incentive income or carried interest is earned after the investor has received a full return of their invested capital, plus a preferred return. With respect to the Company’s private equity investment management strategies, the Company grants its employees, that act as portfolio managers for its private equity fund products, membership into the respective general partner entities that are the general partner of the funds they manage. These awards entitle the employees to share in future distributions of carried interest earned by the general partners. These arrangements are accounted for as profit sharing awards and accordingly amounts are reflected in compensation payable in the accompanying condensed consolidated financial statements of financial condition and employee compensation and benefits expense in the accompanying condensed consolidated statements of operation based on the probable and estimable payments under the terms of the awards. Investment Income Investment income earned by the Op Co segment is earned from investing the Company's capital in various strategies which align to existing businesses within Op Co and from investments in private capital raising transactions of its investment banking clients. Asset Company The Asset Co segment generates revenue through three principle sources: management fees, incentive income and investment income from the Company's own capital. Investment income is excluded from ASC Topic 606. Management fees The Company earns management fees from investment funds and certain managed accounts for which it serves as the investment manager; such fees earned are typically based on committed and invested capital. The management fees are earned as the investment management services are provided and are not subject to reversals. The performance obligation related to the transfer of these services is satisfied over time because the customer is receiving and consuming the benefits as they are provided by the Company. Several investment managers and/or general partners of the investment funds are owned jointly by the Company and third parties. Accordingly, the management fees generated by these funds are split between the Company and these third parties based on the proportionate ownership of the management company. Pursuant to US GAAP, these fees received by the management companies are accounted for under the equity method of accounting and are reflected under net gains (losses) on securities, derivatives and other investments in the accompanying condensed consolidated statements of operations. Management fees are generally paid on a quarterly basis and are prorated for capital inflows (or commitments) and redemptions (or distributions) and are recognized as revenue at that time as they relate specifically to the services provided in that period, which are distinct from the services provided in other periods. While some investors may have separately negotiated fees, in general, the management fees are as follows: • Hedge Funds. Management fees for the Company's hedge funds are generally charged at an annual rate of up to 2% of utilized invested capital, committed capital or notional trading level. Management fees are generally calculated monthly at the end of each month. • Real Estate. Management fees from the Company's real estate business are generally charged at an annual rate from 0.25% to 1.50% of total capital commitments during the investment period and of invested capital or net asset value of the applicable real estate fund after the investment period has ended. Management fees are typically paid to the general partners on a quarterly basis, at the beginning of the quarter in arrears. Incentive income The Company earns incentive income based on net profits (as defined in the respective investment management or partnership agreement) related to certain of the Company's investment funds and managed accounts. The incentive income is either allocated to the Company or is charged to the investment funds in accordance with their corresponding investment management or partnership agreement. For the hedge funds the Company offers, incentive income earned is typically up to 20% (in certain cases on performance in excess of a benchmark) of the net profits earned for the full year that are attributable to each fee-paying investor. For the private equity and debt fund products the Company offers, the carried interest earned is typically up to 20% of the distributions made to investors after return of their contributed capital and generally a preferred return. In relation to ASC Topic 606, the Company applies an accounting policy election to recognize incentive income allocated to the Company under an equity ownership model as net gains (losses) on securities, derivatives and other investments in the accompanying condensed consolidated statements of operations. The Company previously recognized these amounts as incentive income. Under the equity method of accounting the Company recognizes its allocations of incentive income or carried interest within net gains (losses) along with the allocations proportionate to the Company’s ownership interests in the investment funds. The Company recognizes incentive income charged to the Company's hedge funds based on the net profits of the hedge funds. The Company recognizes such incentive income when the fees are no longer subject to reversal or are crystalized. For certain hedge funds, the incentive fee crystallizes annually when the high-water mark for such hedge funds is reset, which delays recognition of the incentive fee until year end. In periods following a period of a net loss attributable to an investor, the Company generally does not earn incentive income on any future profits attributable to such investor until the accumulated net loss from prior periods is recovered, an arrangement commonly referred to as a “high-water mark.” Generally, incentive income or carried interest is earned after the investor has received a full return of their invested capital, plus a preferred return. However, for certain private equity structures, the Company is entitled to receive incentive fees earlier, provided that the investors have received their preferred return on a current basis or on an investor by investor basis. These private equity structures are generally subject to a potential clawback of these incentive fees upon the liquidation of the private equity structure if the investor has not received a full return of its invested capital plus the preferred return thereon. Several investment managers and/or general partners of the Company's investment funds are jointly owned by the Company and third parties. Accordingly, the incentive fees generated by these investment funds are split between the Company and these third parties. Pursuant to US GAAP, incentive income received by the general partners that are accounted for under the equity method of accounting are reflected under net gains (losses) on securities, derivatives and other investments in the accompanying condensed consolidated statements of operations. Investment Income Investment income earned by the Asset Co segment is earned from investing the Company's capital in various strategies. Revenue from contracts with customers For the three and nine months ended September 30, 2019 and 2018 , the following tables presents revenues from contracts with customers disaggregated by fee type and segment. Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (dollars in thousands) Revenue from contracts with customers Operating Company Investment Banking Underwriting fees $ 38,936 $ 46,537 $ 162,140 $ 181,056 Strategic/financial advisory fees 17,889 22,195 49,565 51,053 Placement and sales agent fees 15,842 13,191 48,855 32,628 Expense reimbursements from clients 4,625 — 11,543 — Total Investment Banking Revenue 77,292 81,923 272,103 264,737 Brokerage Commissions 82,715 84,882 263,831 270,917 Trade conversion revenue 3,700 2,931 12,364 12,268 Equity and credit research fees 4,235 5,022 13,180 14,585 Total Brokerage Revenue from Customers 90,650 92,835 289,375 297,770 Management Fees 7,052 6,595 20,492 19,556 Incentive Income 701 33 710 97 Total revenue from contracts with customers - Op Co $ 175,695 $ 181,386 $ 582,680 $ 582,160 Asset Company Management Fees 248 951 988 2,780 Incentive Income — — 14 — Total revenue from contracts with customers - Asset Co 248 951 1,002 2,780 Total revenue from contracts with customers $ 175,943 $ 182,337 $ 583,682 $ 584,940 Interest and dividends Interest and dividends are earned by the Company from various sources. The Company receives interest and dividends primarily from securities finance activities and securities held by the Company for purposes of investing capital, investments held by its Consolidated Funds and its brokerage balances. Interest is recognized on an accrual basis and interest income is recognized on the debt of those issuers that is deemed collectible. Interest income and expense includes premiums and discounts amortized and accreted on debt investments based on criteria determined by the Company using the effective yield method, which assumes the reinvestment of all interest payments. Dividends are recognized on the ex-dividend date. Reimbursement from affiliates The Company allocates, at its discretion, certain expenses incurred on behalf of its investment management businesses. These expenses relate to the administration of such subsidiaries and assets that the Company manages for its investment funds. In addition, pursuant to the investment funds' offering documents, the Company charges certain allowable expenses to the investment funds, including charges and personnel costs for legal, compliance, accounting, tax compliance, risk and technology expenses that directly relate to administering the assets of the investment funds. Such expenses that have been reimbursed at their actual costs are included in the accompanying condensed consolidated statements of operations as employee compensation and benefits, professional, advisory and other fees, communications, occupancy and equipment, client services and business development and other expenses. Reinsurance-related contracts Premiums for reinsurance-related contracts are earned over the coverage period. In most cases, premiums are recognized as revenues ratably over the term of the contract with unearned premiums computed on a monthly basis. For each of its contracts, the Company determines if the contract provides indemnification against loss or liability relating to insurance risk, in accordance with US GAAP. If the Company determines that a contract does not expose it to a reasonable possibility of a significant loss from insurance risk, the Company records the contract under the deposit method of accounting with any net amount receivable reflected as an asset in other assets, and any net amount payable reflected as a liability within accounts payable, accrued expenses and other liabilities on the condensed consolidated statements of financial condition. The liabilities for losses and loss adjustment expenses are recorded at the estimated ultimate payment amounts, including reported losses. Estimated ultimate payment amounts are based upon (1) reports of losses from policyholders, (2) individual case estimates and (3) estimates of incurred but unreported losses. Provisions for losses and loss adjustment expenses are charged to earnings after deducting amounts recovered and estimates of recoverable amounts and are included in other expenses on the condensed consolidated statements of operations. Costs of acquiring new policies, which vary with and are directly related to the production of new policies, have been deferred to the extent that such costs are deemed recoverable from future premiums or gross profits. Such costs include commissions and allowances as well as certain costs of policy issuance and underwriting and are included within other assets in the condensed consolidated statements of financial condition. Interest and dividends expense Interest and dividends expense relates primarily to securities finance activities, trading activity with respect to the Company's investments and interest expense on debt.
Recently issued accounting pronouncements	Recent pronouncements Recently adopted In 2018, the FASB issued guidance related to the Tax Cuts and Jobs Act of 2017 (“TCJ Act”) for the optional reclassification of the residual tax effects, arising from the change in corporate tax rate, in accumulated other comprehensive loss to retained earnings. The reclassification is the difference between the amount previously recorded in other comprehensive income at the historical U.S. federal tax rate that remains in accumulated other comprehensive loss at the time the TCJ Act was effective and the amount that would have been recorded using the newly enacted rate. This guidance became effective during the first quarter of 2019; however, we did not elect to make the optional reclassification. In 2018, the FASB issued final guidance aligning the measurement and classification guidance for share-based payments to nonemployees with the guidance for share-based payments to employees, with certain exceptions. Under the guidance, the measurement of equity-classified nonemployee awards will be fixed at the grant date, which may lower their cost and reduce volatility in the income statement. The guidance became effective during the first quarter of 2019 and impacted the Company’s recognition and measurement of the retention bonus pool established in connection with the Company’s acquisition of Quarton International AG, which include share based payment to employees and nonemployees. Please refer to Note 3 for more information. In 2017, the FASB issued guidance to amend the amortization period for certain purchased callable debt securities held at a premium. Under prior guidance, entities generally amortized the premium as an adjustment of yield over the contractual life of the instrument. The new guidance shortened the amortization period for the premium to the earliest call date. The amendments do not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. This guidance became effective during the first quarter of 2019; however, the guidance did not have an impact on the Company's financials as it does not have investments in callable debt securities measured on an amortized cost basis. In 2017, the FASB issued guidance that simplifies the subsequent measurement of goodwill. The new guidance eliminated Step 2 from the goodwill impairment test which was required in computing the implied fair value of goodwill. Instead, under the new amendments, an entity should perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. The Company early adopted these amendments during the second quarter of 2019. Please refer to Note 2j for more information. In 2016, the FASB issued guidance that amends and supersedes its previous guidance regarding leases. The new guidance requires the lessee to recognize the right to use lease assets and lease liabilities that arise from leases greater than one year, and present them in its statement of financial condition. The guidance became effective during the first quarter of 2019. Please refer to Note 17 for more information. Recently issued In October 2018, the FASB issued guidance that made targeted changes to the related party consolidation guidance. The new guidance changes how entities evaluate decision-making fees under the variable interest entity guidance. To determine whether decision-making fees represent a variable interest, an entity will consider indirect interests held through related parties under common control on a proportionate basis under the new guidance, rather than in their entirety, as has been the case under current guidance. The guidance is effective in annual periods beginning after December 15, 2019 and interim periods within those fiscal years with early adoption permitted. The Company is currently evaluating the impact of the new guidance and does not expect this guidance to have a material impact on its consolidated statements of financial condition or its consolidated statements of operations. In August 2018, the FASB issued guidance for accounting for upfront costs and fees paid by a customer in a cloud computing arrangement. The guidance requires capitalization of implementation costs incurred in connection with a hosting arrangement or the development or obtainment of internal use software. The guidance is effective for public business entities for fiscal years beginning after December 15, 2019 and interim periods within those fiscal years for any implementation costs incurred after adoption. The Company is currently evaluating the impact of this guidance on the Company’s consolidated financial statements and does not expect this guidance to have a material impact on its consolidated statements of financial condition or its consolidated statements of operations. In August 2018, as part of its disclosure framework project, the FASB amended the disclosure requirements for fair value measurement. The amendments update and eliminate various disclosure requirements that improve the overall usefulness of the disclosure requirement for financial statement users and reduce costs by eliminating disclosures that may not be useful. The guidance is effective for public business entities for fiscal years beginning after December 15, 2019 and interim periods within those fiscal years. Since the guidance only relates to disclosure requirements, the Company does not expect this guidance to have a material impact on its consolidated statements of financial condition or its consolidated statements of operations. In June 2016, the FASB issued guidance that impacts the impairment model for certain financial assets measured at amortized cost by requiring a current expected credit loss (“CECL”) methodology to estimate expected credit losses over the entire life of the financial asset, recorded at inception or purchase. The Company has performed a preliminary scoping assessment and identified securities borrowed and other financial instruments carried at amortized cost as impacted. Under the accounting update, the Company has the ability to determine there are no expected credit losses in certain circumstances, e.g., based on collateral arrangements for lending and financing transactions or based on the credit quality of the borrower or issuer. For securities borrowed, the Company will apply a practical expedient to measure the allowance for credit losses based on the fair value of the collateral. If the fair value of the collateral held exceeds the amortized cost and the borrower is expected to continue to replenish the collateral as needed, the Company will not recognize an allowance. If the fair value of collateral is less than amortized cost and the borrower is expected to continue to replenish the collateral as needed, the CECL model will be applied only to the shortfall between the fair value of the collateral and amortized cost. For public companies, the guidance is effective for reporting periods beginning after December 15, 2019 and interim periods within those fiscal years. Based on the Company's preliminary scoping analysis and impact assessment, the Company does not expect the increase in the allowance for credit losses, resulting from the adoption of this standard, to be significant to our consolidated statements of financial condition or its consolidated statements of operations.
Segment Reporting	Segment Reporting Change in Segments During the second quarter of 2019 the Company realigned the information that the Chief Operating Decision Maker regularly reviews to evaluate performance for operating decision-making purposes, including evaluation and allocation of resources. As a result of this change in segment reporting, the Company retrospectively revised prior period results, by segment, to conform to the current period presentation (see Note 1 ). This structure includes two business segments: Op Co and Asset Co. The structure is based on the Company's domain expertise as a driver of balance sheet harmonization and repeatable revenues for its operating business versus the Company’s long-term monetization strategies. The Op Co segment consists of Cowen Investment Management (“CIM”), Investment Banking, Markets and Research. The Asset Co segment consists of the Company’s private investments, private real estate investments and other legacy multi-sector long/short equity strategies. Performance Measures The performance measure for these segments is Economic Income (Loss), which management uses to evaluate the financial performance of and make operating decisions for the segments including determining appropriate compensation levels. Expenses not directly associated with specific segments are allocated based on the most relevant measures applicable, including headcount, square footage and other factors. In general, Economic Income (Loss) is a pre-tax measure that (i) eliminates the impact of consolidation for Consolidated Funds and excludes (ii) goodwill and intangible impairment (iii) certain other transaction-related adjustments and/or reorganization expenses and (iv) certain costs associated with debt. Economic Operating Income (Loss) represents Economic Income (Loss) before depreciation and amortization expenses. In addition, Economic Income (Loss) revenues include investment income that represents the income the Company has earned in investing its own capital, including realized and unrealized gains and losses, interest and dividends, net of associated investment related expenses. For US GAAP purposes, these items are included in each of their respective line items. Economic Income (Loss) revenues also include management fees, incentive income and investment income earned through the Company's investment as a general partner in certain real estate entities and the Company's investment in the activist business and certain investment funds. For US GAAP purposes, all of these items, are recorded in other income (loss). Economic Income (Loss) recognizes (a) incentive fees during periods when the fees are not yet crystallized for US GAAP reporting and (b) retainer fees, relating to investment banking activities, earned during the period that would otherwise be deferred until closing for US GAAP reporting. In addition, Economic Income (Loss) expenses are reduced by reimbursement from affiliates, which for US GAAP purposes is presented gross as part of revenue. As further stated below, one major difference between Economic Income (Loss) and US GAAP net income (loss) is that Economic Income (Loss) presents the segments' results of operations without the impact resulting from the full consolidation of any of the Consolidated Funds. The consolidation of these investment funds' results include the pro rata share of the income or loss attributable to other owners of such entities which is reflected in net income (loss) attributable to non-controlling interest in consolidated subsidiaries in the accompanying condensed consolidated statements of operations. This pro rata share has no effect on the overall financial performance for the segments, as ultimately, this income or loss is not income or loss for the segments themselves. Included in Economic Income (Loss) is the actual pro rata share of the income or loss attributable to the Company as an investor in such entities, which is relevant in management making operating decisions and evaluating financial performance. The Company does not disclose total asset information for its business segments as the information is not reviewed by the CODM. The following tables set forth operating results for the Company's Op Co and Asset Co segments and related adjustments necessary to reconcile the Company's Economic Income (Loss) measure to arrive at the Company's consolidated US GAAP net income (loss):
Leases of Lessee Disclosure [Text Block]	Right-of-use assets and lease liabilities Effective January 1, 2019, the Company adopted ASC Topic 842, Leases ("ASC 842"). The new guidance increases transparency and comparability by requiring the recognition of right-of-use assets and lease liabilities on the condensed consolidated statements of financial condition. The recognition of these lease assets and lease liabilities represents a change from previous US GAAP requirements, which did not require lease assets and lease liabilities to be recognized for most leases. The recognition, measurement, and presentation of expenses and cash flows arising from a lease by a lessee, have not significantly changed from previous US GAAP requirements. Under the effective date transition method selected by the Company, leases existing at, or entered into after January 1, 2019 were required to be recognized and measured. Prior period amounts have not been adjusted and continue to be reflected in accordance with the Company’s historical Accounting Standards. In applying ASC 842, the Company made an accounting policy election not to recognize the right-of-use assets and lease liabilities relating to short term leases. Refer to the Company's Annual Report on Form 10-K for the year ended December 31, 2018 for discussions related to the Company's previous lease recognition policies. Implementation of ASC 842 included an analysis of contracts, including real estate leases and service contracts to identify embedded leases, to determine the initial recognition of right-of-use assets and lease liabilities, which required subjective assessment over the determination of the associated discount rates. ASC 842 also provided various practical expedients which were assessed to determine the ultimate impact of ASC 842 upon adoption. The standard includes a package of three practical expedients which permit the Company to not reassess (1) whether any expired or existing contracts are or contain a lease, (2) the lease classification for any expired or existing leases and (3) any initial direct costs for any existing leases as of the effective date. The Company has elected to apply the package of practical expedients, hindsight practical expedient, and land easement practical expedient. The adoption of ASC 842 resulted in the recording of operating lease right-of-use assets of $103.7 million and operating lease liabilities of $110.5 million at January 1, 2019. The Company determines if an arrangement is or contains a lease at inception. The Company’s operating lease arrangements are primarily for real estate and facility leases as well as office equipment. The Company has applied an accounting policy election to combine its lease and nonlease components for its real estate and facility leases. ROU assets represent the Company’s right to use the underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Right-of-use assets and lease liabilities are recognized at the commencement date based on the present value of lease payments over the lease term. The Company's variable lease payments consist of nonlease services related to the lease. Variable lease payments are excluded from the right-of-use asset and lease liabilities to the extent they are not based on consumer priced index or a market index and are recognized in the period in which the obligation for those payments is incurred. As most of the Company's leases do not provide an implicit rate and the implicit rate is not readily determinable, the Company uses its incremental borrowing rate based on the information available at the commencement date in determining the present value of lease payments. Right-of-use assets also include any lease payments made and exclude lease incentives. Many of the Company's operating lease agreements include options to extend the lease, which the Company does not include in the determination of the minimum lease term unless the options are reasonably certain to be exercised. Expense for lease payments related to operating leases is recognized on a straight-line basis over the lease term. The Company reconciles the operating lease expense with operating lease payments by presenting the amortization of the operating ROU asset and change in the operating lease liability in a single line item within the adjustments to reconcile net income (loss) to net cash provided by / (used in) operating activities in the accompanying Condensed Consolidated Statements of Cash Flows. Please refer to Note 18 for information on the Company’s finance leases (formerly capital leases).

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Property, Plant and Equipment Useful Life	Asset Depreciable Lives Depreciation and/or Amortization Method Telephone and computer equipment 5 years Straight-line Computer software 4 years Straight-line Furniture and fixtures 5 years Straight-line Leasehold improvements Term of Lease Straight-line Finance lease right-of-use asset 5 years Straight-line
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	For the three and nine months ended September 30, 2019 and 2018 , the following tables presents revenues from contracts with customers disaggregated by fee type and segment. Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (dollars in thousands) Revenue from contracts with customers Operating Company Investment Banking Underwriting fees $ 38,936 $ 46,537 $ 162,140 $ 181,056 Strategic/financial advisory fees 17,889 22,195 49,565 51,053 Placement and sales agent fees 15,842 13,191 48,855 32,628 Expense reimbursements from clients 4,625 — 11,543 — Total Investment Banking Revenue 77,292 81,923 272,103 264,737 Brokerage Commissions 82,715 84,882 263,831 270,917 Trade conversion revenue 3,700 2,931 12,364 12,268 Equity and credit research fees 4,235 5,022 13,180 14,585 Total Brokerage Revenue from Customers 90,650 92,835 289,375 297,770 Management Fees 7,052 6,595 20,492 19,556 Incentive Income 701 33 710 97 Total revenue from contracts with customers - Op Co $ 175,695 $ 181,386 $ 582,680 $ 582,160 Asset Company Management Fees 248 951 988 2,780 Incentive Income — — 14 — Total revenue from contracts with customers - Asset Co 248 951 1,002 2,780 Total revenue from contracts with customers $ 175,943 $ 182,337 $ 583,682 $ 584,940

Acquisition (Tables)

Acquisition (Tables)	9 Months Ended
	Sep. 30, 2019
Business Combinations [Abstract]
Finite-lived Intangible Assets Amortization Expense [Table Text Block]	The estimated amortization expense related to these intangible assets in future periods is as follows: (dollars in thousands) 2019 $ 2,227 2020 8,908 2021 2,608 2022 1,775 2023 — Thereafter — $ 15,518
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The table below summarizes the purchase price allocation of net tangible and intangible assets acquired and liabilities assumed as of January 2, 2019: (dollars in thousands) Cash and cash equivalents $ 12,236 Fees receivable 7,269 Fixed assets 1,085 Operating lease right-of-use assets 3,200 Intangible assets 22,200 Other assets 667 Compensation payable (637 ) Operating lease liabilities (3,200 ) Due to related parties (4,750 ) Accounts payable, accrued expenses and other liabilities (16,257 ) Total identifiable net assets acquired and liabilities assumed 21,813 Goodwill 81,150 Total estimated purchase price $ 102,963 The allocation of the intangible assets is shown within the following table: Estimated intangible assets acquired Estimated average remaining useful lives (dollars in thousands) (in years) Intangible asset class Trade name $ 900 3 Customer relationships 7,100 4 Backlog 12,600 2 Proprietary software 1,600 3 Total intangible assets $ 22,200
Business Acquisition, Pro Forma Information	Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 (dollars in thousands, except per share data) Net revenues $ 206,797 $ 661,759 Net income (loss) attributable to Cowen Inc. common stockholders 15,728 35,616 Net income (loss) per common share: Basic $ 0.51 $ 1.16 Diluted 0.49 1.12

Investments of Operating Enti_2

Investments of Operating Entities and Consolidated Funds - (Tables)	9 Months Ended
	Sep. 30, 2019
Investment Holdings [Line Items]
Carried Interest	The carried interest as of September 30, 2019 and December 31, 2018 , included the following: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Cowen Healthcare Investments II LP (*) 19,365 6,778 Other private investment (a) (*) 4,388 4,273 RCG IO Renergys Sarl 863 6,369 Ramius Multi-Strategy Fund LP (*) 570 575 $ 25,186 $ 17,995 (a) Other private investment represents the Company's closed end investment in a Portfolio Fund that invests in a wireless broadband communication provider in Italy. * These carried interest balances are earned from affiliates of the Company.
Marketable Securities	As of September 30, 2019 and December 31, 2018 , securities owned, at fair value consisted of the following: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Common stock (*) $ 853,786 $ 472,299 Preferred stock (*) 16,585 5,617 Warrants and rights (*) 19,865 7,990 Government bonds (a) 2,905 13,398 Corporate bonds (c) 18,366 13,041 Convertible bonds (b) (*) 2,541 3,000 Term loan (*) 1,054 — Trade claims (*) 7,062 5,543 $ 922,164 $ 520,888 (a) As of September 30, 2019 , maturities range from October 2019 to March 2020 with an interest rate of 0% . As of December 31, 2018 , maturities ranged from April 2019 to August 2019 with an interest rate of 0% . (b) As of September 30, 2019 , maturities range from April 2020 to March 2022 with an interest rate of 8% . As of December 31, 2018 , the maturity was June 2020 with an interest rate of 8% . (c) As of September 30, 2019 , maturities ranged from December 2019 to August 2044 and interest rates ranged from 0.00% to 15.00% . As of December 31, 2018 , maturities ranged from April 2019 to April 2049 and interest rates ranged from 2% to 15.50% . * The Company has elected the fair value option for securities owned, at fair value with a fair value of $18.3 million and $9.4 million , respectively, at September 30, 2019 and December 31, 2018 .
Schedule of Derivative Instruments	The Company's long and short exposure to derivatives is as follows: Receivable on derivative contracts As of September 30, 2019 As of December 31, 2018 Number of contracts / Notional Value Fair value Number of contracts / Notional Value Fair value (dollars in thousands) Futures $ 33,474 $ 103 $ 42,288 $ 334 Currency forwards $ 79,804 640 $ 395 1 Swaps $ 103,591 4,242 $ 13,702 917 Options other (a) 349,434 34,769 654,506 23,130 Pay to hold $ — — $ — 743 $ 39,754 $ 25,125 (a) Includes index, equity, commodity future and cash conversion options. Payable for derivative contracts As of September 30, 2019 As of December 31, 2018 Number of contracts / Notional Value Fair value Number of contracts / Notional Value Fair value (dollars in thousands) Currency forwards $ 24,636 91 $ 96,406 709 Swaps $ 164,056 6,502 $ 52,905 2,162 Options other (a) 190,321 26,162 90,730 13,211 $ 32,755 $ 16,082 (a) Includes index, equity, commodity future and cash conversion options. The following tables present the gross and net derivative positions and the related offsetting amount, as of September 30, 2019 and December 31, 2018 . This table does not include the impact of over-collateralization. Gross amounts not offset in the Condensed Consolidated Statement of Financial Condition Gross amounts recognized Gross amounts offset on the Condensed Consolidated Statements of Financial Condition (a) Net amounts included on the Condensed Consolidated Statements of Financial Condition Financial instruments Cash Collateral pledged (b) Net amounts (dollars in thousands) As of September 30, 2019 Receivable on derivative contracts, at fair value $ 39,754 $ — $ 39,754 $ — $ 4,882 $ 34,872 Payable for derivative contracts, at fair value 32,755 — 32,755 — 6,592 26,163 As of December 31, 2018 Receivable on derivative contracts, at fair value $ 25,125 $ — $ 25,125 $ — $ 1,662 $ 23,463 Payable for derivative contracts, at fair value 16,082 — 16,082 — 2,871 13,211 (a) Includes financial instruments subject to enforceable master netting provisions that are permitted to be offset to the extent an event of default has occurred. (b) Includes the amount of collateral held or posted.
Schedule of Other Investments	As of September 30, 2019 and December 31, 2018 , other investments included the following: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Portfolio funds, at fair value (1) $ 131,740 $ 123,241 Carried interest (2) 25,186 17,995 Equity method investments (3) 47,242 40,171 $ 204,168 $ 181,407
Schedule of Other Investments, Portfolio Funds	The Portfolio Funds, at fair value as of September 30, 2019 and December 31, 2018 , included the following: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Starboard Value and Opportunity Fund LP (c)(*) $ 36,566 $ 32,579 Formation8 Partners Fund I, L.P. (f) 33,613 34,099 RCG Longview Debt Fund V, L.P. (g)(*) 1,909 4,394 RCG Longview II LP (g) (*) 3,734 4,400 Cowen Healthcare Investments II LP (i) (*) 18,036 14,939 Eclipse Ventures Fund I, L.P. (b) 4,901 4,412 HealthCare Royalty Partners LP (a)(*) 1,367 1,833 Lagunita Biosciences, LLC (d) 4,868 3,833 Starboard Leaders Fund LP (e)(*) 1,511 1,230 Eclipse SPV I, LP (j)(*) 1,446 1,447 RCG Longview Equity Fund, LP (g) (*) 713 802 RCG Longview Debt Fund VI, LP (g) (*) 1,895 1,586 RCG Park Liberty GP Member LLC (g) (*) 952 1,023 HealthCare Royalty Partners II LP (a)(*) 1,681 1,037 RCGL PE MPA, LLC (g)(*) — 618 RCG LPP2 PNW5 Co-Invest, L.P. (h)(*) 10 296 Difesa Partners, LP (c) (*) 500 — Other private investment (k)(*) 14,711 11,625 Other affiliated funds (l)(*) 3,327 3,088 $ 131,740 $ 123,241 * These Portfolio Funds are affiliates of the Company. The Company has no unfunded commitments regarding the Portfolio Funds held by the Company except as noted in Note 17 . (a) HealthCare Royalty Partners, L.P. and HealthCare Royalty Partners II, L.P. are private equity funds and therefore distributions will be made when cash flows are received from the underlying investments, typically on a quarterly basis. (b) Eclipse Ventures Fund I, L.P. is a private equity fund which invests in early stage and growth hardware companies. Distributions will be made when the underlying investments are liquidated. (c) Starboard Value and Opportunity Fund LP and Difesa Partners, LP permits quarterly withdrawals upon 90 days' notice. (d) Lagunita Biosciences, LLC, is a healthcare investment company that creates and grows early stage companies to commercialize impactful translational science that addresses significant clinical needs, is a private equity structure and therefore distributions will be made when the underlying investments are liquidated. (e) Starboard Leaders Fund LP does not permit withdrawals, but instead allows terminations with respect to capital commitments upon 30 days' prior written notice at any time following the first anniversary of an investor's initial capital contribution. (f) Formation8 Partners Fund I, L.P. is a private equity fund which invests in early stage and growth transformational information and energy technology companies. Distributions will be made when the underlying investments are liquidated. (g) RCG Longview Debt Fund V, L.P., RCG Longview II LP, RCG Park Liberty GP Member LLC, RCG Longview Equity Fund, LP, RCGL PE MPA, LLC and RCG Longview Debt Fund VI, LP are real estate private equity structures. The timing of distributions depends on the nature of the underlying investments and therefore will be made either quarterly or when the underlying investments are liquidated. (h) RCG LPP2 PNW5 Co-Invest, L.P. is a single purpose entity formed to participate in a joint venture which acquired five multi-unit residential rental properties located in the Pacific Northwest. RCG LPP2 PNW5 Co-Invest, L.P. is a private equity structure and therefore distributions will be made when the underlying investments are liquidated. (i) Cowen Healthcare Investments II LP are private equity funds. Distributions are made from these funds when cash flows or securities are received from the underlying investments. Investors do not have redemption rights. (j) Eclipse SPV I, L.P. is a co-investment vehicle organized to invest in a private company focused on software-driven automation projects. Distributions will be made when the underlying investments are liquidated. (k) Other private investment represents the Company's closed end investment in a Portfolio Fund that invests in a wireless broadband communication provider in Italy. (l) The majority of these investment funds are affiliates of the Company or are managed by the Company and the investors can redeem from these funds as investments are liquidated.
Schedule Equity Method Investments	The following table summarizes equity method investments held by the Company: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Surf House Ocean Views Holdings, LLC $ 9,946 $ 7,589 Starboard Value LP 22,627 12,699 RCG Longview Debt Fund V Partners, LLC 3,827 11,000 RCG Longview Management, LLC 2,474 1,167 RCG Longview Debt Fund VI Partners LLC 449 1,254 HealthCare Royalty GP, LLC 111 149 HealthCare Royalty GP II, LLC 285 176 RCG Longview Debt Fund IV Management, LLC 331 331 HealthCare Royalty GP III, LLC 2,190 1,573 TriArtisan ES Partners LLC 1,026 1,500 TriArtisan PFC Partners LLC 999 — RCG Kennedy House, LLC 65 131 RCG Longview Equity Management, LLC 105 114 RCG LPP II GP, LLC 30 272 RCG Park Liberty GP Member Manager, LLC 1,014 1,248 HCR Stafford Fund GP, LLC 682 — Other 1,081 968 $ 47,242 $ 40,171 For the period ended September 30, 2019 , one equity method investment has met the significance criteria as defined under Regulation S-X Rule 4-08(g) of the SEC guidance ("Reg S-X 4-08(g)"). As such, the Company is presenting the following summarized financial information for the significant investee for the periods ended September 30, 2019 and December 31, 2018, and three and nine months ended September 30, 2019 and 2018, and such information is as follows: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Assets Cash $ 2,553 $ 37 Performance & management fee receivable 68,052 16,594 Investments 4,266 3,599 Liabilities — — Equity $ 74,871 $ 20,230 Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (dollars in thousands) Revenues $ 4,564 $ (1,843 ) $ 83,287 $ 24,083 Expenses — — — — Net realized and unrealized gains (losses) 55 29 717 271 Net Income $ 4,619 $ (1,814 ) $ 84,004 $ 24,354
Schedule of Securities Sold, Not yet Purchased	As of September 30, 2019 and December 31, 2018 , securities sold, not yet purchased, at fair value consisted of the following: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Common stock $ 349,408 $ 194,305 Corporate bonds (a) 1,281 750 Government bonds (b) 2,250 — Preferred stock 4,394 199 Warrants and rights 7,409 53 $ 364,742 $ 195,307 (a) As of September 30, 2019 , the maturities ranged from February 2024 to April 2037 and interest rates ranged from 5.00% to 5.50% . As of December 31, 2018 , the maturities ranged from October 2022 to January 2034 and interest rates ranged from 2.25% to 9.38% .
Schedule of Assets and Associated Liabilities Accounted for as Secured Borrowings	The following tables present the contractual gross and net securities borrowing and lending agreements and securities sold under agreements to repurchase and the related offsetting amount as of September 30, 2019 and December 31, 2018 . Gross amounts not offset on the Condensed Consolidated Statement of Financial Condition Gross amounts recognized Gross amounts offset on the Condensed Consolidated Statements of Financial Condition (a) Net amounts included on the Condensed Consolidated Statements of Financial Condition Additional Amounts Available Financial instruments Cash Collateral pledged (b) Net amounts (dollars in thousands) As of September 30, 2019 Securities borrowed $ 1,228,036 $ — $ 1,228,036 $ — $ 1,209,672 $ — $ 18,364 Securities loaned 1,339,647 — 1,339,647 — 1,282,340 — 57,307 Securities sold under agreements to repurchase 23,772 — 23,772 — 25,635 — (1,863 ) As of December 31, 2018 Securities borrowed $ 407,795 $ — $ 407,795 $ — $ 383,593 $ — $ 24,202 Securities loaned 414,852 — 414,852 — 391,310 — 23,542 (a) Includes financial instruments subject to enforceable master netting provisions that are permitted to be offset to the extent an event of default has occurred. (b) Includes the amount of cash collateral held/posted.
Investments Classified by Contractual Maturity Date	The following tables present gross obligations for securities loaned and securities sold under agreements to repurchase by remaining contractual maturity and class of collateral pledged as of September 30, 2019 and December 31, 2018 : Open and Overnight Up to 30 days 31 - 90 days Greater than 90 days Total (dollars in thousands) As of September 30, 2019 Securities loaned Common stock $ 1,024,436 $ — $ — $ — $ 1,024,436 Corporate bonds 315,211 — — — 315,211 Securities sold under agreements to repurchase — 15,951 7,821 — 23,772 As of December 31, 2018 Securities loaned Common stock $ 414,852 $ — $ — $ — $ 414,852
Fair Value, Concentration of Risk	Investment's percentage of the Company's stockholders' equity Issuer Security Type Country Industry Percentage of Stockholders' Equity Market Value (dollars in thousands) As of September 30, 2019 Linkem Equity Italy Wireless Broadband 8.56 % $ 69,927 As of December 31, 2018 Linkem Equity Italy Wireless Broadband 8.36 % $ 66,439
Consolidated Funds
Investment Holdings [Line Items]
Marketable Securities	As of September 30, 2019 and December 31, 2018 , securities owned, at fair value, held by the Consolidated Funds consisted of the following: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Preferred stock $ 46,268 $ 24,314 Common stock 202,017 95,565 Government bonds (a) 100,724 38,377 Corporate bonds (b) 14,717 24,098 Warrants and rights 5,465 5,279 $ 369,191 $ 187,633 (a) As of September 30, 2019 , maturities ranged from November 2019 to December 2019 and interest rates were 0% . As of December 31, 2018 , maturities ranged from January 2019 to April 2019 and interest rates were 0% . (b) As of September 30, 2019 , maturities ranged from May 2022 to May 2026 and interest rates ranged from 4.87% to 6.50% . As of December 31, 2018 , maturities ranged from August 2020 to March 2026 and interest rates ranged from 5.88% to 7.63% .
Schedule of Derivative Instruments	As of September 30, 2019 and December 31, 2018 , receivable on derivative contracts, at fair value, held by the Consolidated Funds are comprised of: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Currency forwards $ 31 $ 186 Equity swaps 1,296 2,477 Options 2,558 1,753 $ 3,885 $ 4,416 Payable for derivative contracts As of September 30, 2019 and December 31, 2018 , payable for derivative contracts, at fair value, held by the Consolidated Funds are comprised of: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Currency forwards $ 2,341 $ 96 Equity swaps 5,022 713 Options 415 854 $ 7,778 $ 1,663
Schedule of Other Investments, Portfolio Funds	Investments in Portfolio Funds, at fair value As of September 30, 2019 and December 31, 2018 , investments in Portfolio Funds, at fair value, included the following: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Investments of Enterprise LP $ 96,308 $ 97,656 Investments of Merger Fund 74,878 88,739 $ 171,186 $ 186,395
Enterprise Master
Investment Holdings [Line Items]
Marketable Securities	Securities owned by Enterprise Master, at fair value As of December 31, 2018 (dollars in thousands) Common stock $ 469 $ 469
Schedule of Other Investments, Portfolio Funds	Portfolio Funds, owned by Enterprise Master, at fair value As of December 31, 2018 Strategy (dollars in thousands) RCG Special Opportunities Fund, Ltd* Multi-Strategy $ 111,548 Other Private Investments Various 846 $ 112,394 * Affiliates of the Company.
Merger Master
Investment Holdings [Line Items]
Marketable Securities	Merger Master As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Securities owned by Merger Master, at fair value Common stock $ 166,669 $ 162,811 Corporate bonds 10,343 116,488 $ 177,012 $ 279,299 Securities sold, not yet purchased, by Merger Master, at fair value Common stock $ 58,444 $ 9,610 $ 58,444 $ 9,610
Schedule of Derivative Instruments	Receivable on derivative contracts, at fair value, owned by Merger Master As of September 30, 2019 As of December 31, 2018 Description (dollars in thousands) Options $ 2,691 $ 3,450 Equity swaps 99 5,320 $ 2,790 $ 8,770 Payable for derivative contracts, at fair value, owned by Merger Master As of September 30, 2019 As of December 31, 2018 Description (dollars in thousands) Options $ 856 $ 1,430 Currency forwards 13,936 270 Equity swaps 49 28 $ 14,841 $ 1,728

Fair Value Measurements for O_2

Fair Value Measurements for Operating Entities and Consolidated Funds (Tables)	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following table presents the assets and liabilities that are measured at fair value on a recurring basis on the accompanying condensed consolidated statements of financial condition by caption and by level within the valuation hierarchy as of September 30, 2019 and December 31, 2018 : Assets at Fair Value as of September 30, 2019 Level 1 Level 2 Level 3 Total (dollars in thousands) Operating Entities Securities owned, at fair value Government bonds $ 2,905 $ — $ — $ 2,905 Preferred stock 8,750 — 7,835 16,585 Common stock 840,473 — 13,313 853,786 Convertible bonds — — 2,541 2,541 Corporate bonds — 16,293 2,073 18,366 Trade claims — — 7,062 7,062 Term Loan — 1,054 — 1,054 Warrants and rights 19,281 — 584 19,865 Receivable on derivative contracts, at fair value Futures 103 — — 103 Currency forwards — 640 — 640 Swaps — 4,242 — 4,242 Options 34,769 — — 34,769 Consolidated Funds Securities owned, at fair value Government bonds 100,724 — — 100,724 Preferred stock 41,875 — 4,393 46,268 Common stock 202,017 — — 202,017 Corporate bonds — 14,717 — 14,717 Warrants and rights — — 5,465 5,465 Receivable on derivative contracts, at fair value Currency forwards — 31 — 31 Equity swaps — 1,296 — 1,296 Options 2,558 — — 2,558 $ 1,253,455 $ 38,273 $ 43,266 $ 1,334,994 Percentage of total assets measured at fair value on a recurring basis 93.9 % 2.9 % 3.2 % Portfolio Funds measured at net asset value (a) 131,740 Carried interest (a) 25,186 Consolidated Funds' Portfolio Funds measured at net asset value (a) 171,186 Equity method investments 47,242 Total investments $ 1,710,348 Liabilities at Fair Value as of September 30, 2019 Level 1 Level 2 Level 3 Total (dollars in thousands) Operating Entities Securities sold, not yet purchased, at fair value Government bonds $ — $ — $ 2,250 $ 2,250 Common stock 349,408 — — 349,408 Corporate bonds — 81 1,200 1,281 Preferred stock 4,394 — — 4,394 Warrants and rights 7,409 — — 7,409 Payable for derivative contracts, at fair value Currency forwards — 91 — 91 Swaps — 6,502 — 6,502 Options 23,662 — 2,500 26,162 Accounts payable, accrued expenses and other liabilities Contingent consideration liability (b) — — 29,834 29,834 Consolidated Funds Payable for derivative contracts, at fair value Currency forwards — 2,341 — 2,341 Options 415 — — 415 Equity swaps — 5,022 — 5,022 $ 385,288 $ 14,037 $ 35,784 $ 435,109 Percentage of total liabilities measured at fair value 88.5 % 3.2 % 8.2 % (a) In accordance with US GAAP, certain investments that are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient and carried interest in portfolio funds have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the condensed consolidated statement of financial condition. (b) In accordance with the terms of the purchase agreements for acquisitions that closed during the second quarter of 2016 and the first quarter of 2019, the Company is required to pay to the sellers a portion of future net income and/or revenues of the acquired businesses, if certain targets are achieved through the periods ended December 2019 and December 2023, respectively. For the acquisition that closed during 2016, the Company estimated the contingent consideration liability using the income approach (discounted cash flow method) which requires the Company to make estimates and assumptions regarding the future cash flows and profits. For the acquisition that closed during 2019, the Company estimated the contingent consideration liability using the present value of the monte carlo simulated revenue. Changes in these estimates and assumptions could have a significant impact on the amounts recognized. The undiscounted amounts as of September 30, 2019 can range from $1.6 million to $40.0 million . Assets at Fair Value as of December 31, 2018 Level 1 Level 2 Level 3 Total (dollars in thousands) Operating Entities Securities owned, at fair value Government bonds $ 13,398 $ — $ — $ 13,398 Preferred stock 449 — 5,168 5,617 Common stock 459,601 2,848 9,850 472,299 Convertible bonds — — 3,000 3,000 Corporate bonds — 13,041 — 13,041 Trade claims — — 5,543 5,543 Warrants and rights 6,324 — 1,666 7,990 Receivable on derivative contracts, at fair value Futures 334 — — 334 Currency forwards — 1 — 1 Swaps — 917 — 917 Options 23,130 — — 23,130 Pay to hold — 743 — 743 Consolidated Funds Securities owned, at fair value Government bonds 38,377 — — 38,377 Preferred stock — — 24,314 24,314 Common stock 95,471 — 94 95,565 Corporate bonds — 24,098 — 24,098 Warrants and rights — — 5,279 5,279 Receivable on derivative contracts, at fair value Currency forwards — 186 — 186 Equity swaps — 2,477 — 2,477 Options 1,753 — — 1,753 $ 638,837 $ 44,311 $ 54,914 $ 738,062 Percentage of total assets measured at fair value on a recurring basis 86.6 % 6.0 % 7.4 % Portfolio Funds measured at net asset value (a) 123,241 Carried interest (a) 17,995 Consolidated Funds' Portfolio Funds measured at net asset value (a) 186,395 Equity method investments 40,171 Total investments $ 1,105,864 Liabilities at Fair Value as of December 31, 2018 Level 1 Level 2 Level 3 Total (dollars in thousands) Operating Entities Securities sold, not yet purchased, at fair value Common stock $ 194,305 $ — $ — $ 194,305 Corporate bonds — 750 — 750 Preferred stock 199 — — 199 Warrants and rights 53 — — 53 Payable for derivative contracts, at fair value Currency forwards — 709 — 709 Swaps — 2,162 — 2,162 Options 11,115 — 2,096 13,211 Accounts payable, accrued expenses and other liabilities Contingent consideration liability (b) — — 3,070 3,070 Consolidated Funds Payable for derivative contracts, at fair value Currency forwards — 96 — 96 Options 854 — — 854 Equity swaps — 713 — 713 $ 206,526 $ 4,430 $ 5,166 $ 216,122 Percentage of total liabilities measured at fair value 95.6 % 2.0 % 2.4 % (a) In accordance with US GAAP, certain investments that are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient and carried interest in portfolio funds have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the condensed consolidated statement of financial condition. (b) In accordance with the terms of the purchase agreements for the acquisition that closed during the second quarter of 2016, the Company is required to pay to the sellers a portion of future net income and/or revenues of the acquired business, if certain targets are achieved through the periods ended December 2020. The Company estimated the contingent consideration liability using the income approach (discounted cash flow method) which requires the Company to make estimates and assumptions regarding the future cash flows and profits. Changes in these estimates and assumptions could have a significant impact on the amounts recognized. The undiscounted amounts as of December 31, 2018 can range from $2.8 million to $3.4 million .
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	The following table includes a roll forward of the amounts for the three and nine months ended September 30, 2019 and 2018 for financial instruments classified within level 3. The classification of a financial instrument within level 3 is based upon the significance of the unobservable inputs to the overall fair value measurement. Three Months Ended September 30, 2019 Balance at June 30, 2019 Transfers in Transfers out Purchases/(covers) (Sales)/shorts Realized and Unrealized gains/losses Balance at September 30, 2019 Change in unrealized gains/losses relating to instruments still held (1) (dollars in thousands) Operating Entities Preferred stock $ 7,401 $ — $ (1,000 ) (e) $ — $ — $ 1,434 $ 7,835 $ 2,295 Common stock 11,006 — — 2,579 (480 ) 208 13,313 210 Convertible bonds 6,318 (2,801 ) (e) 1,049 (2,072 ) 47 2,541 4 Corporate bond 775 20 (d) — 1,117 — 161 2,073 161 Options, liability 2,779 — — — — (279 ) 2,500 (279 ) Warrants and rights 595 — — — (72 ) 61 584 (12 ) Trade claims 10,488 — — 1,871 (5,354 ) 57 7,062 57 Corporate bond, liability — 2,525 (d) — — — (1,325 ) 1,200 (1,325 ) Government bonds, liability — 4,681 (d) — — — (2,431 ) 2,250 (2,431 ) Contingent consideration liability 29,536 — — — — 298 29,834 298 Consolidated Funds Preferred stock 24,322 — (19,929 ) (e) — — — 4,393 — Common stock 1,017 — (94 ) (e) — (957 ) 34 — — Warrants and rights 6,274 — — — (670 ) (139 ) 5,465 (809 ) Three Months Ended September 30, 2018 Balance at June 30, 2018 Transfers in Transfers out Purchases/(covers) (Sales)/shorts Realized and Unrealized gains/losses Balance at September 30, 2018 Change in unrealized gains/losses relating to instruments still held (1) (dollars in thousands) Operating Entities Preferred stock $ 7,422 $ — $ (1,141 ) (b) $ — $ — $ (1,123 ) $ 5,158 $ (1,124 ) Common stock 5,848 — — — — (174 ) 5,674 (174 ) Options, liability 301 — — — — 2,246 2,547 2,246 Warrants and rights 1,544 — — — 38 1,582 38 Trade claims 5,699 — — 44 — 3 5,746 3 Lehman claim 295 — — — (234 ) (61 ) — — Contingent consideration liability 2,870 — — — (227 ) — 2,643 — Consolidated Funds Preferred stock 24,314 — — — — — 24,314 — Common stock 94 — — — — — 94 — Warrants and rights 4,738 — — — 110 4,848 110 Nine Months Ended September 30, 2019 Balance at December 31, 2018 Transfers in Transfers out Purchases/(covers) (Sales)/shorts Realized and Unrealized gains/losses Balance at September 30, 2019 Change in unrealized gains/losses relating to instruments still held (1) (dollars in thousands) Operating Entities Preferred stock $ 5,168 $ — $ (1,000 ) (e) $ 3,243 $ (1,000 ) $ 1,424 $ 7,835 $ 2,285 Common stock 9,850 — — 16,737 (12,952 ) (322 ) 13,313 (122 ) Convertible bonds 3,000 — (4,826 ) (b) (e) 16,021 (11,764 ) 110 2,541 41 Corporate bond — 20 (d) — 1,892 — 161 2,073 161 Options, liability 2,096 — — — (4 ) 408 2,500 408 Warrants and rights 1,666 — — — (188 ) (894 ) 584 20 Trade claims 5,543 — — 6,965 (5,506 ) 60 7,062 57 Corporate Bond, liability — 2,525 (d) — — — (1,325 ) 1,200 (1,325 ) Government bonds, liability — 4,681 (d) — — — (2,431 ) 2,250 (2,431 ) Contingent consideration liability 3,070 — — 27,700 (1,234 ) 298 29,834 298 Consolidated Funds Preferred stock 24,314 — (19,929 ) (e) — — 8 4,393 8 Common stock 94 — (94 ) (e) 407 (958 ) 551 — — Warrants and rights 5,279 — — — (1,758 ) 1,944 5,465 190 Nine Months Ended September 30, 2018 Balance at December 31, 2017 Transfers in Transfers out Purchases/(covers) (Sales)/shorts Realized and Unrealized gains/losses Balance at September 30, 2018 Change in unrealized gains/losses relating to instruments still held (1) (dollars in thousands) Operating Entities Preferred stock $ 8,115 $ — $ (1,141 ) (b) $ 1,415 $ (695 ) $ (2,536 ) $ 5,158 $ (2,301 ) Common stock 7,570 — — 531 (1,333 ) (1,094 ) 5,674 (1,128 ) Convertible bonds 282 — — — (307 ) 25 — — Options, asset 1,455 — — — (1,455 ) — — — Options, liability 22,401 — (28,973 ) (c) — (259 ) 9,378 2,547 9,378 Warrants and rights 2,517 — — — (143 ) (792 ) 1,582 (933 ) Trade claim 5,950 — — 44 (334 ) 86 5,746 23 Lehman claim 301 — — — (234 ) (67 ) — — Contingent consideration liability 3,440 — — — (797 ) — 2,643 — Consolidated Funds Preferred stock 50,445 — (38,552 ) (a) 3,066 — 9,355 24,314 9,355 Common stock 50 — — — — 44 94 44 Warrants and rights 3,568 — (20 ) (a) (1,340 ) — 2,640 4,848 1,300 (1) Unrealized gains/losses are reported in other income (loss) in the accompanying condensed consolidated statements of operations. (a) The Company deconsolidated an investment fund. (b) The investments were converted to common stock. (c) On June 26, 2018, the Company received shareholder approval which allows the Company to settle its convertible note (see Note 18 ) entirely in class A common shares. Upon receiving shareholder approval, the Company reclassified the embedded conversion option, associated with the convertible debt, to equity. (see Note 19 ). (d) The investments had a change of valuation methodology due to increased activity in foreign market. (e) The entity in which the Company is invested completed an initial public offering.
Fair Value Inputs, Assets, Quantitative Information	The following table includes quantitative information as of September 30, 2019 and December 31, 2018 for financial instruments classified within level 3. The table below quantifies information about the significant unobservable inputs used in the fair value measurement of the Company's level 3 financial instruments. Quantitative Information about Level 3 Fair Value Measurements Fair Value September 30, 2019 Valuation Techniques Unobservable Inputs Range Level 3 Assets (dollars in thousands) Common and preferred stocks $ 314 Discounted cash flows Discount rate 8% Trade claims 28 Discounted cash flows Discount rate 20% Warrants and rights 6,048 Model based Discounted cash flows Volatility Discount rate 30% 6% to 7% Corporate and convertible bonds 533 Discounted cash flows Recovery Discount rate Probability of recovery 20% Other level 3 assets (a) 36,343 Total level 3 assets $ 43,266 Level 3 Liabilities Options 2,500 Option pricing models Volatility 35% to 40% Contingent consideration liability 29,834 Discounted cash flows Monte Carlo simulation Discount rate Volatility 14%-23% 14%-20% Other level 3 liabilities (a) 3,450 Total level 3 liabilities $ 35,784 Quantitative Information about Level 3 Fair Value Measurements Fair Value at Valuation Techniques Unobservable Inputs Range Level 3 Assets (dollars in thousands) Common and preferred stocks $ 4,323 Guideline companies/Discounted cash flows Discount rate 8%-14% Trade claims 25 Discounted cash flows Discount rate 20% Warrants and rights 1,666 Model based Discounted cash flows Discount rate 7% to 9% Other level 3 assets (a) 48,900 Total level 3 assets $ 54,914 Level 3 Liabilities Options 2,096 Option pricing models Volatility 35% to 40% Contingent consideration liability 3,070 Discounted cash flows Projected cash flow and discount rate 23% Total level 3 liabilities $ 5,166 (a) The quantitative disclosures exclude financial instruments for which the determination of fair value is based on prices from recent transactions.
Fair Value Measurements, Nonrecurring	The following table presents the carrying values and fair values, at September 30, 2019 and December 31, 2018 , of financial assets and liabilities and information on their classification within the fair value hierarchy which are not measured at fair value on a recurring basis. For additional information regarding the financial instruments within the scope of this disclosure, and the methods and significant assumptions used to estimate their fair value see Note 2 . September 30, 2019 December 31, 2018 Fair Value Hierarchy Carrying Amount Fair Value Carrying Amount Fair Value (dollars in thousands) Financial Assets Operating companies Cash and cash equivalents $ 260,994 $ 260,994 $ 259,148 $ 259,148 Level 1 Cash collateral pledged 18,609 18,609 6,318 6,318 Level 2 Segregated cash 128,782 128,782 176,647 176,647 Level 1 Securities borrowed 1,228,036 1,209,672 407,795 383,593 Level 2 Loans receivable 38,121 38,121 (d) 36,021 36,021 (d) Level 3 Consolidated Funds Cash and cash equivalents 3,364 3,364 38,118 38,118 Level 1 Financial Liabilities Securities sold under agreements to repurchase 23,772 25,635 — — Level 2 Securities loaned 1,339,647 1,282,340 414,852 391,310 Level 2 Convertible debt 117,469 (a) 148,509 (b) 134,489 (a) 157,433 (b) Level 2 Notes payable and other debt 343,286 363,777 (c) 262,965 258,546 (c) Level 2 (a) The carrying amount of the convertible debt includes an unamortized discount of $16.0 million and $19.5 million as of September 30, 2019 and December 31, 2018 , respectively. (b) The convertible debt includes the conversion option and is based on the last broker quote available. (c) Notes payable and other debt are based on the last broker quote available. (d) The fair market value of level 3 loans is calculated using discounted cash flows where applicable.

Receivables from and payables_2

Receivables from and payables to brokers, dealers and clearing organizations receivables from brokers, dealers, and clearing organization (Tables)	9 Months Ended
	Sep. 30, 2019
Receivables from Brokers-Dealers and Clearing Organizations [Abstract]
Schedule of Due to (from) Broker-Dealers and Clearing Organizations	As of September 30, 2019 and December 31, 2018 , amounts receivable from brokers, dealers and clearing organizations include: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Broker-dealers $ 676,674 $ 692,581 Securities failed to deliver 17,943 72,918 Clearing organizations 5,929 15,319 Securities borrowed interest receivable 17,088 5,295 $ 717,634 $ 786,113 As of September 30, 2019 and December 31, 2018 , amounts payable to brokers, dealers and clearing organizations include: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Broker-dealers $ 210,913 $ 159,443 Securities failed to receive 25,840 28,826 Clearing organizations 21,236 36,338 Securities loaned interest payable 13,023 4,124 $ 271,012 $ 228,731

Goodwill and Intangibles (Table

Goodwill and Intangibles (Tables)	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangibles [Abstract]
Goodwill Disclosure [Text Block]	The following table presents the changes in the Company's goodwill balance, by reporting unit for the periods ended September 30, 2019 and December 31, 2018 : Investment Management Investment Bank Cowen Investment Management Asset Co Total (dollars in thousands) Beginning balance - December 31, 2017 Goodwill $ 29,026 $ 51,337 $ — $ — 80,363 Accumulated impairment charges (10,200 ) (9,485 ) — — (19,685 ) Net 18,826 41,852 — — 60,678 Activity: 2018 Recognized goodwill — — — — — Goodwill impairment charges — — — — — Ending balance: December 31, 2018 Goodwill 29,026 51,337 — — 80,363 Accumulated impairment charges (10,200 ) (9,485 ) — — (19,685 ) Net 18,826 41,852 — — 60,678 Activity: 2019 Recognized goodwill (See note 3) — 81,150 — — 81,150 Realignment of segment goodwill: Goodwill (29,026 ) — 22,705 6,321 — Accumulated impairment charges 10,200 — (7,979 ) (2,221 ) — Goodwill impairment charges — — — (4,100 ) (4,100 ) Ending balance: September 30, 2019 Goodwill — 132,487 22,705 6,321 161,513 Accumulated impairment charges — (9,485 ) (7,979 ) (6,321 ) (23,785 ) Net $ — $ 123,002 $ 14,726 $ — $ 137,728

Redeemable Non-Controlling In_2

Redeemable Non-Controlling Interests in Consolidated Subsidiaries and Funds (Tables)	9 Months Ended
	Sep. 30, 2019
Noncontrolling Interest [Abstract]
Redeemable non-controlling interests in consolidated subsidiaries and funds	on-controlling interests in consolidated subsidiaries and investment funds and the related net income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds are comprised as follows: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Redeemable non-controlling interests in consolidated subsidiaries and investment funds Consolidated Funds $ 348,424 $ 216,923 Nonredeemable non-controlling interests in consolidated subsidiaries and investment funds Operating companies 15,268 7,457 Consolidated Funds 69,491 57,423 $ 433,183 $ 281,803
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (dollars in thousands) Income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds Operating companies $ (2,126 ) $ 1,306 $ (1,586 ) $ 2,805 Consolidated Funds 4,896 2,804 8,774 34,993 $ 2,770 $ 4,110 $ 7,188 $ 37,798

Share-Based Compensation and _2

Share-Based Compensation and Employee Ownership Plans (Tables)	9 Months Ended
	Sep. 30, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity	Restricted shares and restricted stock units are referred to collectively as restricted stock. The following table summarizes the Company's restricted share and restricted stock unit activity for the nine months ended September 30, 2019 and 2018 : Nine Months Ended September 30, 2019 Nine Months Ended September 30, 2018 Nonvested Restricted Class A Common Shares and Class A Common Restricted Stock Units Weighted-Average Nonvested Restricted Class A Common Shares and Class A Common Restricted Stock Units Weighted-Average Beginning balance outstanding 5,962,295 $ 15.73 5,579,293 $ 16.33 Granted 2,322,996 16.62 2,255,794 14.27 Vested (1,545,850 ) 16.26 (1,423,075 ) 16.08 Canceled (584,333 ) 11.49 — — Forfeited (156,528 ) 13.97 (61,997 ) 14.13 Ending balance outstanding 5,998,580 $ 16.40 6,350,015 $ 15.68 Included in the restricted share and restricted stock unit activity are performance linked restricted stock units of 481,438 which were awarded to employees of the Company in December 2013 and January 2014. An additional 700,000 performance linked restricted stock units were awarded in March 2016 and 333,333 in April of 2019. Of the awards granted, 130,438 have been forfeited and 584,333 have been canceled, as they did not meet the performance criteria, through September 30, 2019 . The remaining awards, included in the outstanding balance as of September 30, 2019 , vest between May 2019 and December 2021 and will be earned only to the extent that the Company attains specified market conditions relating to its volume-weighted average share price and total shareholder return in relation to certain benchmark indices and performance goals relating to aggregate net income and average return on shareholder equity. The actual number of RSUs ultimately earned could vary from zero , if performance goals are not met, to as much as 200% of the targeted award. Each RSU is equal to the one share of the Company’s Class A common stock. Compensation expense is recognized to the extent that it is probable that the Company will attain the performance goals.

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Operating Lease, Lease Income [Table Text Block]	For the three and nine months ended September 30, 2019 , quantitative information regarding the Company's operating lease obligations reflected in the accompanying condensed consolidated statement of operations were as follows: Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 (dollars in thousands) Lease Cost Operating lease cost $ 5,748 $ 17,690 Short-term lease cost 23 113 Variable lease cost 388 834 Sublease income (232 ) (739 ) Total lease costs $ 5,927 $ 17,898 The following table summarizes the supplemental cash flow information and certain other information related to operating leases for the nine months ended September 30, 2019 : Nine Months Ended September 30, 2019 (dollars in thousands) Other Information Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 19,103 Weighted average remaining lease term - operating leases (in Years) 5.52 Weighted average discount rate - operating leases 4.14 %
Future Minimum Annual Lease and Service Payments	As of September 30, 2019 , maturities of the outstanding operating lease liabilities for the Company were as follows: Equipment Leases (operating) (b) Real Estate and Other Facility Rental (a) (dollars in thousands) 2019 $ 94 $ 4,530 2020 364 24,350 2021 177 24,049 2022 61 20,586 2023 — 17,416 Thereafter — 25,958 Total Operating Leases 696 116,889 Less discount 114 16,424 Less short term leases — 113 Total Lease Liability $ 582 $ 100,352 (a) The Company has entered into various agreements to sublease certain of its premises. (b) In the third quarter of 2019, the Company recognized operating ROU assets and leases liabilities of $0.1 million for equipment leases. Prior to the adoption of the new lease accounting guidance, the minimum rental commitments under non-cancelable operating leases at December 31, 2018 , were as follows: Equipment Leases (a) Service Payments Real Estate and other Facility Rental (b) (dollars in thousands) 2019 $ 2,434 $ 21,758 $ 24,584 2020 1,492 7,514 22,608 2021 1,382 1,877 22,321 2022 1,123 1,372 19,166 2023 374 735 16,204 Thereafter — 735 21,478 $ 6,805 $ 33,991 $ 126,361 (a) Equipment Leases includes the Company's commitments relating to operating and capital leases. See Note 18 for further information on the capital lease minimum payments which are included in the table. (b) The Company has entered into various agreements to sublease certain of its premises. The Company recorded sublease income related to these leases of $1.4 million , $1.1 million , and $2.2 million for the years ended December 31, 2018, 2017, and 2016 respectively. Other Commitments As of September 30, 2019 , future minimum annual service payments for the Company were as follows: Service Payments (dollars in thousands) 2019 $ 6,691 2020 15,210 2021 8,483 2022 5,971 2023 3,573 Thereafter 6,331 Total Operating Leases $ 46,259
Other Commitments	The following table summarizes unfunded commitments as of September 30, 2019 : Entity Unfunded Commitments Commitment term (dollars in thousands) HealthCare Royalty Partners funds (a) 5,867 2 years Eclipse Ventures Fund I, L.P. (formerly Formation8 Partners Hardware Fund I, L.P.) 98 5 years Lagunita Biosciences, LLC 500 4 years Eclipse Fund II, L.P. 225 6 years Eclipse Continuity Fund I, L.P. 175 7 years Cowen Healthcare Investments II LP 6,891 2 years Cowen Healthcare Investments III LP 10,000 7 years Cowen Sustainable Investments I LP 25,000 10 years (a) The Company is a limited partner of the HealthCare Royalty Partners funds (which are managed by Healthcare Royalty Management) and is a member of HealthCare Royalty Partners General Partners. The Company will make its pro-rata investment in the HealthCare Royalty Partners funds along with the other limited partners.

Convertible Debt and Notes Pa_2

Convertible Debt and Notes Payable (Tables)	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Direct Financing Lease, Lease Income [Table Text Block]	As of September 30, 2019 and December 31, 2018, the remaining balance on these finance leases was $4.1 million and $5.0 million , respectively. For the three and nine months ended September 30, 2019 and 2018 , quantitative information regarding the Company's finance lease obligations reflected in the accompanying condensed consolidated statement of operations, the supplemental cash flow information and certain other information related to finance leases were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (dollars in thousands) Lease Cost Finance Lease Cost: Amortization of finance lease right-of-use assets $ 299 $ 409 $ 966 $ 1,124 Interest on lease liabilities 54 64 172 167 Other Information Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from finance leases 172 167 Financing cash flows from finance leases $ 951 $ 1,630
Schedule of Debt and Capital Lease Obligations	As of September 30, 2019 and December 31, 2018 , the Company's outstanding debt was as follows: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Convertible debt $ 117,469 $ 134,489 Notes payable 306,645 229,740 Term loan 32,180 28,200 Other notes payable 395 — Finance lease obligations 4,066 5,025 $ 460,755 $ 397,454
Schedule of Maturities of Debt and Future Minimum Lease Payments for Capital Leases	Annual scheduled maturities of debt and minimum payments (of principal and interest) for all debt outstanding as of September 30, 2019 , are as follows: Convertible Debt Notes Payable Term loan Other Notes Payable Finance Lease (dollars in thousands) 2019 $ 2,025 $ 7,301 $ 489 $ 405 $ 231 2020 4,050 23,548 33,126 — 1,356 2021 4,050 23,548 — — 1,356 2022 139,050 23,548 — — 1,125 2023 — 23,548 — — 374 Thereafter — 433,025 — — — Subtotal 149,175 534,518 33,615 405 4,442 Less (a) (31,706 ) (227,873 ) (1,435 ) (10 ) (376 ) Total $ 117,469 $ 306,645 $ 32,180 $ 395 $ 4,066 (a) Amount necessary to reduce net minimum payments to present value calculated at the Company's implicit rate at inception. This amount also includes capitalized debt costs and the unamortized discount on the convertible debt.
Schedule of Line of Credit Facilities	As of September 30, 2019 , the Company has the following seven irrevocable letters of credit, related to leased office space, for which there is cash collateral pledged, which the Company pays a fee on the stated amount of the letter of credit. The Company also has pledged collateral for reinsurance agreements which amounted to $13.9 million , as of September 30, 2019 , and $1.0 million , as of December 31, 2018 , which is released annually between March 2020 and March 2023 based on the policy periods covered by the reinsurance agreements . Location Amount Maturity (dollars in thousands) Boston $ 392 March 2020 New York $ 358 April 2020 New York $ 71 October 2019 New York $ 398 October 2019 New York $ 1,125 October 2019 New York $ 1,623 November 2019 San Francisco $ 713 October 2025

Stockholder's Equity (Tables)

Stockholder's Equity (Tables)	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Treasury Stock Activity	The following represents the activity relating to the treasury stock held by the Company during the nine months ended September 30, 2019 : Treasury stock shares Cost Average cost per share Balance outstanding at December 31, 2018 15,336,871 $ 234,142 $ 15.27 Shares purchased for minimum tax withholding under the Equity Plans or other similar transactions 674,792 10,153 15.05 Shares of stock received in respect of indemnification claims 10,917 167 15.34 Purchase of treasury stock 1,440,396 22,420 15.57 Balance outstanding at September 30, 2019 17,462,976 $ 266,882 $ 15.28

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2019
Accumulated Other Comprehensive Income / (Loss) [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (dollars in thousands) Beginning Balance $ (3 ) $ (7 ) $ (5 ) $ (8 ) Foreign currency translation (2 ) 4 — 5 Ending Balance $ (5 ) $ (3 ) $ (5 ) $ (3 )

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Share, Basic and Diluted	The computation of earnings per share is as follows: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 (dollars in thousands, except share and per share data) Net income (loss) $ 6,583 $ 19,598 $ 26,596 $ 75,538 Net income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds 2,770 4,110 7,188 37,798 Net income (loss) attributable to Cowen Inc. 3,813 15,488 19,408 37,740 Preferred stock dividends 1,698 1,698 5,094 5,094 Net income (loss) attributable to Cowen Inc. common stockholders $ 2,115 $ 13,790 $ 14,314 $ 32,646 Shares for basic and diluted calculations: Weighted average shares used in basic computation 29,529 29,610 29,687 29,662 Restricted stock 1,735 1,234 1,694 951 Weighted average shares used in diluted computation 31,264 30,844 31,381 30,613 Earnings (loss) per share: Basic $ 0.07 $ 0.47 $ 0.48 $ 1.10 Diluted $ 0.07 $ 0.45 $ 0.46 $ 1.07

Segment Reporting (Tables)

Segment Reporting (Tables)	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Segment Reporting Information, by Segment	Three Months Ended September 30, 2019 Adjustments Operating Company Asset Company Total Economic Income/(Loss) Funds Other US GAAP (dollars in thousands) Revenues Investment banking $ 70,022 $ — $ 70,022 $ — $ 7,270 (a) $ 77,292 Brokerage 105,860 — 105,860 — (11,865 ) (b) 93,995 Management fees 10,321 586 10,907 (574 ) (3,033 ) (c) 7,300 Incentive income (loss) 15,384 (1,007 ) 14,377 (13 ) (13,663 ) (c) 701 Investment income (loss) 15,231 822 16,053 — (16,053 ) (d) — Interest and dividends — — — — 60,707 (b)(d) 60,707 Reimbursement from affiliates — — — (27 ) 265 (e) 238 Reinsurance premiums — — — — 8,146 (f) 8,146 Other revenue (132 ) 6 (126 ) (26 ) 1,389 (f) 1,237 Consolidated Funds revenues — — — 2,431 — 2,431 Total revenues 216,686 407 217,093 1,791 33,163 252,047 Interest expense (Economic Income/(Loss)) / Interest and dividend expense (US GAAP) 5,758 1,389 7,147 — 49,330 (b)(d) 56,477 Total net revenues 210,928 (982 ) 209,946 1,791 (16,167 ) 195,570 Expenses Non interest expense 200,637 1,403 202,040 — 15,408 (a)(e)(h)(i) 217,448 Consolidated Funds expenses — — — 2,516 — 2,516 Total expenses 200,637 1,403 202,040 2,516 15,408 219,964 Total other income (loss) — — — 5,621 26,721 (c)(d)(i) 32,342 Income taxes expense / (benefit) — — — — 1,365 (h) 1,365 Income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds 661 — 661 4,896 (2,787 ) 2,770 Income (loss) attributable to Cowen Inc. 9,630 (2,385 ) 7,245 — (3,432 ) 3,813 Less: Preferred stock dividends 1,341 357 1,698 — — 1,698 Economic Income (Loss)/ Income (loss) attributable to Cowen Inc. common stockholders 8,289 (2,742 ) 5,547 $ — $ (3,432 ) $ 2,115 Add back: Depreciation and Amortization expense 5,073 9 5,082 Economic operating income (loss) $ 13,362 $ (2,733 ) $ 10,629 Three Months Ended September 30, 2018 Adjustments Operating Company Asset Company Total Funds Other US GAAP (dollars in thousands) Revenues Investment banking $ 77,510 $ — $ 77,510 $ — $ 4,413 (a) $ 81,923 Brokerage 101,672 — 101,672 — (9,637 ) (b) 92,035 Management fees 10,840 1,546 12,386 (381 ) (4,459 ) (c) 7,546 Incentive income (loss) 1,859 5,051 6,910 (20 ) (6,857 ) (c)(a) 33 Investment income (loss) 25,779 1,893 27,672 — (27,672 ) (d)(g) — Interest and dividends — — — — 26,448 (b)(d) 26,448 Reimbursement from affiliates — — — (65 ) 418 (e) 353 Aircraft lease revenue — — — — 375 (g) 375 Reinsurance premiums — — — — 8,378 (f) 8,378 Other revenue 4 79 83 — 1,551 (f) 1,634 Consolidated Funds revenues — — — 2,303 — 2,303 Total revenues 217,664 8,569 226,233 1,837 (7,042 ) 221,028 Interest expense (Economic Income/(Loss)) / Interest and dividend expense (US GAAP) 4,878 1,541 6,419 — 19,581 (b)(d) $ 26,000 Total net revenues 212,786 7,028 219,814 1,837 (26,623 ) 195,028 Expenses Non interest expense 189,516 6,672 196,188 — 14,454 (a)(e)(h)(i) 210,642 Consolidated Funds expenses — — — 1,687 — 1,687 Total expenses 189,516 6,672 196,188 1,687 14,454 212,329 Total other income (loss) — — — 2,654 39,328 (c)(d)(i)(j) 41,982 Income taxes expense / (benefit) — — — — 5,083 (h) 5,083 Income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds 898 44 942 2,804 364 4,110 Income (loss) attributable to Cowen Inc. 22,372 312 22,684 — (7,196 ) 15,488 Less: Preferred stock dividends 1,290 408 1,698 — — 1,698 Economic Income (Loss)/ Income (loss) attributable to Cowen Inc. common stockholders 21,082 (96 ) 20,986 $ — $ (7,196 ) $ 13,790 Add back: Depreciation and Amortization expense 2,865 43 2,908 Economic operating income (loss) $ 23,947 $ (53 ) $ 23,894 Nine Months Ended September 30, 2019 Adjustments Operating Company Asset Company Total Economic Income (Loss) Funds Consolidation Other Adjustments US GAAP Net Income (Loss) (dollars in thousands) Revenues Investment banking $ 257,234 $ — $ 257,234 $ — $ 14,869 (a) $ 272,103 Brokerage 331,689 — 331,689 — (28,849 ) (b) 302,840 Management fees 30,016 1,788 31,804 (1,640 ) (8,684 ) (c) 21,480 Incentive income (loss) 34,654 699 35,353 (557 ) (34,072 ) (c) 724 Investment income (loss) 28,233 5,289 33,522 — (33,522 ) (d) — Interest and dividends — — — — 129,846 (b)(d) 129,846 Reimbursement from affiliates — — — (94 ) 874 (e) 780 Reinsurance premiums — — — — 29,068 (f) 29,068 Other revenue 5,295 56 5,351 (14 ) (2,109 ) (f) 3,228 Consolidated Funds revenues — — — 8,239 — 8,239 Total revenues 687,121 7,832 694,953 5,934 67,421 768,308 Interest expense (Economic Income/(Loss)) / Interest and dividend expense (US GAAP) 16,371 4,046 20,417 — 104,672 (b)(d) 125,089 Total net revenues 670,750 3,786 674,536 5,934 (37,251 ) 643,219 Expenses Non interest expense 623,167 7,025 630,192 — 49,463 (a)(e)(h)(i) 679,655 Goodwill impairment — — — — 4,100 4,100 Consolidated Funds expenses — — — 6,229 — 6,229 Total expenses 623,167 7,025 630,192 6,229 53,563 689,984 Total other income (loss) — — — 9,069 73,907 (c)(d)(i) 82,976 Income taxes expense / (benefit) — — — — 9,615 (h) 9,615 Income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds 2,944 — 2,944 8,774 (4,530 ) 7,188 Income (loss) attributable to Cowen Inc. 44,639 (3,239 ) 41,400 — (21,992 ) $ 19,408 Less: Preferred stock dividends 4,058 1,036 5,094 — — 5,094 Economic Income (Loss)/ Income (loss) attributable to Cowen Inc. common stockholders 40,581 (4,275 ) 36,306 $ — $ (21,992 ) $ 14,314 Add back: Depreciation and Amortization expense 14,957 30 14,987 Economic operating income (loss) $ 55,538 $ (4,245 ) $ 51,293 Nine Months Ended September 30, 2018 Adjustments Operating Company Asset Company Total Economic Income (Loss) Funds Consolidation Other Adjustments US GAAP Net Income (Loss) (dollars in thousands) Revenues Investment banking $ 251,476 $ — $ 251,476 $ — $ 13,261 (a) $ 264,737 Brokerage 328,929 — 328,929 — (27,876 ) (b) 301,053 Management fees 33,057 4,941 37,998 (2,197 ) (13,465 ) (c) 22,336 Incentive income (loss) 17,219 4,251 21,470 (37 ) (21,336 ) (c) 97 Investment income (loss) 62,488 (561 ) 61,927 — (61,927 ) (d)(g) — Interest and dividends — — — — 77,511 (b)(d) 77,511 Reimbursement from affiliates — — — (198 ) 1,264 (e) 1,066 Aircraft lease revenue — — — — 1,509 (g) 1,509 Reinsurance premiums — — — — 26,251 (f) 26,251 Other revenue (143 ) 393 250 — 3,596 (f) 3,846 Consolidated Funds revenues — — — 8,579 — 8,579 Total revenues 693,026 9,024 702,050 6,147 (1,212 ) 706,985 Interest expense (Economic Income/(Loss)) / Interest and dividend expense (US GAAP) 12,539 3,961 16,500 — 58,346 (b)(d) 74,846 Total net revenues 680,487 5,063 685,550 6,147 (59,558 ) 632,139 Expenses Non interest expense 601,480 12,081 613,561 — 42,738 (a)(e)(h)(i) 656,299 Consolidated Funds expenses — — — 7,267 — 7,267 Total expenses 601,480 12,081 613,561 7,267 42,738 663,566 Total other income (loss) — — — 36,113 86,851 (c)(d)(i)(j) 122,964 Income taxes expense / (benefit) — — — — 15,999 (h) 15,999 Income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds 2,805 700 3,505 34,993 (700 ) 37,798 Income (loss) attributable to Cowen Inc. 76,202 (7,718 ) 68,484 — (30,744 ) 37,740 Less: Preferred stock dividends 3,871 1,223 5,094 — — 5,094 Economic Income (Loss)/ Income (loss) attributable to Cowen Inc. common stockholders 72,331 (8,941 ) 63,390 $ — $ (30,744 ) $ 32,646 Add back: Depreciation and Amortization expense 8,707 147 8,854 Economic operating income (loss) $ 81,038 $ (8,794 ) $ 72,244 The following is a summary of the adjustments made to US GAAP net income (loss) to arrive at Economic Income (Loss): Funds Consolidation: The impacts of consolidation and the related elimination entries of the Consolidated Funds are not included in Economic Income (Loss). Adjustments to reconcile to US GAAP net income (loss) included elimination of incentive income and management fees earned from the Consolidated Funds and addition of investment fund expenses excluding management fees paid, investment fund revenues and investment income (loss). Other Adjustments: (a) Economic Income (Loss) presents underwriting expenses net of investment banking revenues, expenses reimbursed from clients within their respective expense category. Economic Income (Loss) also records retainer fees, relating to investment banking activities, collectible during the period that would otherwise be deferred until closing for US GAAP reporting. (b) Economic Income (Loss) brokerage revenues included net securities borrowed and securities loaned activities which are shown gross in interest income and interest expense for US GAAP. (c) Economic Income (Loss) recognizes revenues (i) net of distribution fees paid to agents, (ii) records income from uncrystallized incentive fees and (iii) the Company's proportionate share of management and incentive fees of certain real estate operating entities, the healthcare royalty business and the activist business. (d) Economic Income (Loss) recognizes Company income from proprietary trading (including interest and dividends). (e) Reimbursement from affiliates is shown as a reduction of Economic Income expenses, but is included as a part of revenues under US GAAP. (f) Economic Income (Loss) recognizes underwriting income from the Company's insurance related activities, net of expenses, within other revenue. (g) Aircraft lease revenue is shown net of expenses in investment income for Economic Income (Loss). (h) Economic Income (Loss) excludes income taxes and acquisition related adjustments as management does not consider these items when evaluating the performance of the segment. (i) Economic Income (Loss) recognizes the Company's proportionate share of expenses, for certain real estate operating entities and the activist business, for which the investments are recorded under the equity method of accounting for investments. (j) Economic Income (Loss) excludes gain/(loss) on debt extinguishment.

Regulatory Requirements Regulat

Regulatory Requirements Regulatory (Tables)	9 Months Ended
	Sep. 30, 2019
Regulatory [Abstract]
Computation of Net Capital under Securities and Exchange Commission Regulation	As of September 30, 2019 , these regulated broker-dealers had regulatory net capital or financial resources, regulatory net capital requirements or minimum FCA requirement and excess as follows : Subsidiary Net Capital Minimum Net Capital Requirement Excess Net Capital (dollars in thousands) Cowen and Company $ 88,162 $ 1,000 $ 87,162 Cowen Execution $ 104,559 $ 1,069 $ 103,490 ATM Execution $ 5,538 $ 250 $ 5,288 Cowen Prime $ 17,449 $ 250 $ 17,199 Westminster $ 24,048 $ 250 $ 23,798 Cowen International Ltd $ 14,475 $ 9,925 $ 4,550 Cowen Execution Ltd $ 4,957 $ 2,043 $ 2,914 Cowen Asia $ 1,088 $ 383 $ 705

Guarantees and Off-Balance Sh_2

Guarantees and Off-Balance Sheet Arrangements Details (Tables)	9 Months Ended
	Sep. 30, 2019
Guarantees and Off Balance Sheet Arrangements [Abstract]
Schedule of Subordinated Borrowing	The Company maintains uncommitted financing arrangements with large financial institutions, the details of which are summarized below as of September 30, 2019 . Lender Contractual Amount Available Amount Maturity Date Description Pledge Lines (dollars in thousands) Texas Capital Bank $ 75,000 $ 75,000 None Secured Depository Trust Company Pledge Line BMO Harris Bank 75,000 75,000 None Secured Tri-Party Pledge Facility BMO Harris Bank 150,000 150,000 None Secured Depository Trust Company Pledge Line Total 300,000 300,000 Revolving Credit Facility BMO Harris Bank Canadian Imperial Bank of Commerce Texas Capital Bank 70,000 70,000 August 21, 2020 (Syndicated) Unsecured liquidity facility to cover increases in National Securities Clearing Corporation margin deposit requirements Total Credit Lines $ 370,000 $ 370,000

Organization and Business (Deta

Organization and Business (Details)	9 Months Ended
	Sep. 30, 2019segmentdivision
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of business segments | segment	2
Number of divisions | division	4

Significant Accounting Polici_4

Significant Accounting Policies All Other - Quarterly (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)cowenfund	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)cowenfund	Sep. 30, 2018USD ($)	Jun. 30, 2019USD ($)	Jan. 01, 2019USD ($)	Dec. 31, 2018USD ($)	Jun. 30, 2018USD ($)	Dec. 31, 2017USD ($)
Operating right of use assets	$ 96,664		$ 96,664			$ 103,694	$ 0
Operating lease liabilities	100,934		100,934			$ 110,505	0
Variable Interest Entity, Consolidated, Carrying Amount, Assets	656,400		656,400				468,000
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	34,300		34,300				40,500
Cumulative Effect on Retained Earnings, Net of Tax				$ 559
Fees receivable	(101,508)		(101,508)				(111,946)
Other investments	204,168		204,168				181,407
Total Stockholders' Equity	817,055	$ 808,244	817,055	808,244	$ 817,424		$ 794,407	$ 793,207	$ 748,019
Investment banking	77,292	81,923	272,103	264,737
Revenues	252,047	221,028	768,308	706,985
Underwriting expenses	2,846	4,412	12,383	13,260
Costs and Expenses	219,964	212,329	689,984	663,566
Net gains (losses) on securities, derivatives and other investments	18,446	32,040	61,440	64,728
Net Income (Loss) Available to Common Stockholders, Basic	2,115	13,790	14,314	32,646
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	6,583	19,598	26,596	75,538
Gain (Loss) on Investments (excluding broker dealer)			(57,808)	(61,927)
Fees receivable, net of allowance			17,707	(6,211)
Payments to Acquire Other Investments			(15,899)	(21,355)
Revenue from Contract with Customer, Excluding Assessed Tax	175,943	182,337	583,682	584,940
Management Fees	7,300	7,546	21,480	22,336
Incentive income	$ 701	33	$ 724	97
Other investment companies
Number of funds, Consolidated | cowenfund	5		5
Furniture and Fixtures
Property, Plant and Equipment, Useful Life			5 years
Assets Held under Capital Leases
Property, Plant and Equipment, Useful Life			5 years
Minimum
Redeemable Noncontrolling Interest, Redemption Fee, Percent			1.00%
Minimum | Telephone and computer equipment
Property, Plant and Equipment, Useful Life			3 years
Minimum | Proprietary software
Property, Plant and Equipment, Useful Life			3 years
Maximum
Redeemable Noncontrolling Interest, Redemption Fee, Percent			5.00%
Maximum | Telephone and computer equipment
Property, Plant and Equipment, Useful Life			5 years
Maximum | Proprietary software
Property, Plant and Equipment, Useful Life			8 years
Hedge Funds
Asset Management Fees, Percent Fee			2.00%
Real Estate Funds | Minimum
Asset Management Fees, Percent Fee			0.25%
Real Estate Funds | Maximum
Asset Management Fees, Percent Fee			1.50%
Other Healthcare Royalty Partners | Minimum
Asset Management Fees, Percent Fee			0.20%
Other Healthcare Royalty Partners | Maximum
Asset Management Fees, Percent Fee			1.00%
During investment period | Healthcare Royalty Partners | Minimum
Asset Management Fees, Percent Fee			1.00%
During investment period | Healthcare Royalty Partners | Maximum
Asset Management Fees, Percent Fee			2.00%
After investment period | Healthcare Royalty Partners | Minimum
Asset Management Fees, Percent Fee			0.50%
After investment period | Healthcare Royalty Partners | Maximum
Asset Management Fees, Percent Fee			2.00%
Hedge Funds
Incentive Fees, Percent Fee			20.00%
Operating Company
Revenue from Contract with Customer, Excluding Assessed Tax	$ 175,695	181,386	$ 582,680	582,160
Management Fees	7,052	6,595	20,492	19,556
Incentive income	701	33	710	97
Operating Company | Underwriting fees
Revenue from Contract with Customer, Excluding Assessed Tax	38,936	46,537	162,140	181,056
Operating Company | Strategic/financial advisory fees
Revenue from Contract with Customer, Excluding Assessed Tax	17,889	22,195	49,565	51,053
Operating Company | Placement and sales agent fees
Revenue from Contract with Customer, Excluding Assessed Tax	15,842	13,191	48,855	32,628
Operating Company | Expense reimbursements from clients
Revenue from Contract with Customer, Excluding Assessed Tax	4,625	0	11,543	0
Operating Company | Investment Banking Revenue [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	77,292	81,923	272,103	264,737
Operating Company | Commissions
Revenue from Contract with Customer, Excluding Assessed Tax	82,715	84,882	263,831	270,917
Operating Company | Trade conversion
Revenue from Contract with Customer, Excluding Assessed Tax	3,700	2,931	12,364	12,268
Operating Company | Equity and credit research fees
Revenue from Contract with Customer, Excluding Assessed Tax	4,235	5,022	13,180	14,585
Operating Company | Brokerage
Revenue from Contract with Customer, Excluding Assessed Tax	90,650	92,835	289,375	297,770
Asset Company
Revenue from Contract with Customer, Excluding Assessed Tax	248	951	1,002	2,780
Management Fees	248	951	988	2,780
Incentive income	0	0	14	0
Operating Segments
Investment banking	70,022	77,510	257,234	251,476
Revenues	217,093	226,233	694,953	702,050
Costs and Expenses	202,040	196,188	630,192	613,561
Net Income (Loss) Available to Common Stockholders, Basic	5,547	20,986	36,306	63,390
Management Fees	10,907	12,386	31,804	37,998
Incentive income	14,377	6,910	35,353	21,470
Operating Segments | Operating Company
Investment banking	70,022	77,510	257,234	251,476
Revenues	216,686	217,664	687,121	693,026
Costs and Expenses	200,637	189,516	623,167	601,480
Net Income (Loss) Available to Common Stockholders, Basic	8,289	21,082	40,581	72,331
Management Fees	10,321	10,840	30,016	33,057
Incentive income	15,384	1,859	34,654	17,219
Operating Segments | Asset Company
Investment banking	0	0	0	0
Revenues	407	8,569	7,832	9,024
Costs and Expenses	1,403	6,672	7,025	12,081
Net Income (Loss) Available to Common Stockholders, Basic	(2,742)	(96)	(4,275)	(8,941)
Management Fees	586	1,546	1,788	4,941
Incentive income	$ (1,007)	$ 5,051	$ 699	$ 4,251

Acquisition (Narrative) (Detail

Acquisition (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jan. 02, 2019	Jan. 01, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Purchase of business			$ 48,581	$ 0
Revenues	$ 252,047	$ 221,028	768,308	706,985
Net income (loss) attributable to Cowen Inc.	3,813	$ 15,488	19,408	$ 37,740
Operating lease right-of-use assets	96,664		96,664			$ 103,694	$ 0
Quarton
Business Acquisition [Line Items]
Total estimated purchase price	103,000
Purchase of business	75,300
Business combination, contingent consideration, liability					$ 40,000
Other payments to acquire businesses	600
Business combination, contingency liability, retention of employee, bonus pool, maximum			$ 10,000
Business combination, contingency liability, retention of employee, bonus pool, period			5 years
Business combination, contingency liability, retention of employee, bonus pool, annual maximum payout			$ 2,500
Intangible assets					22,200
Amortization of Intangible Assets	2,200		6,700
Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Cost Expensed	100		1,200
Revenues	14,100		26,300
Net income (loss) attributable to Cowen Inc.	$ 3,200		$ 5,600
Operating lease right-of-use assets					$ 3,200
Common Stock Class A | Quarton
Business Acquisition [Line Items]
Business acquisition, equity interest issued or issuable, number of shares	1,033,350
Business acquisition, share price					$ 14.52
Fair Value, Measurements, Recurring | Level 3 | Quarton
Business Acquisition [Line Items]
Business combination, contingent consideration, liability					$ 27,700
Minimum | Quarton
Business Acquisition [Line Items]
Business combination, contingent consideration, liability					10,000
Maximum | Quarton
Business Acquisition [Line Items]
Business combination, contingent consideration, liability					$ 40,000

Acquisition (Preliminary Purcha

Acquisition (Preliminary Purchase Price Allocation) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Jan. 02, 2019	Jan. 01, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Operating lease right-of-use assets	$ 96,664	$ 96,664		$ 103,694	$ 0
Operating lease liabilities	(100,934)	(100,934)		$ (110,505)	$ 0
Quarton
Business Acquisition [Line Items]
Operating lease right-of-use assets			$ 3,200
Intangible assets			22,200
Operating lease liabilities			(3,200)
Total estimated purchase price	$ 103,000
Scenario, Plan | Quarton
Business Acquisition [Line Items]
Cash and cash equivalents			12,236
Fees receivable			7,269
Fixed assets			1,085
Intangible assets			22,200
Other assets			667
Compensation payable			637
Due to related parties			4,750
Accounts payable, accrued expenses and other liabilities			16,257
Total identifiable net assets acquired and liabilities assumed			$ 21,813
Goodwill		81,150
Total estimated purchase price		$ 102,963

Acquisition (Intangible Assets)

Acquisition (Intangible Assets) (Details) - Quarton - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Jan. 02, 2019
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross		$ 22,200
Trade name
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross		900
Finite-Lived Intangible Asset, Useful Life	3 years
Customer relationships
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross		7,100
Finite-Lived Intangible Asset, Useful Life	4 years
Backlog
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross		12,600
Finite-Lived Intangible Asset, Useful Life	2 years
Proprietary software
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross		$ 1,600
Finite-Lived Intangible Asset, Useful Life	3 years

Acquisition (Pro Forma) (Detail

Acquisition (Pro Forma) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Business Acquisition [Line Items]
Revenues	$ 252,047	$ 221,028	$ 768,308	$ 706,985
Net income (loss) attributable to Cowen Inc.	3,813	15,488	19,408	37,740
Quarton
Business Acquisition [Line Items]
Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Cost Expensed	100		1,200
Net revenues		206,797		661,759
Net income (loss)		$ 15,728		$ 35,616
Basic (usd per share)		$ 0.51		$ 1.16
Diluted (usd per share)		$ 0.49		$ 1.12
Revenues	14,100		26,300
Net income (loss) attributable to Cowen Inc.	$ 3,200		$ 5,600

Acquisition (Amortization Expen

Acquisition (Amortization Expense) (Details) - Quarton $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2019USD ($)
Business Acquisition [Line Items]
Amortization of Intangible Assets	$ 2,200	$ 6,700
Scenario, Plan
Business Acquisition [Line Items]
2019	2,227	2,227
2020	8,908	8,908
2023	2,608	2,608
2024	1,775	1,775
2025	0	0
Thereafter	0	0
Finite-Lived Intangible Assets, Net	$ 15,518	$ 15,518

Cash Collateral Pledged (Detail

Cash Collateral Pledged (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Cash collateral pledged	$ 18,609	$ 6,318	$ 16,092
Facility Leases
Cash collateral pledged	4,700	5,300
Collateral Reinsurance Agreement
Cash collateral pledged	$ 13,900	$ 1,000

Segregated Cash (Details)

Segregated Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Segregated Cash [Abstract]
Segregated cash	$ 128,782	$ 176,647	$ 154,191

Investments of Operating Enti_3

Investments of Operating Entities and Consolidated Funds - Securities Owned at Fair Value (Details) - USD ($) $ in Thousands		9 Months Ended	12 Months Ended
		Sep. 30, 2019	Dec. 31, 2018
Investment Holdings [Line Items]
Securities owned, at fair value		$ 922,164	$ 520,888
Securities owned, at fair value		369,191	187,633
Estimate of Fair Value Measurement [Member]
Investment Holdings [Line Items]
Securities owned, at fair value		18,300	9,400
Preferred Stock
Investment Holdings [Line Items]
Trading Securities, Equity	[1]	16,585	5,617
Securities owned, at fair value		46,268	24,314
Common Stock
Investment Holdings [Line Items]
Trading Securities, Equity	[1]	853,786	472,299
Securities owned, at fair value		202,017	95,565
Warrants and Rights
Investment Holdings [Line Items]
Trading Securities, Equity	[1]	19,865	7,990
Securities owned, at fair value		5,465	5,279
Government Securities
Investment Holdings [Line Items]
Debt Securities, Trading	[2]	$ 2,905	$ 13,398
Investment Interest Rate		0.00%	0.00%
Securities owned, at fair value	[3]	$ 100,724	$ 38,377
Corporate Bonds
Investment Holdings [Line Items]
Debt Securities, Trading	[4]	18,366	13,041
Securities owned, at fair value	[5]	$ 14,717	$ 24,098
Corporate Bonds | Minimum
Investment Holdings [Line Items]
Investment Interest Rate		0.00%	2.00%
Corporate Bonds | Maximum
Investment Holdings [Line Items]
Investment Interest Rate		15.00%	15.50%
Convertible Bonds
Investment Holdings [Line Items]
Debt Securities, Trading	[1],[6]	$ 2,541	$ 3,000
Investment Interest Rate		8.00%	8.00%
Trade Claims
Investment Holdings [Line Items]
Debt Securities, Trading	[1]	$ 7,062	$ 5,543
Loans
Investment Holdings [Line Items]
Debt Securities, Trading	[1]	$ 1,054	$ 0
Consolidated Funds | Government Securities
Investment Holdings [Line Items]
Investment Interest Rate		0.00%	0.00%
Consolidated Funds | Corporate Bonds | Minimum
Investment Holdings [Line Items]
Investment Interest Rate		4.87%	5.88%
Consolidated Funds | Corporate Bonds | Maximum
Investment Holdings [Line Items]
Investment Interest Rate		6.50%	7.63%
Enterprise Master
Investment Holdings [Line Items]
Securities owned, at fair value			$ 469
Enterprise Master | Common Stock
Investment Holdings [Line Items]
Securities owned, at fair value			$ 469
[1]	* The Company has elected the fair value option for securities owned, at fair value with a fair value of $18.3 million and $9.4 million, respectively, at September 30, 2019 and December 31, 2018.
[2]	As of September 30, 2019, maturities range from October 2019 to March 2020 with an interest rate of 0%. As of December 31, 2018, maturities ranged from April 2019 to August 2019 with an interest rate of 0%.
[3]	As of September 30, 2019, maturities ranged from November 2019 to December 2019 and interest rates were 0%. As of December 31, 2018, maturities ranged from January 2019 to April 2019 and interest rates were 0%.
[4]	As of September 30, 2019, maturities ranged from December 2019 to August 2044 and interest rates ranged from 0.00% to 15.00%. As of December 31, 2018, maturities ranged from April 2019 to April 2049 and interest rates ranged from 2% to 15.50%.
[5]	As of September 30, 2019, maturities ranged from May 2022 to May 2026 and interest rates ranged from 4.87% to 6.50%. As of December 31, 2018, maturities ranged from August 2020 to March 2026 and interest rates ranged from 5.88% to 7.63%.
[6]	As of September 30, 2019, maturities range from April 2020 to March 2022 with an interest rate of 8%. As of December 31, 2018, the maturity was June 2020 with an interest rate of 8%

Investments of Operating Enti_4

Investments of Operating Entities and Consolidated Funds - Derivatives (Details)		Dec. 05, 2016	Sep. 30, 2019USD ($)contract	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)contract	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)contract
Derivative [Line Items]
Stockholders' Equity Note, Stock Split, Conversion Ratio		0.25
Receivable on derivative contracts, at fair value			$ 39,754,000		$ 39,754,000		$ 25,125,000
Payable for derivative contracts, at fair value			32,755,000		32,755,000		16,082,000
Receivable on derivative contracts, at fair value			3,885,000		3,885,000		4,416,000
Payable for derivative contracts, at fair value, Consolidated Funds			7,778,000		7,778,000		1,663,000
Equity Swap
Derivative [Line Items]
Receivable on derivative contracts, at fair value			1,296,000		1,296,000		2,477,000
Payable for derivative contracts, at fair value, Consolidated Funds			5,022,000		5,022,000		713,000
Futures
Derivative [Line Items]
Derivative Asset, Notional Amount			33,473,750		33,473,750		42,288,209
Receivable on derivative contracts, at fair value			103,000		103,000		334,000
Currency Forwards
Derivative [Line Items]
Derivative Asset, Notional Amount			79,804,033		79,804,033		394,875
Receivable on derivative contracts, at fair value			640,000		640,000		1,000
Derivative Liability, Notional Amount			24,636,000		24,636,000		96,406,000
Payable for derivative contracts, at fair value			91,000		91,000		709,000
Receivable on derivative contracts, at fair value			31,000		31,000		186,000
Payable for derivative contracts, at fair value, Consolidated Funds			2,341,000		2,341,000		96,000
Swaps
Derivative [Line Items]
Derivative Asset, Notional Amount			103,591,441		103,591,441		13,702,458
Receivable on derivative contracts, at fair value			4,242,000		4,242,000		917,000
Derivative Liability, Notional Amount			164,056,000		164,056,000		52,905,000
Payable for derivative contracts, at fair value			$ 6,502,000		$ 6,502,000		$ 2,162,000
Options
Derivative [Line Items]
Derivative Asset, Number of Instruments Held | contract	[1]		349,434		349,434		654,506
Receivable on derivative contracts, at fair value	[1]		$ 34,769,000		$ 34,769,000		$ 23,130,000
Receivable on derivative contracts, at fair value			2,558,000		2,558,000		1,753,000
Payable for derivative contracts, at fair value, Consolidated Funds			$ 415,000		$ 415,000		$ 854,000
Option
Derivative [Line Items]
Derivative Liability, Number of Instruments Held | contract	[2]		190,321		190,321		90,730
Payable for derivative contracts, at fair value	[2]		$ 26,162,000		$ 26,162,000		$ 13,211,000
Pay to hold
Derivative [Line Items]
Derivative Asset, Number of Instruments Held | contract			0		0		0
Receivable on derivative contracts, at fair value			$ 0		$ 0		$ 743,000
Receivable on derivatives contracts, at fair value [Member]
Derivative [Line Items]
Receivable on derivative contracts, at fair value			39,754,000		39,754,000		25,125,000
Derivative Asset, Fair Value, Gross Asset			39,754,000		39,754,000		25,125,000
Derivative Asset, Fair Value, Amount Offset Against Collateral	[3]		0		0		0
Financial Instruments, Owned and Pledged as Collateral, at Fair Value			0		0		0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	[4]		4,882,000		4,882,000		1,662,000
Derivative asset, net of offset			34,872,000		34,872,000		23,463,000
Payable for derivatives contracts, at fair value [Member]
Derivative [Line Items]
Payable for derivative contracts, at fair value			32,755,000		32,755,000		16,082,000
Financial Instruments, Owned and Pledged as Collateral, at Fair Value			0		0		0
Derivative Liability, Fair Value, Gross Liability			32,755,000		32,755,000		16,082,000
Derivative Liability, Fair Value, Amount Offset Against Collateral	[3]		0		0		0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	[4]		6,592,000		6,592,000		2,871,000
Derivative Liability, net of offset			26,163,000		26,163,000		13,211,000
Receivables from Brokers-Dealers and Clearing Organizations
Derivative [Line Items]
Collateral posted			8,200,000		8,200,000		$ 11,200,000
Other Income [Member]
Derivative [Line Items]
Realized and unrealized gains/(losses) related to derivatives trading activities			$ 7,100,000	$ (7,500,000)	$ 2,300,000	$ 6,400,000
[1]	Includes index, equity, commodity future and cash conversion options.
[2]	Includes index, equity, commodity future and cash conversion options.
[3]	Includes financial instruments subject to enforceable master netting provisions that are permitted to be offset to the extent an event of default has occurred.
[4]	Includes the amount of collateral held or posted.

Investments of Operating Enti_5

Investments of Operating Entities and Consolidated Funds - Other Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2019		Dec. 31, 2018
Investment Holdings [Line Items]
Other investments	$ 204,168		$ 181,407
Portfolio Funds, Consolidated Funds	171,186		186,395
Portfolio Funds
Investment Holdings [Line Items]
Other investments	131,740	[1]	123,241	[2]
Carried interest [Member]
Investment Holdings [Line Items]
Other investments	25,186	[1]	17,995	[2]
Equity Method Investments
Investment Holdings [Line Items]
Other investments	47,242		40,171
Enterprise LP [Member]
Investment Holdings [Line Items]
Portfolio Funds, Consolidated Funds	96,308		97,656
Merger Fund [Member]
Investment Holdings [Line Items]
Portfolio Funds, Consolidated Funds	$ 74,878		$ 88,739
[1]	In accordance with US GAAP, certain investments that are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient and carried interest in portfolio funds have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the condensed consolidated statement of financial condition.
[2]	In accordance with US GAAP, certain investments that are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient and carried interest in portfolio funds have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the condensed consolidated statement of financial condition.

Investments of Operating Enti_6

Investments of Operating Entities and Consolidated Funds - Portfolio Funds - (Details) $ in Thousands		9 Months Ended
		Sep. 30, 2019USD ($)		Dec. 31, 2018USD ($)
Investment Holdings [Line Items]
Other investments		$ 204,168		$ 181,407
number of investments		1
Portfolio Funds
Investment Holdings [Line Items]
Other investments		$ 131,740	[1]	123,241	[2]
Portfolio Funds | Starboard Value and Opportunity Fund LP | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[3],[4]	$ 36,566		32,579
Required notice period, withdrawal		90 days
Portfolio Funds | Formation 8 Partners Fund I LP
Investment Holdings [Line Items]
Other investments	[5]	$ 33,613		34,099
Portfolio Funds | RCGLongview Debt Fund V, L.P. | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[4],[6]	1,909		4,394
Portfolio Funds | RCG Longview II, LP | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[4],[6]	3,734		4,400
Portfolio Funds | Cowen Healthcare Investments II LP | Affiliated Entity
Investment Holdings [Line Items]
Other investments		18,036	[4],[7]	14,939
Portfolio Funds | Eclipse Ventures Fund I, L.P.
Investment Holdings [Line Items]
Other investments	[8]	4,901		4,412
Portfolio Funds | Healthcare Royalty Partners | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[4],[9]	1,367		1,833
Portfolio Funds | Lagunita Biosciences, LLC
Investment Holdings [Line Items]
Other investments	[10]	4,868		3,833
Portfolio Funds | Starboard Leaders Fund LP | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[4],[11]	$ 1,511		1,230
Unfunded Commitment cancellation		30 days
Portfolio Funds | Elipse SPV I,LP | Affiliated Entity
Investment Holdings [Line Items]
Other investments		$ 1,446	[4],[12]	1,447
Portfolio Funds | RCG Longview Equity Fund, LP | Affiliated Entity
Investment Holdings [Line Items]
Other investments		713	[4],[6]	802
Portfolio Funds | RCG Longview Debt Fund VI, LP | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[4],[6]	1,895		1,586
Portfolio Funds | RCG Park Liberty GP Member LLC | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[4],[6]	952		1,023
Portfolio Funds | Healthcare Royalty Partners II | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[4],[9]	1,681		1,037
Portfolio Funds | RCGL PE MPA LLC | Affiliated Entity
Investment Holdings [Line Items]
Other investments		0	[4],[6]	618
Portfolio Funds | RCG LPP2 PNW5 Co-Invest, L.P. | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[4],[13]	10		296
Portfolio Funds | Difesa Partners LP [Member] | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[4],[13]	500		0
Portfolio Funds | Other Private Investment | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[4],[14]	14,711		11,625
Portfolio Funds | Other Funds | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[4],[15]	$ 3,327		3,088
Enterprise Master | Portfolio Funds
Investment Holdings [Line Items]
Other investments				112,394
Multi-strategy | Enterprise Master | Portfolio Funds | RCG Special Opportunities Fund, Ltd | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[16]			111,548
Various Strategies | Enterprise Master | Portfolio Funds | Other Private Investment
Investment Holdings [Line Items]
Other investments				$ 846
[1]	In accordance with US GAAP, certain investments that are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient and carried interest in portfolio funds have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the condensed consolidated statement of financial condition.
[2]	In accordance with US GAAP, certain investments that are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient and carried interest in portfolio funds have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the condensed consolidated statement of financial condition.
[3]	Starboard Value and Opportunity Fund LP and Difesa Partners, LP permits quarterly withdrawals upon 90 days' notice.
[4]	These Portfolio Funds are affiliates of the Company.
[5]	Formation8 Partners Fund I, L.P. is a private equity fund which invests in early stage and growth transformational information and energy technology companies. Distributions will be made when the underlying investments are liquidated.
[6]	RCG Longview Debt Fund V, L.P., RCG Longview II LP, RCG Park Liberty GP Member LLC, RCG Longview Equity Fund, LP, RCGL PE MPA, LLC and RCG Longview Debt Fund VI, LP are real estate private equity structures. The timing of distributions depends on the nature of the underlying investments and therefore will be made either quarterly or when the underlying investments are liquidated.
[7]	Cowen Healthcare Investments II LP are private equity funds. Distributions are made from these funds when cash flows or securities are received from the underlying investments. Investors do not have redemption rights
[8]	Eclipse Ventures Fund I, L.P. is a private equity fund which invests in early stage and growth hardware companies. Distributions will be made when the underlying investments are liquidated.
[9]	HealthCare Royalty Partners, L.P. and HealthCare Royalty Partners II, L.P. are private equity funds and therefore distributions will be made when cash flows are received from the underlying investments, typically on a quarterly basis.
[10]	Lagunita Biosciences, LLC, is a healthcare investment company that creates and grows early stage companies to commercialize impactful translational science that addresses significant clinical needs, is a private equity structure and therefore distributions will be made when the underlying investments are liquidated.
[11]	Starboard Leaders Fund LP does not permit withdrawals, but instead allows terminations with respect to capital commitments upon 30 days' prior written notice at any time following the first anniversary of an investor's initial capital contribution.
[12]	Eclipse SPV I, L.P. is a co-investment vehicle organized to invest in a private company focused on software-driven automation projects. Distributions will be made when the underlying investments are liquidated.
[13]	RCG LPP2 PNW5 Co-Invest, L.P. is a single purpose entity formed to participate in a joint venture which acquired five multi-unit residential rental properties located in the Pacific Northwest. RCG LPP2 PNW5 Co-Invest, L.P. is a private equity structure and therefore distributions will be made when the underlying investments are liquidated.
[14]	Other private investment represents the Company's closed end investment in a Portfolio Fund that invests in a wireless broadband communication provider in Italy.
[15]	The majority of these investment funds are affiliates of the Company or are managed by the Company and the investors can redeem from these funds as investments are liquidated.
[16]	Affiliates of the Company.

Investments of Operating Enti_7

Investments of Operating Entities and Consolidated Funds - Equity Method Investments - (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Summarized Financial Information, Cash	$ 2,553		$ 2,553		$ 37
number of investments			1
Equity method investments	47,242		$ 47,242		40,171
Liabilities	0		0		0
Equity	74,871		74,871		20,230
Revenue	4,564	$ (1,843)	83,287	$ 24,083
Expenses	0	0	0	0
Net realized and unrealized gain (loss)	55	29	717	271
Net Income	4,619	(1,814)	84,004	24,354
Equity Method Investment, Summarized Financial Information, Performance And Management Fee Receivable	68,052		68,052		16,594
Equity Method Investment, Summarized Financial Information, Investments in Portfolio Funds	4,266		4,266		3,599
Other than Temporary Impairment Losses, Investments				7,100
Surf House Ocean Views Holdings, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	9,946		9,946		7,589
Starboard Value LP
Schedule of Equity Method Investments [Line Items]
Equity method investments	22,627		22,627		12,699
RCG Longview Debt Fund V Partners, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	3,827		3,827		11,000
RCG Longview Management, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	2,474		2,474		1,167
Income (Loss) from Equity Method Investments	200		200
RCG Longview Debt Fund VI, LP
Schedule of Equity Method Investments [Line Items]
Equity method investments	449		449		1,254
Healthcare Royalty GP, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	111		111		149
Healthcare Royalty GP II, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	285		285		176
RCG Longview Debt Fund IV Management, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	331		331		331
Healthcare Royalty GP III, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	2,190		2,190		1,573
Triartisan ES Partners, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments	1,026		1,026		1,500
Triartisan PFC Partners, LLC [Member] [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments	999		999		0
RCG Kennedy House, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	65		65		131
RCG Longview Equity Management, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	105		105		114
RCG LPP II GP, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	30		30		272
RCG Park Liberty GP Member Manager, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	1,014		1,014		1,248
HCR Stafford Fund GP, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments	682		682		0
Equity Method Investee, Other
Schedule of Equity Method Investments [Line Items]
Equity method investments	1,081		1,081		968
Net Gains (Losses) on Securities, Derivatives and Other Investments
Schedule of Equity Method Investments [Line Items]
Income (Loss) from Equity Method Investments	$ 2,700	$ (4,700)	$ 23,100	$ 7,200
Minimum
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	1.00%		1.00%
Maximum
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	56.00%		56.00%
Clawback Obligation | RCG Longview Partners II, LLC
Schedule of Equity Method Investments [Line Items]
Contractual obligation	$ 6,500		$ 6,500		$ 6,500

Investments of Operating Enti_8

Investments of Operating Entities and Consolidated Funds - Securities Sold, Not Yet Purchased (Details) - USD ($)		Sep. 30, 2019	Dec. 31, 2018
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, at fair value		$ 364,742,000	$ 195,307,000
Common Stock
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, at fair value		349,408,000	194,305,000
Corporate Bonds
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, at fair value	[1]	$ 1,281,000	$ 750,000
Corporate Bonds | Minimum
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, interest rate		5.00%	2.25%
Corporate Bonds | Maximum
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, interest rate		5.50%	9.38%
Government Securities | Minimum
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, interest rate		7.00%
Government Securities | Maximum
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, interest rate		8.25%
US Government Debt Securities
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, at fair value	[2]	$ 2,250,000	$ 0
Preferred Stock
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, at fair value		4,394,000	199,000
Warrants and Rights
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, at fair value		$ 7,409,000	$ 53,000
[1]	As of September 30, 2019, the maturities ranged from February 2024 to April 2037 and interest rates ranged from 5.00% to 5.50%. As of December 31, 2018, the maturities ranged from October 2022 to January 2034 and interest rates ranged from 2.25% to 9.38%.
[2]	As of September 30, 2019, the maturities ranged from October 2019 to March 2038 and interest rates ranged from 7.00% to 8.25%.

Investments of Operating Enti_9

Investments of Operating Entities and Consolidated Funds - Securities borrowed and securities loaned (Details) - USD ($) $ in Thousands		Sep. 30, 2019	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Securities borrowed		$ 1,228,036	$ 407,795
Securities Borrowed, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election	[1]	0	0
Securities borrowed, net amounts included on the condensed consolidated statements of financial condition		1,228,036	407,795
Securities borrowed, additional amounts, asset		0	0
Securities Borrowed, Collateral, Obligation to Return Securities		1,209,672	383,593
Securities Borrowed, Collateral, Obligation to Return Cash	[2]	0	0
Securities Borrowed, Amount Offset Against Collateral		18,364	24,202
Securities borrowed, cash collateral pledged		0
Securities Loaned		1,339,647	414,852
Securities Loaned, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election	[1]	0	0
Securities Loaned, Gross amounts recognized		1,339,647	414,852
Securities Loaned, Additional Amounts Available		0	0
Securities Loaned, Collateral, Right to Reclaim Securities		1,282,340	391,310
Securities Loaned, Collateral, Right to Reclaim Cash	[2]	0	0
Securities Loaned, Amount Offset Against Collateral		57,307	23,542
Securities Sold under Agreements to Repurchase, Asset		23,772
Securities Loaned, Financial instruments		25,635
Securities Loaned, Net amounts		(1,863)
Securities Sold under Agreements to Repurchase		23,772	$ 0
Securities Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement		0
Securities sold under agreements to repurchase, additional amounts		$ 0
[1]	Includes financial instruments subject to enforceable master netting provisions that are permitted to be offset to the extent an event of default has occurred.
[2]	Includes the amount of cash collateral held/posted.

Investments of Operating Ent_10

Investments of Operating Entities and Consolidated Funds - Securities loaned transactions by remaining contractual maturity and class of collateral pledged (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Common stock	$ 1,339,647	$ 414,852
Securities sold, not yet purchased, at fair value	364,742	195,307
Common stock
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Common stock	1,024,436	414,852
Common stock | Open and Overnight
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Common stock	1,024,436	414,852
Common stock | Up to 30 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Common stock	0	0
Common stock | 31 - 90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Common stock	0	0
Common stock | Greater than 90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Common stock	0	$ 0
Corporate Bonds
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Common stock	315,211
Securities sold, not yet purchased, at fair value	23,772
Corporate Bonds | Open and Overnight
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Common stock	315,211
Securities sold, not yet purchased, at fair value	0
Corporate Bonds | Up to 30 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Common stock	0
Securities sold, not yet purchased, at fair value	15,951
Corporate Bonds | 31 - 90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Common stock	0
Securities sold, not yet purchased, at fair value	7,821
Corporate Bonds | Greater than 90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Common stock	0
Securities sold, not yet purchased, at fair value	$ 0

Investments of Operating Ent_11

Investments of Operating Entities and Consolidated Funds - Variable Interest Entities (Details) - Variable Interest Entity, Not Primary Beneficiary - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Variable Interest Entity [Line Items]
Total assets of nonconsolidated variable interest entities	$ 5,600	$ 5,100
Total liabilities of nonconsolidated variable interest entities	258.5	157.6
Variable Interest Entity, Nonconsolidated, Comparison of Carrying Amount of Assets and Liabilities to Maximum Loss Exposure	241.1	301.4
Maximum exposure regarding nonconsolidated variable interest entities	$ 264.3	$ 332.4

Investments of Operating Ent_12

Investments of Operating Entities and Consolidated Funds - Indirect Concentration of the Underlying Investments Held by Consolidated Funds (Details) $ in Thousands	Sep. 30, 2019USD ($)investments	Dec. 31, 2018USD ($)investments
Investment [Line Items]
Concentration of risk, number of investments | investments	1	1
Equity Securities | Linkem | ITALY | 517210 Wireless Telecommunications Carriers (except Satellite)
Investment [Line Items]
Market Value	$ 69,927
Equity Securities | Linkem | ITALY | 517312 Wireless Telecommunications Carriers (except Satellite) [Member]
Investment [Line Items]
Percentage of Stockholders' Equity	8.55842%	8.36%
Market Value		$ 66,439

Investments of Operating Ent_13

Investments of Operating Entities and Consolidated Funds - Merger Master Narrative (Details) - USD ($) $ in Thousands		Sep. 30, 2019	Dec. 31, 2018
Investment [Line Items]
Trading securities		$ 922,164	$ 520,888
Securities sold, not yet purchased, at fair value		364,742	195,307
Merger Master
Investment [Line Items]
Trading securities		177,012	279,299
Securities sold, not yet purchased, at fair value		58,444	9,610
Common Stock
Investment [Line Items]
Securities sold, not yet purchased, at fair value		349,408	194,305
Common Stock | Merger Master
Investment [Line Items]
Trading securities		166,669	162,811
Securities sold, not yet purchased, at fair value		58,444	9,610
Corporate Bonds
Investment [Line Items]
Securities sold, not yet purchased, at fair value	[1]	1,281	750
Corporate Bonds | Merger Master
Investment [Line Items]
Trading securities		$ 10,343	$ 116,488
[1]	As of September 30, 2019, the maturities ranged from February 2024 to April 2037 and interest rates ranged from 5.00% to 5.50%. As of December 31, 2018, the maturities ranged from October 2022 to January 2034 and interest rates ranged from 2.25% to 9.38%.

Investments of Operating Ent_14

Investments of Operating Entities and Consolidated Funds - Merger Master Derivatives (Details) - USD ($) $ in Thousands		Sep. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Derivative Asset		$ 39,754	$ 25,125
Derivative Liability		32,755	16,082
Merger Master
Derivative [Line Items]
Derivative Asset		2,790	8,770
Derivative Liability		14,841	1,728
Option
Derivative [Line Items]
Derivative Liability	[1]	26,162	13,211
Option | Merger Master
Derivative [Line Items]
Derivative Liability		856	1,430
Options
Derivative [Line Items]
Derivative Asset	[2]	34,769	23,130
Options | Merger Master
Derivative [Line Items]
Derivative Asset		2,691	3,450
Swaps
Derivative [Line Items]
Derivative Asset		4,242	917
Derivative Liability		6,502	2,162
Swaps | Merger Master
Derivative [Line Items]
Derivative Asset		99	5,320
Derivative Liability		49	28
Currency Forwards
Derivative [Line Items]
Derivative Asset		640	1
Derivative Liability		91	709
Currency Forwards | Merger Master
Derivative [Line Items]
Derivative Liability		$ 13,936	$ 270
[1]	Includes index, equity, commodity future and cash conversion options.
[2]	Includes index, equity, commodity future and cash conversion options.

Investments of Operating Ent_15

Investments of Operating Entities and Consolidated Funds Carried Interest (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2019		Dec. 31, 2018
Carried Interest [Abstract]
Carried Interest		The carried interest as of September 30, 2019 and December 31, 2018 , included the following: As of September 30, 2019 As of December 31, 2018 (dollars in thousands) Cowen Healthcare Investments II LP (*) 19,365 6,778 Other private investment (a) (*) 4,388 4,273 RCG IO Renergys Sarl 863 6,369 Ramius Multi-Strategy Fund LP (*) 570 575 $ 25,186 $ 17,995 (a) Other private investment represents the Company's closed end investment in a Portfolio Fund that invests in a wireless broadband communication provider in Italy. * These carried interest balances are earned from affiliates of the Company.
Investment [Line Items]
Other investments		$ 204,168		$ 181,407
Carried interest [Member]
Investment [Line Items]
Other investments		25,186	[1]	17,995	[2]
Cowen Healthcare Investments II LP | Carried interest [Member] | Affiliated Entity
Investment [Line Items]
Other investments	[3]	19,365		6,778
Other Private Investment | Carried interest [Member] | Affiliated Entity
Investment [Line Items]
Other investments	[3],[4]	4,388		4,273
RCG IO Renergys Sarl | Carried interest [Member] | Affiliated Entity
Investment [Line Items]
Other investments	[3]	863		6,369
Ramius Mutli-Strategy Fund LP [Member] | Carried interest [Member] | Affiliated Entity
Investment [Line Items]
Other investments	[3]	$ 570		$ 575
[1]	In accordance with US GAAP, certain investments that are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient and carried interest in portfolio funds have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the condensed consolidated statement of financial condition.
[2]	In accordance with US GAAP, certain investments that are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient and carried interest in portfolio funds have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the condensed consolidated statement of financial condition.
[3]	These carried interest balances are earned from affiliates of the Company.
[4]	Other private investment represents the Company's closed end investment in a Portfolio Fund that invests in a wireless broadband communication provider in Italy.

Fair Value Measurements for O_3

Fair Value Measurements for Operating Entities and Consolidated Funds Assets and Liabilities at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands		Sep. 30, 2019		Jun. 30, 2019	Dec. 31, 2018		Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		$ 364,742			$ 195,307
Securities sold, not yet purchased, at fair value		364,742			195,307
Derivative Liability		32,755			16,082
Derivative Asset		39,754			25,125
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, Low		1,600			2,800
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High		40,000			3,400
Other investments		204,168			181,407
Other Investments, Consolidated Funds		171,186			186,395
Investments		$ 1,710,348			$ 1,105,864
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of Total Assets at Fair Value		93.90%			86.60%
Percentage of Total Liabilities at Fair Value		88.50%			95.60%
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of Total Assets at Fair Value		2.90%			6.00%
Percentage of Total Liabilities at Fair Value		3.20%			2.00%
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance Liability Value		$ 35,784			$ 5,166
Percentage of Total Assets at Fair Value		3.20%			7.40%
Percentage of Total Liabilities at Fair Value		8.20%			2.40%
Contingent liability payable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance Liability Value		$ 29,834		$ 29,536	$ 3,070		$ 2,643	$ 2,870	$ 3,440
Futures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		103			334
Swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		6,502			2,162
Derivative Asset		4,242			917
Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	[1]	34,769			23,130
Options | Options | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance Liability Value		2,500
Pay to hold
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		0			743
Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance Liability Value		1,200		$ 0	0
Derivative Assets | Futures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		103
Derivative Assets | Futures | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		103
Derivative Assets | Futures | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		0
Derivative Assets | Futures | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		0
Portfolio Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments		131,740	[2]		123,241	[3]
Other Investments, Consolidated Funds		171,186	[2]		186,395	[3]
Carried interest [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments		25,186	[2]		17,995	[3]
Equity Method Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments		47,242			40,171
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment Sold, Not yet Purchased and Derivative Liability, at Fair Value		435,109			216,122
Assets, Fair Value Disclosure, Recurring (Deprecated 2018-01-31)		1,334,994			738,062
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment Sold, Not yet Purchased and Derivative Liability, at Fair Value		385,288			206,526
Assets, Fair Value Disclosure, Recurring (Deprecated 2018-01-31)		1,253,455			638,837
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment Sold, Not yet Purchased and Derivative Liability, at Fair Value		14,037			4,430
Assets, Fair Value Disclosure, Recurring (Deprecated 2018-01-31)		38,273			44,311
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment Sold, Not yet Purchased and Derivative Liability, at Fair Value		35,784			5,166
Assets, Fair Value Disclosure, Recurring (Deprecated 2018-01-31)		43,266			54,914
Fair Value, Measurements, Recurring | Preferred Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		4,394			199
Fair Value, Measurements, Recurring | Preferred Stock | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		4,394			199
Fair Value, Measurements, Recurring | Preferred Stock | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		0			0
Fair Value, Measurements, Recurring | Preferred Stock | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		0			0
Fair Value, Measurements, Recurring | Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		349,408			194,305
Fair Value, Measurements, Recurring | Common Stock | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		349,408			194,305
Fair Value, Measurements, Recurring | Common Stock | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		0			0
Fair Value, Measurements, Recurring | Common Stock | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		0			0
Fair Value, Measurements, Recurring | Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		1,281			750
Fair Value, Measurements, Recurring | Corporate Bonds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		0			0
Fair Value, Measurements, Recurring | Corporate Bonds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		81			750
Fair Value, Measurements, Recurring | Corporate Bonds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		1,200			0
Fair Value, Measurements, Recurring | Warrants and Rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		7,409			53
Fair Value, Measurements, Recurring | Warrants and Rights | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		7,409			53
Fair Value, Measurements, Recurring | Warrants and Rights | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		0			0
Fair Value, Measurements, Recurring | Warrants and Rights | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		0			0
Fair Value, Measurements, Recurring | Contingent liability payable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability		29,834	[4]		3,070
Fair Value, Measurements, Recurring | Contingent liability payable | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability		0	[4]		0	[5]
Fair Value, Measurements, Recurring | Contingent liability payable | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability		0	[4]		0	[5]
Fair Value, Measurements, Recurring | Contingent liability payable | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability		29,834	[4]		3,070	[5]
Fair Value, Measurements, Recurring | Currency forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		640			1
Fair Value, Measurements, Recurring | Currency forward | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		0			0
Fair Value, Measurements, Recurring | Currency forward | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		640			1
Fair Value, Measurements, Recurring | Currency forward | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		0			0
Fair Value, Measurements, Recurring | Currency forward | Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		91			709
Fair Value, Measurements, Recurring | Currency forward | Options | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		0			0
Fair Value, Measurements, Recurring | Currency forward | Options | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		91			709
Fair Value, Measurements, Recurring | Currency forward | Options | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		0			0
Fair Value, Measurements, Recurring | Swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		4,242
Fair Value, Measurements, Recurring | Swaps | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		0
Fair Value, Measurements, Recurring | Swaps | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		4,242
Fair Value, Measurements, Recurring | Swaps | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		0
Fair Value, Measurements, Recurring | Swaps | Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		6,502			2,162
Fair Value, Measurements, Recurring | Swaps | Options | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		0			0
Fair Value, Measurements, Recurring | Swaps | Options | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		6,502			2,162
Fair Value, Measurements, Recurring | Swaps | Options | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		0			0
Fair Value, Measurements, Recurring | Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		34,769
Fair Value, Measurements, Recurring | Options | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		34,769
Fair Value, Measurements, Recurring | Options | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		0
Fair Value, Measurements, Recurring | Options | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		0
Fair Value, Measurements, Recurring | Options | Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		26,162			13,211
Fair Value, Measurements, Recurring | Options | Options | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		23,662			11,115
Fair Value, Measurements, Recurring | Options | Options | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		0			0
Fair Value, Measurements, Recurring | Options | Options | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability					2,096
Fair Value, Measurements, Recurring | Pay to hold
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset					743
Fair Value, Measurements, Recurring | Pay to hold | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset					0
Fair Value, Measurements, Recurring | Pay to hold | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset					743
Fair Value, Measurements, Recurring | Pay to hold | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset					0
Fair Value, Measurements, Recurring | Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		2,905			13,398
Fair Value, Measurements, Recurring | Government Securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		2,905			13,398
Fair Value, Measurements, Recurring | Government Securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		0			0
Fair Value, Measurements, Recurring | Government Securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		0			0
Fair Value, Measurements, Recurring | Preferred Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		16,585			5,617
Fair Value, Measurements, Recurring | Preferred Stock | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		8,750			449
Fair Value, Measurements, Recurring | Preferred Stock | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		0			0
Fair Value, Measurements, Recurring | Preferred Stock | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		7,835			5,168
Fair Value, Measurements, Recurring | Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		853,786			472,299
Fair Value, Measurements, Recurring | Common Stock | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		840,473			459,601
Fair Value, Measurements, Recurring | Common Stock | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		0			2,848
Fair Value, Measurements, Recurring | Common Stock | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		13,313			9,850
Fair Value, Measurements, Recurring | Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		18,366			13,041
Fair Value, Measurements, Recurring | Corporate Bonds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		0			0
Fair Value, Measurements, Recurring | Corporate Bonds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		16,293			13,041
Fair Value, Measurements, Recurring | Corporate Bonds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		2,073			0
Fair Value, Measurements, Recurring | Convertible Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		2,541			3,000
Fair Value, Measurements, Recurring | Convertible Bonds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		0			0
Fair Value, Measurements, Recurring | Convertible Bonds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		0			0
Fair Value, Measurements, Recurring | Convertible Bonds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		2,541			3,000
Fair Value, Measurements, Recurring | Trade Claims
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		7,062			5,543
Fair Value, Measurements, Recurring | Trade Claims | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		0			0
Fair Value, Measurements, Recurring | Trade Claims | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		0			0
Fair Value, Measurements, Recurring | Trade Claims | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		7,062			5,543
Fair Value, Measurements, Recurring | Warrants and Rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		19,865			7,990
Fair Value, Measurements, Recurring | Warrants and Rights | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		19,281			6,324
Fair Value, Measurements, Recurring | Warrants and Rights | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		0			0
Fair Value, Measurements, Recurring | Warrants and Rights | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		584			1,666
Fair Value, Measurements, Recurring | Derivative Assets | Futures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset					334
Fair Value, Measurements, Recurring | Derivative Assets | Futures | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset					334
Fair Value, Measurements, Recurring | Derivative Assets | Futures | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset					0
Fair Value, Measurements, Recurring | Derivative Assets | Futures | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset					0
Fair Value, Measurements, Recurring | Derivative Assets | Swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset					917
Fair Value, Measurements, Recurring | Derivative Assets | Swaps | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset					0
Fair Value, Measurements, Recurring | Derivative Assets | Swaps | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset					917
Fair Value, Measurements, Recurring | Derivative Assets | Swaps | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset					0
Fair Value, Measurements, Recurring | Derivative Assets | Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset					23,130
Fair Value, Measurements, Recurring | Derivative Assets | Options | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset					23,130
Fair Value, Measurements, Recurring | Derivative Assets | Options | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset					0
Fair Value, Measurements, Recurring | Derivative Assets | Options | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset					0
Fair Value, Measurements, Recurring | Term loan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		1,054
Fair Value, Measurements, Recurring | Term loan | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		0
Fair Value, Measurements, Recurring | Term loan | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		1,054
Fair Value, Measurements, Recurring | Term loan | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		0
Fair Value, Measurements, Recurring | Operating Companies [Member] | US Government Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		2,250
Fair Value, Measurements, Recurring | Operating Companies [Member] | US Government Debt Securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		0
Fair Value, Measurements, Recurring | Operating Companies [Member] | US Government Debt Securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		0
Fair Value, Measurements, Recurring | Operating Companies [Member] | US Government Debt Securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		2,250
Fair Value, Measurements, Recurring | Consolidated Funds | Currency forward | Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		2,341			96
Fair Value, Measurements, Recurring | Consolidated Funds | Currency forward | Options | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		0			0
Fair Value, Measurements, Recurring | Consolidated Funds | Currency forward | Options | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		2,341			96
Fair Value, Measurements, Recurring | Consolidated Funds | Currency forward | Options | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		0			0
Fair Value, Measurements, Recurring | Consolidated Funds | Equity Swap | Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		5,022			713
Fair Value, Measurements, Recurring | Consolidated Funds | Equity Swap | Options | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		0			0
Fair Value, Measurements, Recurring | Consolidated Funds | Equity Swap | Options | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		5,022			713
Fair Value, Measurements, Recurring | Consolidated Funds | Equity Swap | Options | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		0			0
Fair Value, Measurements, Recurring | Consolidated Funds | Options | Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		415			854
Fair Value, Measurements, Recurring | Consolidated Funds | Options | Options | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		415			854
Fair Value, Measurements, Recurring | Consolidated Funds | Options | Options | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		0			0
Fair Value, Measurements, Recurring | Consolidated Funds | Options | Options | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability		0			0
Fair Value, Measurements, Recurring | Consolidated Funds | Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		100,724			38,377
Fair Value, Measurements, Recurring | Consolidated Funds | Government Securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		100,724			38,377
Fair Value, Measurements, Recurring | Consolidated Funds | Government Securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		0			0
Fair Value, Measurements, Recurring | Consolidated Funds | Government Securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		0			0
Fair Value, Measurements, Recurring | Consolidated Funds | Preferred Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		46,268			24,314
Fair Value, Measurements, Recurring | Consolidated Funds | Preferred Stock | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		41,875			0
Fair Value, Measurements, Recurring | Consolidated Funds | Preferred Stock | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		0			0
Fair Value, Measurements, Recurring | Consolidated Funds | Preferred Stock | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		4,393			24,314
Fair Value, Measurements, Recurring | Consolidated Funds | Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		202,017			95,565
Fair Value, Measurements, Recurring | Consolidated Funds | Common Stock | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		202,017			95,471
Fair Value, Measurements, Recurring | Consolidated Funds | Common Stock | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		0			0
Fair Value, Measurements, Recurring | Consolidated Funds | Common Stock | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		0			94
Fair Value, Measurements, Recurring | Consolidated Funds | Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		14,717			24,098
Fair Value, Measurements, Recurring | Consolidated Funds | Corporate Bonds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		0			0
Fair Value, Measurements, Recurring | Consolidated Funds | Corporate Bonds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		14,717			24,098
Fair Value, Measurements, Recurring | Consolidated Funds | Corporate Bonds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		0			0
Fair Value, Measurements, Recurring | Consolidated Funds | Warrants and Rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		5,465			5,279
Fair Value, Measurements, Recurring | Consolidated Funds | Warrants and Rights | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		0			0
Fair Value, Measurements, Recurring | Consolidated Funds | Warrants and Rights | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		0			0
Fair Value, Measurements, Recurring | Consolidated Funds | Warrants and Rights | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		5,465			5,279
Fair Value, Measurements, Recurring | Consolidated Funds | Derivative Assets | Currency forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		31			186
Fair Value, Measurements, Recurring | Consolidated Funds | Derivative Assets | Currency forward | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		0			0
Fair Value, Measurements, Recurring | Consolidated Funds | Derivative Assets | Currency forward | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		31			186
Fair Value, Measurements, Recurring | Consolidated Funds | Derivative Assets | Currency forward | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		0			0
Fair Value, Measurements, Recurring | Consolidated Funds | Derivative Assets | Equity Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		1,296			2,477
Fair Value, Measurements, Recurring | Consolidated Funds | Derivative Assets | Equity Swap | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		0			0
Fair Value, Measurements, Recurring | Consolidated Funds | Derivative Assets | Equity Swap | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		1,296			2,477
Fair Value, Measurements, Recurring | Consolidated Funds | Derivative Assets | Equity Swap | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		0			0
Fair Value, Measurements, Recurring | Consolidated Funds | Derivative Assets | Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		2,558			1,753
Fair Value, Measurements, Recurring | Consolidated Funds | Derivative Assets | Options | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		2,558			1,753
Fair Value, Measurements, Recurring | Consolidated Funds | Derivative Assets | Options | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		0			0
Fair Value, Measurements, Recurring | Consolidated Funds | Derivative Assets | Options | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset		$ 0			$ 0
[1]	Includes index, equity, commodity future and cash conversion options.
[2]	In accordance with US GAAP, certain investments that are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient and carried interest in portfolio funds have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the condensed consolidated statement of financial condition.
[3]	In accordance with US GAAP, certain investments that are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient and carried interest in portfolio funds have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the condensed consolidated statement of financial condition.
[4]	In accordance with the terms of the purchase agreements for acquisitions that closed during the second quarter of 2016 and the first quarter of 2019, the Company is required to pay to the sellers a portion of future net income and/or revenues of the acquired businesses, if certain targets are achieved through the periods ended December 2019 and December 2023, respectively. For the acquisition that closed during 2016, the Company estimated the contingent consideration liability using the income approach (discounted cash flow method) which requires the Company to make estimates and assumptions regarding the future cash flows and profits. For the acquisition that closed during 2019, the Company estimated the contingent consideration liability using the present value of the monte carlo simulated revenue. Changes in these estimates and assumptions could have a significant impact on the amounts recognized. The undiscounted amounts as of September 30, 2019 can range from $1.6 million to $40.0 million.
[5]	In accordance with the terms of the purchase agreements for the acquisition that closed during the second quarter of 2016, the Company is required to pay to the sellers a portion of future net income and/or revenues of the acquired business, if certain targets are achieved through the periods ended December 2020. The Company estimated the contingent consideration liability using the income approach (discounted cash flow method) which requires the Company to make estimates and assumptions regarding the future cash flows and profits. Changes in these estimates and assumptions could have a significant impact on the amounts recognized. The undiscounted amounts as of December 31, 2018 can range from $2.8 million to $3.4 million.

Fair Value Measurements for O_4

Fair Value Measurements for Operating Entities and Consolidated Funds Unobservable Input Roll Forward (Details) - USD ($)		3 Months Ended				9 Months Ended
		Sep. 30, 2019		Sep. 30, 2018		Sep. 30, 2019		Sep. 30, 2018
Preferred Stock
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value		$ 7,401,000		$ 7,422,000		$ 5,168,000		$ 8,115,000
Asset, Transfers In		0		0		0		0
Asset, Transfers Out		(1,000,000)	[1]	(1,141,000)	[2]	(1,000,000)	[1]	(1,141,000)	[2]
Purchases/(covers)		0		0		3,243,000		1,415,000
(Sales)/short buys		0		0		(1,000,000)		(695,000)
Realized and unrealized gains (losses), asset		1,434,000		(1,123,000)		1,424,000		(2,536,000)
Change in Unrealized Gain (Loss), instruments still held, asset	[3]	2,295,000		(1,124,000)		2,285,000		(2,301,000)
Balance Asset Value		7,835,000		5,158,000		7,835,000		5,158,000
Common Stock
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value		11,006,000		5,848,000		9,850,000		7,570,000
Asset, Transfers In		0		0		0		0
Asset, Transfers Out		0		0		0		0
Purchases/(covers)		2,579,000		0		16,737,000		531,000
(Sales)/short buys		(480,000)		0		(12,952,000)		(1,333,000)
Realized and unrealized gains (losses), asset		208,000		(174,000)		(322,000)		(1,094,000)
Change in Unrealized Gain (Loss), instruments still held, asset	[3]	210,000		(174,000)		(122,000)		(1,128,000)
Balance Asset Value		13,313,000		5,674,000		13,313,000		5,674,000
Corporate Bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value		775,000				0
Balance Liability Value		0				0
Asset, Transfers In	[4]	20,000				20,000
Liability, Transfers In	[4]	2,525,000				2,525,000
Liability, Transfers Out		0				0
Asset, Transfers Out		0				0
Purchases/(covers)		1,117,000				1,892,000
Liability, Purchases		0				0
(Sales)/short buys		0				0
Liability, Sales		0				0
Realized and unrealized gains (losses), asset		161,000				161,000
Realized and unrealized gains (losses), liability		(1,325,000)				1,325,000
Change in Unrealized Gain (Loss), instruments still held, asset	[3]	161,000				161,000
Change in Unrealized Gain (Loss), instruments still held, liabilities	[3]	(1,325,000)				1,325,000
Balance Asset Value		2,073,000				2,073,000
Balance Liability Value		1,200,000				1,200,000
Convertible Bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value		6,318,000				3,000,000		282,000
Asset, Transfers In						0		0
Asset, Transfers Out		(2,801,000)	[1]			(4,826,000)	[1],[2]	0
Purchases/(covers)		1,049,000				16,021,000		0
(Sales)/short buys		(2,072,000)				(11,764,000)		(307,000)
Realized and unrealized gains (losses), asset		47,000				110,000		25,000
Change in Unrealized Gain (Loss), instruments still held, asset	[3]	4,000				41,000		0
Balance Asset Value		2,541,000		0		2,541,000		0
Options
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value								1,455,000
Asset, Transfers In								0
Asset, Transfers Out								0
Purchases/(covers)								0
(Sales)/short buys								(1,455,000)
Realized and unrealized gains (losses), asset								0
Change in Unrealized Gain (Loss), instruments still held, asset	[3]							0
Balance Asset Value				0				0
Warrants and Rights
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value		595,000		1,544,000		1,666,000		2,517,000
Asset, Transfers In		0		0		0		0
Asset, Transfers Out		0		0		0		0
Purchases/(covers)		0		0		0		0
(Sales)/short buys		(72,000)				(188,000)		(143,000)
Realized and unrealized gains (losses), asset		61,000		38,000		(894,000)		(792,000)
Change in Unrealized Gain (Loss), instruments still held, asset	[3]	(12,000)		38,000		20,000		(933,000)
Balance Asset Value		584,000		1,582,000		584,000		1,582,000
Trade Claims
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value		10,488,000		5,699,000		5,543,000		5,950,000
Asset, Transfers In		0		0		0		0
Asset, Transfers Out		0		0		0		0
Purchases/(covers)		1,871,000		44,000		6,965,000		44,000
(Sales)/short buys		(5,354,000)		0		(5,506,000)		(334,000)
Realized and unrealized gains (losses), asset		57,000		3,000		60,000		86,000
Change in Unrealized Gain (Loss), instruments still held, asset	[3]	57,000		3,000		57,000		23,000
Balance Asset Value		7,062,000		5,746,000		7,062,000		5,746,000
Lehman claims, at fair value
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value				295,000				301,000
Asset, Transfers In				0				0
Asset, Transfers Out				0				0
Purchases/(covers)				0				0
(Sales)/short buys				(234,000)				(234,000)
Realized and unrealized gains (losses), asset				(61,000)				(67,000)
Change in Unrealized Gain (Loss), instruments still held, asset	[3]			0				0
Balance Asset Value				0				0
US Government Debt Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Liability Value		0				0
Liability, Transfers In	[4]	4,681,000				4,681,000
Liability, Transfers Out		0				0
Liability, Purchases		0				0
Liability, Sales		0				0
Realized and unrealized gains (losses), liability		2,431,000				(2,431,000)
Change in Unrealized Gain (Loss), instruments still held, liabilities	[3]	2,431,000				2,431,000
Balance Liability Value		2,250,000				2,250,000
Consolidated Funds | Preferred Stock
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value		24,322,000		24,314,000		24,314,000		50,445,000
Asset, Transfers In		0		0		0		0
Asset, Transfers Out		19,929,000	[1]	0		(19,929,000)	[1]	(38,552,000)	[5]
Purchases/(covers)		0		0		0		3,066,000
(Sales)/short buys		0		0		0		0
Realized and unrealized gains (losses), asset		0		0		8,000		9,355,000
Change in Unrealized Gain (Loss), instruments still held, asset	[3]	0		0		8,000		9,355,000
Balance Asset Value		4,393,000		24,314,000		4,393,000		24,314,000
Consolidated Funds | Common Stock
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value		1,017,000		94,000		94,000		50,000
Asset, Transfers In		0		0		0		0
Asset, Transfers Out		94,000	[1]	0		(94,000)	[1]	0
Purchases/(covers)		0		0		407,000		0
(Sales)/short buys		(957,000)		0		(958,000)		0
Realized and unrealized gains (losses), asset		34,000		0		551,000		44,000
Change in Unrealized Gain (Loss), instruments still held, asset	[3]	0		0		0		44,000
Balance Asset Value		0		94,000		0		94,000
Consolidated Funds | Warrants and Rights
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value		6,274,000		4,738,000		5,279,000		3,568,000
Asset, Transfers In		0		0		0		0
Asset, Transfers Out		0		0		0		(20,000)	[5]
Purchases/(covers)		0				0		(1,340,000)
(Sales)/short buys		(670,000)		0		(1,758,000)		0
Realized and unrealized gains (losses), asset		(139,000)		110,000		1,944,000		2,640,000
Change in Unrealized Gain (Loss), instruments still held, asset	[3]	(809,000)		110,000		190,000		1,300,000
Balance Asset Value		5,465,000		4,848,000		5,465,000		4,848,000
Options, liability
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Liability Value		2,779,000		301,000		2,096,000		22,401,000
Liability, Transfers In		0		0		0		0
Liability, Transfers Out		0		0		0		(28,973,000)	[6]
Liability, Purchases		0		0		0		0
Liability, Sales		0		0		(4,000)		(259,000)
Realized and unrealized gains (losses), liability		(279,000)		2,246,000		408,000		9,378,000
Change in Unrealized Gain (Loss), instruments still held, liabilities	[3]	279,000		(2,246,000)		(408,000)		(9,378,000)
Balance Liability Value		2,500,000		2,547,000		2,500,000		2,547,000
Contingent liability payable
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Liability Value		29,536,000		2,870,000		3,070,000		3,440,000
Liability, Transfers In		0		0		0		0
Liability, Transfers Out		0		0		0		0
Liability, Purchases		0		0		27,700,000		0
Liability, Sales		0		(227,000)		(1,234,000)		(797,000)
Realized and unrealized gains (losses), liability		298,000		0		298,000		0
Change in Unrealized Gain (Loss), instruments still held, liabilities	[3]	(298,000)		0		(298,000)		0
Balance Liability Value		$ 29,834,000		$ 2,643,000		$ 29,834,000		$ 2,643,000
[1]	The entity in which the Company is invested completed an initial public offering
[2]	The investments were converted to common stock.
[3]	Unrealized gains/losses are reported in other income (loss) in the accompanying condensed consolidated statements of operations.
[4]	The investments had a change of valuation methodology due to increased activity in foreign market.
[5]	The Company deconsolidated an investment fund.
[6]	On June 26, 2018, the Company received shareholder approval which allows the Company to settle its convertible note (see Note 18) entirely in class A common shares. Upon receiving shareholder approval, the Company reclassified the embedded conversion option, associated with the convertible debt, to equity. (see Note 19).

Fair Value Measurements for O_5

Fair Value Measurements for Operating Entities and Consolidated Funds Fair Value Inputs, Unobservable Inputs, Quantitative Information (Details) - USD ($) $ in Thousands		9 Months Ended	12 Months Ended
		Sep. 30, 2019	Dec. 31, 2018	Jun. 30, 2019	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Contingent liability payable
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Liability Value		$ 29,834	$ 3,070	$ 29,536	$ 2,643	$ 2,870	$ 3,440
Corporate Bonds
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		2,073	0	775
Balance Liability Value		1,200	0	0
Trade Claims
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		7,062	5,543	10,488	5,746	5,699	5,950
Warrants and Rights [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		584	1,666	$ 595	1,582	$ 1,544	2,517
Options
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value					$ 0		$ 1,455
Level 3
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		43,266	54,914
Balance Liability Value		$ 35,784	$ 5,166
Level 3 | Contingent liability payable | Monte Carlo [Member] | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		14.00%
Level 3 | Contingent liability payable | Monte Carlo [Member] | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		23.00%
Level 3 | Contingent liability payable | Income Approach and Market Approach Valuation Techniques
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs			23.00%
Level 3 | Contingent liability payable | Income Approach and Market Approach Valuation Techniques | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		14.00%
Level 3 | Contingent liability payable | Income Approach and Market Approach Valuation Techniques | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		20.00%
Level 3 | Contingent liability payable | Market Approach, Income Approach and Replacement Cost Valuation Techniques [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Liability Value			$ 3,070
Level 3 | Other Liabilities [Member] | Income Approach and Market Approach Valuation Techniques
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Liability Value	[1]	$ 3,450
Level 3 | Corporate Bonds | Income Approach and Market Approach Valuation Techniques
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		533
Level 3 | Common and Preferred Stock | Market Approach, Income Approach and Replacement Cost Valuation Techniques [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		$ 314	$ 4,323
Level 3 | Common and Preferred Stock | Market Approach, Income Approach and Replacement Cost Valuation Techniques [Member] | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs			650.00%
Level 3 | Common and Preferred Stock | Market Approach, Income Approach and Replacement Cost Valuation Techniques [Member] | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs			700.00%
Level 3 | Trade Claims | Market Approach Valuation Technique
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		20.00%	20.00%
Level 3 | Trade Claims | Market Approach, Income Approach and Replacement Cost Valuation Techniques [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		$ 28	$ 25
Level 3 | Warrants and Rights [Member] | Income Approach and Market Approach Valuation Techniques
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		6,048
Level 3 | Warrants and Rights [Member] | Market Approach, Income Approach and Replacement Cost Valuation Techniques [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value			1,666
Level 3 | Other Investments | Income Approach and Market Approach Valuation Techniques
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value	[1]	36,343
Level 3 | Other Investments | Market Approach, Income Approach and Replacement Cost Valuation Techniques [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value	[1]		$ 48,900
Level 3 | Options | Market Approach Valuation Technique
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs
Level 3 | Options | Options
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Liability Value		$ 2,500
Fair Value, Measurements, Recurring | Level 3 | Option | Options | Market Approach, Income Approach and Replacement Cost Valuation Techniques [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Financial Liabilities Fair Value Disclosure			$ 2,096
Discount rate | Level 3 | Common and Preferred Stock | Market Approach, Income Approach and Replacement Cost Valuation Techniques [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		8.00%
Discount rate | Level 3 | Common and Preferred Stock | Market Approach, Income Approach and Replacement Cost Valuation Techniques [Member] | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs			8.00%
Discount rate | Level 3 | Common and Preferred Stock | Market Approach, Income Approach and Replacement Cost Valuation Techniques [Member] | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs			14.00%
Discount rate | Level 3 | Warrants and Rights [Member] | Market Approach Valuation Technique | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		6.00%	7.00%
Discount rate | Level 3 | Warrants and Rights [Member] | Market Approach Valuation Technique | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		7.00%	9.00%
Volatility | Level 3 | Warrants and Rights [Member] | Market Approach Valuation Technique
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs
Volatility | Level 3 | Warrants and Rights [Member] | Market Approach Valuation Technique | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		30.00%
Volatility | Level 3 | Options | Market Approach Valuation Technique | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		35.00%	35.00%
Volatility | Level 3 | Options | Market Approach Valuation Technique | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		40.00%	40.00%
[1]	The quantitative disclosures exclude financial instruments for which the determination of fair value is based on prices from recent transactions.

Fair Value Measurements for O_6

Fair Value Measurements for Operating Entities and Consolidated Funds Carrying Value Disclosures (Details) - USD ($) $ in Thousands		Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Cash and cash equivalents		$ 260,994	$ 259,148	$ 193,066
Cash collateral pledged		18,609	6,318	16,092
Segregated cash		128,782	176,647	$ 154,191
Securities borrowed		1,228,036	407,795
Securities Borrowed, Collateral, Obligation to Return Securities		1,209,672	383,593
Loans Receivable, Net		38,121	36,021
Cash and cash equivalents, Consolidated Funds		3,364	38,118
Securities Sold under Agreements to Repurchase		23,772	0
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure			0
Securities Loaned		1,339,647	414,852
Securities Loaned, Collateral, Right to Reclaim Securities		1,282,340	391,310
Convertible debt	[1]	117,469	134,489
Notes payable and other debt		343,286	262,965
Convertible Debt
Convertible debt, unamortized discount		16,000	19,500
Level 1
Cash and cash equivalents, Fair Value		260,994	259,148
Segregated cash fair value disclosures		128,782	176,647
Cash and cash equivalents, Consolidated Funds, Fair Value		3,364	38,118
Level 2
Cash collateral pledged, Fair Value		18,609	6,318
Securities Borrowed, Fair Value Disclosure			383,593
Securities loaned, fair value disclosure			391,310
Convertible debt, Fair Value	[2]	148,509	157,433
Notes payable and other debt, Fair Value	[3]	363,777	258,546
Level 3
Loans Receivable, Fair Value Disclosure	[4]	$ 38,121	$ 36,021
[1]	The carrying amount of the convertible debt includes an unamortized discount of $16.0 million and $19.5 million as of September 30, 2019 and December 31, 2018, respectively.
[2]	The convertible debt includes the conversion option and is based on the last broker quote available.
[3]	Notes payable and other debt are based on the last broker quote available.
[4]	The fair market value of level 3 loans is calculated using discounted cash flows where applicable.

Deposits with Clearing Organi_2

Deposits with Clearing Organizations, Brokers and Banks (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Deposits with Clearing Organizations, Brokers and Banks [Abstract]
Deposits with clearing organizations, brokers and banks	$ 91,450	$ 89,423

Receivables from and payables_3

Receivables from and payables to brokers, dealers and clearing organizations (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Brokers and Dealers [Abstract]
Receivable from Broker-dealers	$ 676,674	$ 692,581
Securities Failed-to-Deliver	17,943	72,918
Receivable from Clearing organizations	5,929	15,319
Stock borrow interest receivable	17,088	5,295
Receivable from brokers, dealers and clearing organizations	717,634	786,113
Payable to Broker-Dealers	210,913	159,443
Securities Failed-to-Receive	25,840	28,826
Payable to clearing organizations	21,236	36,338
Stock loan interest payable	13,023	4,124
Payables to brokers, dealers and clearing organizations	$ 271,012	$ 228,731

Receivable from and Payable t_2

Receivable from and Payable to Customers (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Receivables and Payable to Customers [Abstract]
Receivable from customers	$ 46,126	$ 37,858
Payable to customers	$ 525,064	$ 525,153

Goodwill and Intangibles Schedu

Goodwill and Intangibles Schedule of Goodwill by Segment (Details) (Annual) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Line Items]
Goodwill, gross	$ 161,513,000		$ 161,513,000		$ 80,363,000	$ 80,363,000
Accumulated impairment charges	(23,785,000)		(23,785,000)		(19,685,000)	(19,685,000)
Goodwill, net	(137,728,000)		(137,728,000)		(60,678,000)	(60,678,000)
Recognized goodwill			81,150,000		0
Realignment, goodwill	0		0
Realignment goodwill, accumulated impairment charges	0		0
Goodwill Impairment	0	$ 0	(4,100,000)	$ 0	0
Investment Management Reporting Unit
Goodwill [Line Items]
Goodwill, gross	0		0		29,026,000	29,026,000
Accumulated impairment charges	0		0		(10,200,000)	(10,200,000)
Goodwill, net	0		0		(18,826,000)	18,826,000
Recognized goodwill			0		0
Realignment, goodwill	(29,026,000)		(29,026,000)
Realignment goodwill, accumulated impairment charges	10,200,000		10,200,000
Goodwill Impairment			0		0
Investment Bank Reporting Unit
Goodwill [Line Items]
Goodwill, gross	132,487,000		132,487,000		51,337,000	51,337,000
Accumulated impairment charges	(9,485,000)		(9,485,000)		(9,485,000)	(9,485,000)
Goodwill, net	(123,002,000)		(123,002,000)		(41,852,000)	(41,852,000)
Recognized goodwill			81,150,000		0
Realignment, goodwill	0		0
Realignment goodwill, accumulated impairment charges	0		0
Goodwill Impairment			0		0
Cowen Investment Management Reporting Unit
Goodwill [Line Items]
Goodwill, gross	22,705,000		22,705,000		0	0
Accumulated impairment charges	(7,979,000)		(7,979,000)		0	0
Goodwill, net	(14,726,000)		(14,726,000)		0	0
Recognized goodwill			0
Realignment, goodwill	22,705,000		22,705,000
Realignment goodwill, accumulated impairment charges	(7,979,000)		(7,979,000)
Goodwill Impairment			0
Asset Company Reporting Unit
Goodwill [Line Items]
Goodwill, gross	6,321,000		6,321,000		0	0
Accumulated impairment charges	(6,321,000)		(6,321,000)		0	0
Goodwill, net	0		0		$ 0	$ 0
Recognized goodwill			0
Realignment, goodwill	6,321,000		6,321,000
Realignment goodwill, accumulated impairment charges	$ (2,221,000)		(2,221,000)
Goodwill Impairment			$ (4,100,000)

Goodwill and Intangibles Qtlry

Goodwill and Intangibles Qtlry (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill Impairment	$ 0	$ 0	$ 4,100,000	$ 0	$ 0
Goodwill, Acquired During Period			81,150,000		$ 0
Quarton
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill, Acquired During Period			81,200,000
Finite-lived Intangible Assets Acquired			$ 22,200,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			2 years 9 months 18 days
Amortization of Intangible Assets	$ 2,200,000		$ 6,700,000
Minimum | Quarton
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life			2 years
Maximum | Quarton
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life			4 years
Asset Company Reporting Unit
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill Impairment			$ 4,100,000
Goodwill, Acquired During Period			$ 0

Commission Management Payable (

Commission Management Payable (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Commission Management Payable [Abstract]
Commission management payable	$ 89,124	$ 95,270

Redeemable Non-Controlling In_3

Redeemable Non-Controlling Interests in Consolidated Subsidiaries and Funds (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Noncontrolling Interest [Line Items]
Redeemable non-controlling interests in consolidated subsidiaries and funds	$ 348,424		$ 348,424		$ 216,923
Nonredeemable Noncontrolling Interest	433,183		433,183		281,803
Net Income (Loss) Attributable to Noncontrolling Interest	2,770	$ 4,110	7,188	$ 37,798
Operating Entities
Noncontrolling Interest [Line Items]
Nonredeemable Noncontrolling Interest	15,268		15,268		7,457
Net Income (Loss) Attributable to Noncontrolling Interest	(2,126)	1,306	(1,586)	2,805
Consolidated Funds
Noncontrolling Interest [Line Items]
Redeemable non-controlling interests in consolidated subsidiaries and funds	348,424		348,424		216,923
Nonredeemable Noncontrolling Interest	69,491		69,491		$ 57,423
Net Income (Loss) Attributable to Noncontrolling Interest	$ 4,896	$ 2,804	$ 8,774	$ 34,993

Reinsurance (Details)

Reinsurance (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Incurred and paid claims	$ 126	$ 1,911	$ 7,046	$ 9,640
Historical Average Claims Ratios, Period, Maximum			10 years
Hollenfels
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Claims IBNR	$ 833	$ 665	$ 11,724	$ 9,076

Share-Based Compensation and _3

Share-Based Compensation and Employee Ownership Plans Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares		88,504		88,504
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	200,000		200,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number					253,772
Equity Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-compensation expense recognized in connection with compensation plan	$ 10	$ 8.5	$ 27.2	$ 27.6
Tax benefit of stock-compensation expense recognized in connection with compensation plan	2.6	$ 2.4	$ 6.8	$ 7.2
Equity Plans | Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, initial term			7 years
Equity Plans | Employee Stock Option | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation award, vesting period			2 years
Equity Plans | Employee Stock Option | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation award, vesting period			5 years
Equity Plans | Restricted Shares and Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 70.3		$ 70.3
Vested, shares			1,545,850	1,423,075
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	5,998,580	6,350,015	5,998,580	6,350,015	5,962,295	5,579,293
Equity Plans | Restricted Stock | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation award, vesting period			2 years
Equity Plans | Restricted Stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation award, vesting period			5 years
Equity Plans | Restricted Stock Units (RSUs) | Non-employee Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares			0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	216,912		216,912
Equity Plans | Stock Appreciation Rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
SAR's, initial term			5 years
Deferred Cash Award | Cowen Group, Inc. 2010 Equity and Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation award, vesting period			4 years
Deferred cash award granted	$ 0.6		$ 42.7
Deferred cash award, interest rate			0.70%
Deferred cash awards, unrecognized compensation expense	$ 67.6		$ 67.6

Share-Based Compensation and _4

Share-Based Compensation and Employee Ownership Plans Restricted Shares and Restricted Stock Units (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		2 Months Ended	3 Months Ended	9 Months Ended
	Apr. 30, 2019	Mar. 31, 2016	Jan. 31, 2014	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Nonvested Restricted Shares and Restricted Stock Units
Balance outstanding, beginning of period, shares					253,772
Weighted-Average Grant Date Fair Value
Granted, shares				88,504		88,504
Equity Plans | Restricted Shares and Restricted Stock Units (RSUs)
Nonvested Restricted Shares and Restricted Stock Units
Balance outstanding, beginning of period, shares					5,962,295	5,579,293
Granted, shares					2,322,996	2,255,794
Vested, shares					(1,545,850)	(1,423,075)
Canceled, shares					(584,333)	0
Forfeited, shares					(156,528)	(61,997)
Balance outstanding, end of period, shares				6,350,015	5,998,580	6,350,015
Weighted-Average Grant Date Fair Value
Balance outstanding, beginning of period, in dollars per share					$ 15.73	$ 16.33
Granted, in dollars per share					16.62	14.27
Vested, in dollars per share					16.26	16.08
Canceled, in dollars per share					11.49	0
Forfeited, in dollars per share					13.97	14.13
Balance outstanding, end of period, in dollars per share				$ 15.68	$ 16.40	$ 15.68
Unrecognized compensation expense					$ 70.3
Weighted-average recognition period for unrecognized compensation expense					2 years 2 months 23 days
Equity Plans | Performance based restricted stock
Nonvested Restricted Shares and Restricted Stock Units
Granted, shares	333,333	700,000	481,438
Vested, shares					(584,333)
Forfeited, shares					(130,438)
Non-employee Director | Equity Plans | Restricted Stock Units (RSUs)
Nonvested Restricted Shares and Restricted Stock Units
Balance outstanding, end of period, shares					216,912
Weighted-Average Grant Date Fair Value
Granted, shares					0
Stock Issued During Period, Shares, Issued for Services					120,430
Maximum
Nonvested Restricted Shares and Restricted Stock Units
Percent of RSU's earned					200.00%
Minimum
Nonvested Restricted Shares and Restricted Stock Units
Percent of RSU's earned					0.00%

Income Taxes - Quarterly (Detai

Income Taxes - Quarterly (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Income Tax Contingency [Line Items]
Effective income tax rate, percent	26.55%	17.48%
Statutory rate, percent	21.00%	21.00%
Convergex Group
Income Tax Contingency [Line Items]
Taxes payable	$ 0.3

Commitments and Contingencies_2

Commitments and Contingencies (Details) - USD ($)		3 Months Ended	9 Months Ended	12 Months Ended
		Sep. 30, 2019	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2019
Contractual Commitments, Commitment [Line Items]
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability			$ 100,000
Operating Lease, Payments			19,103
Lease Cost		$ 5,748,000	17,690,000
Short-term lease cost		23,000	113,000
Variable lease cost		388,000	834,000
Sublease income		(232,000)	(739,000)
Total lease costs		$ 5,927,000	$ 17,898,000
Weighted average remaining lease term - operating leases (in Years)		5 years 6 months 7 days	5 years 6 months 7 days
Weighted average discount rate -operating leases		4.14%	4.14%
Future minimum annual lease and service payments
Total Lease Liability		$ 100,934,000	$ 100,934,000	$ 0			$ 110,505,000
Sublease income related to operating leases				1,400,000	$ 1,100,000	$ 2,200,000
RCG Longview Partners II, LLC | Clawback Obligation
Future minimum annual lease and service payments
Contractual obligation		6,500,000	6,500,000	6,500,000
Equipment Leases
Contractual Commitments, Commitment [Line Items]
Contractual Obligation, Due in Next Fiscal Year				2,434,000
Contractual Obligation, Due in Second Year				1,492,000
Contractual Obligation, Due in Third Year				1,382,000
Contractual Obligation, Due in Fourth Year				1,123,000
Contractual Obligation, Due in Fifth Year				374,000
Contractual Obligation, Due after Fifth Year				0
Contractual Obligation				6,805,000
Future minimum annual lease and service payments
2019	[1]	94,000	94,000
2020	[1]	364,000	364,000
2021	[1]	177,000	177,000
2022	[1]	61,000	61,000
2023	[1]	0	0
Thereafter	[1]	0	0
Future minimum annual lease and service payments	[1]	696,000	696,000
Less discount		114,000	114,000
Total Lease Liability		582,000	582,000
Service Payments
Contractual Commitments, Commitment [Line Items]
Contractual Obligation, Due in Next Fiscal Year		6,691,000	6,691,000	21,758,000
Contractual Obligation, Due in Second Year		15,210,000	15,210,000	7,514,000
Contractual Obligation, Due in Third Year		8,483,000	8,483,000	1,877,000
Contractual Obligation, Due in Fourth Year		5,971,000	5,971,000	1,372,000
Contractual Obligation, Due in Fifth Year		3,573,000	3,573,000	735,000
Contractual Obligation, Due after Fifth Year		6,331,000	6,331,000	735,000
Contractual Obligation		46,259,000	46,259,000	33,991,000
Facility Leases
Contractual Commitments, Commitment [Line Items]
Contractual Obligation, Due in Next Fiscal Year				24,584,000
Contractual Obligation, Due in Second Year				22,608,000
Contractual Obligation, Due in Third Year				22,321,000
Contractual Obligation, Due in Fourth Year				19,166,000
Contractual Obligation, Due in Fifth Year				16,204,000
Contractual Obligation, Due after Fifth Year				21,478,000
Contractual Obligation				$ 126,361,000
Future minimum annual lease and service payments
2019	[2]	4,530,000	4,530,000
2020	[2]	24,350,000	24,350,000
2021	[2]	24,049,000	24,049,000
2022	[2]	20,586,000	20,586,000
2023	[2]	17,416,000	17,416,000
Thereafter	[2]	25,958,000	25,958,000
Future minimum annual lease and service payments	[2]	116,889,000	116,889,000
Less discount		16,424,000	16,424,000
Total Lease Liability		$ 100,352,000	$ 100,352,000
[1]	In the third quarter of 2019, the Company recognized operating ROU assets and leases liabilities of $0.1 million for equipment leases.
[2]	The Company has entered into various agreements to sublease certain of its premises.

Commitments and Contingencies S

Commitments and Contingencies Service Payments (Details) - Service Payments - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Other Commitments [Line Items]
Contractual Obligation, Due in Next Fiscal Year	$ 6,691	$ 21,758
Contractual Obligation, Due in Second Year	15,210	7,514
Contractual Obligation, Due in Third Year	8,483	1,877
Contractual Obligation, Due in Fourth Year	5,971	1,372
Contractual Obligation, Due in Fifth Year	3,573	735
Thereafter	6,331	735
Total Operating Leases	$ 46,259	$ 33,991

Commitments and Contingencies_3

Commitments and Contingencies Schedules of Unfunded Commitments (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)
Healthcare Royalty Partners | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 5,867	[1]
Healthcare Royalty Partners | Commitment to Invest
Other Commitments [Line Items]
Commitments term	2 years
Eclipse Ventures Fund I, L.P. | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 98
Eclipse Ventures Fund I, L.P. | Commitment to Invest
Other Commitments [Line Items]
Commitments term	5 years
Lagunita Biosciences, LLC | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 500
Lagunita Biosciences, LLC | Commitment to Invest
Other Commitments [Line Items]
Commitments term	4 years
Eclipse Fund II, L.P. | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 225
Eclipse Fund II, L.P. | Commitment to Invest
Other Commitments [Line Items]
Commitments term	6 years
Eclipse Continuity Fund I, L.P. | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 175
Eclipse Continuity Fund I, L.P. | Commitment to Invest
Other Commitments [Line Items]
Commitments term	7 years
Cowen Healthcare Investments II LP | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 6,891
Cowen Healthcare Investments II LP | Commitment to Invest
Other Commitments [Line Items]
Commitments term	2 years
Cowen Healthcare Investments III LP | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 10,000
Cowen Healthcare Investments III LP | Commitment to Invest
Other Commitments [Line Items]
Commitments term	7 years
Cowen Sustainable Investments I LP | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 25,000
Cowen Sustainable Investments I LP | Commitment to Invest
Other Commitments [Line Items]
Commitments term	10 years
[1]	The Company is a limited partner of the HealthCare Royalty Partners funds (which are managed by Healthcare Royalty Management) and is a member of HealthCare Royalty Partners General Partners. The Company will make its pro-rata investment in the HealthCare Royalty Partners funds along with the other limited partners.

Convertible Debt and Notes Pa_3

Convertible Debt and Notes Payable (Details)		Dec. 05, 2016	Sep. 30, 2019USD ($)letters_of_credit$ / sharesshares	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)letters_of_credit$ / sharesshares	Sep. 30, 2018USD ($)	May 07, 2019USD ($)	Dec. 31, 2018USD ($)$ / sharesshares	Dec. 14, 2017USD ($)$ / shares	Dec. 08, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 10, 2014USD ($)
Debt and Capital Lease Obligations [Line Items]
Finance Lease, Right-of-Use Asset, Amortization			$ 299,000	$ 409,000	$ 966,000	$ 1,124,000
Finance Lease, Interest Expense			54,000	64,000	172,000	167,000
Finance Lease, Interest Payment on Liability					172,000	167,000
Finance Lease, Principal Payments					951,000	1,630,000
Preferred stock dividends			(1,698,000)	(1,698,000)	(5,094,000)	(5,094,000)
Components of short-term borrowings and other debt
Convertible debt	[1]		117,469,000		117,469,000			$ 134,489,000
Note payable			306,645,000		306,645,000			229,740,000
Loans Payable to Bank			32,180,000		32,180,000			28,200,000
Other Notes Payable			395,000		395,000			0
Capital lease obligations			4,066,000		4,066,000			5,025,000
Debt, Long-term and Short-term, Combined Amount			460,755,000		460,755,000			397,454,000
Purchase of treasury stock, cost					22,420,000
Interest on Convertible Debt, Net of Tax				1,000,000		3,000,000
Amortization of debt discount					3,511,000	4,177,000
Stockholders' Equity Note, Stock Split, Conversion Ratio		0.25
Letter of credit, borrowing capacity			370,000,000		370,000,000
Capital Lease Obligations Incurred					6,000,000
Future minimum lease payments for capital lease obligations
2019			231,000		231,000
2020			1,356,000		1,356,000
2021			1,356,000		1,356,000
2022			1,125,000		1,125,000
2023			374,000		374,000
Thereafter			0		0
Subtotal			4,442,000		4,442,000
Less: Amount representing interest	[2]		(376,000)		(376,000)
Capital lease obligations			$ 4,066,000		$ 4,066,000			5,025,000
Number of letters of credit | letters_of_credit			7		7
Cash collateral pledged			$ 18,609,000	16,092,000	$ 18,609,000	16,092,000		$ 6,318,000
Preferred stock, shares authorized | shares			10,000,000		10,000,000			10,000,000
Preferred stock, par value (in dollars per share) | $ / shares			$ 0.01		$ 0.01			$ 0.01
Finance Lease, Weighted Average Remaining Lease Term			3 years 4 months 28 days		3 years 4 months 28 days
Finance Lease, Weighted Average Discount Rate, Percent			4.93%		4.93%
Letter of Credit, Boston Office, Expires March 2020 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, borrowing capacity			$ 391,943		$ 391,943
Letter of Credit, NY Office 1, Expires April 2020 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, borrowing capacity			357,543		357,543
Letter of Credit, NY Office 2, Expires October 2019 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, borrowing capacity			71,416		71,416
Letter of Credit, NY Office 3, Expires October 2019 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, borrowing capacity			397,591		397,591
Letter of Credit, NY Office 4, Expires October 2019 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, borrowing capacity			1,125,056		1,125,056
Letter of Credit, NY Office 5, Expires November 2019 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, borrowing capacity			1,623,455		1,623,455
Letter of Credit, San Francisco Office, Expires October 2025 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, borrowing capacity			713,335		713,335
Convertible Debt
Components of short-term borrowings and other debt
Convertible debt, unamortized discount			16,000,000		16,000,000			$ 19,500,000
Repayments on long-term and short-term borrowings
2019			2,025,000		2,025,000
2020			4,050,000		4,050,000
2021			4,050,000		4,050,000
2022			139,050,000		139,050,000
2023			0		0
Thereafter			0		0
Subtotal			149,175,000		149,175,000
Less: Amount representing interest	[2]		(31,706,000)		(31,706,000)
Senior Notes
Components of short-term borrowings and other debt
Note payable			306,645,000		306,645,000
Repayments on long-term and short-term borrowings
2019			7,301,000		7,301,000
2020			23,548,000		23,548,000
2021			23,548,000		23,548,000
2022			23,548,000		23,548,000
2023			23,548,000		23,548,000
Thereafter			433,025,000		433,025,000
Subtotal			534,518,000		534,518,000
Less: Amount representing interest	[2]		(227,873,000)		(227,873,000)
Notes Payable to Banks
Components of short-term borrowings and other debt
Debt Instrument, Face Amount											$ 28,200,000
Interest Expense, Debt, Excluding Amortization			$ 500,000	400,000	$ 1,400,000	1,200,000
Short-term Debt, Percentage Bearing Variable Interest Rate			3.75%		3.75%
Insurance Note
Components of short-term borrowings and other debt
Interest rate			2.51%		2.51%
Short-term Debt, Maximum Amount Outstanding During Period					$ 2,200,000
Debt Instrument, Periodic Payment, Principal					200,000
Loans
Repayments on long-term and short-term borrowings
2019			$ 489,000		489,000
2020			33,126,000		33,126,000
2021			0		0
2022			0		0
2023			0		0
Thereafter			0		0
Subtotal			33,615,000		33,615,000
Less: Amount representing interest	[2]		(1,435,000)		(1,435,000)
Insurance Note and Aircraft [Member]
Repayments on long-term and short-term borrowings
2019			405,000		405,000
2020			0		0
2021			0		0
2022			0		0
2023			0		0
Thereafter			0		0
Subtotal			405,000		405,000
Less: Amount representing interest	[2]		$ (10,000)		$ (10,000)
Common Stock Class A
Debt and Capital Lease Obligations [Line Items]
Common stock, shares authorized | shares			62,500,000		62,500,000			62,500,000
Common stock, par value (in dollars per share) | $ / shares			$ 0.01		$ 0.01			$ 0.01
2022 convertible note | Convertible Debt
Components of short-term borrowings and other debt
Convertible debt			$ 135,000,000		$ 135,000,000
Debt Instrument, Face Amount									$ 135,000,000
Debt Instrument, Convertible, Conversion Price | $ / shares									$ 17.375
Purchase of treasury stock, cost					19,500,000
Interest on Convertible Debt, Net of Tax			1,000,000		3,000,000
Convertible debt, unamortized discount												$ 23,400,000
Amortization of debt discount			1,100,000	1,000,000	3,200,000	3,000,000
Debt Instrument, Interest Rate, Effective Percentage												7.13%
Debt Issuance Costs, Gross												$ 2,200,000
2019 convertible note | Convertible Debt
Components of short-term borrowings and other debt
Debt Instrument, Face Amount												149,500,000
Debt Instrument, Repurchase Amount												$ 115,100,000
Interest on Convertible Debt, Net of Tax				200,000	100,000	900,000
Amortization of debt discount				300,000	300,000	1,200,000
Debt Instrument, Interest Rate, Effective Percentage												8.89%
Interest rate												3.00%
2024 Notes | Senior Notes
Components of short-term borrowings and other debt
Debt Instrument, Face Amount							$ 53,000,000
Debt Instrument, Unamortized Premium			500,000		500,000
Debt Issuance Costs, Gross			600,000		600,000		$ 1,500,000
Interest rate							7.25%
Debt Instrument, Additional amount issued			25,000,000		25,000,000
Interest Expense, Debt, Excluding Amortization			900,000		1,500,000
2033 Notes | Senior Notes
Components of short-term borrowings and other debt
Debt Instrument, Face Amount									$ 10,000,000	$ 90,000,000
Debt Issuance Costs, Gross										$ 3,600,000
Interest rate										7.75%
Interest Expense, Debt, Excluding Amortization			1,900,000	1,900,000	5,800,000	2,300,000
2027 Notes | Senior Notes
Components of short-term borrowings and other debt
Debt Instrument, Face Amount									$ 18,000,000	$ 120,000,000
Debt Issuance Costs, Gross										$ 5,000,000
Interest rate										7.35%
Interest Expense, Debt, Excluding Amortization			2,500,000	2,500,000	7,600,000	7,600,000
Collateral Reinsurance Agreement
Future minimum lease payments for capital lease obligations
Cash collateral pledged			13,900,000		13,900,000			$ 1,000,000
Retained Earnings/(Accumulated deficit) | Convertible Preferred Stock
Debt and Capital Lease Obligations [Line Items]
Preferred stock dividends			$ (1,698,000)	$ (1,698,000)	$ (5,094,000)	$ (5,094,000)
[1]	The carrying amount of the convertible debt includes an unamortized discount of $16.0 million and $19.5 million as of September 30, 2019 and December 31, 2018, respectively.
[2]	Amount necessary to reduce net minimum payments to present value calculated at the Company's implicit rate at inception. This amount also includes capitalized debt costs and the unamortized discount on the convertible debt.

Stockholder's Equity - Quarterl

Stockholder's Equity - Quarterly (Details) - USD ($)	May 19, 2015	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Mar. 10, 2014
Equity, Class of Stock [Line Items]
Preferred stock dividends declared		$ 1,698,000	$ 1,698,000	$ 5,094,000	$ 5,094,000
Convertible Preferred Stock, Shares Issued upon Conversion	38.0619
Convertible Preferred Stock, Threshold Percentage of Stock Price Trigger				150.00%
Treasury Stock, Shares [Roll Forward]
Treasury stock, shares, beginning of period				15,336,871
Purchase of treasury stock, shares				1,440,396
Treasury stock, shares, end of period		17,462,976		17,462,976
Treasury stock, cost, beginning of period				$ 234,142,000
Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions				22,420,000	8,544,000
Purchase of treasury stock, cost				22,420,000
Treasury stock, cost, end of period		$ 266,882,000		$ 266,882,000
Treasury stock, average cost per share, beginning of period, in dollars per share				$ 15.27
Purchase of treasury stock, average cost per share, in dollars per share				15.57
Treasury stock, average cost per share, end of period, in dollars per share		$ 15.28		$ 15.28
Embedded Cash Conversion Option			1,000	$ (596,000)	28,974,000
Treasury Stock
Treasury Stock, Shares [Roll Forward]
Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions				674,792
Treasury stock shares received, other				10,917
Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions				$ 10,153,000
Treasury stock received, value, other				$ 167,000
Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions, Average Cost Per Share				$ 15.05
Treasury stock received, per share, other				$ 15.34
Call Option
Equity, Class of Stock [Line Items]
Option indexed to Issuer's Equity, Value	$ 15,900,000
Minimum
Equity, Class of Stock [Line Items]
Convertible Preferred Stock, Threshold Consecutive Trading Days				20 days
Minimum | Call Option
Equity, Class of Stock [Line Items]
Option Indexed to Issuer's Equity, Strike Price				$ 26.27
Maximum
Equity, Class of Stock [Line Items]
Convertible Preferred Stock, Threshold Consecutive Trading Days				30 days
Maximum | Call Option
Equity, Class of Stock [Line Items]
Option Indexed to Issuer's Equity, Strike Price				$ 33.54
Convertible Preferred Stock
Equity, Class of Stock [Line Items]
Preferred stock issuance, net of issuance costs, shares	120,750
Preferred Stock, Dividend Rate, Percentage				5.625%
Proceeds from Issuance of Preferred Stock, net of issuance costs				$ 117,200,000
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs				3,600,000
Preferred Stock, Liquidation Preference Per Share	$ 1,000
Convertible Preferred Stock | Retained Earnings/(Accumulated deficit)
Equity, Class of Stock [Line Items]
Preferred stock dividends declared		$ 1,698,000	1,698,000	5,094,000	$ 5,094,000
Convertible Debt
Treasury Stock, Shares [Roll Forward]
Convertible debt, unamortized discount		$ 16,000,000		16,000,000		$ 19,500,000
2022 convertible note | Convertible Debt
Treasury Stock, Shares [Roll Forward]
Purchase of treasury stock, cost				$ 19,500,000
Convertible debt, unamortized discount							$ 23,400,000
Embedded Cash Conversion Option			$ 28,973,000

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Accumulated Other Comprehensive Income / (Loss) [Abstract]
Beginning Balance	$ (3)	$ (7)	$ (5)	$ (8)
Foreign currency translation	(2)	4	0	5
Ending Balance	$ (5)	$ (3)	$ (5)	$ (3)

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Computation of earnings per share:
Net income (loss)	$ 6,583	$ 19,598	$ 26,596	$ 75,538
Net Income (Loss) Attributable to Noncontrolling Interest	2,770	4,110	7,188	37,798
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	(6,848)		(4,187)	22,501
Net income (loss) attributable to Cowen Inc.	3,813	15,488	19,408	37,740
Preferred stock dividends	1,698	1,698	5,094	5,094
Net income (loss) attributable to Cowen Inc. common stockholders	$ 2,115	$ 13,790	$ 14,314	$ 32,646
Shares for basic and diluted calculations:
Weighted average shares used in basic computation, shares	29,529,000	29,610,000	29,687,000	29,662,000
Weighted average shares used in diluted computation, shares	31,264,000	30,844,000	31,381,000	30,613,000
Earnings (loss) per share:
Earnings Per Share, Basic (in dollars per share)	$ 0.07	$ 0.47	$ 0.48	$ 1.10
Earnings Per Share, Diluted (in dollars per share)	$ 0.07	$ 0.45	$ 0.46	$ 1.07
Restricted Stock
Shares for basic and diluted calculations:
Shares attributable to share-based payment awards, shares	1,735,000	1,234,000	1,694,000	951,000
Common Stock Class A
Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]
Common stock, shares outstanding, shares	29,013,137	29,142,547	29,013,137	29,142,547	29,480,287	28,437,860	29,609,472	29,632,020
Common stock, restricted shares, shares	216,912		216,912			253,772

Segment Reporting (Details)

Segment Reporting (Details)		3 Months Ended				9 Months Ended				12 Months Ended
		Sep. 30, 2019USD ($)		Sep. 30, 2018USD ($)		Sep. 30, 2019USD ($)segmentcustomer		Sep. 30, 2018USD ($)		Dec. 31, 2018USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | segment						2
Entity-wide revenue, major customer, number | customer						0
Revenues
Investment banking		$ 77,292,000		$ 81,923,000		$ 272,103,000		$ 264,737,000
Brokerage		93,995,000		92,035,000		302,840,000		301,053,000
Management fees		7,300,000		7,546,000		21,480,000		22,336,000
Incentive income		701,000		33,000		724,000		97,000
Investment Income		0		0		0		0
Interest and dividends		60,707,000		26,448,000		129,846,000		77,511,000
Reimbursement from affiliates		238,000		353,000		780,000		1,066,000
Aircraft lease revenue		0		375,000		0		1,509,000
Reinsurance premiums		8,146,000		8,378,000		29,068,000		26,251,000
Other revenues		1,237,000		1,634,000		3,228,000		3,846,000
Total revenues		252,047,000		221,028,000		768,308,000		706,985,000
Interest expense		56,477,000		26,000,000		125,089,000		74,846,000
Total net revenues		195,570,000		195,028,000		643,219,000		632,139,000
Expenses
Non-interest expense		217,448,000		210,642,000		679,655,000		656,299,000
Goodwill Impairment		0		0		4,100,000		0		$ 0
Total expenses		219,964,000		212,329,000		689,984,000		663,566,000
Other income (loss)
Total other income (loss)		32,342,000		41,982,000		82,976,000		122,964,000
Income tax expense (benefit)		1,365,000		5,083,000		9,615,000		15,999,000
(Net Income (Loss) Attributable to Noncontrolling Interest		(2,770,000)		(4,110,000)		(7,188,000)		(37,798,000)
Economic Income (Loss) / Net income (loss) attributable to Cowen Group, Inc.		3,813,000		15,488,000		19,408,000		37,740,000
Preferred stock dividends		1,698,000		1,698,000		5,094,000		5,094,000
Net income (loss) attributable to Cowen Inc. common stockholders		2,115,000		13,790,000		14,314,000		32,646,000
Consolidated Funds
Revenues
Total revenues		2,431,000		2,303,000		8,239,000		8,579,000
Expenses
Total expenses		2,516,000		1,687,000		6,229,000		7,267,000
Other income (loss)
(Net Income (Loss) Attributable to Noncontrolling Interest		(4,896,000)		(2,804,000)		(8,774,000)		(34,993,000)
Operating Company
Revenues
Management fees		7,052,000		6,595,000		20,492,000		19,556,000
Incentive income		701,000		33,000		710,000		97,000
Asset Company
Revenues
Management fees		248,000		951,000		988,000		2,780,000
Incentive income		0		0		14,000		0
Operating Segments
Revenues
Investment banking		70,022,000		77,510,000		257,234,000		251,476,000
Brokerage		105,860,000		101,672,000		331,689,000		328,929,000
Management fees		10,907,000		12,386,000		31,804,000		37,998,000
Incentive income		14,377,000		6,910,000		35,353,000		21,470,000
Investment Income		16,053,000		27,672,000		33,522,000		61,927,000
Interest and dividends		0		0		0		0
Reimbursement from affiliates		0		0		0		0
Aircraft lease revenue				0				0
Reinsurance premiums		0		0		0		0
Other revenues		(126,000)		83,000		5,351,000		250,000
Total revenues		217,093,000		226,233,000		694,953,000		702,050,000
Interest expense		7,147,000		6,419,000		20,417,000		16,500,000
Total net revenues		209,946,000		219,814,000		674,536,000		685,550,000
Expenses
Non-interest expense		202,040,000		196,188,000		630,192,000		613,561,000
Goodwill Impairment						0
Total expenses		202,040,000		196,188,000		630,192,000		613,561,000
Other income (loss)
Total other income (loss)		0		0		0		0
Income tax expense (benefit)		0		0		0		0
(Net Income (Loss) Attributable to Noncontrolling Interest		(661,000)		(942,000)		(2,944,000)		(3,505,000)
Economic Income (Loss) / Net income (loss) attributable to Cowen Group, Inc.		7,245,000		22,684,000		41,400,000		68,484,000
Preferred stock dividends		1,698,000		1,698,000		5,094,000		5,094,000
Net income (loss) attributable to Cowen Inc. common stockholders		5,547,000		20,986,000		36,306,000		63,390,000
Other Depreciation and Amortization		5,082,000		2,908,000		14,987,000		8,854,000
Economic Operating Income		10,629,000		23,894,000		51,293,000		72,244,000
Operating Segments | Consolidated Funds
Revenues
Total revenues		0		0		0		0
Expenses
Total expenses		0		0		0		0
Operating Segments | Operating Company
Revenues
Investment banking		70,022,000		77,510,000		257,234,000		251,476,000
Brokerage		105,860,000		101,672,000		331,689,000		328,929,000
Management fees		10,321,000		10,840,000		30,016,000		33,057,000
Incentive income		15,384,000		1,859,000		34,654,000		17,219,000
Investment Income		15,231,000		25,779,000		28,233,000		62,488,000
Interest and dividends		0		0		0		0
Reimbursement from affiliates		0		0		0		0
Aircraft lease revenue				0				0
Reinsurance premiums		0		0		0		0
Other revenues		(132,000)		4,000		5,295,000		(143,000)
Total revenues		216,686,000		217,664,000		687,121,000		693,026,000
Interest expense		5,758,000		4,878,000		16,371,000		12,539,000
Total net revenues		210,928,000		212,786,000		670,750,000		680,487,000
Expenses
Non-interest expense		200,637,000		189,516,000		623,167,000		601,480,000
Goodwill Impairment						0
Total expenses		200,637,000		189,516,000		623,167,000		601,480,000
Other income (loss)
Total other income (loss)		0		0		0		0
Income tax expense (benefit)		0		0		0		0
(Net Income (Loss) Attributable to Noncontrolling Interest		(661,000)		(898,000)		(2,944,000)		(2,805,000)
Economic Income (Loss) / Net income (loss) attributable to Cowen Group, Inc.		9,630,000		22,372,000		44,639,000		76,202,000
Preferred stock dividends		1,341,000		1,290,000		4,058,000		3,871,000
Net income (loss) attributable to Cowen Inc. common stockholders		8,289,000		21,082,000		40,581,000		72,331,000
Other Depreciation and Amortization		5,073,000		2,865,000		14,957,000		8,707,000
Economic Operating Income		13,362,000		23,947,000		55,538,000		81,038,000
Operating Segments | Operating Company | Consolidated Funds
Revenues
Total revenues		0		0		0		0
Expenses
Total expenses		0		0		0		0
Operating Segments | Asset Company
Revenues
Investment banking		0		0		0		0
Brokerage		0		0		0		0
Management fees		586,000		1,546,000		1,788,000		4,941,000
Incentive income		(1,007,000)		5,051,000		699,000		4,251,000
Investment Income		822,000		1,893,000		5,289,000		(561,000)
Interest and dividends		0		0		0		0
Reimbursement from affiliates		0		0		0		0
Aircraft lease revenue				0				0
Reinsurance premiums		0		0		0		0
Other revenues		6,000		79,000		56,000		393,000
Total revenues		407,000		8,569,000		7,832,000		9,024,000
Interest expense		1,389,000		1,541,000		4,046,000		3,961,000
Total net revenues		(982,000)		7,028,000		3,786,000		5,063,000
Expenses
Non-interest expense		1,403,000		6,672,000		7,025,000		12,081,000
Goodwill Impairment						0
Total expenses		1,403,000		6,672,000		7,025,000		12,081,000
Other income (loss)
Total other income (loss)		0		0		0		0
Income tax expense (benefit)		0		0		0		0
(Net Income (Loss) Attributable to Noncontrolling Interest		0		(44,000)		0		(700,000)
Economic Income (Loss) / Net income (loss) attributable to Cowen Group, Inc.		(2,385,000)		312,000		(3,239,000)		(7,718,000)
Preferred stock dividends		357,000		408,000		1,036,000		1,223,000
Net income (loss) attributable to Cowen Inc. common stockholders		(2,742,000)		(96,000)		(4,275,000)		(8,941,000)
Other Depreciation and Amortization		9,000		43,000		30,000		147,000
Economic Operating Income		(2,733,000)		(53,000)		(4,245,000)		(8,794,000)
Operating Segments | Asset Company | Consolidated Funds
Revenues
Total revenues		0		0		0		0
Expenses
Total expenses		0		0		0		0
Adjustments | Funds Consolidation
Revenues
Investment banking		0		0		0		0
Brokerage		0		0		0		0
Management fees		(574,000)		(381,000)		(1,640,000)		(2,197,000)
Incentive income		(13,000)		(20,000)		(557,000)		(37,000)
Investment Income		0		0		0		0
Interest and dividends		0		0		0		0
Reimbursement from affiliates		(27,000)		(65,000)		(94,000)		(198,000)
Aircraft lease revenue				0				0
Reinsurance premiums		0		0		0		0
Other revenues		(26,000)		0		(14,000)		0
Total revenues		1,791,000		1,837,000		5,934,000		6,147,000
Interest expense		0		0		0		0
Total net revenues		1,791,000		1,837,000		5,934,000		6,147,000
Expenses
Non-interest expense		0		0		0		0
Goodwill Impairment						0
Total expenses		2,516,000		1,687,000		6,229,000		7,267,000
Other income (loss)
Total other income (loss)		5,621,000		2,654,000		9,069,000		36,113,000
Income tax expense (benefit)		0		0		0		0
(Net Income (Loss) Attributable to Noncontrolling Interest		(4,896,000)		(2,804,000)		(8,774,000)		(34,993,000)
Economic Income (Loss) / Net income (loss) attributable to Cowen Group, Inc.		0		0		0		0
Preferred stock dividends		0		0		0		0
Net income (loss) attributable to Cowen Inc. common stockholders		0		0		0		0
Adjustments | Funds Consolidation | Consolidated Funds
Revenues
Total revenues		2,431,000		2,303,000		8,239,000		8,579,000
Expenses
Total expenses		2,516,000		1,687,000		6,229,000		7,267,000
Adjustments | Other Adjustments
Revenues
Investment banking	[1]	7,270,000		4,413,000		14,869,000		13,261,000
Brokerage	[2]	(11,865,000)		(9,637,000)		(28,849,000)		(27,876,000)
Management fees	[3]	(3,033,000)		(4,459,000)		(8,684,000)		(13,465,000)
Incentive income	[3]	(13,663,000)		(6,857,000)	[1]	(34,072,000)		(21,336,000)
Investment Income	[4]	(16,053,000)		(27,672,000)		(33,522,000)		(61,927,000)	[5]
Interest and dividends	[4]	60,707,000	[2]	26,448,000		129,846,000	[2]	77,511,000	[2]
Reimbursement from affiliates	[6]	265,000		418,000		874,000		1,264,000
Aircraft lease revenue	[5]			375,000				1,509,000
Reinsurance premiums	[7]	8,146,000		8,378,000		29,068,000		26,251,000
Other revenues	[7]	1,389,000		1,551,000		(2,109,000)		3,596,000
Total revenues		33,163,000		(7,042,000)		67,421,000		(1,212,000)
Interest expense	[2],[4]	49,330,000		19,581,000		104,672,000		58,346,000
Total net revenues		(16,167,000)		(26,623,000)		(37,251,000)		(59,558,000)
Expenses
Non-interest expense	[1],[6],[8],[9]	15,408,000		14,454,000		49,463,000		42,738,000
Goodwill Impairment						4,100,000
Total expenses		15,408,000		14,454,000		53,563,000		42,738,000
Other income (loss)
Total other income (loss)	[3],[4],[9]	26,721,000		39,328,000	[10]	73,907,000		86,851,000	[10]
Income tax expense (benefit)		1,365,000	[8]	5,083,000	[10]	9,615,000	[8]	15,999,000	[8]
(Net Income (Loss) Attributable to Noncontrolling Interest		2,787,000		(364,000)		4,530,000		700,000
Economic Income (Loss) / Net income (loss) attributable to Cowen Group, Inc.		(3,432,000)		(7,196,000)		(21,992,000)		(30,744,000)
Preferred stock dividends		0		0		0		0
Net income (loss) attributable to Cowen Inc. common stockholders		(3,432,000)		(7,196,000)		(21,992,000)		(30,744,000)
Adjustments | Other Adjustments | Consolidated Funds
Revenues
Total revenues		0		0		0		0
Expenses
Total expenses		$ 0		$ 0		$ 0		$ 0
[1]	Economic Income (Loss) presents underwriting expenses net of investment banking revenues, expenses reimbursed from clients within their respective expense category. Economic Income (Loss) also records retainer fees, relating to investment banking activities, collectible during the period that would otherwise be deferred until closing for US GAAP reporting.
[2]	Economic Income (Loss) brokerage revenues included net securities borrowed and securities loaned activities which are shown gross in interest income and interest expense for US GAAP.
[3]	Economic Income (Loss) recognizes revenues (i) net of distribution fees paid to agents, (ii) records income from uncrystallized incentive fees and (iii) the Company's proportionate share of management and incentive fees of certain real estate operating entities, the healthcare royalty business and the activist business.
[4]	Economic Income (Loss) recognizes Company income from proprietary trading (including interest and dividends).
[5]	Aircraft lease revenue is shown net of expenses in investment income for Economic Income (Loss).
[6]	Reimbursement from affiliates is shown as a reduction of Economic Income expenses, but is included as a part of revenues under US GAAP.
[7]	Economic Income (Loss) recognizes underwriting income from the Company's insurance related activities, net of expenses, within other revenue.
[8]	Economic Income (Loss) excludes income taxes and acquisition related adjustments as management does not consider these items when evaluating the performance of the segment.
[9]	Economic Income (Loss) recognizes the Company's proportionate share of expenses, for certain real estate operating entities and the activist business, for which the investments are recorded under the equity method of accounting for investments.
[10]	Economic Income (Loss) excludes gain/(loss) on debt extinguishment.

Regulatory Requirements (Detail

Regulatory Requirements (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2019USD ($)
Regulatory Requirements for Broker-Dealers [Line Items]
Interest Income, Related Party	$ 100,000	$ 0
Minimum net capital required	250,000	250,000
Cowen and Company
Regulatory Requirements for Broker-Dealers [Line Items]
Net capital requirement under alternative method	1,000,000	1,000,000
Net capital	88,162,000	88,162,000
Excess capital	87,162,000	87,162,000
Cowen Execution
Regulatory Requirements for Broker-Dealers [Line Items]
Cash and securities segregated under securities exchange commission regulation	17,000,000	17,000,000
Net capital requirement under alternative method	1,069,000	1,069,000
Required net capital under commodity exchange act	103,500,000	103,500,000
Net capital	104,559,000	104,559,000
Excess capital	103,490,000	103,490,000
Cowen and Company (Asia) Limited [Member]
Regulatory Requirements for Broker-Dealers [Line Items]
Financial resources	1,088,000	1,088,000
Financial resources requirement	383,000	383,000
Excess financial resources	705,000	705,000
ATM Execution LLC
Regulatory Requirements for Broker-Dealers [Line Items]
Net capital requirement under alternative method	250,000	250,000
Net capital	5,538,000	5,538,000
Excess capital	5,288,000	5,288,000
Cowen Prime
Regulatory Requirements for Broker-Dealers [Line Items]
Net capital requirement under alternative method	250,000	250,000
Net capital	17,449,000	17,449,000
Excess capital	17,199,000	17,199,000
Westminster Research
Regulatory Requirements for Broker-Dealers [Line Items]
Net capital requirement under alternative method	250,000	250,000
Net capital	24,048,000	24,048,000
Excess capital	23,798,000	23,798,000
RCG Insurance Company
Regulatory Requirements for Broker-Dealers [Line Items]
Minimum net capital required	300,000	300,000
Net capital	32,900,000	32,900,000
Options Clearing Corporation | Cowen Execution
Regulatory Requirements for Broker-Dealers [Line Items]
Minimum net capital required	2,000,000	$ 2,000,000
Minimum net capital required, percent		2.00%
U.K. Financial Services Authority | Cowen International Limited
Regulatory Requirements for Broker-Dealers [Line Items]
Financial resources	14,475,000	$ 14,475,000
Financial resources requirement	9,925,000	9,925,000
Excess financial resources	4,550,000	4,550,000
U.K. Financial Services Authority | Cowen Execution Services Ltd
Regulatory Requirements for Broker-Dealers [Line Items]
Financial resources	4,957,000	4,957,000
Financial resources requirement	2,043,000	2,043,000
Excess financial resources	2,914,000	2,914,000
Minimum | Cowen Execution
Regulatory Requirements for Broker-Dealers [Line Items]
Cash and securities segregated under securities exchange commission regulation	6,300,000	6,300,000
Required net capital under commodity exchange act	45,000	45,000
Special Reserve Accounts | Cowen Execution
Regulatory Requirements for Broker-Dealers [Line Items]
Cash and securities segregated under securities exchange commission regulation	26,900,000	26,900,000
Special Reserve Accounts | Minimum | Cowen Execution
Regulatory Requirements for Broker-Dealers [Line Items]
Cash and securities segregated under securities exchange commission regulation	$ 20,300,000	$ 20,300,000

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Related Party Transaction [Line Items]
Fees receivable	$ (101,508)		$ (101,508)		$ (111,946)
Due to Other Related Parties	500		500
Interest Income, Related Party	100		0
Due from related parties	27,849		27,849		33,870
Redeemable non-controlling interests, Related Party	348,424		348,424		216,923
Net income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds	6,848		4,187	$ (22,501)
Employees
Related Party Transaction [Line Items]
Redeemable non-controlling interests, Related Party	34,900		34,900		25,100
Net income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds	(3,600)	$ (4,100)	(4,700)	(8,400)
Employee Loans
Related Party Transaction [Line Items]
Due from employees	14,200		14,200		17,000
Forgivable Loan Balances	7,400		7,400		8,800
Amortization on Forgivable Loans	1,000	800	$ 2,800	$ 2,200
Employee Loans | Minimum
Related Party Transaction [Line Items]
Forgivable Loans, Vesting Period			1 year
Employee Loans | Maximum
Related Party Transaction [Line Items]
Forgivable Loans, Vesting Period			3 years
Affiliated Entity
Related Party Transaction [Line Items]
Fees receivable	(19,900)		$ (19,900)		(19,400)
Investor
Related Party Transaction [Line Items]
Due to Affiliate	300		300		600
Other Funds
Related Party Transaction [Line Items]
Due from related parties	6,600		6,600		8,900
Starboard Value LP
Related Party Transaction [Line Items]
Effective interest rate				5.00%
Interest Income, Related Party	100	$ 100	300	$ 300
Due from related parties	$ 7,000		$ 7,000		$ 7,700
Finance Period			5 years

Guarantees and Off-Balance Sh_3

Guarantees and Off-Balance Sheet Arrangements (Details)	Sep. 30, 2019USD ($)
Debt Instrument [Line Items]
Letter of credit, borrowing capacity	$ 370,000,000
Line of credit facility, remaining borrowing capacity	370,000,000
Pledge Lines
Debt Instrument [Line Items]
Letter of credit, borrowing capacity	300,000,000
Line of credit facility, remaining borrowing capacity	300,000,000
Texas Capital Bank | Pledge Lines
Debt Instrument [Line Items]
Letter of credit, borrowing capacity	75,000,000
Line of credit facility, remaining borrowing capacity	75,000,000
BMO Harris Bank | Pledge Lines
Debt Instrument [Line Items]
Letter of credit, borrowing capacity	150,000,000
Line of credit facility, remaining borrowing capacity	150,000,000
BMO Harris Bank | Tri-Party Pledge Line
Debt Instrument [Line Items]
Letter of credit, borrowing capacity	75,000,000
Line of credit facility, remaining borrowing capacity	75,000,000
BMO Harris Bank | Revolving Credit Facility
Debt Instrument [Line Items]
Letter of credit, borrowing capacity	70,000,000
Line of credit facility, remaining borrowing capacity	$ 70,000,000

Subsequent Events - Narrative (

Subsequent Events - Narrative (Details) - Subsequent Event $ in Millions	Oct. 23, 2019USD ($)
Subsequent Event [Line Items]
Stock Repurchase Program Additional Authorized Amount	$ 17.8
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 25