Cowen (COWN) 10-Q 29 Oct 20 2020 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Oct. 28, 2020
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	001-34516
Entity Registrant Name	Cowen Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-0423711
Entity Address, Address Line One	599 Lexington Avenue
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10022
City Area Code	646
Local Phone Number	562-1000
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		26,568,614
Entity Central Index Key	0001466538
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false
Common Stock Class A | The Nasdaq Global Market
Entity Information [Line Items]
Title of 12(b) Security	Class A Common Stock, par value $0.01 per share
Trading Symbol	COWN
Security Exchange Name	NASDAQ
2027 Notes | The Nasdaq Global Market
Entity Information [Line Items]
Title of 12(b) Security	7.35% Senior Notes due 2027
Trading Symbol	COWNZ
Security Exchange Name	NASDAQ
2033 Notes | The Nasdaq Global Market
Entity Information [Line Items]
Title of 12(b) Security	7.75% Senior Notes due 2033
Trading Symbol	COWNL
Security Exchange Name	NASDAQ

Consolidated Statements of Fina

Consolidated Statements of Financial Condition - USD ($) $ in Thousands		Sep. 30, 2020		Dec. 31, 2019
Assets
Cash and cash equivalents		$ 539,733	[1]	$ 301,123
Cash collateral pledged		110,666		6,563
Segregated cash		139,152		107,328
Securities owned, at fair value ($254,383 and $941,595 were pledged to various parties)		1,088,566		1,633,552
Receivable on derivative contracts, at fair value		58,194		62,977
Securities borrowed		1,272,428		754,441
Other investments ($123,787 and $114,504 at fair value, respectively)		204,610		185,722
Deposits with clearing organizations, brokers and banks		90,075		91,755
Receivable from brokers, dealers and clearing organizations, net of allowance of $730 and $721, respectively		1,390,821		681,695
Receivable from customers, net of allowance of $653 and $650, respectively		83,208		105,647
Fees receivable, net of allowance of $3,677 and $2,620, respectively		138,234		126,358
Due from related parties		23,480		26,749
Fixed assets, net of accumulated depreciation and amortization of $38,347 and $32,846, respectively		37,052		33,661
Operating lease right-of-use assets		80,805		92,852
Goodwill		137,728		137,728
Intangible assets, net of accumulated amortization of $34,746 and $26,395, respectively		26,043		35,200
Deferred tax asset, net		31,110		79,166
Other assets		50,917		84,158
Consolidated Funds
Cash and cash equivalents, Consolidated Funds		946		30,874
Securities owned, at fair value		187,991		375,278
Receivable on derivative contracts, at fair value, Consolidated Funds		0		5,833
Other Investments, Consolidated Funds		98,267		175,769
Receivable from brokers, Consolidated Funds		0		25,964
Other assets, Consolidated Funds		692		1,632
Total Assets		5,790,718		5,162,025
Liabilities
Securities sold, not yet purchased, at fair value		440,930		451,836
Securities Sold under Agreements to Repurchase		6,218		23,244
Payable for derivative contracts, at fair value		62,054		60,761
Securities Loaned		1,326,917		1,601,866
Payables to brokers, dealers and clearing organizations		312,850		271,018
Payable to customers		1,151,139		430,224
Commission management payable		117,778		71,620
Compensation payable		345,470		223,139
Operating lease liabilities		84,044		97,581
Notes payable and other debt	[2]	383,722		345,451
Convertible debt	[3]	122,485		118,688
Fees payable		81,851		21,540
Accounts payable, accrued expenses and other liabilities		173,706		141,557
Consolidated Funds
Due to related parties		136		581
Payable for derivative contracts, at fair value		0		4,769
Payable to brokers		0		864
Capital withdrawals payable		0		1,276
Accounts payable, accrued expenses and other liabilities		217		560
Total Liabilities		4,609,517		3,866,575
Commitments and Contingencies
Redeemable non-controlling interests in consolidated subsidiaries and funds		0		391,275
Stockholders' equity
Additional paid-in capital		1,146,848		1,110,635
(Accumulated deficit) retained earnings		98,139		(16,809)
Accumulated other comprehensive income (loss)		(7)		(5)
Less: Class A common stock held in treasury, at cost, 22,093,020 and 18,605,581 shares as of September 30, 2020 and December 31, 2019, respectively.		(334,100)		(284,300)
Cowen Inc. Stockholders' Equity		911,180		809,855
Nonredeemable non-controlling interests		270,021		94,320
Permanent Equity		1,181,201		904,175
Total Liabilities and Stockholders' Equity		5,790,718		5,162,025
Convertible Preferred Stock
Stockholders' equity
Preferred stock		1		1
Common Stock Class A
Stockholders' equity
Common stock		334		334
Less: Class A common stock held in treasury, at cost, 22,093,020 and 18,605,581 shares as of September 30, 2020 and December 31, 2019, respectively.		(334,135)		(284,301)
Permanent Equity		$ 1,181,201		$ 904,175
Common stock, shares issued		48,662,355		47,215,938
Common stock, shares outstanding		26,569,335		28,610,357
Common Stock Class B
Stockholders' equity
Common stock		$ 0		$ 0
Common stock, shares issued		0		0
Common stock, shares outstanding		0		0
[1]	As of September 30, 2020, cash and cash equivalents include Level 1 cash in the amount of $479.7 million and Level 2 certificates of deposit of $60.0 million.
[2]	The carrying amount of the notes payable and other debt includes an unamortized premium of $0.4 million and $0.5 million as of September 30, 2020 and December 31, 2019, respectively.
[3]	The carrying amount of the convertible debt includes an unamortized discount of $11.4 million and $14.9 million as of September 30, 2020 and December 31, 2019, respectively.

Consolidated Statements of Fi_2

Consolidated Statements of Financial Condition (Parenthetical) - USD ($)	Sep. 30, 2020		Dec. 31, 2019
Assets
Security Owned and Pledged as Collateral, Fair Value	$ 254,383,000		$ 941,595,000
Allowance for receivable from customers	653,000		650,000
Allowance for fees receivable	3,677,000		2,620,000
Allowance for receivable from brokers	730,000		721,000
Other investments	204,610,000		185,722,000
Fixed assets, accumulated depreciation and amortization (in dollars)	38,347,000		32,846,000
Intangible assets, accumulated amortization (in dollars)	$ 34,746,000		$ 26,395,000
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, Liquidation Preference, Value	$ 120,750,000		$ 120,750,000
Portfolio Funds
Assets
Other investments	$ 123,787,000	[1]	$ 114,504,000
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	48,662,355		47,215,938
Common stock, shares outstanding	26,569,335		28,610,357
Common stock, restricted shares	334,230		216,912
Treasury Stock, Shares	22,093,020		18,605,581
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
[1]	In accordance with US GAAP, certain investments are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient. 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.

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues
Investment banking	$ 194,341,000	$ 77,292,000	$ 503,351,000	$ 272,103,000
Brokerage	138,483,000	93,995,000	425,069,000	302,840,000
Management fees	11,954,000	7,300,000	35,211,000	21,480,000
Incentive income	127,000	701,000	127,000	724,000
Interest and dividends	37,552,000	60,707,000	127,547,000	129,846,000
Reimbursement from affiliates	269,000	238,000	777,000	780,000
Reinsurance premiums	2,505,000	8,146,000	18,943,000	29,068,000
Other revenues	1,369,000	1,237,000	4,709,000	3,228,000
Consolidated Funds
Interest and dividends	1,135,000	2,374,000	3,992,000	8,148,000
Other revenues	0	57,000	658,000	91,000
Total revenues	387,735,000	252,047,000	1,120,384,000	768,308,000
Interest and dividends expense	37,754,000	56,477,000	125,850,000	125,089,000
Total net revenues	349,981,000	195,570,000	994,534,000	643,219,000
Expenses
Employee compensation and benefits	153,427,000	120,320,000	583,137,000	388,611,000
Brokerage and trade execution costs	33,660,000	25,808,000	101,412,000	78,578,000
Underwriting expenses	4,013,000	2,846,000	16,524,000	12,383,000
Professional, advisory and other fees	15,085,000	15,535,000	40,519,000	39,396,000
Service fees	4,727,000	5,943,000	18,332,000	17,266,000
Communications	7,992,000	8,295,000	24,241,000	24,654,000
Occupancy and equipment	9,096,000	9,784,000	27,599,000	30,160,000
Depreciation and amortization	5,682,000	5,082,000	17,324,000	14,990,000
Client services and business development	2,343,000	10,364,000	16,906,000	33,549,000
Goodwill Impairment	0	0	0	4,100,000
Reinsurance claims, commissions and amortization of deferred acquisition costs	4,852,000	8,195,000	21,716,000	25,139,000
Other expenses	7,868,000	5,276,000	19,417,000	14,929,000
Consolidated Funds
Interest and dividends	0	1,153,000	2,064,000	3,376,000
Professional, advisory and other fees	334,000	857,000	1,598,000	1,375,000
Brokerage and trade execution costs	0	15,000	37,000	103,000
Other expenses	160,000	491,000	1,094,000	1,375,000
Total expenses	249,239,000	219,964,000	891,920,000	689,984,000
Other income (loss)
Net gains (losses) on securities, derivatives and other investments	(68,781,000)	18,446,000	83,738,000	61,440,000
Consolidated Funds
Net realized and unrealized gains (losses) on investments and other transactions	6,385,000	13,613,000	(31,222,000)	22,793,000
Net realized and unrealized gains (losses) on derivatives	0	293,000	1,850,000	(1,188,000)
Net gains (losses) on foreign currency transactions	0	(10,000)	(38,000)	(69,000)
Total other income (loss)	(62,396,000)	32,342,000	54,328,000	82,976,000
Income (loss) before income taxes	38,346,000	7,948,000	156,942,000	36,211,000
Income tax expense (benefit)	8,830,000	1,365,000	52,589,000	9,615,000
Net income (loss)	29,516,000	6,583,000	104,353,000	26,596,000
Net Income (Loss) Attributable to Noncontrolling Interest	9,232,000	2,770,000	(19,843,000)	7,188,000
Net income (loss) attributable to Cowen Inc.	20,284,000	3,813,000	124,196,000	19,408,000
Preferred stock dividends	1,698,000	1,698,000	5,094,000	5,094,000
Net income (loss) attributable to Cowen Inc. common stockholders	$ 18,586,000	$ 2,115,000	$ 119,102,000	$ 14,314,000
Weighted average common shares outstanding:
Basic (in shares)	27,663	29,529	28,078	29,687
Diluted (in shares)	29,970	31,264	29,646	31,381
Earnings (loss) per share:
Earnings Per Share, Basic (in dollars per share)	$ 0.67	$ 0.07	$ 4.24	$ 0.48
Earnings Per Share, Diluted (in dollars per share)	$ 0.62	$ 0.07	$ 4.02	$ 0.46

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 29,516	$ 6,583	$ 104,353	$ 26,596
Other comprehensive income (loss), net of tax:
Foreign currency translation	(2)	(2)	(2)	0
Total other comprehensive income (loss), net of tax	(2)	(2)	(2)	0
Comprehensive income (loss)	29,514	6,581	104,351	26,596
Net Income (Loss) Attributable to Noncontrolling Interest	9,232	2,770	(19,843)	7,188
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 20,282	$ 3,811	$ 124,194	$ 19,408

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]	Common Stock Class A	Common Stock Class ARetained Earnings/(Accumulated deficit)	Preferred Stock	Convertible Preferred StockRetained Earnings/(Accumulated deficit)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total Stockholders' Equity	$ 794,407
Stockholders' Equity Attributable to Noncontrolling Interest						$ 64,880
Common stock								$ 324
Common stock, shares outstanding, start at Dec. 31, 2018								28,437,860
Balance, start at Dec. 31, 2018		$ 234,142	$ 1,062,877	$ (5)	$ (34,648)			$ 859,287		$ 1
Preferred stock, shares outstanding, start at Dec. 31, 2018										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 non-controlling interests in consolidated subsidiaries and investment funds	(4,187)
Capital contributions	213,391					11,442	11,442
Capital withdrawals	(77,703)					(2,938)	(2,938)
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)
Common stock issued during period, shares, acquisitions								1,033,350
Common stock issued during period, value, acquisitions	14,446		14,436				14,446	$ 10
Preferred dividends paid	(5,094)						(5,094)				$ (5,094)
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		(266,882)	1,103,941	(5)	(20,334)			$ 901,814		$ 1
Preferred stock, shares outstanding, end at Sep. 30, 2019										120,750
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt, Subsequent Adjustments			(596)				(596)
Redeemable Non-controlling Interest, end at Sep. 30, 2019	348,424
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation	0
Noncontrolling Interest, Decrease from Deconsolidation	0
Total Stockholders' Equity	817,424
Stockholders' Equity Attributable to Noncontrolling Interest						75,923
Common stock								$ 334
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 non-controlling interests in consolidated subsidiaries and investment funds	(6,848)
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 dividends paid	(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		(266,882)	1,103,941	(5)	(20,334)			$ 901,814		$ 1
Preferred stock, shares outstanding, end at Sep. 30, 2019										120,750
Redeemable Non-controlling Interest, end at Sep. 30, 2019	348,424
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation	(2)			(2)			(2)
Total Stockholders' Equity	817,055
Stockholders' Equity Attributable to Noncontrolling Interest						84,759
Common stock								334
Total Stockholders' Equity	809,855
Stockholders' Equity Attributable to Noncontrolling Interest	94,320					94,320
Common stock								$ 334
Common stock, shares outstanding, start at Dec. 31, 2019								28,610,357
Balance, start at Dec. 31, 2019	904,175	(284,301)	1,110,635	(5)	(16,809)			$ 904,175		$ 1
Preferred stock, shares outstanding, start at Dec. 31, 2019										120,750
Redeemable Non-controlling Interest, start at Dec. 31, 2019	391,275
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	(10)				(10)		(10)
Net income (loss) attributable to Cowen Inc.	124,196				124,196		124,196
Noncontrolling Interest in Net Income (Loss) Other Noncontrolling Interests, Nonredeemable						13,081	13,081
Net income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds	(32,924)
Capital contributions	184,223					163,019	163,019
Capital withdrawals	(181,863)					(48,995)	(48,995)
Restricted stock awards issued, shares								1,371,723
Purchase of treasury stock, at cost, shares								(3,487,439)
Purchase of treasury stock, at cost	(49,834)	(49,834)					49,834
Common stock issued during period, shares, acquisitions								74,694
Common stock issued during period, value, acquisitions	926		926				926	$ 0
Preferred dividends paid	(5,094)						(5,094)				(5,094)
Dividends, Cash	(4,144)						(4,144)		$ (4,144)
Amortization of share based compensation	35,287		35,287				35,287
Common stock, shares outstanding, end at Sep. 30, 2020								26,569,335
Balance, end at Sep. 30, 2020	1,181,201	(334,135)	1,146,848	(7)	98,139			$ 1,181,201		$ 1
Preferred stock, shares outstanding, end at Sep. 30, 2020										120,750
Redeemable Non-controlling Interest, end at Sep. 30, 2020	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation	(2)			(2)			(2)
Increase in noncontrolling interest due to consolidation of entity	48,596					(48,596)	(48,596)
Noncontrolling Interest, Decrease from Deconsolidation	(360,711)
Total Stockholders' Equity	901,685
Stockholders' Equity Attributable to Noncontrolling Interest						188,925
Common stock								$ 334
Common stock, shares outstanding, start at Jun. 30, 2020								27,641,600
Balance, start at Jun. 30, 2020		(314,971)	1,135,141	(5)	81,185			$ 1,090,610		$ 1
Preferred stock, shares outstanding, start at Jun. 30, 2020										120,750
Redeemable Non-controlling Interest, start at Jun. 30, 2020	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to Cowen Inc.	20,284				20,284		20,284
Noncontrolling Interest in Net Income (Loss) Other Noncontrolling Interests, Nonredeemable						9,232	9,232
Net income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds	0
Capital contributions	0					74,337	74,337
Capital withdrawals	0					(2,473)	(2,473)
Restricted stock awards issued, shares								88,811
Purchase of treasury stock, at cost, shares								(1,161,076)
Purchase of treasury stock, at cost	(19,164)	(19,164)					19,164
Preferred dividends paid	(1,698)						(1,698)				$ (1,698)
Dividends, Cash	(1,632)						(1,632)		$ (1,632)
Amortization of share based compensation	11,707		11,707				11,707
Common stock, shares outstanding, end at Sep. 30, 2020								26,569,335
Balance, end at Sep. 30, 2020	1,181,201	$ (334,135)	$ 1,146,848	(7)	$ 98,139			$ 1,181,201		$ 1
Preferred stock, shares outstanding, end at Sep. 30, 2020										120,750
Redeemable Non-controlling Interest, end at Sep. 30, 2020	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation	(2)			$ (2)			$ (2)
Total Stockholders' Equity	911,180
Stockholders' Equity Attributable to Noncontrolling Interest	$ 270,021					$ 270,021
Common stock								$ 334

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ / shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2020		Sep. 30, 2019
Cash flows from operating activities:
Net income (loss)	$ 104,353		$ 26,596
Adjustments to reconcile net income (loss) to net cash provided by / (used in) operating activities:
Depreciation and amortization	17,324		14,990
Goodwill Impairment	0		4,100
Amortization of debt issuance costs (premium)	1,023		804
Amortization of debt discount	3,393		3,511
Noncash lease expense	(1,490)		(2,607)
Share-based compensation	35,287		27,224
Change in deferred taxes	48,056		8,420
Net loss (gain) on disposal of fixed assets	0		367
Purchases of securities owned, at fair value	(1,275,400)		(1,405,478)
Proceeds from sales of securities owned, at fair value	1,318,623		1,282,527
Proceeds from sales of securities sold, not yet purchased, at fair value	729,526		902,271
Payments to cover securities sold, not yet purchased, at fair value	(745,683)		(939,072)
Proceeds from other investments	21,964		19,693
Net (gains) losses on securities, derivatives and other investments	(80,533)		(57,808)
Consolidated Funds
Purchases of securities owned, at fair value	(1,912,137)		(2,016,225)
Proceeds from sales of securities owned, at fair value	1,793,399		1,880,160
Purchases of other investments	(2,090)		(2,798)
Proceeds from other investments	6,734		23,865
Net realized and unrealized (gains) losses on investments and other transactions	27,216		(51,925)
(Increase) decrease in operating assets:
Securities owned, at fair value, held at broker-dealer	603,885		(250,579)
Receivable on derivative contracts, at fair value	4,783		(14,629)
Securities borrowed	(517,987)		(820,241)
Deposits with clearing organizations, brokers and banks	1,680		(2,027)
Receivable from brokers, dealers and clearing organizations	(709,126)		68,479
Receivable from customers, net of allowance	22,439		(8,268)
Fees receivable, net of allowance	(11,876)		17,707
Due from related parties	3,086		6,020
Other assets	69,185		1,038
Consolidated Funds
Cash and cash equivalents	8,989		34,809
Receivable on derivative contracts, at fair value	(19,710)		531
Receivable from brokers	(961)		(9,579)
Other assets	273		10
Increase (decrease) in operating liabilities:
Securities sold, not yet purchased, at fair value, held at broker dealer	2,302		191,640
Securities sold under agreement to repurchase	(17,026)		23,772
Payable for derivative contracts, at fair value	1,293		16,672
Securities loaned	(274,949)		924,795
Payable to brokers, dealers and clearing organizations	41,832		42,281
Payable to customers	720,915		(88)
Commission management payable	46,158		(6,146)
Compensation payable	116,035		(92,903)
Fees payable	60,311		11,060
Due to related parties	24		(4,402)
Accounts payable, accrued expenses and other liabilities	37,729		(2,679)
Consolidated Funds
Contributions received in advance	450		0
Payable to brokers	8,560		(8,355)
Payable for derivative contracts, at fair value	11,967		6,115
Due To Related Parties, Consolidated Funds	(257)		615
Accounts payable, accrued expenses and other liabilities	75		(184)
Net Cash Provided by (Used in) Operating Activities	299,644		(156,655)
Cash flows from investing activities:
Purchases of other investments	(38,658)		(15,899)
Purchase of business	0		(48,581)
Proceeds from sales of other investments	29,784		18,103
Purchase of fixed assets and intangibles	(11,558)		(7,862)
Net Cash Provided by (Used in) Investing Activities	(20,432)		(54,239)
Cash flows from financing activities:
Repayments on convertible debt	0		(20,860)
Payments of Debt Issuance Costs	1,700		1,480
Borrowings on notes and other debt	134,810		84,640
Repayments on notes and other debt	(95,458)		(2,740)
Purchase of treasury stock	$ (43,442)		$ (10,153)
Cash dividends paid	$ (3,433)		$ 0
Preferred dividends paid	$ (5,094)		$ (5,094)
Contingent liability payment	(5,653)		(1,235)
Capital contributions by non-controlling interests in operating entities	7,276		11,110
Capital withdrawals to non-controlling interests in operating entities	(4,330)		(1,713)
Consolidated Funds
Capital contributions by non-controlling interests in Consolidated Funds	339,966		213,723
Capital withdrawals to non-controlling interests in Consolidated Funds	(227,617)		(89,032)
Net Cash Provided by (Used in) Financing Activities	95,325		177,166
Change in cash and cash equivalents	374,537		(33,728)
Total cash beginning of period	415,014		442,113
Cash and cash equivalents	539,733	[1]	260,994
Cash collateral pledged	110,666		18,609
Segregated cash	139,152		128,782
Total cash at end of period	789,551		408,385
Supplemental information
Cash paid during the year for interest	116,457		98,363
Cash paid during the year for taxes	1,984		3,815
Purchase of treasury stock, at cost, through net settlement	6,296		22,420
Other Preferred Stock Dividends and Adjustments	5,094		5,094
Net assets (liabilities) acquired upon acquisition (net of cash)			90,727
Initial recognition of right of use asset			103,694
Initial recognition of lease liability			110,505
Noncash transfer of net assets from Unconsolidated Master Fund to Consolidated Fund			97,655
Decrease in noncontrolling interest due to deconsolidation of entity	360,711
Increase in noncontrolling interest due to consolidation of entity	48,596
Common stock issuance upon close of acquisition	$ 926		$ 14,446
[1]	As of September 30, 2020, cash and cash equivalents include Level 1 cash in the amount of $479.7 million and Level 2 certificates of deposit of $60.0 million.

Organization and Business

Organization and Business	9 Months Ended
	Sep. 30, 2020
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 banking, research, sales and trading, prime brokerage, global clearing, commission management services and investment management 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 advisory and global capital markets origination, domain knowledge-driven research, sales and trading platforms for institutional investors, global clearing, commission management services and also a comprehensive suite of prime brokerage service. 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.

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2020
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 on consolidation. Certain investment funds 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 specialized industry accounting. The accompanying financial statements should be read in conjunction with the Company’s financial statements and notes thereto included in the our Annual Report on Form 10-K for the year ended December 31, 2019 (the "2019 Form 10-K"). Certain footnote disclosures included in the 2019 Form 10-K have been condensed or omitted from these financial statements as they are not required for interim reporting under US GAAP or are insignificant to the interim reporting period. 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. The Company consolidates five investment funds for which it acts as the managing member/general partner and investment manager. At September 30, 2020 , the Company consolidated the following investment funds: Ramius Enterprise LP (“Enterprise LP”), Cowen Private Investments LP ("Cowen Private"), Cowen Sustainable Investments I LP ("CSI I LP"), CSI I Golden Holdco LP ("Golden HoldCo") and CSI I Prodigy Holdco LP ("Prodigy HoldCo") (each a "Consolidated Fund" and collectively the "Consolidated Funds"). During the second quarter of 2020, the Company deconsolidated Ramius Merger Fund LLC (the "Merger Fund") and UCITS Fund ("UCITS Fund") due to a partial redemption of the Company’s direct portfolio fund investment in Merger Fund and a partial termination of the notional value of UCITS Fund units referenced in a total return swap with a third party. The Company continues to hold a direct retained portfolio fund investment in the Merger Fund and continues to have economic exposure to the returns of UCITS Fund through a total return swap with a third party. Both Merger Fund and UCITS Fund continue to be related parties of the Company after deconsolidation. 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 consolidation requirements, 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 determines whether it is the primary beneficiary of a VIE upon its initial involvement with the VIE and reassesses whether it is the primary beneficiary on an ongoing basis as long as it has any continuing involvement with the 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, 2020, the total assets and total liabilities of the consolidated VIEs were $449.0 million and $6.6 million, respectively. As of December 31, 2019, the total assets and total liabilities of the consolidated VIEs were $685.4 million and $24.9 million, respectively. The deconsolidation of two Consolidated Funds decreased the 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. At December 31, 2019, the Company held a variable interest in Ramius Merger Master Fund Ltd ("Merger Master" or the "Unconsolidated Master Fund") through the consolidated Merger Fund. 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 had not consolidated the Unconsolidated Master Fund. 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 Company does not consolidate the Unconsolidated Master Fund or real estate funds that are VIEs due to the Company's conclusion that it is not the primary beneficiary of these funds 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 a general partner and a 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), 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. 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"), 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. 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 Effective January 1, 2020, the Company adopted ASC Topic 326, Financial Instruments – Credit Losses (“ASC 326”). ASC 326 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. 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 or based on the credit quality of the borrower or issuer). The Company identified securities borrowed and fees and other receivables carried at amortized cost (including, but not limited to, receivables related to securities transactions, corporate finance and syndicate receivables, management fees and incentive fees receivable) as impacted by the new guidance. ASC 326 specifies that the Company adopt the new guidance prospectively by means of a cumulative-effect adjustment to the opening retained earnings as of the beginning of the first reporting period effective. Accordingly, the Company recognized a cumulative effective adjustment of $0.01 million upon adoption. The allowance for credit losses is based on the Company's expectation of the collectability of financial instruments carried at amortized cost, including securities borrowed and fees and other receivables utilizing the CECL framework. The Company considers factors such as historical experience, credit quality, age of balances and current and future economic conditions that may affect the Company’s expectation of the collectability in determining the allowance for credit losses. The Company’s expectation is that the credit risk associated with fees and other receivables is not significant until they are 90 days past due based on the contractual arrangement and expectation of collection in accordance with industry standards. For securities borrowed, the Company applies 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 Company applies the CECL model, utilizing a probability and loss given default methodology, only to the extent of the shortfall between the fair value of the collateral and amortized cost. 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. Inputs reflect unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. 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 based on their proportional rights of the underlying portfolio company, and 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 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. 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, are classified as level 2 when their inputs can be corroborated by market data. OTC derivatives, such as swaps and options, with significant inputs that cannot be corroborated by readily available or observable market data are classified as level 3. Other Investments —Other investments consist primarily of portfolio funds, real estate investments, carried interest and equity method investments, which are valued as follows: i. Portfolio Funds— Portfolio funds (“Portfolio Funds”) include 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 applies the practical expedient provided by the US GAAP fair value measurements and disclosures guidance relating to investments in certain entities that calculate net asset value (“NAV”) per share (or its equivalent). The practical expedient permits an entity holding investments in certain entities that either are investment companies or have attributes similar to an investment company, and calculate NAV per share or its equivalent for which the fair value is not readily determinable, to measure the fair value of such investments on the basis of that NAV per share, or its equivalent, without adjustment. 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 measured 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. iii. Carried Interest— For the private equity and debt fund products the Company offers, the Company is allocated incentive income by the investment funds based on the extent by which the investment funds performance exceeds predetermined thresholds. Carried interest allocations are generally structured from a legal standpoint as an allocation of capital in the Company’s capital account. The Company accounts for carried interest allocations by applying an equity ownership model. Accordingly, the Company accrues performance allocations quarterly based on the fair value of the underlying investments assuming hypothetical liquidation at book value. iv. 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 applies 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. f. Receivable from and payable to brokers Receivable from brokers, dealers, and clearing organizations includes amounts receivable for securities failed to deliver by the Company to a purchaser by the settlement date, amounts receivable from broker-dealers and clearing organizations, commissions receivable from broker-dealers, and interest receivable from securities financing arrangements. Payable to brokers, dealers and clearing organizations includes amounts payable for securities failed to receive by the Company from a seller by the settlement date, amounts payable to broker-dealers and clearing organizations for unsettled trades, interest payable for securities financing arrangements, and payables of deposits held in proprietary account of brokers and dealers. Pursuant to the master netting agreements the Company has entered into with its brokers, dealers and clearing organizations, receivables and payables arising from unsettled trade 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. g. Receivable from and payable to customers Receivable from customers includes amounts owed by customers on cash and margin transactions, recorded on a settlement-date basis and prepaid research, net of allowance for credit losses. For prepaid research, a prepaid research asset is established for research and related services disbursed in advance of anticipated client commission volumes. Payable to customers primarily consists of amounts owed to customers relating to securities transactions not completed on settlement date, recorded on a settlement-date basis on the statement of financial condition, and other miscellaneous customer payables. Securities owned by customers, including those that collateralize margin, are not reflected as assets of the Company on the statement of financial condition. The Company holds these securities with the intention of settlement against customer orders and are held as collateral for customer receivables. h. Fees receivable Fees related to security transactions are reported net of an allowance for credit losses. 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 2m). i. 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. See Note 2d for further information. 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, 2020 and December 31, 2019, the Company did not have any securities lending transactions for which fair value basis of accounting was elected. j. 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

Acquisition

Acquisition	3 Months Ended
	Sep. 30, 2020
Business Combinations [Abstract]
Acquisitions	Acquisition Quarton On January 2, 2019 (the "Quarton 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 "Quarton 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 Quarton 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 Quarton Acquisition Date, and the assets acquired and liabilities assumed were recorded at their fair value as of the Quarton Acquisition Date. Subsequent to the Quarton Acquisition, the operations of Quarton were integrated within the Company's existing businesses. The aggregate estimated purchase price of the Quarton Acquisition was $103.0 million. On the Quarton 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 Quarton 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 Quarton 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 Quarton 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 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 Quarton Acquisition Date, the estimated fair value of the Company's intangible assets, as acquired through the Quarton Acquisition, was $22.2 million and had a weighted average useful life of 2.8 years. 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 each of the three and nine months ended September 30, 2020 and 2019 was $2.2 million and $6.7 million, 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) 2020 $ 2,227 2021 2,608 2022 1,775 2023 — 2024 — Thereafter — $ 6,610

Cash Collateral Pledged

Cash Collateral Pledged	9 Months Ended
	Sep. 30, 2020
Cash and Cash Equivalents [Abstract]
Cash Collateral Pledged	Cash Collateral Pledged As of September 30, 2020 and December 31, 2019, the Company pledged cash collateral in the amount of $4.5 million and $4.6 million respectively, which relates to letters of credit issued to the landlords of the Company's premises in New York City, Boston and San Francisco. The Company also has pledged cash collateral for re insurance agreements which amounted to $106.1 million, as of September 30, 2020, and $2 million, as of December 31, 2019, which are expected to be released periodically as per the terms of the reinsurance policy between March 31, 2021 and March 31, 2024 (see Notes 14 and 18). As of September 30, 2020 , the Company has the following irrevocable letters of credit, rela ted 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. Location Amount Maturity (dollars in thousands) New York $ 358 April 2021 New York $ 1,424 October 2020 New York $ 1,637 November 2020 Boston $ 386 March 2021 San Francisco $ 712 October 2025 $ 4,517 To the extent any letter of credit is drawn upon, interest will be assessed at the prime commercial lending rate. As of September 30, 2020 and December 31, 2019 there were no amounts due related to these letters of credit.

Segregated Cash

Segregated Cash	9 Months Ended
	Sep. 30, 2020
Segregated Cash [Abstract]
Segregated Cash	Segregated CashAs of September 30, 2020 and December 31, 2019, cash segregated in compliance with federal regulations and other restricted deposits of $139.2 million and $107.3 million, respectively, consisted of cash deposited in Special Reserve Bank 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, 2020
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, 2020 and December 31, 2019, securities owned, at fair value consisted of the following: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Common stock $ 920,849 $ 1,546,484 Preferred stock 63,605 12,656 Warrants and rights 20,505 22,109 Government bonds 20,324 15,916 Corporate bonds 36,701 25,500 Convertible bonds 5,081 2,500 Term loan (*) 12,111 1,067 Trade claims (*) 9,390 7,320 $ 1,088,566 $ 1,633,552 (*) The Company has elected the fair value option for securities owned, at fair value with a fair value of $9.0 million and $8.4 million, respectively, at September 30, 2020 and December 31, 2019. Receivable on and Payable for derivative contracts, at fair value The Company's direct involvement with derivative financial instruments includes futures, currency forwards, equity swaps, credit default swaps and options. The Company's derivatives trading activities expose 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, 2020 As of December 31, 2019 Number of contracts / Notional Value Fair value Number of contracts / Notional Value Fair value (dollars in thousands) Currency forwards $ 82,100 $ 870 $ — $ — Swaps $ 244,090 4,644 $ 383,752 2,911 Options other (a) 256,841 52,680 550,188 60,066 $ 58,194 $ 62,977 (a) Includes the volume of contracts for index, equity, commodity future and cash conversion options. Payable for derivative contracts As of September 30, 2020 As of December 31, 2019 Number of contracts / Notional Value Fair value Number of contracts / Notional Value Fair value (dollars in thousands) Futures $ 9,895 $ 123 $ 10,224 $ 217 Currency forwards $ 103,500 717 $ 77,790 851 Swaps $ 376,331 7,514 $ 607,717 23,169 Options other (a) 252,576 53,700 306,306 36,524 $ 62,054 $ 60,761 (a) Includes the volume of contracts for 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, 2020 and December 31, 2019. This table does not include the impact of over-collateralization. Gross amounts offset on the Condensed Consolidated Statements of Financial Condition (a) Net amounts included on the Condensed Consolidated Statements of Financial Condition Gross amounts not offset in the Condensed Consolidated Statements of Financial Condition Gross amounts recognized Financial instruments Cash Collateral pledged Net amounts (dollars in thousands) As of September 30, 2020 Receivable on derivative contracts, at fair value $ 80,780 $ 22,586 $ 58,194 $ 3,631 $ 60 $ 54,503 Payable for derivative contracts, at fair value 67,295 5,241 62,054 3,631 2,777 55,646 As of December 31, 2019 Receivable on derivative contracts, at fair value $ 66,217 $ 3,240 $ 62,977 $ — $ 2,911 $ 60,066 Payable for derivative contracts, at fair value 64,001 3,240 60,761 — 24,020 36,741 (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. The realized and unrealized gains/(losses) related to derivatives trading activities were $(53.9) million and $7.1 million for the three months ended September 30, 2020 and 2019, respectively, and $(63.2) million and $2.3 million for the nine months ended September 30, 2020 and 2019, 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. These amounts are recognized in receivable from brokers, dealers and clearing organizations and payable to brokers, dealers and clearing organizations respectively. As of September 30, 2020 and December 31, 2019, all derivative contracts were with major financial institutions. Other investments As of September 30, 2020 and December 31, 2019, other investments included the following: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Portfolio funds, at fair value (1) $ 123,787 $ 114,504 Carried interest (2) 47,343 30,360 Equity method investments (3) 33,480 40,858 $ 204,610 $ 185,722 (1) Portfolio Funds, at fair value The Portfolio Funds, at fair value as of September 30, 2020 and December 31, 2019, included the following: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Starboard Value and Opportunity Fund (c)(*) $ 41,354 $ 37,895 Formation8 Partners Fund I, L.P. (f) 31,916 33,613 Cowen Healthcare Investments II LP (i) (*) 20,691 14,652 Lagunita Biosciences, LLC (d) 4,124 4,802 Eclipse Ventures Fund I, L.P. (b) 4,464 3,960 HealthCare Royalty Partners II LP (a)(*) 1,627 1,781 RCG Longview Debt Fund V, L.P. (g)(*) 1,232 1,732 HealthCare Royalty Partners LP (a)(*) 1,157 1,326 Starboard Leaders Fund LP (e)(*) 1,656 1,560 Eclipse SPV I, LP (j)(*) 1,680 1,447 Ramius Merger Fund LLC (m)(*) 1,952 — TriArtisan ES Partners LLC (k)(*) 1,342 1,082 Cowen Healthcare Investments III LP (i)(*) 4,346 1,398 TriArtisan PFC Partners LLC (l)(*) 628 909 RCG Longview Equity Fund, LP (g) (*) 445 835 Difesa Partners, LP (h) (*) 681 508 BDC Fund I Coinvest 1, L.P. (n) (*) 1,250 — Other private investment (o)(*) 315 4,448 Other affiliated funds (p)(*) 2,927 2,556 $ 123,787 $ 114,504 * 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 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. and RCG Longview Equity Fund, 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) Difesa Partners, LP permits semi-annual withdrawals occurring on or after the anniversary of initial contribution upon 90 days written notice. (i) Cowen Healthcare Investments II LP and Cowen Healthcare Investments III LP are private equity funds. Distributions are made from the fund 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) TriArtisan ES Partners LLC is a co-investment vehicle organized to invest in a privately held nuclear services company. Distributions will be made when the underlying investment is liquidated. (l) TriArtisan PFC Partners LLC is a co-investment vehicle organized to invest in a privately held casual dining restaurant chain. Distributions will be made when the underlying investment in liquidated. (m) Ramius Merger Fund LLC permits monthly withdrawals on 45 days prior notice. (n) BDC Fund I Coinvest 1, L.P. is a private equity fund focused on investing in growth companies in industries disrupted by digitization. Distributions will be made when the underlying investments are liquidated. (o) Other private investment represents the Company's closed end investment in a Portfolio Fund that invests in a wireless broadband communication provider in Italy. (p) 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 in 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. All carried interest balances are earned from affiliates of the Company. 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. The carried interest as of September 30, 2020 and December 31, 2019, included the following: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Cowen Healthcare Investments II LP $ 35,829 $ 23,759 Cowen Healthcare Investments III LP 5,357 — TriArtisan TGIF Partners LLC 2,881 — TriArtisan ES Partners LLC 1,354 — TriArtisan PFC Partners LLC 1,116 — Ramius Multi-Strategy Fund LP 612 — Ramius Merger Fund LLC 13 — Other private investment (a) — 4,737 RCG IO Renergys Sarl 181 1,251 Ramius Multi-Strategy Fund LP — 613 $ 47,343 $ 30,360 (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. (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 15% to 55%. 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. During the second quarter of 2020, 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 other than temporary impairment charge of $11.3 million was recognized to reduce the carrying value of the investment to fair value. The Company recorded no impairment charges in relation to its other equity method investments for the three and nine months ended September 30, 2020 and 2019. 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, 2020 As of December 31, 2019 (dollars in thousands) Starboard Value LP $ 25,392 $ 24,292 Surf House Ocean Views Holdings, LLC — 7,804 HealthCare Royalty GP III, LLC 2,198 2,230 RCG Longview Debt Fund V Partners, LLC 1,721 2,889 RCG Longview Management, LLC 253 583 HealthCare Royalty GP, LLC 675 108 HealthCare Royalty GP II, LLC 276 302 RCG Longview Debt Fund IV Management, LLC 331 331 RCG Longview Equity Management, LLC 105 105 HCR Stafford Fund GP, LLC 850 880 Liberty Harbor North 292 292 Other 1,387 1,042 $ 33,480 $ 40,858 The Company's income (loss) from equity method investments was income of $4.0 million and $2.7 million for the three months ended September 30, 2020 and 2019 and $10.5 million and $23.1 million for the nine months ended September 30, 2020 and 2019, respectively, and is included in net gains (losses) on securities, derivatives and other investments on the accompanying condensed consolidated statements of operations. Regulation S-X Rule 10-01(b)(1) For the periods ended September 30, 2020 and December 31, 2019 and for the nine months periods ended September 30, 2020 and September 30, 2019, certain investments subject to Regulation S-X Rule 10-01(b)(1) of the SEC guidance held by the Company have met the significance criteria as defined thereunder. As such, the Company is required to present summarized financial information for these significant investees as of September 30, 2020 and December 31, 2019 and for the three and nine months ended September 30, 2020 and 2019, and such information is as follows: Other equity method investments As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Assets $ 59,379 $ 95,825 Liabilities — 82,482 Equity $ 59,379 $ 13,343 Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (dollars in thousands) Revenues $ 274 $ 4,564 $ 54,717 $ 83,287 Expenses — — — — Net realized and unrealized gains (losses) 77 55 412 717 Net income $ 351 $ 4,619 $ 55,129 $ 84,004 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. As of September 30, 2020 and December 31, 2019, securities sold, not yet purchased, at fair value consisted of the following: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Common stock $ 404,409 $ 425,448 Corporate bonds 15,324 5,933 Government bonds 1,500 1,950 Preferred stock 10,767 3,686 Warrants and rights 8,930 14,819 $ 440,930 $ 451,836 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, 2020 and December 31, 2019. Gross amounts not offset on the Condensed Consolidated Statements of Financial Condition Gross amounts recognized, net of allowance 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, 2020 Securities borrowed $ 1,272,428 $ — $ 1,272,428 $ — $ 1,213,253 $ — $ 59,175 Securities loaned 1,326,917 — 1,326,917 — 1,278,129 — 48,788 Securities sold under agreements to repurchase 6,218 — 6,218 — 7,587 — (1,369) As of December 31, 2019 Securities borrowed $ 754,441 $ — $ 754,441 $ — $ 751,913 $ — $ 2,528 Securities loaned 1,601,866 — 1,601,866 — 1,585,036 — 16,830 Securities sold under agreements to repurchase 23,244 — 23,244 — 27,384 — (4,140) (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, 2020 and December 31, 2019: Open and Overnight Up to 30 days 31 - 90 days Greater than 90 days Total (dollars in thousands) As of September 30, 2020 Securities loaned Common stock $ 933,956 $ — $ — $ — $ 933,956 Corporate bonds 392,961 — — — 392,961 Securities sold under agreements to repurchase — — 6,218 — 6,218 As of December 31, 2019 Securities loaned Common stock $ 1,343,478 $ — $ — $ — $ 1,343,478 Corporate bonds 258,388 — — — $ 258,388 Securities sold under agreements to repurchase — — 23,244 — $ 23,244 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, ar e $7.1 billion and $1.1 billion as of September 30, 2020 and $6.1 billion and $617.5 million as of December 31, 2019, respectively. The carrying value of the Company's exposure to loss for these variable interest entities as of September 30, 2020 was $127.6 million , and as of December 31, 2019 was $241.2 million, all of which is included in other investments, at fair value in the accompanying condensed consolidated statements of financial condition. Additionally, the Company's maximum exposure to loss for the variable interest entities noted above as of September 30, 2020 and December 31, 2019, was $244.5 million and $261.7 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, 2020 and December 31, 2019, securities owned, at fair value, held by the Consolidated Funds consisted of the following: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Preferred stock $ — $ 4,393 Common stock 106,549 200,306 Government bonds — 161,607 Corporate bonds — 3,405 Convertible bonds 75,538 — Warrants and rights 5,904 5,567 $ 187,991 $ 375,278 Receivable on derivative contracts As of September 30, 2020 and December 31, 2019, receivable on derivative contracts, at fair value, held by the Consolidated Funds are comprised of: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Currency forwards $ — $ 3,302 Equity swaps — 927 Options — 1,604 $ — $ 5,833 Payable for derivative contracts As of September 30, 2020 and December 31, 2019, payable for derivative contracts, at fair value, held by the Consolidated Funds are comprised of: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Currency forwards $ — $ 88 Equity swaps — 3,931 Options — 750 $ — $ 4,769 Other investments, at fair value Investments in Portfolio Funds, at fair value As of September 30, 2020 and December 31, 2019, investments in Portfolio Funds, at fair value, included the following: As of September 30, 2020 As of December 31, 2019 As of December 31, 2020 2019 (dollars in thousands) Investments of Enterprise LP $ 98,016 $ 99,153 Investments of Merger Fund — 76,616 Investment of Prodigy HoldCo 251 — $ 98,267 $ 175,769 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, 2020 and December 31, 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 investments directly as well as through affiliated portfolio funds. Consolidated portfolio fund investments of Merger Fund The Merger Fund, which was deconsolidated during the second quarter of 2020 (See Note 2b), operates under a "master-feeder" structure, whereby Merger Master shareholders are Merger Fund and Ramius Merger Fund Ltd. The consolidated investments in Portfolio Funds include Merger Fund's investment of $76.6 million in Merger Master as of December 31, 2019. 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. Consolidated portfolio fund investment of Prodigy HoldCo The Prodigy Holdco fund, which was consolidated upon its formation during the third quarter of 2020 (See Note 2b), invests, along with other securities, in a fund named CSI PRTA Co-Investment LP. CSI PRTA Co-Investment LP was organized to hold an investment in a manufacturer and technology provider of heavy-duty electric transportation. Prodigy HoldCo will receive distributable proceeds when CSI PRTA Co-Investment LP’s s underlying investment is monetized. Indirect Concentration of the Underlying Investments Held by Consolidated Funds From time to time, either directly held by the Company, indirectly through the Company's consolidated entities 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, 2020 and December 31, 2019, 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, 2020 and December 31, 2019, respectively. 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, 2020 Linkem Equity, loans and warrants Italy Wireless Broadband 9.01 % $ 82,074 As of December 31, 2019 Linkem Equity, loans and warrants Italy Wireless Broadband 9.53 % $ 77,142 Underlying Investments of Unconsolidated Funds Held by Consolidated Funds During the second quarter of 2020, the Company deconsolidated the Merger Fund due to a partial redemption of the Company’s direct portfolio fund investment in Merger Fund. The Company continues to hold a direct retained portfolio fund investment in the Merger Fund. Merger Master As of December 31, 2019, Merger Fund's investment in Merger Master represented 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 Merger Master as of December 31, 2019: Merger Master As of December 31, 2019 Securities owned by Merger Master, at fair value (dollars in thousands) Common stock $ 76,531 Warrants and rights 748 Corporate bonds 2,074 $ 79,353 Securities sold, not yet purchased, by Merger Master, at fair value Common stock $ 29,623 Exchange traded funds 38,527 $ 68,150 Receivable on derivative contracts, at fair value, owned by Merger Master As of December 31, 2019 Description (dollars in thousands) Options $ 2,047 Equity swaps 406 $ 2,453 Payable for derivative contracts, at fair value, owned by Merger Master As of December 31, 2019 Description (dollars in thousands) Options $ 1,158 Equity swaps 268 $ 1,426

Fair Value Measurements for Ope

Fair Value Measurements for Operating Entities and Consolidated Funds	9 Months Ended
	Sep. 30, 2020
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, 2020 and December 31, 2019: Assets at Fair Value as of September 30, 2020 Level 1 Level 2 Level 3 Total (dollars in thousands) Operating Entities Securities owned, at fair value Government bonds $ 20,324 $ — $ — $ 20,324 Preferred stock 10,187 — 53,418 63,605 Common stock 900,885 508 19,456 920,849 Convertible bonds — — 5,081 5,081 Corporate bonds — 36,181 520 36,701 Trade claims — — 9,390 9,390 Term loan — — 12,111 12,111 Warrants and rights 15,522 — 4,983 20,505 Receivable on derivative contracts, at fair value Currency forwards — 870 — 870 Swaps — 4,644 — 4,644 Options 52,329 — 351 52,680 Consolidated Funds Securities owned, at fair value Common stock 3,598 — 102,951 106,549 Warrants and rights — — 5,904 5,904 Convertible bonds — — 75,538 75,538 $ 1,002,845 $ 42,203 $ 289,703 $ 1,334,751 Percentage of total assets measured at fair value on a recurring basis 75.1 % 3.2 % 21.7 % Portfolio Funds measured at net asset value (a) 123,787 Carried interest (a) 47,343 Consolidated Funds' Portfolio Funds measured at net asset value (a) 98,267 Equity method investments 33,480 Total investments $ 1,637,628 Liabilities at Fair Value as of September 30, 2020 Level 1 Level 2 Level 3 Total (dollars in thousands) Operating Entities Securities sold, not yet purchased, at fair value Government bonds $ — $ — $ 1,500 $ 1,500 Common stock 404,409 — — 404,409 Corporate bonds — 14,524 800 15,324 Preferred stock 10,767 — — 10,767 Warrants and rights 8,930 — — 8,930 Payable for derivative contracts, at fair value Futures 123 — — 123 Currency forwards — 717 — 717 Swaps — 7,514 — 7,514 Options 50,746 — 2,954 53,700 Accounts payable, accrued expenses and other liabilities Contingent consideration liability (b) — — 30,024 30,024 $ 474,975 $ 22,755 $ 35,278 $ 533,008 Percentage of total liabilities measured at fair value 89.1 % 4.3 % 6.6 % (a) In accordance with US GAAP, certain investments are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient. 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 31, 2019 and December 31, 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, 2020 can range from $0.9 million to $35.1 million. Assets at Fair Value as of December 31, 2019 Level 1 Level 2 Level 3 Total (dollars in thousands) Operating Entities Securities owned, at fair value Government bonds $ 15,916 $ — $ — $ 15,916 Preferred stock 4,821 — 7,835 12,656 Common stock 1,527,769 1,249 17,466 1,546,484 Convertible bonds — — 2,500 2,500 Corporate bonds — 23,079 2,421 25,500 Trade claims — — 7,320 7,320 Term loan — 1,067 — 1,067 Warrants and rights 21,515 — 594 22,109 Receivable on derivative contracts, at fair value Swaps — 2,911 — 2,911 Options 59,730 — 336 60,066 Consolidated Funds Securities owned, at fair value Government bonds 161,607 — — 161,607 Preferred stock — — 4,393 4,393 Common stock 200,306 — — 200,306 Corporate bonds — 3,405 — 3,405 Warrants and rights — — 5,567 5,567 Receivable on derivative contracts, at fair value Currency forwards — 3,302 — 3,302 Equity swaps — 927 — 927 Options 1,604 — — 1,604 $ 1,993,268 $ 35,940 $ 48,432 $ 2,077,640 Percentage of total assets measured at fair value on a recurring basis 95.9 % 1.7 % 2.3 % Portfolio Funds measured at net asset value (a) 114,504 Carried interest (a) 30,360 Consolidated Funds' Portfolio Funds measured at net asset value (a) 175,769 Equity method investments 40,858 Total investments $ 2,439,131 Liabilities at Fair Value as of December 31, 2019 Level 1 Level 2 Level 3 Total (dollars in thousands) Operating Entities Securities sold, not yet purchased, at fair value US Government securities $ — $ — $ 1,950 $ 1,950 Common stock 425,448 — — 425,448 Corporate bonds — 4,933 1,000 5,933 Preferred stock 3,686 — — 3,686 Warrants and rights 14,819 — — 14,819 Payable for derivative contracts, at fair value Futures 217 — — 217 Currency forwards — 851 — 851 Swaps — 23,169 — 23,169 Options 33,604 — 2,920 36,524 Accounts payable, accrued expenses and other liabilities Contingent consideration liability (b) — — 30,896 30,896 Consolidated Funds Payable for derivative contracts, at fair value Currency forwards — 88 — 88 Options 750 — — 750 Equity swaps — 3,931 — 3,931 $ 478,524 $ 32,972 $ 36,766 $ 548,262 Percentage of total liabilities measured at fair value 87.3 % 6.0 % 6.7 % (a) In accordance with US GAAP, certain investments are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient. 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 31, 2019 and December 31, 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 December 31, 2019 can range from $1.3 million to $40.0 million. The following table includes a roll forward of the amounts for the three and nine months ended September 30, 2020 and 2019 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, 2020 Balance at June 30, 2020 Transfers in Transfers out Purchases/(covers) (Sales)/shorts Realized and Unrealized gains/losses Balance at September 30, 2020 Change in unrealized gains/losses relating to instruments still held (1) (dollars in thousands) Operating Entities Preferred stock $ 51,480 $ — $ (7,744) (b) $ 5,282 $ (3,770) $ 8,170 $ 53,418 $ 2,926 Common stock 14,816 — (3) (e) 4,000 — 643 19,456 562 Convertible bonds 5,081 — — — — — 5,081 — Corporate bonds 758 — (312) (b) 72 — 2 520 22 Options, asset 337 — — — — 14 351 14 Options, liability 2,177 — — — — 777 2,954 777 Term Loan 11,359 — — 245 — 507 12,111 506 Warrants and rights 4,625 3 (e) — — — 355 4,983 337 Trade claims 7,587 — — 2,690 (648) (239) 9,390 (239) Corporate bond, liability 800 — — — — — 800 — Government bonds, liability 1,500 — — — — — 1,500 — Contingent consideration liability 27,001 — — — — 3,023 30,024 3,023 Consolidated Funds Common stock 102,951 — — — — — 102,951 — Warrants and rights 5,858 — — — — 46 5,904 46 Convertible bonds — — — 75,000 — 538 75,538 538 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) (f) $ — $ — $ 1,434 $ 7,835 $ 2,295 Common stock 11,006 — — 2,579 (480) 208 13,313 210 Convertible bonds 6,318 — (2,801) (f) 1,049 (2,072) 47 2,541 4 Corporate bonds 775 20 (e) — 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 (e) — — — (1,325) 1,200 (1,325) Government bonds, liability — 4,681 (e) — — — (2,431) 2,250 (2,431) Contingent consideration liability 29,536 — — — — 298 29,834 298 Consolidated Funds Preferred stock 24,322 — (19,929) (f) — — — 4,393 — Common stock 1,017 — (94) (f) — (957) 34 — — Warrants and rights 6,274 — — — (670) (139) 5,465 (809) Nine Months Ended September 30, 2020 Balance at December 31, 2019 Transfers in Transfers out Purchases/(covers) (Sales)/shorts Realized and Unrealized gains/losses Balance at September 30, 2020 Change in unrealized gains/losses relating to instruments still held (1) (dollars in thousands) Operating Entities Preferred stock $ 7,835 $ 45,530 (c) $ (7,744) (b) $ 5,647 $ (5,870) $ 8,020 $ 53,418 $ 5,337 Common stock 17,466 — (29) (a)(e) 5,798 (3,712) (67) 19,456 (1,023) Convertible bonds 2,500 — — 2,581 — — 5,081 — Corporate bond 2,421 — (312) (b) 592 (1,938) (243) 520 (180) Options, asset 336 — — — — 15 351 15 Options, liability 2,920 — — — — 34 2,954 35 Term loan — 11,149 (c) — 245 — 717 12,111 717 Warrants and rights 594 3,636 (a)(c) — — — 753 4,983 753 Trade claims 7,320 1,044 (a)(e) — 4,663 (2,863) (774) 9,390 (795) Corporate bond, liability 1,000 — — — — (200) 800 (200) Government bonds, liability 1,950 — — — — (450) 1,500 (450) Contingent consideration liability 30,896 — — — (5,653) 4,781 30,024 4,781 Consolidated Funds Preferred stock 4,393 — (4,000) (d) — — (393) — — Common stock — 4,000 (d) — 100,000 — (1,049) 102,951 (1,049) Warrants and rights 5,567 — — — — 337 5,904 337 Convertible bonds $ — $ — $ — $ 75,000 $ — $ 538 $ 75,538 $ 538 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) (f) $ 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)(f) 16,021 (11,764) 110 2,541 41 Corporate bond — 20 (e) — 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 claim 5,543 — — 6,965 (5,506) 60 7,062 57 Corporate bond, liability — 2,525 (e) — — — (1,325) 1,200 (1,325) Government bonds, liability — 4,681 (e) — — — (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) (f) — — 8 4,393 8 Common stock 94 — (94) (f) 407 (958) 551 — — Warrants and rights $ 5,279 $ — $ — $ — $ (1,758) $ 1,944 $ 5,465 $ 190 (1) Unrealized gains/losses are reported in other income (loss) in the accompanying condensed consolidated statements of operations. (a) The security stopped trading on an open market. (b) The investments were converted to common stock. (c) The Company consolidated an operating entity which holds preferred stock, loans and warrants. (d) The investment was involved in a reverse merger and preferred stock was converted to common shares. (e) The transfers between level 1 and level 3 are due to the change in the availability of observable inputs. (f) 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 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. The following table includes quantitative information as of September 30, 2020 and December 31, 2019 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, 2020 Valuation Techniques Unobservable Inputs Range Weighted Average Level 3 Assets (dollars in thousands) Common and preferred stocks $ 61,220 Discounted cash flows Guideline companies Discount rate EBITDA Market Multiples 10% - 12% 6.25x - 6.75x 11% 6.5x Options 352 Discounted cash flows Guideline companies Discount rate EBITDA Market Multiples 10% - 12% 6.25x - 6.75x 11% 6.5x Trade claims 3,446 Discounted cash flows Discount rate 15% 15% Warrants and rights 10,865 Discounted cash flows Guideline companies Discount rate EBITDA Market Multiples 4% - 11% 6.25x - 6.75x 7.0% 6.5x Corporate, convertible bonds and term loan 12,110 Discounted cash flows Guideline companies Discount rate EBITDA Market Multiples 10% - 12% 6.25x - 6.75x 11% 6.5x Other level 3 assets (a) 201,710 Total level 3 assets $ 289,703 Level 3 Liabilities Options 2,954 Option pricing models Volatility 35% 35% Contingent consideration liability 30,024 Discounted cash flows Monte Carlo simulation Discount rate Volatility 15% - 22% 22% 15% 22% Other level 3 liabilities (a) 2,300 Total level 3 liabilities $ 35,278 Quantitative Information about Level 3 Fair Value Measurements Fair Value at December 31, 2019 Valuation Techniques Unobservable Inputs Range Weighted Average Level 3 Assets (dollars in thousands) Common and preferred stocks $ 10,876 Discounted cash flows Guideline companies Discount rate EBITDA Market Multiples 8% - 11.25% 6.5x - 7x 10.4% 6.75x Trade claims 24 Discounted cash flows Discount rate 20% 20% Warrants and rights 6,162 Model based Discounted cash flows Volatility Discount rate 30% 6% - 7% —% 6.1% Options 336 Option pricing models Discount rate EBITDA Market Multiples 9.75% - 11.25% 6.5x - 7x 10.5% 6.75x Corporate and convertible bonds 311 Discounted cash flows Recovery Discount rate Probability of recovery 20% 1% - 3% 20% 2.3% Other level 3 assets (a) 30,723 Total level 3 assets $ 48,432 Level 3 Liabilities Options 2,920 Option pricing models Volatility 35% to 40% 35% Contingent consideration liability 30,896 Discounted cash flows Discount rate Volatility 15% - 22% 17% 15% 17% Other level 3 liabilities (a) 2,950 Total level 3 liabilities $ 36,766 (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, procedures and internal control infrastructure over the fair value measurement of financial instruments. In the event that observable inputs are not available, the control processes are designed to ensure that the valuation approach utilized is applicable, reasonable and consistently applied. Where a pricing model is used to determine fair value, these control processes include reviews of the methodology and inputs for both reasonableness and applicability. Consistent with best practices, recently executed comparable transactions and other observable market data are used for the purposes of validating both the model and the assumptions used to calculate fair value. Independent of trading and valuation functions, the Company’s Valuation Committee in conjunction with its Price Verification team, plays an important role in determining that financial instruments are appropriately valued and that fair value measurements are both reasonable and reliable. This is particularly important where prices or valuations that require inputs are less observable. 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. 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 regularly reviews a 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, 2020 and December 31, 2019, 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 2e). September 30, 2020 December 31, 2019 Fair Value Hierarchy Carrying Amount Fair Value Carrying Amount Fair Value (dollars in thousands) Financial Assets Operating companies Cash and cash equivalents $ 539,733 (f) $ 539,733 (f) $ 301,123 $ 301,123 Level 1 & 2 Cash collateral pledged 110,666 110,666 6,563 6,563 Level 2 Segregated cash 139,152 139,152 107,328 107,328 Level 1 Securities borrowed 1,272,428 1,272,428 754,441 754,441 Level 2 Loans receivable 9,045 9,045 (d) 42,830 42,830 (d) Level 3 Consolidated Funds Cash and cash equivalents 946 946 30,874 30,874 Level 1 Financial Liabilities Securities sold under agreements to repurchase 6,218 7,587 23,244 27,384 Level 2 Securities loaned 1,326,917 1,326,917 1,601,866 1,601,866 Level 2 Convertible debt 122,485 (a) 147,166 (b) 118,688 (a) 148,786 (b) Level 2 Notes payable and other debt 383,722 (e) 406,309 (c) 345,451 (e) 372,591 (c) Level 2 (a) The carrying amount of the convertible debt includes an unamortized discount of $11.4 million and $14.9 million as of September 30, 2020 and December 31, 2019, 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. (e) The carrying amount of the notes payable and other debt includes an unamortized premium of $0.4 million and $0.5 million as of September 30, 2020 and December 31, 2019, respectively.

Deposits with Clearing Organiza

Deposits with Clearing Organizations, Brokers and Banks	9 Months Ended
	Sep. 30, 2020
Deposits with Clearing Organizations, Brokers and Banks [Abstract]
Deposits with Clearing Organizations, Brokers and Banks	Deposits with Clearing Organizations, Brokers and BanksUnder 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, 2020 and December 31, 2019, the Company had a total of $90.1 million and $91.8 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, 2020
Brokers and Dealers [Abstract]
Receivables From and Payables to Brokers, Dealers and Clearing Organizations	Receivable From and Payable To Brokers, Dealers and Clearing OrganizationsReceivable 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, 2020 and December 31, 2019, amounts receivable from brokers, dealers and clearing organizations include: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Broker-dealers $ 1,263,635 $ 623,523 Securities failed to deliver 71,280 45,673 Clearing organizations 49,978 3,180 Securities borrowed interest receivable 5,928 9,319 $ 1,390,821 $ 681,695 As of September 30, 2020 and December 31, 2019, amounts payable to brokers, dealers and clearing organizations include: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Broker-dealers $ 228,628 $ 185,838 Securities failed to receive 39,496 57,580 Clearing organizations 39,077 18,063 Securities loaned interest payable 5,649 9,537 $ 312,850 $ 271,018

Receivable from and Payable to

Receivable from and Payable to Customers	9 Months Ended
	Sep. 30, 2020
Receivables and Payable to Customers [Abstract]
Receivable from and Payables to Customers [Text Block]	Receivable From and Payable To CustomersAs of September 30, 2020 and December 31, 2019, receivable from customers of $83.2 million and $105.6 million, respectively, consist of amounts owed by customers relating to securities transactions not completed on settlement date and receivables arising from prepaid research. As of September 30, 2020 and December 31, 2019, payable to customers of $1.2 billion and $430.2 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.

Commission Management Payable

Commission Management Payable	9 Months Ended
	Sep. 30, 2020
Commission Management Payable [Abstract]
Commission Management Payable	Commission Management PayableThe Company receives a gross commission from various 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 $117.8 million and $71.6 million, as of September 30, 2020 and December 31, 2019, respectively, are classified as commission management payable in the accompanying condensed consolidated statements of financial condition.

Non-Controlling Interests in Co

Non-Controlling Interests in Consolidated Subsidiaries and Funds	9 Months Ended
	Sep. 30, 2020
Noncontrolling Interest [Abstract]
Redeemable Non-Controlling Interests in Consolidated Subsidiaries and Funds	Non-Controlling Interests in Consolidated Subsidiaries and Investment Funds Redeemable and nonredeemable 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, 2020 As of December 31, 2019 (dollars in thousands) Redeemable non-controlling interests in consolidated subsidiaries and investment funds Consolidated Funds $ — $ 391,275 Nonredeemable non-controlling interests in consolidated subsidiaries and investment funds Operating companies 72,569 11,513 Consolidated Funds 197,452 82,807 $ 270,021 $ 485,595 Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (dollars in thousands) Income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds Operating companies $ 6,283 $ (2,126) $ 9,514 $ (1,586) Consolidated Funds 2,949 4,896 (29,357) 8,774 $ 9,232 $ 2,770 $ (19,843) $ 7,188

Revenue from Contracts with Cus

Revenue from Contracts with Customers	9 Months Ended
	Sep. 30, 2020
Revenue Recognition and Deferred Revenue [Abstract]
Revenue from Contract with Customer	Revenue from Contracts with Customers For the three and nine months ended September 30, 2020 and 2019, 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, 2020 2019 2020 2019 (dollars in thousands) Revenue from contracts with customers Operating Company Investment banking Underwriting fees $ 121,390 $ 38,936 $ 318,355 $ 162,140 Strategic/financial advisory fees 39,431 17,889 101,061 49,565 Placement and sales agent fees 28,427 15,842 71,999 48,855 Expense reimbursements from clients 5,093 4,625 11,936 11,543 Total investment banking revenue 194,341 77,292 503,351 272,103 Brokerage Commissions 112,953 82,715 367,564 263,831 Trade conversion revenue 3,404 3,700 12,370 12,364 Equity research fees 4,605 4,235 13,632 13,180 Total brokerage revenue from customers 120,962 90,650 393,566 289,375 Management fees 11,721 7,052 34,492 20,492 Incentive income 127 701 127 710 Total revenue from contracts with customers - Op Co $ 327,151 $ 175,695 $ 931,536 $ 582,680 Asset Company Management fees 233 248 719 988 Incentive income — — — 14 Total revenue from contracts with customers - Asset Co 233 248 719 1,002 Total revenue from contracts with customers $ 327,384 $ 175,943 $ 932,255 $ 583,682

Reinsurance

Reinsurance	9 Months Ended
	Sep. 30, 2020
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 claims incurred and paid during the periods below, as well as the change in claims outstanding or incurred but not reported ("Claims IBNR") during these periods were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (dollars in thousands) Incurred and paid claims $ 2,570 $ 126 $ 10,498 $ 7,046 Change in Claims IBNR 2,722 833 $ 26,638 $ 11,724 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, 2020, 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, 2020 and 2019. From time to time, Hollenfels may enter into reinsurance agreements that require it to post collateral of cash or US government bonds to cover certain exposures as defined in the respective reinsurance agreements. As of September 30, 2020, Hollenfels pledged $120.5 million of collateral towards such reinsurance obligations, of which $106.1 million was cash and $14.4 million was US government bonds. As of December 31, 2019, total collateral pledged was $15.0 million, of which $2.0 million was cash and $13.0 million was US government bonds. Hollenfels expects $101.2 million and none of the cash collateral pledged as of September 30, 2020 and December 31, 2019, respectively, to be released on September 30, 2023. The remaining cash collateral of $4.9 million and all of the US government bonds pledged as of September 30, 2020 as well as all cash and US government bonds pledged as of December 31, 2019 are expected to be released periodically between March 31, 2021 and March 31, 2024 in accordance with the terms of the underlying reinsurance agreements.

Share-Based Compensation and Em

Share-Based Compensation and Employee Ownership Plans	9 Months Ended
	Sep. 30, 2020
Share-based Payment Arrangement [Abstract]
Share-Based Compensation and Employee Ownership Plans	Share-Based Payments, Deferred Compensation and Employee Ownership Plans The Company has issued share-based compensation under the 2010 and 2020 Equity and Incentive Plan (the "Equity Plans"). The Equity Plans permits the grant of options, restricted shares, restricted stock units, and other equity-based awards to the Company's employees and directors. Stock options granted generally vest over two five seven two five Under the Equity Plan, the Company awarded $0.1 million and $50.3 million of deferred cash awards to its employees during the three and nine months ended September 30, 2020. These awards vest over a four 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 Plan, the Company recognized compensation expense of $11.6 million and $10.0 million for the three months ended September 30, 2020 and 2019 and $35.2 million and $27.2 million for the nine months ended September 30, 2020 and 2019, respectively. The income tax effect recognized for the Equity Plans was a benefit of $3.1 million and $2.6 million for the three months ended September 30, 2020 and 2019 and $8.4 million and $6.8 million for the nine months ended September 30, 2020 and 2019, 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, 2020 and 2019: Nine Months Ended September 30, 2020 Nine Months Ended September 30, 2019 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 5,364,486 $ 16.67 5,962,295 $ 15.73 Granted 2,638,544 17.14 2,322,996 16.62 Vested (1,320,318) 15.20 (1,545,850) 16.26 Canceled (87,348) 14.80 (584,333) 11.49 Forfeited (111,212) 15.55 (156,528) 13.97 Ending balance outstanding 6,484,152 $ 17.20 5,998,580 $ 16.40 Included in the restricted share and restricted stock unit activity are performance-linked restricted stock units of 1,366,666 which were awarded in March 2016, April 2019 and July 2020. Of the awards granted, 145,986 have vested and 320,681 have been canceled, as they did not meet the performance criteria, through September 30, 2020. The remaining awards, included in the outstanding balance as of September 30, 2020, vest between December 2020 and December 2022 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, 2020, there was $81.8 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 2.24 years. Restricted Shares and Restricted Stock Units Granted to Non-Employee Board Members There were 90,645 restricted stock units awarded and 48,021 delivered to non-employee board members during the three and nine months ended September 30, 2020. As of September 30, 2020 there were 259,536 restricted stock units outstanding for 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 December 31, 2019 there were 216,912 restricted stock units outstanding.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2020
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 are 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, South Africa, Canada 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 redeemable non-controlling interests in consolidated subsidiaries and investment funds. Based on these methodologies, the Company’s effective income tax rate was 33.51% and 26.55% for the nine months ended September 30, 2020 and 2019, respectively. During the nine months ended September 30, 2020, the items whose tax impact were recorded discretely related primarily to foreign taxes, as well as stock compensation. For the nine months ended September 30, 2020, the effective tax rate differs from the statutory rate of 21% primarily due to losses attributabl e to non-controlling interests in consolidated subsidiaries and investment funds, foreign taxes, stock compensation, as well as other nondeductible expenses. For th e 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. As a result of the enactment of Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) signed on March 27, 2020, the Company is required to assess the tax impact of the Act in the quarter the law was enacted. Based on the management analysis, there was no material impact on the Company's financial statements as of September 30, 2020. The Company maintained an uncertain tax position liability of $0.3 million as of September 30, 2020 and December 31, 2019 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, 2020, 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 and State of Massachusetts for the 2013 to 2017 tax years and 2016 to 2017 tax years, respectively. Management is not expecting a material tax liability from these audits.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2020
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. The Company records the expenses related to occupancy and equipment on a straight-line basis over the lease term and these expenses 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, 2020 and 2019, quantitative information regarding the Company's operating lease obligations reflected in the accompanying condensed consolidated statements of operations were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (dollars in thousands) Lease cost Operating lease cost $ 5,687 $ 5,748 $ 17,044 $ 17,690 Short-term lease cost 52 23 155 113 Variable lease cost 829 1,156 2,431 2,668 Sublease income (190) (232) (623) (739) Total lease costs $ 6,378 $ 6,695 $ 19,007 $ 19,732 The following table summarizes the supplemental cash flow information and certain other information related to operating leases for the nine months ended September 30, 2020 and 2019: Nine Months Ended September 30, 2020 2019 (dollars in thousands) Other information Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 20,228 $ 19,103 Weighted average remaining lease term - operating leases (in years) 4.78 5.52 Weighted average discount rate - operating leases 3.69 % 4.14 % As of September 30, 2020, maturities of the outstanding operating lease liabilities for the Company were as follows: Equipment Leases (operating) Real Estate and Other Facility Rental (a) (b) (dollars in thousands) 2020 $ 90 $ 4,302 2021 223 24,723 2022 91 21,484 2023 3 18,095 2024 — 14,784 Thereafter — 10,166 Total operating leases 407 93,554 Less discount 25 9,816 Less short-term leases — 76 Total lease liability $ 382 $ 83,662 (a) The Company has entered into various agreements to sublease certain of its premises. (b) During the nine months ended September 30, 2020, the Company recognized $0.3 operating right-of-use assets and leases liabilities increases for facility leases. See Note 18 for further information on the finance lease minimum payments. Other Commitments As of September 30, 2020, future minimum annual service payments for the Company were as follows: Service Payments (dollars in thousands) 2020 $ 8,262 2021 23,563 2022 14,295 2023 7,188 2024 4,351 Thereafter 13,201 Total service payment commitments $ 70,860 Unfunded Commitments The following table summarizes unfunded commitments as of September 30, 2020: Entity Unfunded Commitments Commitment Term (dollars in thousands) HealthCare Royalty Partners funds (a) $ 7,816 4.3 years Eclipse Ventures Fund I, L.P. $ 59 4.3 years Lagunita Biosciences, LLC $ 250 3.1 years Eclipse Fund II, L.P. $ 110 5.3 years Eclipse Continuity Fund I, L.P. $ 58 6.3 years Cowen Healthcare Investments II LP $ 1,201 1.3 years Cowen Healthcare Investments III LP $ 6,164 6.3 years Cowen Sustainable Investments I LP $ 3,926 9.3 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, the Company receives 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.

Convertible Debt and Notes Paya

Convertible Debt and Notes Payable	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Convertible Debt and Notes Payable	Convertible Debt and Notes Payable As of September 30, 2020 and December 31, 2019, the Company's outstanding debt was as follows: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Convertible debt $ 122,485 $ 118,688 Notes payable 307,437 306,818 Term loans — 32,180 Other notes payable 73,253 2,516 Finance lease obligations 3,032 3,937 $ 506,207 $ 464,139 Convertible Debt December 2022 Convertible Notes The Company, on December 14, 2017, issued $135.0 million aggregate principal amount of 3.0% 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. As of September 30, 2020, 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. Pursuant to the indenture governing the December 2022 Convertible Notes, conversions of the December 2022 Convertible Notes will be settled by the delivery and/or payment, as the case may be, of Cowen’s Class A Common Stock, cash, or a combination thereof, at the Company's election. The Company has the intent and ability to settle the convertible notes in cash and, as a result, the convertible notes do not have an impact on the Company's diluted earnings per share calculation (See Note 21). The Company recorded interest expense of $1.0 million and $1.0 million for the three months ended September 30, 2020 and 2019, and $3.0 million and $3.0 million for the nine months ended September 30, 2020 and 2019, 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 $1.2 million and $1.1 million for the three months ended September 30, 2020 and 2019, and $3.5 million and $3.2 million for the nine months ended September 30, 2020 and 2019, 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 in interest and dividends expense in the accompanying condensed consolidated statements of operations. 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 $1.4 million and $0.9 million for three months ended September 30, 2020 and 2019, and $4.2 million and $1.5 million for the nine months ended September 30, 2020 and 2019, respectively. The Company capitalized debt issuance costs of approximately $1.5 million in May 2019 and $0.6 million in December 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 in interest and dividends expense in the accompanying condensed consolidated statements of operations. 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, 2020 and 2019, and $5.8 million and $5.8 million for the nine months ended September 30, 2020 and 2019, 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 in interest and dividends expense in the accompanying condensed consolidated statements of operations. 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, 2020 and 2019,and $7.6 million and $7.6 million for the nine months ended September 30, 2020 and 2019, respectively. The Company capitalized debt issuance costs of approximately $5.0 million which is a direct deduction from the carrying value of the debt and will be amortized over the life of the December 2027 Notes in interest and dividends expense in the accompanying condensed consolidated statements of operations. 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 Loans On June 30, 2017, a subsidiary of the Company borrowed $28.2 million to fund general corporate purposes. In July 2019, the subsidiary of the Company borrowed separately, from the same lender, $4.0 million to fund general corporate purposes. Each loan was secured by the value of the Company's limited partnership interests in two affiliated investment funds. The Company had provided a guarantee for these loans. Both loans had an effective interest rate of LIBOR plus 3.75% with a lump sum payment of the entire combined principal amount due (as amended) on June 26, 2020 when they were both fully repaid. The Company recorded interest expense of $0.5 million for the three months ended September 30, 2019, and $0.8 million and $1.4 million for the nine months ended September 30, 2020 and 2019, respectively. Other Notes Payable During January 2020, the Company borrowed $2.9 million to fund insurance premium payments. This note had an effective interest rate of 2.01% and was due in December 2020, with monthly payment requirements of $0.3 million. As of September 30, 2020, the outstanding balance on this note was $0.8 million. Interest expense for the three and nine months ended September 30, 2020 and 2019 was insignificant. During November 2019, the Company borrowed $2.6 million to fund general corporate capital expenditures. This note had an effective interest rate of 6% and is due in November 2024, with monthly payment requirements of $0.1 million. As of September 30, 2020, the outstanding balance on this note was $2.2 million. Interest expense for the nine months ended September 30, 2020 was $0.1 million. On September 30, 2020, the Company borrowed $72 million from Purple Protected Asset S-91 ("PPA S-91"), a Luxembourg entity unrelated to Cowen. The loan is payable on September 30, 2023, has an interest rate of 1.4 times the Secured Overnight Financing Rate ("SOFR") plus 6.07% until December 31, 2020 and 1.4 times the SOFR plus 5.8% thereafter with quarterly interest payments. The loan obligation, as well as a loan issued by The Military Mutual Ltd (a United Kingdom company unrelated to Cowen) with principal of $28.4 million that was sold by Hollenfels to PPA S-91 at fair value for no gain or loss on September 30, 2020, are fully cash collateralized through a reinsurance policy provided by Hollenfels which is reflected in cash collateral pledged in the consolidated statements of financial condition as of September 30, 2020 (see Notes 4 and 14). The Company capitalized debt issuance costs of approximately $1.7 million which is a direct deduction from the carrying value of the loan and will be amortized over the life of the loan in interest and dividends expense in the accompanying condensed consolidated statements of operations. There was no interest expense as of September 30, 2020. Spike Line Pursuant to an amendment in May 2020, Cowen and Company replaced Cowen Execution as the borrower and accepted, reaffirmed and assumed all of Cowen Execution’s rights, duties, obligations and liabilities under the spike line facility and the related loan documents. In August 2020, Cowen and Company renewed a one-year committed spike line facility to cover short term increases in National Securities Clearing Corporation margin deposit requirements. The spike line facility has a capacity of $70 million. This facility has (i) an effective interest rate equal to the Federal Funds rate plus 2.50% on any money drawn from the liquidity facility and (ii) a commitment or unused line fee that is 50 basis points on the undrawn amount. All amounts outstanding under this facility were fully repaid during the second quarter of 2020. Interest expense for the three and nine months ended September 30, 2020 was $0.0 million and $0.2 million, respectively. Revolving Credit Facility In December 2019, the Company entered into a two-year committed corporate credit facility with a capacity of $25 million. This credit facility has (i) an effective interest rate equal to LIBOR plus 3.25% on any money drawn from the credit facility and (ii) a commitment or unused line fee that is 50 basis points on the undrawn amount. All amounts outstanding under this corporate credit facility were fully repaid during the second quarter of 2020. Interest expense for the nine months ended September 30, 2020 was $0.3 million. Finance Lease Obligations The Company has entered into various finance leases for computer equipment. These finance lease obligations are included in notes payable and other debt in the accompanying condensed consolidated statements of financial condition. For the three and nine months ended September 30, 2020 and 2019, quantitative information regarding the Company's finance lease obligations reflected in the accompanying condensed consolidated statements 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, 2020 2019 2020 2019 (dollars in thousands) Lease cost Finance lease cost: Amortization of finance lease right-of-use assets $ 308 $ 299 $ 924 $ 966 Interest on lease liabilities $ 42 $ 54 $ 134 $ 172 Other information Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from finance leases $ 134 $ 172 Financing cash flows from finance leases $ 901 $ 951 Weighted average remaining lease term - operating leases (in years) 2.48 3.40 Weighted average discount rate - operating leases 4.89 % 4.93 % Annual scheduled maturities of debt and minimum payments (of principal and interest) for all debt outstanding as of September 30, 2020, are as follows: Convertible Debt Notes Payable Other Notes Payable Finance Lease (dollars in thousands) 2020 $ 2,025 $ 7,300 $ 933 $ 251 2021 4,050 23,548 593 1,396 2022 139,050 23,548 593 1,165 2023 — 23,548 72,593 411 2024 — 98,721 543 11 Thereafter — 334,304 — — Subtotal 145,125 510,969 75,255 3,234 Less (a) (22,640) (203,532) (2,002) (202) Total $ 122,485 $ 307,437 $ 73,253 $ 3,032 (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 Company's convertible debt. Letters of Credit As of September 30, 2020, the Company has six 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 cash collateral for re insurance agreements (See Note 4). To the extent any letter of credit is drawn upon, interest will be assessed at the prime commercial lending rate. As of September 30, 2020 and December 31, 2019 there were no amounts due related to these letters of credit.

Stockholder's Equity

Stockholder's Equity	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Stockholder's Equity	Stockholder's Equity Preferred Stock 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, 2020 and 2019 and $5.1 million and $5.1 million for the nine months ended September 30, 2020 and 2019, 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 dividend 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, when the Company's capped call option expired, 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. The Company has the intent and ability to settle the preferred shares in cash and, as a result, the preferred shares do not have an impact on the Company's diluted earnings per share calculation (See Note 21). 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. Cash Dividends to Common Stockholders During the first quarter of 2020, the Company began the declaration of a quarterly cash dividend payable on its common stock. During March, June and July 2020, the Board of Directors declared a cash dividend of $0.04 per common share. Dividends are payable on all outstanding shares and on granted but unvested shares under the Equity Plans on the date of record (See Note 15). During the three and nine months ended September 30, 2020, the Company paid $1.1 million and $3.4 million, respectively, of cash dividends to its common stockholders. Treasury Stock Treasury stock of $334.1 million as of September 30, 2020, compared to $284.3 million as of December 31, 2019, resulted from $6.3 million acquired through repurchases of shares to cover employee minimum tax withholding obligations related to stock compensation vesting events under the Equity Plans or other similar transactions, $0.10 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 $43.4 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, 2020: Treasury Stock Shares Cost Average Cost per Share Balance outstanding at December 31, 2019 18,605,581 $ 284,301 $ 15.28 Shares purchased for minimum tax withholding under the 2010 Equity Plan or other similar transactions 505,702 6,296 12.45 Shares of stock received in respect of indemnification claims 7,026 96 13.66 Purchase of treasury stock 2,974,711 43,442 14.60 Balance outstanding at September 30, 2020 22,093,020 $ 334,135 $ 15.12

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2020
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, 2020 2019 2020 2019 (dollars in thousands) Beginning balance $ (5) $ (3) $ (5) $ (5) Foreign currency translation (2) (2) (2) — Ending balance $ (7) $ (5) $ (7) $ (5)

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per ShareBasic 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, 2020, there were 26,569,335 shares of Class A common stock outstanding. As of September 30, 2020, the Company has included 259,536 fully vested, unissued restricted stock units in its calculation of basic earnings per share. As of December 31, 2019, there were 28,610,357 shares of Class A common stock outstanding. As of December 31, 2019, the Company has included 216,912 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 SARs. 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, 2020 2019 2020 2019 (dollars and share data in thousands, except per share data) Net income (loss) $ 29,516 $ 6,583 $ 104,353 26,596 Net income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds 9,232 2,770 (19,843) 7,188 Net income (loss) attributable to Cowen Inc. 20,284 3,813 124,196 19,408 Preferred stock dividends 1,698 1,698 5,094 5,094 Net income (loss) attributable to Cowen Inc. common stockholders $ 18,586 $ 2,115 $ 119,102 $ 14,314 Shares for basic and diluted calculations: Weighted average shares used in basic computation 27,663 29,529 28,078 29,687 Contingently issuable common stock in connection with an acquisition (see Note 3) 22 — 22 — Restricted stock 2,285 1,735 1,546 1,694 Weighted average shares used in diluted computation 29,970 31,264 29,646 31,381 Earnings (loss) per share: Basic $ 0.67 $ 0.07 $ 4.24 $ 0.48 Diluted $ 0.62 $ 0.07 $ 4.02 $ 0.46

Segment Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting The Company has two reportable business segments: Op Co and Asset Co. The Op Co segment consists of CIM, Investment Banking, Markets and Research. The Asset Co segment consists of the Company's private investments, private real estate investments and other legacy investment 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) includes management reclassifications which the Company believes provides additional insight on the performance of the Company’s core businesses and divisions (ii) eliminates the impact of consolidation for Consolidated Funds and excludes (iii) goodwill and intangible impairment (iv) certain other transaction-related adjustments and/or reorganization expenses and (v) certain costs associated with debt. 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. 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, excluding non-controlling interests, 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 consolidated US GAAP net income (loss) and related reclassifications and adjustments necessary to reconcile to the Company's Economic Income (Loss) measure which represents the Company's Op Co and Asset Co segments' results: Three Months Ended September 30, 2020 US GAAP Reclassifications and Adjustments Economic Income Net income (loss) Management Reclassifications Fund Consolidation Reclassifications (k) Income Statement Adjustments Operating Company Asset Company (dollars in thousands) Revenues Economic Proceeds Investment banking $ 194,341 $ (9,190) a, b $ — $ — Investment banking $ 185,151 $ — Brokerage 138,483 28,601 c, h — — Brokerage 167,084 — Management fees 11,954 2,519 d, e 163 — Management fees 14,374 262 Incentive income (loss) 127 (1,462) e 33 — Incentive income (loss) (2,621) 1,319 — (90,488) f — — Investment income (loss) (90,364) (124) Interest and dividends 37,552 (37,552) c — — — — Reimbursement from affiliates 269 (269) b — — — — Reinsurance premiums 2,505 (2,505) g — — — — Other revenue 1,369 (2,160) g (3) — Other revenues (796) 2 Consolidated Funds revenues 1,135 — (1,135) — — — Total revenues 387,735 (112,506) (942) — Total Economic proceeds 272,828 1,459 Interest and dividend expense 37,754 (29,467) c — (1,152) l Interest expense 6,026 1,109 Total net revenues 349,981 (83,039) (942) 1,152 Total Economic net proceeds 266,802 350 Expenses Economic Costs Compensation & benefits 153,427 359 i — — Compensation & Benefits 152,829 957 — 37,708 e, j — (3,324) m Fixed non-compensation expense 34,257 127 — 37,742 j — — Variable non-compensation expense 37,736 6 Other non-compensation expenses 89,636 (89,636) a, b, d, g, i — — — — Depreciation & amortization 5,682 — — (7) n Depreciation & Amortization 5,670 5 — 2,105 j — — Economic Non-Controlling Interest 2,105 — Consolidated Funds expenses 494 — (494) — — — Total expenses 249,239 (11,722) (494) (3,331) Total Economic costs 232,597 1,095 Other income (loss) (62,396) 64,896 e, f, h (2,500) — — — — — — 1,698 Preferred stock dividends 1,415 283 Income (loss) before income taxes $ 38,346 $ (6,421) * $ (2,948) * $ 2,785 Economic income (loss) $ 32,790 $ (1,028) Three Months Ended September 30, 2019 US GAAP Reclassifications and Adjustments Economic Income Net income (loss) Management Reclassifications Fund Consolidation Reclassifications (k) Income Statement Adjustments Operating Company Asset Company (dollars in thousands) Revenues Economic Proceeds Investment banking $ 77,292 $ (7,859) a, b $ — $ — Investment banking $ 69,433 $ — Brokerage 93,995 16,183 c, h — — Brokerage 110,178 — Management fees 7,300 3,033 d, e 574 — Management fees 10,321 586 Incentive income (loss) 701 13,675 e 13 — Incentive income (loss) 15,251 (862) — 11,735 f — — Investment income (loss) 10,913 822 Interest and dividends 60,707 (60,707) c — — — — Reimbursement from affiliates 238 (265) b 27 — — — Reinsurance premiums 8,146 (8,146) g — — — — Other revenue 1,237 (1,389) g 26 — Other revenues (132) 6 Consolidated Funds revenues 2,431 — (2,431) — — — Total revenues 252,047 (33,740) (1,791) — Total Economic proceeds 215,964 552 Interest and dividend expense 56,477 (48,238) c — (1,092) l Interest expense 5,758 1,389 Total net revenues 195,570 14,498 (1,791) 1,092 Total Economic net proceeds 210,206 (837) Expenses Economic Costs Compensation & benefits 120,320 2,299 i — — Compensation & Benefits 121,890 729 — 37,559 e, j — (476) m Fixed non-compensation expense 36,458 625 — 37,256 j — — Variable non-compensation expense 37,216 40 Other non-compensation expense 92,046 (92,046) a, b, d, g, i — — — — Depreciation & amortization 5,082 — — — Depreciation & Amortization 5,073 9 — 661 j — — Economic Non-Controlling Interest 661 — Consolidated Funds expenses 2,516 — (2,516) — — — Total expenses 219,964 (14,271) (2,516) (476) Total Economic costs 201,298 1,403 Other income (loss) 32,342 (26,721) e, f, h (5,621) — — — — — — 1,698 Preferred stock dividends 1,341 357 Income (loss) before income taxes $ 7,948 $ 2,048 * $ (4,896) * $ (130) Economic income (loss) $ 7,567 $ (2,597) Nine Months Ended September 30, 2020 US GAAP Reclassifications and Adjustments Economic Income Net income (loss) Management Reclassifications Fund Consolidation Reclassifications (k) Income Statement Adjustments Operating Company Asset Company (dollars in thousands) Revenues Economic Proceeds Investment banking $ 503,351 $ (28,573) a, b $ — $ — Investment banking $ 474,778 $ — Brokerage 425,069 41,754 c, h — — Brokerage 466,823 — Management fees 35,211 5,672 d, e 1,475 — Management fees 41,724 634 Incentive income (loss) 127 40,827 e 33 — Incentive income (loss) 40,829 158 — 18,895 f — — Investment income (loss) 32,566 (13,671) Interest and dividends 127,547 (127,547) c — — — — Reimbursement from affiliates 777 (827) b 50 — — — Reinsurance premiums 18,943 (18,943) g — — — — Other revenue 4,709 (4,982) g (21) — Other revenues (298) 4 Consolidated Funds revenues 4,650 — (4,650) — — — Total revenues 1,120,384 (73,724) (3,113) — Total Economic proceeds 1,056,422 (12,875) Interest and dividend expense 125,850 (99,971) c — (3,394) l Interest expense 18,471 4,014 Total net revenues 994,534 26,247 (3,113) 3,394 Total Economic net proceeds 1,037,951 (16,889) Expenses Economic Costs Compensation & benefits 583,137 1,436 i — — Compensation & Benefits 582,480 2,093 — 111,880 e, j — (5,152) m Fixed non-compensation expense 106,350 378 — 121,864 j — — Variable non-compensation expense 121,846 18 Other non-compensation expense 286,666 (286,666) a, b, d, g, i — — — — Depreciation & amortization 17,324 — — (551) n Depreciation & Amortization 16,756 17 — 5,584 j — — Economic Non-Controlling Interest 5,584 — Consolidated Funds expenses 4,793 — (4,793) — — — Total expenses 891,920 (45,902) (4,793) (5,703) Total Economic costs 833,016 2,506 Other income (loss) 54,328 (82,006) e, f, h 27,678 — — — — — — 5,094 Preferred stock dividends 4,160 934 Income (loss) before income taxes $ 156,942 $ (9,857) * $ 29,358 * $ 4,003 Economic income (loss) $ 200,775 $ (20,329) Nine Months Ended September 30, 2019 US GAAP Reclassifications and Adjustments Economic Income Net income (loss) Management Reclassifications Fund Consolidation Reclassifications (k) Income Statement Adjustments Operating Company Asset Company (dollars in thousands) Revenues Economic Proceeds Investment banking $ 272,103 $ (17,729) a, b $ — $ — Investment banking $ 254,374 $ — Brokerage 302,840 43,255 c, h — — Brokerage 346,095 — Management fees 21,480 8,684 d, e 1,640 — Management fees 30,016 1,788 Incentive income (loss) 724 33,479 e 557 — Incentive income (loss) 33,998 762 — 19,116 f — — Investment income (loss) 13,827 5,289 Interest and dividends 129,846 (129,846) c — — — — Reimbursement from affiliates 780 (874) b 94 — — — Reinsurance premiums 29,068 (29,068) g — — — — Other revenue 3,228 2,109 g 14 — Other revenues 5,295 56 Consolidated Funds revenues 8,239 — (8,239) — — — Total revenues 768,308 (70,874) (5,934) — Total Economic proceeds 683,605 7,895 Interest and dividend expense 125,089 (101,464) c — (3,208) l Interest expense 16,371 4,046 Total net revenues 643,219 30,590 (5,934) 3,208 Total Economic net proceeds 667,234 3,849 Expenses Economic Costs Compensation & benefits 388,611 2,365 i — — Compensation & Benefits 386,593 4,383 — 112,038 e, j — (1,664) m Fixed non-compensation expense 107,889 2,485 — 113,855 j — — Variable non-compensation expense 113,728 127 Other non-compensation expense 276,054 (276,054) a, b, d, g, i — — — — Depreciation & amortization 14,990 (3) — — Depreciation & Amortization 14,957 30 — 2,944 j — — Economic Non-Controlling Interest 2,944 — Goodwill impairment 4,100 — — (4,100) n — — Consolidated Funds expenses 6,229 — (6,229) — — — Total expenses 689,984 (44,855) (6,229) (5,764) Total Economic costs 626,111 7,025 Other income (loss) 82,976 (73,907) e, f, h (9,069) — — — — — — 5,094 Preferred stock dividends 4,058 1,036 Income (loss) before income taxes $ 36,211 $ 1,538 * $ (8,774) * $ 3,878 Economic income (loss) $ 37,065 $ (4,212) Adjustments made to US GAAP Net Income (Loss) to arrive at Economic Income (Loss) Management Reclassifications Management reclassification adjustments and fund consolidation reclassification adjustments have no effect on economic income. These adjustments are reclassifications to change the location of certain line items. a Economic Income (Loss) presents underwriting expenses net of investment banking revenues. b Economic Income (Loss) presents expenses reimbursed from clients and affiliates within their respective expense category but is included as a part of revenues under US GAAP. c 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. d Economic Income (Loss) presents revenues net of fund start-up costs and distribution fees paid to agents. e Economic Income (Loss) recognizes the Company's proportionate share of management and incentive fees and associated share of expenses on a gross basis for certain real estate operating entities, the healthcare royalty business and the activist business. Additionally, carried interest, which the Company applies an equity ownership model to, is recorded in other income (loss) for US GAAP and is shown as incentive income for Economic Income (Loss). f Economic Income (Loss) recognizes Company income from proprietary trading (including interest and dividends) for which the majority of this activity is shown in other income (loss) for US GAAP reporting. g Economic Income (Loss) recognizes underwriting income from the Company's insurance related activities, net of expenses, within other revenue. The costs are recorded within expenses for US GAAP reporting. h Economic Income (Loss) recognizes gains and losses on investments held as part of the Company's facilitation and trading business within brokerage revenues as these investments are directly related to the markets business activities. i Economic Income (Loss) presents certain payments to associated banking partners as compensation rather than non-compensation expenses. j Economic Income (Loss) presents US GAAP expenses as either Fixed non-compensation or Variable non-compensation expenses. The Company also presents US GAAP Income (loss) attributable to non-controlling interests within total other expenses for Economic Income (Loss). * The remainder primarily represents non-controlling interest which is excluded from this reconciliation to income (loss) before income taxes. Fund Consolidation Reclassifications k 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). * The remainder primarily represents non-controlling interest which is excluded from this reconciliation to income (loss) before income taxes. Income Statement Adjustments l Economic Income (Loss) excludes the amortization of discount on convertible debt. m Economic Income (Loss) excludes acquisition related adjustments as management does not consider these items when evaluating the performance of the Company. n Economic Income (Loss) excludes goodwill and intangible impairment.

Regulatory Requirements

Regulatory Requirements	9 Months Ended
	Sep. 30, 2020
Brokers and Dealers [Abstract]
Regulatory Requirements	Regulatory Requirements As registered broker-dealers, Cowen and Company, 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 that rule. Under the alternative method, Cowen and Company's minimum net capital requirement, as defined in (a)(4) of SEC Rule 15c3-1, is $1.0 million or 2% of aggregate debits arising from customer transactions. ATM Execution, Cowen Prime and Westminster are required to maintain minimum net capital, as defined in (a)(1)(ii) of SEC Rule 15c3-1, 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 provisions of SEC Rule 15c3-1 and other regulatory bodies. On May 1, 2020, Cowen and Company completed its merger with Cowen Execution. Cowen and Company is the surviving entity. The merger had no impact to the Company’s financial results. Cowen Prime is also subject to Commodity Futures Trading Commission ("CFTC") 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 and Company 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, 2020, Cowen and Company ha d $385.6 million of net capital in excess of this minimum requirement. Cowen International Ltd and Cowen Ex ecution Ltd are subject to the capital requirements of the FCA, as defined, and must exceed the minimum capital requirement set forth by the FCA. 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, 2020, these regulated broker-dealers had regulatory net capital or financial resources, regulatory net capital requirements or minimum FCA or SFC requirement and excess as follows: Subsidiary Net Capital Minimum Net Capital Requirement Excess Net Capital (dollars in thousands) Cowen and Company $ 388,606 $ 3,043 $ 385,563 ATM Execution $ 4,015 $ 250 $ 3,765 Cowen Prime $ 19,432 $ 250 $ 19,182 Westminster $ 5,305 $ 250 $ 5,055 Cowen International Ltd $ 22,892 $ 17,882 $ 5,010 Cowen Execution Ltd $ 11,501 $ 4,333 $ 7,168 Cowen Asia $ 1,394 $ 387 $ 1,007 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 Prime and ATM Execution claim the (k)(2)(ii) exemption with regard to 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 Prime and Westminster claim the (k)(2)(i) exemption with regards to customer transactions and balances that are cleared, settled and custodied in bank accounts designated as Special Accounts for the Exclusive Benefit of Customers ("Special Bank Accounts"). In accordance with the requirements of SEC Rule 15c3-3, Cowen and Company 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, 2020, Cowen and Company had segregated approximately $43.9 million of cash, while its required deposit was $20.5 million . As a clearing broker-dealer, Cowen and Company is required to compute a reserve requirement for proprietary accounts of broker-dealers ("PAB"), as defined in SEC Rule 15c3-3. Cowen and Company 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 and Company as its clearing broker-dealer to classify its PAB account assets held at Cowen and Company as allowable assets in the correspondent's net capital calculation. At September 30, 2020, Cowen and Company had $35.2 million of cash on deposit in PAB Reserve Bank Accounts, which was more than its required deposit of $16.6 million. Cowen and Company, ATM Execution, and Cowen Prime 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. The Dodd-Frank Wall Street Reform and Consumer Protection Act (the “Dodd-Frank Act”) was signed into law on July 21, 2010. The Dodd-Frank Act contains provisions that require the registration of all swap dealers, major swap participants, security-based swap dealers, and/or major security-based swap participants. The CFTC has finalized rules establishing capital requirements and financial reporting requirements for CFTC registered swap dealers not subject to regulation by a banking regulator, while the SEC is still finalizing its rules. The Company may be required in the future to register one or more subsidiaries as security-based swap dealers with the SEC and will result in some of the Company’s subsidiaries becoming subject to regulatory capital requirements for the first time. 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, 2019, 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, 2020, 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, 2020. RCG Insurance Company’s capital and surplus as of September 30, 2020 totaled approximately $6.1 million.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2020
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, 2020 and December 31, 2019, $22.6 million and $20.5 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, 2020 and 2019, 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, 2020 and December 31, 2019, loans to employees of $11.3 million and $14.9 million, respectively, were included in due from related parties on the accompanying condensed consolidated statements of financial condition. Of these amounts $4.9 million and $7.1 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 As of September 30, 2020 and December 31, 2019, included in due from related parties is $4.8 million and $6.5 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 five The remaining balance included in due from related parties of $7.4 million and $5.3 million as of September 30, 2020 and December 31, 2019, 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 $0.2 million and $0.3 million as of September 30, 2020 and December 31, 2019, 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. 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, 2020 and December 31, 2019, such investments aggregated $192.0 million and $36.0 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 $6.7 million and $3.6 million for the three months ended September 30, 2020 and 2019 and $10.7 million and $4.7 million for the nine months ended September 30, 2020 and 2019, respectively.

Guarantees and Off-Balance Shee

Guarantees and Off-Balance Sheet Arrangements	9 Months Ended
	Sep. 30, 2020
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, 2020 and December 31, 2019. 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, 2020. 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 Spike Line BMO Harris Bank Canadian Imperial Bank of Commerce Texas Capital Bank 70,000 70,000 August 20, 2021 Unsecured committed spike line facility to cover short term increases in National Securities Clearing Corporation margin deposit requirements Revolving Credit Facility BMO Harris Bank 25,000 25,000 December 2, 2021 Unsecured Corporate Revolver Total Credit Lines $ 395,000 $ 395,000

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2020
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On October 1, 2020 (the "MHT Acquisition Date"), the Company, through its indirect wholly owned subsidiary, Cowen and Company, completed its previously announced acquisition (the "MHT Acquisition") of specified net assets of MHT Partners, LP (“MHT Partners”). MHT Partners is an investment bank, based primarily in Dallas and San Francisco, focused on representing innovative companies in growing markets. The MHT Acquisition was completed for a combination of cash and contingent consideration. The contingent consideration is paid after December 2023 and is valued based on a multiple of three year average annual revenues of the acquired business less certain expenses. Due to the limited time since the date of the MHT Acquisition, it is impractical for the Company to make certain business combination disclosures as of the date of this filing as the Company is still finalizing the analysis of the information necessary to provide these disclosures. As a result, the Company is unable to present the allocation of the preliminary purchase price to the fair value of assets acquired and liabilities assumed. The Company plans to provide this information in its annual report on Form 10-K for the year ended December 31, 2020. The MHT Acquisition will be accounted for under the acquisition method in accordance with US GAAP. As such, the results of operations associated with the specified net assets purchased from MHT Partners will be included in the Company's condensed consolidated statements of operations as of the MHT Acquisition Date, and the assets acquired and liabilities assumed will be recorded at their fair value as of the MHT Acquisition Date. Subsequent to the MHT Acquisition, the operations associated with the purchase of specified net assets from MHT Partners will be integrated within the Company's investment bank segment. On October 21, 2020, the Board of Directors declared a quarterly cash dividend payable on its common stock of $0.08 per common share, payable on December 15, 2020, to stockholders of record on December 1, 2020. During the same meeting, the Board of Directors also approved a $19.7 million increase in the Company's share repurchase program (see Note 19) bringing the total remaining shares available for repurchase to $25.0 million.

Significant Accounting Polici_2

Significant Accounting Policies - Quarterly (Policies)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Basis of presentation	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 on consolidation. Certain investment funds 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 specialized industry accounting. The accompanying financial statements should be read in conjunction with the Company’s financial statements and notes thereto included in the our Annual Report on Form 10-K for the year ended December 31, 2019 (the "2019 Form 10-K"). Certain footnote disclosures included in the 2019 Form 10-K have been condensed or omitted from these financial statements as they are not required for interim reporting under US GAAP or are insignificant to the interim reporting period.
Principles of consolidation	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. The Company consolidates five investment funds for which it acts as the managing member/general partner and investment manager. At September 30, 2020 , the Company consolidated the following investment funds: Ramius Enterprise LP (“Enterprise LP”), Cowen Private Investments LP ("Cowen Private"), Cowen Sustainable Investments I LP ("CSI I LP"), CSI I Golden Holdco LP ("Golden HoldCo") and CSI I Prodigy Holdco LP ("Prodigy HoldCo") (each a "Consolidated Fund" and collectively the "Consolidated Funds"). During the second quarter of 2020, the Company deconsolidated Ramius Merger Fund LLC (the "Merger Fund") and UCITS Fund ("UCITS Fund") due to a partial redemption of the Company’s direct portfolio fund investment in Merger Fund and a partial termination of the notional value of UCITS Fund units referenced in a total return swap with a third party. The Company continues to hold a direct retained portfolio fund investment in the Merger Fund and continues to have economic exposure to the returns of UCITS Fund through a total return swap with a third party. Both Merger Fund and UCITS Fund continue to be related parties of the Company after deconsolidation. 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 consolidation requirements, 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 determines whether it is the primary beneficiary of a VIE upon its initial involvement with the VIE and reassesses whether it is the primary beneficiary on an ongoing basis as long as it has any continuing involvement with the 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, 2020, the total assets and total liabilities of the consolidated VIEs were $449.0 million and $6.6 million, respectively. As of December 31, 2019, the total assets and total liabilities of the consolidated VIEs were $685.4 million and $24.9 million, respectively. The deconsolidation of two Consolidated Funds decreased the 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. At December 31, 2019, the Company held a variable interest in Ramius Merger Master Fund Ltd ("Merger Master" or the "Unconsolidated Master Fund") through the consolidated Merger Fund. 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 had not consolidated the Unconsolidated Master Fund. 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 Company does not consolidate the Unconsolidated Master Fund or real estate funds that are VIEs due to the Company's conclusion that it is not the primary beneficiary of these funds 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 a general partner and a 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), 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. 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.
Use of estimates	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.
Allowance for credit losses	Allowance for credit losses Effective January 1, 2020, the Company adopted ASC Topic 326, Financial Instruments – Credit Losses (“ASC 326”). ASC 326 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. 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 or based on the credit quality of the borrower or issuer). The Company identified securities borrowed and fees and other receivables carried at amortized cost (including, but not limited to, receivables related to securities transactions, corporate finance and syndicate receivables, management fees and incentive fees receivable) as impacted by the new guidance. ASC 326 specifies that the Company adopt the new guidance prospectively by means of a cumulative-effect adjustment to the opening retained earnings as of the beginning of the first reporting period effective. Accordingly, the Company recognized a cumulative effective adjustment of $0.01 million upon adoption. The allowance for credit losses is based on the Company's expectation of the collectability of financial instruments carried at amortized cost, including securities borrowed and fees and other receivables utilizing the CECL framework. The Company considers factors such as historical experience, credit quality, age of balances and current and future economic conditions that may affect the Company’s expectation of the collectability in determining the allowance for credit losses. The Company’s expectation is that the credit risk associated with fees and other receivables is not significant until they are 90 days past due based on the contractual arrangement and expectation of collection in accordance with industry standards. For securities borrowed, the Company applies 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 Company applies the CECL model, utilizing a probability and loss given default methodology, only to the extent of the shortfall between the fair value of the collateral and amortized cost. 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. Inputs reflect unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. 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 based on their proportional rights of the underlying portfolio company, and 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 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. 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, are classified as level 2 when their inputs can be corroborated by market data. OTC derivatives, such as swaps and options, with significant inputs that cannot be corroborated by readily available or observable market data are classified as level 3. Other Investments —Other investments consist primarily of portfolio funds, real estate investments, carried interest and equity method investments, which are valued as follows: i. Portfolio Funds— Portfolio funds (“Portfolio Funds”) include 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 applies the practical expedient provided by the US GAAP fair value measurements and disclosures guidance relating to investments in certain entities that calculate net asset value (“NAV”) per share (or its equivalent). The practical expedient permits an entity holding investments in certain entities that either are investment companies or have attributes similar to an investment company, and calculate NAV per share or its equivalent for which the fair value is not readily determinable, to measure the fair value of such investments on the basis of that NAV per share, or its equivalent, without adjustment. 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 measured 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. iii. Carried Interest— For the private equity and debt fund products the Company offers, the Company is allocated incentive income by the investment funds based on the extent by which the investment funds performance exceeds predetermined thresholds. Carried interest allocations are generally structured from a legal standpoint as an allocation of capital in the Company’s capital account. The Company accounts for carried interest allocations by applying an equity ownership model. Accordingly, the Company accrues performance allocations quarterly based on the fair value of the underlying investments assuming hypothetical liquidation at book value. iv. 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 applies 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.
Receivable from and payable to brokers	Receivable from and payable to brokers Receivable from brokers, dealers, and clearing organizations includes amounts receivable for securities failed to deliver by the Company to a purchaser by the settlement date, amounts receivable from broker-dealers and clearing organizations, commissions receivable from broker-dealers, and interest receivable from securities financing arrangements. Payable to brokers, dealers and clearing organizations includes amounts payable for securities failed to receive by the Company from a seller by the settlement date, amounts payable to broker-dealers and clearing organizations for unsettled trades, interest payable for securities financing arrangements, and payables of deposits held in proprietary account of brokers and dealers. Pursuant to the master netting agreements the Company has entered into with its brokers, dealers and clearing organizations, receivables and payables arising from unsettled trade 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.
Receivable from and payable to customers	Receivable from and payable to customers Receivable from customers includes amounts owed by customers on cash and margin transactions, recorded on a settlement-date basis and prepaid research, net of allowance for credit losses. For prepaid research, a prepaid research asset is established for research and related services disbursed in advance of anticipated client commission volumes. Payable to customers primarily consists of amounts owed to customers relating to securities transactions not completed on settlement date, recorded on a settlement-date basis on the statement of financial condition, and other miscellaneous customer payables. Securities owned by customers, including those that collateralize margin, are not reflected as assets of the Company on the statement of financial condition. The Company holds these securities with the intention of settlement against customer orders and are held as collateral for customer receivables.
Fees receivable	Fees receivable Fees related to security transactions are reported net of an allowance for credit losses. 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 2m).
Securities financing arrangements	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. See Note 2d for further information. 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, 2020 and December 31, 2019, 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, 2020 and December 31, 2019, the Company did not have any repos for which fair value basis of accounting was elected.
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 accordance with US GAAP requirements for testing for impairment of goodwill, 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. Intangible assets
Non-controlling interests in consolidated subsidiaries	Non-controlling interests in consolidated subsidiariesNon-controlling interests represent the pro rata share of the income or loss of the non-wholly owned consolidated entities attributable to the other owners of such entities. When non-controlling interest holders have redemption features that can be exercised at the option of the holder currently or contingent upon the occurrence of future events, their ownership has been classified as temporary equity. The remaining non-controlling interests have been classified in permanent equity as the non-controlling interests are either not redeemable at the option of the holder or the holder does not have the unilateral right to redeem its ownership interests
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. Asset Company The Asset Co segment generates revenue through 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 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 placement agency 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 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. Commission 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 research fees. Equity research fees are paid to the Company for providing access to equity 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 international customers of the Company's broker-dealers have executed equity 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 research fees are recognized over the contract period as the customer is benefiting from the research throughout the contract term. When the equity 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 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 1% 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 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 30% 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 crystallized. 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 its 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 Company is generated from investing the Company's capital in various strategies. Investments transactions and related income/expenses Purchases and sales of securities, net of commissions, derivative contracts, and the related revenues and expenses are recorded on a trade-date basis with net trading gains and losses included as a component of net gains (losses) on securities, derivatives and other investments, and with respect to the Consolidated Funds and other real estate entities as a component of net realized and unrealized gains (losses) on investments and other transactions and net realized and unrealized gains (losses) on derivatives, respectively, in the accompanying condensed consolidated statements of operations. 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 in accordance with US GAAP and market convention for the imputation of interest of the host financial instrument. 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.
Income taxes	Income taxes The Company accounts for income taxes in accordance with US GAAP which requires the recognition of tax benefits or expenses based on the estimated future tax effects of temporary differences between the financial statement and tax basis of its assets and liabilities. The effect on deferred taxes of a change in tax rates is recognized as income or loss in the period that includes the enactment date. Valuation allowances are established to reduce deferred tax assets to an amount that is more likely than not to be realized. The Company evaluates its deferred tax assets for recoverability considering negative and positive evidence, including its historical financial performance, projections of future taxable income, future reversals of existing taxable temporary differences, and tax planning strategies. The Company records a valuation allowance against its deferred tax assets to bring them to a level that it is more likely than not to be utilized. In evaluating the need for a valuation allowance, the Company estimates future taxable income based on management approved business plans. This process involves significant management judgment about assumptions that are subject to change from period to period. Because the recognition of deferred tax assets requires management to make significant judgments about future earnings, the periods in which items will impact taxable income and the application of inherently complex tax laws the Company has identified the assessment of deferred tax assets and the need for any related valuation allowance as a critical accounting estimate. US GAAP clarifies the accounting for uncertainty in income taxes recognized in an enterprise's financial statements, requiring the Company to determine whether a tax position is more likely than not to be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. For tax positions meeting the more likely than not threshold, the tax amount recognized in the financial statements is reduced by the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement with the relevant taxing authority. The Company recognizes accrued interest and penalties related to its uncertain tax positions as a component of income tax expense. In accordance with federal and state tax laws, the Company and its subsidiaries file consolidated federal, state, and local income tax returns as well as stand-alone state and local tax returns. The Company also has subsidiaries that are residents in foreign countries where tax filings have to be submitted on a stand-alone or combined basis. These subsidiaries are subject to taxes in their respective countries and the Company is responsible for and therefore reports all taxes incurred by these subsidiaries in the condensed consolidated statements of operations. The foreign jurisdictions where the Company owns subsidiaries and has tax filing obligations are the United Kingdom, Luxembourg, Gibraltar, Germany, Switzerland, South Africa, Canada and Hong Kong.
Recent pronouncements	Recent pronouncements Recently adopted In October 2018, the FASB issued guidance that made targeted changes to the related party consolidation guidance. The accounting standard update aligns the evaluation of whether a decision maker's fee is a variable interest with the guidance in the primary beneficiary test by requiring the decision maker to consider an indirect interest in a VIE held by a related party under common control on a proportionate basis. The standard became effective for the Company in the first quarter of 2020 and was adopted retrospectively with no impact to current and previous consolidation conclusions. In August 2018, the FASB issued guidance for accounting for upfront costs and fees paid by a customer in a cloud computing arrangement. The accounting standard aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal use software. The standard became effective for the Company in the first quarter of 2020 and was adopted prospectively. In June 2016, the FASB issued guidance that impacts the impairment model for certain financial assets measured at amortized cost by requiring CECL methodology to estimate expected credit losses over the entire life of the financial asset, recorded at inception or purchase. The guidance became effective for the Company in the first quarter of 2020. Please refer to Note 2d. for more information. In December 2019, the FASB issued guidance simplifying the accounting for income taxes. The guidance simplifies the accounting for income taxes by removing the following exceptions (i) the incremental approach for intra-period tax allocation when there is a loss from continuing operations and income or a gain from other items (for example, discontinued operations or other comprehensive income), (ii) the requirement to recognize a deferred tax liability for equity method investments when a foreign subsidiary becomes an equity method investment, (iii) the ability not to recognize a deferred tax liability for a foreign subsidiary when a foreign equity method investment becomes a subsidiary and (iv) general methodology for calculating income taxes in an interim period when a year-to-date loss exceeds the anticipated loss for the year. Additionally the guidance requires that an entity (a) recognize a franchise tax (or similar tax) that is partially based on income as an income-based tax and account for any incremental amount incurred as a non-income-based tax, (b) evaluate when a step up in the tax basis of goodwill should be considered part of the business combination in which the book goodwill was originally recognized and when it should be considered a separate transaction and (c) reflect the effect of an enacted change in tax laws or rates in the annual effective tax rate computation in the interim period that includes the enactment date as well as specifying that an entity is not required to allocate the consolidated amount of current and deferred tax expense to a legal entity that is not subject to tax in its separate financial statements. However, an entity may elect to do so (on an entity-by-entity basis) for a legal entity that is both not subject to tax and disregarded by the taxing authority. The guidance also makes minor codification improvements for income taxes related to employee stock ownership plans and investments in qualified affordable housing projects accounted for using the equity method. For public business entities, the guidance is effective for reporting periods beginning after December 15, 2020 and interim periods within those fiscal years with early adoption permitted. The Company early adopted the guidance effective in the first quarter of 2020 and has determined no material impact from the adoption of this guidance on the Company's consolidated financial statements. Recently issued In August 2020, the FASB issued guidance simplifying an issuer’s accounting for convertible instruments by eliminating two of the three models in ASC 470-20 that require separate accounting for embedded conversion features; separate accounting is still required in certain cases. The guidance also simplifies the settlement assessment that entities are required to perform to determine whether a contract qualifies for equity classification. The guidance requires entities to use the if-converted method for all convertible instruments in the diluted earnings per share calculation and include the effect of potential share settlement (if the effect is more dilutive) for instruments that may be settled in cash or shares, except for certain liability-classified share-based payment awards. The guidance requires new disclosures about events that occur during the reporting period and cause conversion contingencies to be met and about the fair value of a public business entity’s convertible debt at the instrument level. For public business entities, the guidance is effective for reporting periods beginning after December 15, 2021 and interim periods within those fiscal years with early adoption permitted. The Company is currently evaluating the impact of the new guidance.
Segment Reporting	Segment Reporting The Company has two reportable business segments: Op Co and Asset Co. The Op Co segment consists of CIM, Investment Banking, Markets and Research. The Asset Co segment consists of the Company's private investments, private real estate investments and other legacy investment 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) includes management reclassifications which the Company believes provides additional insight on the performance of the Company’s core businesses and divisions (ii) eliminates the impact of consolidation for Consolidated Funds and excludes (iii) goodwill and intangible impairment (iv) certain other transaction-related adjustments and/or reorganization expenses and (v) certain costs associated with debt. 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. 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, excluding non-controlling interests, 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 consolidated US GAAP net income (loss) and related reclassifications and adjustments necessary to reconcile to the Company's Economic Income (Loss) measure which represents the Company's Op Co and Asset Co segments' results: Three Months Ended September 30, 2020 US GAAP Reclassifications and Adjustments Economic Income Net income (loss) Management Reclassifications Fund Consolidation Reclassifications (k) Income Statement Adjustments Operating Company Asset Company (dollars in thousands) Revenues Economic Proceeds Investment banking $ 194,341 $ (9,190) a, b $ — $ — Investment banking $ 185,151 $ — Brokerage 138,483 28,601 c, h — — Brokerage 167,084 — Management fees 11,954 2,519 d, e 163 — Management fees 14,374 262 Incentive income (loss) 127 (1,462) e 33 — Incentive income (loss) (2,621) 1,319 — (90,488) f — — Investment income (loss) (90,364) (124) Interest and dividends 37,552 (37,552) c — — — — Reimbursement from affiliates 269 (269) b — — — — Reinsurance premiums 2,505 (2,505) g — — — — Other revenue 1,369 (2,160) g (3) — Other revenues (796) 2 Consolidated Funds revenues 1,135 — (1,135) — — — Total revenues 387,735 (112,506) (942) — Total Economic proceeds 272,828 1,459 Interest and dividend expense 37,754 (29,467) c — (1,152) l Interest expense 6,026 1,109 Total net revenues 349,981 (83,039) (942) 1,152 Total Economic net proceeds 266,802 350 Expenses Economic Costs Compensation & benefits 153,427 359 i — — Compensation & Benefits 152,829 957 — 37,708 e, j — (3,324) m Fixed non-compensation expense 34,257 127 — 37,742 j — — Variable non-compensation expense 37,736 6 Other non-compensation expenses 89,636 (89,636) a, b, d, g, i — — — — Depreciation & amortization 5,682 — — (7) n Depreciation & Amortization 5,670 5 — 2,105 j — — Economic Non-Controlling Interest 2,105 — Consolidated Funds expenses 494 — (494) — — — Total expenses 249,239 (11,722) (494) (3,331) Total Economic costs 232,597 1,095 Other income (loss) (62,396) 64,896 e, f, h (2,500) — — — — — — 1,698 Preferred stock dividends 1,415 283 Income (loss) before income taxes $ 38,346 $ (6,421) * $ (2,948) * $ 2,785 Economic income (loss) $ 32,790 $ (1,028) Three Months Ended September 30, 2019 US GAAP Reclassifications and Adjustments Economic Income Net income (loss) Management Reclassifications Fund Consolidation Reclassifications (k) Income Statement Adjustments Operating Company Asset Company (dollars in thousands) Revenues Economic Proceeds Investment banking $ 77,292 $ (7,859) a, b $ — $ — Investment banking $ 69,433 $ — Brokerage 93,995 16,183 c, h — — Brokerage 110,178 — Management fees 7,300 3,033 d, e 574 — Management fees 10,321 586 Incentive income (loss) 701 13,675 e 13 — Incentive income (loss) 15,251 (862) — 11,735 f — — Investment income (loss) 10,913 822 Interest and dividends 60,707 (60,707) c — — — — Reimbursement from affiliates 238 (265) b 27 — — — Reinsurance premiums 8,146 (8,146) g — — — — Other revenue 1,237 (1,389) g 26 — Other revenues (132) 6 Consolidated Funds revenues 2,431 — (2,431) — — — Total revenues 252,047 (33,740) (1,791) — Total Economic proceeds 215,964 552 Interest and dividend expense 56,477 (48,238) c — (1,092) l Interest expense 5,758 1,389 Total net revenues 195,570 14,498 (1,791) 1,092 Total Economic net proceeds 210,206 (837) Expenses Economic Costs Compensation & benefits 120,320 2,299 i — — Compensation & Benefits 121,890 729 — 37,559 e, j — (476) m Fixed non-compensation expense 36,458 625 — 37,256 j — — Variable non-compensation expense 37,216 40 Other non-compensation expense 92,046 (92,046) a, b, d, g, i — — — — Depreciation & amortization 5,082 — — — Depreciation & Amortization 5,073 9 — 661 j — — Economic Non-Controlling Interest 661 — Consolidated Funds expenses 2,516 — (2,516) — — — Total expenses 219,964 (14,271) (2,516) (476) Total Economic costs 201,298 1,403 Other income (loss) 32,342 (26,721) e, f, h (5,621) — — — — — — 1,698 Preferred stock dividends 1,341 357 Income (loss) before income taxes $ 7,948 $ 2,048 * $ (4,896) * $ (130) Economic income (loss) $ 7,567 $ (2,597) Nine Months Ended September 30, 2020 US GAAP Reclassifications and Adjustments Economic Income Net income (loss) Management Reclassifications Fund Consolidation Reclassifications (k) Income Statement Adjustments Operating Company Asset Company (dollars in thousands) Revenues Economic Proceeds Investment banking $ 503,351 $ (28,573) a, b $ — $ — Investment banking $ 474,778 $ — Brokerage 425,069 41,754 c, h — — Brokerage 466,823 — Management fees 35,211 5,672 d, e 1,475 — Management fees 41,724 634 Incentive income (loss) 127 40,827 e 33 — Incentive income (loss) 40,829 158 — 18,895 f — — Investment income (loss) 32,566 (13,671) Interest and dividends 127,547 (127,547) c — — — — Reimbursement from affiliates 777 (827) b 50 — — — Reinsurance premiums 18,943 (18,943) g — — — — Other revenue 4,709 (4,982) g (21) — Other revenues (298) 4 Consolidated Funds revenues 4,650 — (4,650) — — — Total revenues 1,120,384 (73,724) (3,113) — Total Economic proceeds 1,056,422 (12,875) Interest and dividend expense 125,850 (99,971) c — (3,394) l Interest expense 18,471 4,014 Total net revenues 994,534 26,247 (3,113) 3,394 Total Economic net proceeds 1,037,951 (16,889) Expenses Economic Costs Compensation & benefits 583,137 1,436 i — — Compensation & Benefits 582,480 2,093 — 111,880 e, j — (5,152) m Fixed non-compensation expense 106,350 378 — 121,864 j — — Variable non-compensation expense 121,846 18 Other non-compensation expense 286,666 (286,666) a, b, d, g, i — — — — Depreciation & amortization 17,324 — — (551) n Depreciation & Amortization 16,756 17 — 5,584 j — — Economic Non-Controlling Interest 5,584 — Consolidated Funds expenses 4,793 — (4,793) — — — Total expenses 891,920 (45,902) (4,793) (5,703) Total Economic costs 833,016 2,506 Other income (loss) 54,328 (82,006) e, f, h 27,678 — — — — — — 5,094 Preferred stock dividends 4,160 934 Income (loss) before income taxes $ 156,942 $ (9,857) * $ 29,358 * $ 4,003 Economic income (loss) $ 200,775 $ (20,329) Nine Months Ended September 30, 2019 US GAAP Reclassifications and Adjustments Economic Income Net income (loss) Management Reclassifications Fund Consolidation Reclassifications (k) Income Statement Adjustments Operating Company Asset Company (dollars in thousands) Revenues Economic Proceeds Investment banking $ 272,103 $ (17,729) a, b $ — $ — Investment banking $ 254,374 $ — Brokerage 302,840 43,255 c, h — — Brokerage 346,095 — Management fees 21,480 8,684 d, e 1,640 — Management fees 30,016 1,788 Incentive income (loss) 724 33,479 e 557 — Incentive income (loss) 33,998 762 — 19,116 f — — Investment income (loss) 13,827 5,289 Interest and dividends 129,846 (129,846) c — — — — Reimbursement from affiliates 780 (874) b 94 — — — Reinsurance premiums 29,068 (29,068) g — — — — Other revenue 3,228 2,109 g 14 — Other revenues 5,295 56 Consolidated Funds revenues 8,239 — (8,239) — — — Total revenues 768,308 (70,874) (5,934) — Total Economic proceeds 683,605 7,895 Interest and dividend expense 125,089 (101,464) c — (3,208) l Interest expense 16,371 4,046 Total net revenues 643,219 30,590 (5,934) 3,208 Total Economic net proceeds 667,234 3,849 Expenses Economic Costs Compensation & benefits 388,611 2,365 i — — Compensation & Benefits 386,593 4,383 — 112,038 e, j — (1,664) m Fixed non-compensation expense 107,889 2,485 — 113,855 j — — Variable non-compensation expense 113,728 127 Other non-compensation expense 276,054 (276,054) a, b, d, g, i — — — — Depreciation & amortization 14,990 (3) — — Depreciation & Amortization 14,957 30 — 2,944 j — — Economic Non-Controlling Interest 2,944 — Goodwill impairment 4,100 — — (4,100) n — — Consolidated Funds expenses 6,229 — (6,229) — — — Total expenses 689,984 (44,855) (6,229) (5,764) Total Economic costs 626,111 7,025 Other income (loss) 82,976 (73,907) e, f, h (9,069) — — — — — — 5,094 Preferred stock dividends 4,058 1,036 Income (loss) before income taxes $ 36,211 $ 1,538 * $ (8,774) * $ 3,878 Economic income (loss) $ 37,065 $ (4,212) Adjustments made to US GAAP Net Income (Loss) to arrive at Economic Income (Loss) Management Reclassifications Management reclassification adjustments and fund consolidation reclassification adjustments have no effect on economic income. These adjustments are reclassifications to change the location of certain line items. a Economic Income (Loss) presents underwriting expenses net of investment banking revenues. b Economic Income (Loss) presents expenses reimbursed from clients and affiliates within their respective expense category but is included as a part of revenues under US GAAP. c 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. d Economic Income (Loss) presents revenues net of fund start-up costs and distribution fees paid to agents. e Economic Income (Loss) recognizes the Company's proportionate share of management and incentive fees and associated share of expenses on a gross basis for certain real estate operating entities, the healthcare royalty business and the activist business. Additionally, carried interest, which the Company applies an equity ownership model to, is recorded in other income (loss) for US GAAP and is shown as incentive income for Economic Income (Loss). f Economic Income (Loss) recognizes Company income from proprietary trading (including interest and dividends) for which the majority of this activity is shown in other income (loss) for US GAAP reporting. g Economic Income (Loss) recognizes underwriting income from the Company's insurance related activities, net of expenses, within other revenue. The costs are recorded within expenses for US GAAP reporting. h Economic Income (Loss) recognizes gains and losses on investments held as part of the Company's facilitation and trading business within brokerage revenues as these investments are directly related to the markets business activities. i Economic Income (Loss) presents certain payments to associated banking partners as compensation rather than non-compensation expenses. j Economic Income (Loss) presents US GAAP expenses as either Fixed non-compensation or Variable non-compensation expenses. The Company also presents US GAAP Income (loss) attributable to non-controlling interests within total other expenses for Economic Income (Loss). * The remainder primarily represents non-controlling interest which is excluded from this reconciliation to income (loss) before income taxes. Fund Consolidation Reclassifications k 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). * The remainder primarily represents non-controlling interest which is excluded from this reconciliation to income (loss) before income taxes. Income Statement Adjustments l Economic Income (Loss) excludes the amortization of discount on convertible debt. m Economic Income (Loss) excludes acquisition related adjustments as management does not consider these items when evaluating the performance of the Company. n Economic Income (Loss) excludes goodwill and intangible impairment.
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 SARs. 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 Polici_3

Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Revenue from External Customers by Products and Services	For the three and nine months ended September 30, 2020 and 2019, 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, 2020 2019 2020 2019 (dollars in thousands) Revenue from contracts with customers Operating Company Investment banking Underwriting fees $ 121,390 $ 38,936 $ 318,355 $ 162,140 Strategic/financial advisory fees 39,431 17,889 101,061 49,565 Placement and sales agent fees 28,427 15,842 71,999 48,855 Expense reimbursements from clients 5,093 4,625 11,936 11,543 Total investment banking revenue 194,341 77,292 503,351 272,103 Brokerage Commissions 112,953 82,715 367,564 263,831 Trade conversion revenue 3,404 3,700 12,370 12,364 Equity research fees 4,605 4,235 13,632 13,180 Total brokerage revenue from customers 120,962 90,650 393,566 289,375 Management fees 11,721 7,052 34,492 20,492 Incentive income 127 701 127 710 Total revenue from contracts with customers - Op Co $ 327,151 $ 175,695 $ 931,536 $ 582,680 Asset Company Management fees 233 248 719 988 Incentive income — — — 14 Total revenue from contracts with customers - Asset Co 233 248 719 1,002 Total revenue from contracts with customers $ 327,384 $ 175,943 $ 932,255 $ 583,682

Acquisition (Tables)

Acquisition (Tables)	9 Months Ended
	Sep. 30, 2020
Business Combinations [Abstract]
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
Schedule of Acquired Indefinite-lived Intangible Assets by Major Class	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
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) 2020 $ 2,227 2021 2,608 2022 1,775 2023 — 2024 — Thereafter — $ 6,610

Cash Collateral Pledge (Tables)

Cash Collateral Pledge (Tables)	9 Months Ended
	Sep. 30, 2020
Cash and Cash Equivalents [Abstract]
Schedule of Cash Collateral Pledged	As of September 30, 2020 , the Company has the following irrevocable letters of credit, rela ted 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. Location Amount Maturity (dollars in thousands) New York $ 358 April 2021 New York $ 1,424 October 2020 New York $ 1,637 November 2020 Boston $ 386 March 2021 San Francisco $ 712 October 2025 $ 4,517

Investments of Operating Enti_2

Investments of Operating Entities and Consolidated Funds - (Tables)	9 Months Ended
	Sep. 30, 2020
Investment Holdings [Line Items]
Marketable Securities	As of September 30, 2020 and December 31, 2019, securities owned, at fair value consisted of the following: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Common stock $ 920,849 $ 1,546,484 Preferred stock 63,605 12,656 Warrants and rights 20,505 22,109 Government bonds 20,324 15,916 Corporate bonds 36,701 25,500 Convertible bonds 5,081 2,500 Term loan (*) 12,111 1,067 Trade claims (*) 9,390 7,320 $ 1,088,566 $ 1,633,552
Schedule of Derivative Instruments	The Company's long and short exposure to derivatives is as follows: Receivable on derivative contracts As of September 30, 2020 As of December 31, 2019 Number of contracts / Notional Value Fair value Number of contracts / Notional Value Fair value (dollars in thousands) Currency forwards $ 82,100 $ 870 $ — $ — Swaps $ 244,090 4,644 $ 383,752 2,911 Options other (a) 256,841 52,680 550,188 60,066 $ 58,194 $ 62,977 (a) Includes the volume of contracts for index, equity, commodity future and cash conversion options. Payable for derivative contracts As of September 30, 2020 As of December 31, 2019 Number of contracts / Notional Value Fair value Number of contracts / Notional Value Fair value (dollars in thousands) Futures $ 9,895 $ 123 $ 10,224 $ 217 Currency forwards $ 103,500 717 $ 77,790 851 Swaps $ 376,331 7,514 $ 607,717 23,169 Options other (a) 252,576 53,700 306,306 36,524 $ 62,054 $ 60,761 (a) Includes the volume of contracts for 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, 2020 and December 31, 2019. This table does not include the impact of over-collateralization. Gross amounts offset on the Condensed Consolidated Statements of Financial Condition (a) Net amounts included on the Condensed Consolidated Statements of Financial Condition Gross amounts not offset in the Condensed Consolidated Statements of Financial Condition Gross amounts recognized Financial instruments Cash Collateral pledged Net amounts (dollars in thousands) As of September 30, 2020 Receivable on derivative contracts, at fair value $ 80,780 $ 22,586 $ 58,194 $ 3,631 $ 60 $ 54,503 Payable for derivative contracts, at fair value 67,295 5,241 62,054 3,631 2,777 55,646 As of December 31, 2019 Receivable on derivative contracts, at fair value $ 66,217 $ 3,240 $ 62,977 $ — $ 2,911 $ 60,066 Payable for derivative contracts, at fair value 64,001 3,240 60,761 — 24,020 36,741 (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.
Schedule of Other Investments	As of September 30, 2020 and December 31, 2019, other investments included the following: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Portfolio funds, at fair value (1) $ 123,787 $ 114,504 Carried interest (2) 47,343 30,360 Equity method investments (3) 33,480 40,858 $ 204,610 $ 185,722
Schedule of Other Investments, Portfolio Funds	The Portfolio Funds, at fair value as of September 30, 2020 and December 31, 2019, included the following: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Starboard Value and Opportunity Fund (c)(*) $ 41,354 $ 37,895 Formation8 Partners Fund I, L.P. (f) 31,916 33,613 Cowen Healthcare Investments II LP (i) (*) 20,691 14,652 Lagunita Biosciences, LLC (d) 4,124 4,802 Eclipse Ventures Fund I, L.P. (b) 4,464 3,960 HealthCare Royalty Partners II LP (a)(*) 1,627 1,781 RCG Longview Debt Fund V, L.P. (g)(*) 1,232 1,732 HealthCare Royalty Partners LP (a)(*) 1,157 1,326 Starboard Leaders Fund LP (e)(*) 1,656 1,560 Eclipse SPV I, LP (j)(*) 1,680 1,447 Ramius Merger Fund LLC (m)(*) 1,952 — TriArtisan ES Partners LLC (k)(*) 1,342 1,082 Cowen Healthcare Investments III LP (i)(*) 4,346 1,398 TriArtisan PFC Partners LLC (l)(*) 628 909 RCG Longview Equity Fund, LP (g) (*) 445 835 Difesa Partners, LP (h) (*) 681 508 BDC Fund I Coinvest 1, L.P. (n) (*) 1,250 — Other private investment (o)(*) 315 4,448 Other affiliated funds (p)(*) 2,927 2,556 $ 123,787 $ 114,504 * 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 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. and RCG Longview Equity Fund, 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) Difesa Partners, LP permits semi-annual withdrawals occurring on or after the anniversary of initial contribution upon 90 days written notice. (i) Cowen Healthcare Investments II LP and Cowen Healthcare Investments III LP are private equity funds. Distributions are made from the fund 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) TriArtisan ES Partners LLC is a co-investment vehicle organized to invest in a privately held nuclear services company. Distributions will be made when the underlying investment is liquidated. (l) TriArtisan PFC Partners LLC is a co-investment vehicle organized to invest in a privately held casual dining restaurant chain. Distributions will be made when the underlying investment in liquidated. (m) Ramius Merger Fund LLC permits monthly withdrawals on 45 days prior notice. (n) BDC Fund I Coinvest 1, L.P. is a private equity fund focused on investing in growth companies in industries disrupted by digitization. Distributions will be made when the underlying investments are liquidated. (o) Other private investment represents the Company's closed end investment in a Portfolio Fund that invests in a wireless broadband communication provider in Italy.
Carried Interest	The carried interest as of September 30, 2020 and December 31, 2019, included the following: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Cowen Healthcare Investments II LP $ 35,829 $ 23,759 Cowen Healthcare Investments III LP 5,357 — TriArtisan TGIF Partners LLC 2,881 — TriArtisan ES Partners LLC 1,354 — TriArtisan PFC Partners LLC 1,116 — Ramius Multi-Strategy Fund LP 612 — Ramius Merger Fund LLC 13 — Other private investment (a) — 4,737 RCG IO Renergys Sarl 181 1,251 Ramius Multi-Strategy Fund LP — 613 $ 47,343 $ 30,360 (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.
Schedule Equity Method Investments	The following table summarizes equity method investments held by the Company: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Starboard Value LP $ 25,392 $ 24,292 Surf House Ocean Views Holdings, LLC — 7,804 HealthCare Royalty GP III, LLC 2,198 2,230 RCG Longview Debt Fund V Partners, LLC 1,721 2,889 RCG Longview Management, LLC 253 583 HealthCare Royalty GP, LLC 675 108 HealthCare Royalty GP II, LLC 276 302 RCG Longview Debt Fund IV Management, LLC 331 331 RCG Longview Equity Management, LLC 105 105 HCR Stafford Fund GP, LLC 850 880 Liberty Harbor North 292 292 Other 1,387 1,042 $ 33,480 $ 40,858
Schedule of Securities Sold, Not yet Purchased	As of September 30, 2020 and December 31, 2019, securities sold, not yet purchased, at fair value consisted of the following: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Common stock $ 404,409 $ 425,448 Corporate bonds 15,324 5,933 Government bonds 1,500 1,950 Preferred stock 10,767 3,686 Warrants and rights 8,930 14,819 $ 440,930 $ 451,836
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, 2020 and December 31, 2019. Gross amounts not offset on the Condensed Consolidated Statements of Financial Condition Gross amounts recognized, net of allowance 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, 2020 Securities borrowed $ 1,272,428 $ — $ 1,272,428 $ — $ 1,213,253 $ — $ 59,175 Securities loaned 1,326,917 — 1,326,917 — 1,278,129 — 48,788 Securities sold under agreements to repurchase 6,218 — 6,218 — 7,587 — (1,369) As of December 31, 2019 Securities borrowed $ 754,441 $ — $ 754,441 $ — $ 751,913 $ — $ 2,528 Securities loaned 1,601,866 — 1,601,866 — 1,585,036 — 16,830 Securities sold under agreements to repurchase 23,244 — 23,244 — 27,384 — (4,140) (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, 2020 and December 31, 2019: Open and Overnight Up to 30 days 31 - 90 days Greater than 90 days Total (dollars in thousands) As of September 30, 2020 Securities loaned Common stock $ 933,956 $ — $ — $ — $ 933,956 Corporate bonds 392,961 — — — 392,961 Securities sold under agreements to repurchase — — 6,218 — 6,218 As of December 31, 2019 Securities loaned Common stock $ 1,343,478 $ — $ — $ — $ 1,343,478 Corporate bonds 258,388 — — — $ 258,388 Securities sold under agreements to repurchase — — 23,244 — $ 23,244
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, 2020 Linkem Equity, loans and warrants Italy Wireless Broadband 9.01 % $ 82,074 As of December 31, 2019 Linkem Equity, loans and warrants Italy Wireless Broadband 9.53 % $ 77,142
Significant subsidiary - equity method [Member]
Investment Holdings [Line Items]
Schedule Equity Method Investments	For the periods ended September 30, 2020 and December 31, 2019 and for the nine months periods ended September 30, 2020 and September 30, 2019, certain investments subject to Regulation S-X Rule 10-01(b)(1) of the SEC guidance held by the Company have met the significance criteria as defined thereunder. As such, the Company is required to present summarized financial information for these significant investees as of September 30, 2020 and December 31, 2019 and for the three and nine months ended September 30, 2020 and 2019, and such information is as follows: Other equity method investments As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Assets $ 59,379 $ 95,825 Liabilities — 82,482 Equity $ 59,379 $ 13,343 Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (dollars in thousands) Revenues $ 274 $ 4,564 $ 54,717 $ 83,287 Expenses — — — — Net realized and unrealized gains (losses) 77 55 412 717 Net income $ 351 $ 4,619 $ 55,129 $ 84,004
Consolidated Funds
Investment Holdings [Line Items]
Marketable Securities	As of September 30, 2020 and December 31, 2019, securities owned, at fair value, held by the Consolidated Funds consisted of the following: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Preferred stock $ — $ 4,393 Common stock 106,549 200,306 Government bonds — 161,607 Corporate bonds — 3,405 Convertible bonds 75,538 — Warrants and rights 5,904 5,567 $ 187,991 $ 375,278
Schedule of Derivative Instruments	As of September 30, 2020 and December 31, 2019, receivable on derivative contracts, at fair value, held by the Consolidated Funds are comprised of: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Currency forwards $ — $ 3,302 Equity swaps — 927 Options — 1,604 $ — $ 5,833 Payable for derivative contracts As of September 30, 2020 and December 31, 2019, payable for derivative contracts, at fair value, held by the Consolidated Funds are comprised of: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Currency forwards $ — $ 88 Equity swaps — 3,931 Options — 750 $ — $ 4,769
Schedule of Other Investments, Portfolio Funds	Investments in Portfolio Funds, at fair value As of September 30, 2020 and December 31, 2019, investments in Portfolio Funds, at fair value, included the following: As of September 30, 2020 As of December 31, 2019 As of December 31, 2020 2019 (dollars in thousands) Investments of Enterprise LP $ 98,016 $ 99,153 Investments of Merger Fund — 76,616 Investment of Prodigy HoldCo 251 — $ 98,267 $ 175,769
Merger Master
Investment Holdings [Line Items]
Marketable Securities	Merger Master As of December 31, 2019 Securities owned by Merger Master, at fair value (dollars in thousands) Common stock $ 76,531 Warrants and rights 748 Corporate bonds 2,074 $ 79,353 Securities sold, not yet purchased, by Merger Master, at fair value Common stock $ 29,623 Exchange traded funds 38,527 $ 68,150
Schedule of Derivative Instruments	Receivable on derivative contracts, at fair value, owned by Merger Master As of December 31, 2019 Description (dollars in thousands) Options $ 2,047 Equity swaps 406 $ 2,453 Payable for derivative contracts, at fair value, owned by Merger Master As of December 31, 2019 Description (dollars in thousands) Options $ 1,158 Equity swaps 268 $ 1,426

Fair Value Measurements for O_2

Fair Value Measurements for Operating Entities and Consolidated Funds (Tables)	9 Months Ended
	Sep. 30, 2020
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, 2020 and December 31, 2019: Assets at Fair Value as of September 30, 2020 Level 1 Level 2 Level 3 Total (dollars in thousands) Operating Entities Securities owned, at fair value Government bonds $ 20,324 $ — $ — $ 20,324 Preferred stock 10,187 — 53,418 63,605 Common stock 900,885 508 19,456 920,849 Convertible bonds — — 5,081 5,081 Corporate bonds — 36,181 520 36,701 Trade claims — — 9,390 9,390 Term loan — — 12,111 12,111 Warrants and rights 15,522 — 4,983 20,505 Receivable on derivative contracts, at fair value Currency forwards — 870 — 870 Swaps — 4,644 — 4,644 Options 52,329 — 351 52,680 Consolidated Funds Securities owned, at fair value Common stock 3,598 — 102,951 106,549 Warrants and rights — — 5,904 5,904 Convertible bonds — — 75,538 75,538 $ 1,002,845 $ 42,203 $ 289,703 $ 1,334,751 Percentage of total assets measured at fair value on a recurring basis 75.1 % 3.2 % 21.7 % Portfolio Funds measured at net asset value (a) 123,787 Carried interest (a) 47,343 Consolidated Funds' Portfolio Funds measured at net asset value (a) 98,267 Equity method investments 33,480 Total investments $ 1,637,628 Liabilities at Fair Value as of September 30, 2020 Level 1 Level 2 Level 3 Total (dollars in thousands) Operating Entities Securities sold, not yet purchased, at fair value Government bonds $ — $ — $ 1,500 $ 1,500 Common stock 404,409 — — 404,409 Corporate bonds — 14,524 800 15,324 Preferred stock 10,767 — — 10,767 Warrants and rights 8,930 — — 8,930 Payable for derivative contracts, at fair value Futures 123 — — 123 Currency forwards — 717 — 717 Swaps — 7,514 — 7,514 Options 50,746 — 2,954 53,700 Accounts payable, accrued expenses and other liabilities Contingent consideration liability (b) — — 30,024 30,024 $ 474,975 $ 22,755 $ 35,278 $ 533,008 Percentage of total liabilities measured at fair value 89.1 % 4.3 % 6.6 % (a) In accordance with US GAAP, certain investments are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient. 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 31, 2019 and December 31, 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, 2020 can range from $0.9 million to $35.1 million. Assets at Fair Value as of December 31, 2019 Level 1 Level 2 Level 3 Total (dollars in thousands) Operating Entities Securities owned, at fair value Government bonds $ 15,916 $ — $ — $ 15,916 Preferred stock 4,821 — 7,835 12,656 Common stock 1,527,769 1,249 17,466 1,546,484 Convertible bonds — — 2,500 2,500 Corporate bonds — 23,079 2,421 25,500 Trade claims — — 7,320 7,320 Term loan — 1,067 — 1,067 Warrants and rights 21,515 — 594 22,109 Receivable on derivative contracts, at fair value Swaps — 2,911 — 2,911 Options 59,730 — 336 60,066 Consolidated Funds Securities owned, at fair value Government bonds 161,607 — — 161,607 Preferred stock — — 4,393 4,393 Common stock 200,306 — — 200,306 Corporate bonds — 3,405 — 3,405 Warrants and rights — — 5,567 5,567 Receivable on derivative contracts, at fair value Currency forwards — 3,302 — 3,302 Equity swaps — 927 — 927 Options 1,604 — — 1,604 $ 1,993,268 $ 35,940 $ 48,432 $ 2,077,640 Percentage of total assets measured at fair value on a recurring basis 95.9 % 1.7 % 2.3 % Portfolio Funds measured at net asset value (a) 114,504 Carried interest (a) 30,360 Consolidated Funds' Portfolio Funds measured at net asset value (a) 175,769 Equity method investments 40,858 Total investments $ 2,439,131 Liabilities at Fair Value as of December 31, 2019 Level 1 Level 2 Level 3 Total (dollars in thousands) Operating Entities Securities sold, not yet purchased, at fair value US Government securities $ — $ — $ 1,950 $ 1,950 Common stock 425,448 — — 425,448 Corporate bonds — 4,933 1,000 5,933 Preferred stock 3,686 — — 3,686 Warrants and rights 14,819 — — 14,819 Payable for derivative contracts, at fair value Futures 217 — — 217 Currency forwards — 851 — 851 Swaps — 23,169 — 23,169 Options 33,604 — 2,920 36,524 Accounts payable, accrued expenses and other liabilities Contingent consideration liability (b) — — 30,896 30,896 Consolidated Funds Payable for derivative contracts, at fair value Currency forwards — 88 — 88 Options 750 — — 750 Equity swaps — 3,931 — 3,931 $ 478,524 $ 32,972 $ 36,766 $ 548,262 Percentage of total liabilities measured at fair value 87.3 % 6.0 % 6.7 % (a) In accordance with US GAAP, certain investments are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient. 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.
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, 2020 and 2019 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, 2020 Balance at June 30, 2020 Transfers in Transfers out Purchases/(covers) (Sales)/shorts Realized and Unrealized gains/losses Balance at September 30, 2020 Change in unrealized gains/losses relating to instruments still held (1) (dollars in thousands) Operating Entities Preferred stock $ 51,480 $ — $ (7,744) (b) $ 5,282 $ (3,770) $ 8,170 $ 53,418 $ 2,926 Common stock 14,816 — (3) (e) 4,000 — 643 19,456 562 Convertible bonds 5,081 — — — — — 5,081 — Corporate bonds 758 — (312) (b) 72 — 2 520 22 Options, asset 337 — — — — 14 351 14 Options, liability 2,177 — — — — 777 2,954 777 Term Loan 11,359 — — 245 — 507 12,111 506 Warrants and rights 4,625 3 (e) — — — 355 4,983 337 Trade claims 7,587 — — 2,690 (648) (239) 9,390 (239) Corporate bond, liability 800 — — — — — 800 — Government bonds, liability 1,500 — — — — — 1,500 — Contingent consideration liability 27,001 — — — — 3,023 30,024 3,023 Consolidated Funds Common stock 102,951 — — — — — 102,951 — Warrants and rights 5,858 — — — — 46 5,904 46 Convertible bonds — — — 75,000 — 538 75,538 538 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) (f) $ — $ — $ 1,434 $ 7,835 $ 2,295 Common stock 11,006 — — 2,579 (480) 208 13,313 210 Convertible bonds 6,318 — (2,801) (f) 1,049 (2,072) 47 2,541 4 Corporate bonds 775 20 (e) — 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 (e) — — — (1,325) 1,200 (1,325) Government bonds, liability — 4,681 (e) — — — (2,431) 2,250 (2,431) Contingent consideration liability 29,536 — — — — 298 29,834 298 Consolidated Funds Preferred stock 24,322 — (19,929) (f) — — — 4,393 — Common stock 1,017 — (94) (f) — (957) 34 — — Warrants and rights 6,274 — — — (670) (139) 5,465 (809) Nine Months Ended September 30, 2020 Balance at December 31, 2019 Transfers in Transfers out Purchases/(covers) (Sales)/shorts Realized and Unrealized gains/losses Balance at September 30, 2020 Change in unrealized gains/losses relating to instruments still held (1) (dollars in thousands) Operating Entities Preferred stock $ 7,835 $ 45,530 (c) $ (7,744) (b) $ 5,647 $ (5,870) $ 8,020 $ 53,418 $ 5,337 Common stock 17,466 — (29) (a)(e) 5,798 (3,712) (67) 19,456 (1,023) Convertible bonds 2,500 — — 2,581 — — 5,081 — Corporate bond 2,421 — (312) (b) 592 (1,938) (243) 520 (180) Options, asset 336 — — — — 15 351 15 Options, liability 2,920 — — — — 34 2,954 35 Term loan — 11,149 (c) — 245 — 717 12,111 717 Warrants and rights 594 3,636 (a)(c) — — — 753 4,983 753 Trade claims 7,320 1,044 (a)(e) — 4,663 (2,863) (774) 9,390 (795) Corporate bond, liability 1,000 — — — — (200) 800 (200) Government bonds, liability 1,950 — — — — (450) 1,500 (450) Contingent consideration liability 30,896 — — — (5,653) 4,781 30,024 4,781 Consolidated Funds Preferred stock 4,393 — (4,000) (d) — — (393) — — Common stock — 4,000 (d) — 100,000 — (1,049) 102,951 (1,049) Warrants and rights 5,567 — — — — 337 5,904 337 Convertible bonds $ — $ — $ — $ 75,000 $ — $ 538 $ 75,538 $ 538 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) (f) $ 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)(f) 16,021 (11,764) 110 2,541 41 Corporate bond — 20 (e) — 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 claim 5,543 — — 6,965 (5,506) 60 7,062 57 Corporate bond, liability — 2,525 (e) — — — (1,325) 1,200 (1,325) Government bonds, liability — 4,681 (e) — — — (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) (f) — — 8 4,393 8 Common stock 94 — (94) (f) 407 (958) 551 — — Warrants and rights $ 5,279 $ — $ — $ — $ (1,758) $ 1,944 $ 5,465 $ 190 (1) Unrealized gains/losses are reported in other income (loss) in the accompanying condensed consolidated statements of operations. (a) The security stopped trading on an open market. (b) The investments were converted to common stock. (c) The Company consolidated an operating entity which holds preferred stock, loans and warrants. (d) The investment was involved in a reverse merger and preferred stock was converted to common shares. (e) The transfers between level 1 and level 3 are due to the change in the availability of observable inputs. (f) 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, 2020 and December 31, 2019 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, 2020 Valuation Techniques Unobservable Inputs Range Weighted Average Level 3 Assets (dollars in thousands) Common and preferred stocks $ 61,220 Discounted cash flows Guideline companies Discount rate EBITDA Market Multiples 10% - 12% 6.25x - 6.75x 11% 6.5x Options 352 Discounted cash flows Guideline companies Discount rate EBITDA Market Multiples 10% - 12% 6.25x - 6.75x 11% 6.5x Trade claims 3,446 Discounted cash flows Discount rate 15% 15% Warrants and rights 10,865 Discounted cash flows Guideline companies Discount rate EBITDA Market Multiples 4% - 11% 6.25x - 6.75x 7.0% 6.5x Corporate, convertible bonds and term loan 12,110 Discounted cash flows Guideline companies Discount rate EBITDA Market Multiples 10% - 12% 6.25x - 6.75x 11% 6.5x Other level 3 assets (a) 201,710 Total level 3 assets $ 289,703 Level 3 Liabilities Options 2,954 Option pricing models Volatility 35% 35% Contingent consideration liability 30,024 Discounted cash flows Monte Carlo simulation Discount rate Volatility 15% - 22% 22% 15% 22% Other level 3 liabilities (a) 2,300 Total level 3 liabilities $ 35,278 Quantitative Information about Level 3 Fair Value Measurements Fair Value at December 31, 2019 Valuation Techniques Unobservable Inputs Range Weighted Average Level 3 Assets (dollars in thousands) Common and preferred stocks $ 10,876 Discounted cash flows Guideline companies Discount rate EBITDA Market Multiples 8% - 11.25% 6.5x - 7x 10.4% 6.75x Trade claims 24 Discounted cash flows Discount rate 20% 20% Warrants and rights 6,162 Model based Discounted cash flows Volatility Discount rate 30% 6% - 7% —% 6.1% Options 336 Option pricing models Discount rate EBITDA Market Multiples 9.75% - 11.25% 6.5x - 7x 10.5% 6.75x Corporate and convertible bonds 311 Discounted cash flows Recovery Discount rate Probability of recovery 20% 1% - 3% 20% 2.3% Other level 3 assets (a) 30,723 Total level 3 assets $ 48,432 Level 3 Liabilities Options 2,920 Option pricing models Volatility 35% to 40% 35% Contingent consideration liability 30,896 Discounted cash flows Discount rate Volatility 15% - 22% 17% 15% 17% Other level 3 liabilities (a) 2,950 Total level 3 liabilities $ 36,766
Fair Value Measurements, Nonrecurring	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 2e). September 30, 2020 December 31, 2019 Fair Value Hierarchy Carrying Amount Fair Value Carrying Amount Fair Value (dollars in thousands) Financial Assets Operating companies Cash and cash equivalents $ 539,733 (f) $ 539,733 (f) $ 301,123 $ 301,123 Level 1 & 2 Cash collateral pledged 110,666 110,666 6,563 6,563 Level 2 Segregated cash 139,152 139,152 107,328 107,328 Level 1 Securities borrowed 1,272,428 1,272,428 754,441 754,441 Level 2 Loans receivable 9,045 9,045 (d) 42,830 42,830 (d) Level 3 Consolidated Funds Cash and cash equivalents 946 946 30,874 30,874 Level 1 Financial Liabilities Securities sold under agreements to repurchase 6,218 7,587 23,244 27,384 Level 2 Securities loaned 1,326,917 1,326,917 1,601,866 1,601,866 Level 2 Convertible debt 122,485 (a) 147,166 (b) 118,688 (a) 148,786 (b) Level 2 Notes payable and other debt 383,722 (e) 406,309 (c) 345,451 (e) 372,591 (c) Level 2 (a) The carrying amount of the convertible debt includes an unamortized discount of $11.4 million and $14.9 million as of September 30, 2020 and December 31, 2019, 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. (e) The carrying amount of the notes payable and other debt includes an unamortized premium of $0.4 million and $0.5 million as of September 30, 2020 and December 31, 2019, respectively.

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, 2020
Receivables from Brokers-Dealers and Clearing Organizations [Abstract]
Schedule of Due to (from) Broker-Dealers and Clearing Organizations	As of September 30, 2020 and December 31, 2019, amounts receivable from brokers, dealers and clearing organizations include: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Broker-dealers $ 1,263,635 $ 623,523 Securities failed to deliver 71,280 45,673 Clearing organizations 49,978 3,180 Securities borrowed interest receivable 5,928 9,319 $ 1,390,821 $ 681,695 As of September 30, 2020 and December 31, 2019, amounts payable to brokers, dealers and clearing organizations include: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Broker-dealers $ 228,628 $ 185,838 Securities failed to receive 39,496 57,580 Clearing organizations 39,077 18,063 Securities loaned interest payable 5,649 9,537 $ 312,850 $ 271,018

Non-Controlling Interests in _2

Non-Controlling Interests in Consolidated Subsidiaries and Funds (Tables)	9 Months Ended
	Sep. 30, 2020
Noncontrolling Interest [Abstract]
Noncontrolling interests in consolidated subsidiaries and investment funds	Redeemable and nonredeemable 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, 2020 As of December 31, 2019 (dollars in thousands) Redeemable non-controlling interests in consolidated subsidiaries and investment funds Consolidated Funds $ — $ 391,275 Nonredeemable non-controlling interests in consolidated subsidiaries and investment funds Operating companies 72,569 11,513 Consolidated Funds 197,452 82,807 $ 270,021 $ 485,595
Net income (loss) attributable to non-controlling interests in consolidated subsidiaries and funds	Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (dollars in thousands) Income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds Operating companies $ 6,283 $ (2,126) $ 9,514 $ (1,586) Consolidated Funds 2,949 4,896 (29,357) 8,774 $ 9,232 $ 2,770 $ (19,843) $ 7,188

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	9 Months Ended
	Sep. 30, 2020
Revenue Recognition and Deferred Revenue [Abstract]
Revenue from External Customers by Products and Services	For the three and nine months ended September 30, 2020 and 2019, 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, 2020 2019 2020 2019 (dollars in thousands) Revenue from contracts with customers Operating Company Investment banking Underwriting fees $ 121,390 $ 38,936 $ 318,355 $ 162,140 Strategic/financial advisory fees 39,431 17,889 101,061 49,565 Placement and sales agent fees 28,427 15,842 71,999 48,855 Expense reimbursements from clients 5,093 4,625 11,936 11,543 Total investment banking revenue 194,341 77,292 503,351 272,103 Brokerage Commissions 112,953 82,715 367,564 263,831 Trade conversion revenue 3,404 3,700 12,370 12,364 Equity research fees 4,605 4,235 13,632 13,180 Total brokerage revenue from customers 120,962 90,650 393,566 289,375 Management fees 11,721 7,052 34,492 20,492 Incentive income 127 701 127 710 Total revenue from contracts with customers - Op Co $ 327,151 $ 175,695 $ 931,536 $ 582,680 Asset Company Management fees 233 248 719 988 Incentive income — — — 14 Total revenue from contracts with customers - Asset Co 233 248 719 1,002 Total revenue from contracts with customers $ 327,384 $ 175,943 $ 932,255 $ 583,682

Reinsurance Reinsurance (Tables

Reinsurance Reinsurance (Tables)	9 Months Ended
	Sep. 30, 2020
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Abstract]
Effects of Reinsurance	Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (dollars in thousands) Incurred and paid claims $ 2,570 $ 126 $ 10,498 $ 7,046 Change in Claims IBNR 2,722 833 $ 26,638 $ 11,724

Share-Based Compensation and _2

Share-Based Compensation and Employee Ownership Plans (Tables)	9 Months Ended
	Sep. 30, 2020
Share-based Payment Arrangement [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, 2020 and 2019: Nine Months Ended September 30, 2020 Nine Months Ended September 30, 2019 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 5,364,486 $ 16.67 5,962,295 $ 15.73 Granted 2,638,544 17.14 2,322,996 16.62 Vested (1,320,318) 15.20 (1,545,850) 16.26 Canceled (87,348) 14.80 (584,333) 11.49 Forfeited (111,212) 15.55 (156,528) 13.97 Ending balance outstanding 6,484,152 $ 17.20 5,998,580 $ 16.40

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Operating Lease, Lease Income [Table Text Block]	For the three and nine months ended September 30, 2020 and 2019, quantitative information regarding the Company's operating lease obligations reflected in the accompanying condensed consolidated statements of operations were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (dollars in thousands) Lease cost Operating lease cost $ 5,687 $ 5,748 $ 17,044 $ 17,690 Short-term lease cost 52 23 155 113 Variable lease cost 829 1,156 2,431 2,668 Sublease income (190) (232) (623) (739) Total lease costs $ 6,378 $ 6,695 $ 19,007 $ 19,732 The following table summarizes the supplemental cash flow information and certain other information related to operating leases for the nine months ended September 30, 2020 and 2019: Nine Months Ended September 30, 2020 2019 (dollars in thousands) Other information Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 20,228 $ 19,103 Weighted average remaining lease term - operating leases (in years) 4.78 5.52 Weighted average discount rate - operating leases 3.69 % 4.14 %
Future Minimum Annual Lease and Service Payments	As of September 30, 2020, maturities of the outstanding operating lease liabilities for the Company were as follows: Equipment Leases (operating) Real Estate and Other Facility Rental (a) (b) (dollars in thousands) 2020 $ 90 $ 4,302 2021 223 24,723 2022 91 21,484 2023 3 18,095 2024 — 14,784 Thereafter — 10,166 Total operating leases 407 93,554 Less discount 25 9,816 Less short-term leases — 76 Total lease liability $ 382 $ 83,662 (a) The Company has entered into various agreements to sublease certain of its premises. (b) During the nine months ended September 30, 2020, the Company recognized $0.3 operating right-of-use assets and leases liabilities increases for facility leases. As of September 30, 2020, future minimum annual service payments for the Company were as follows: Service Payments (dollars in thousands) 2020 $ 8,262 2021 23,563 2022 14,295 2023 7,188 2024 4,351 Thereafter 13,201 Total service payment commitments $ 70,860
Other Commitments	The following table summarizes unfunded commitments as of September 30, 2020: Entity Unfunded Commitments Commitment Term (dollars in thousands) HealthCare Royalty Partners funds (a) $ 7,816 4.3 years Eclipse Ventures Fund I, L.P. $ 59 4.3 years Lagunita Biosciences, LLC $ 250 3.1 years Eclipse Fund II, L.P. $ 110 5.3 years Eclipse Continuity Fund I, L.P. $ 58 6.3 years Cowen Healthcare Investments II LP $ 1,201 1.3 years Cowen Healthcare Investments III LP $ 6,164 6.3 years Cowen Sustainable Investments I LP $ 3,926 9.3 years

Convertible Debt and Notes Pa_2

Convertible Debt and Notes Payable (Tables)	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Schedule of Debt and Capital Lease Obligations	As of September 30, 2020 and December 31, 2019, the Company's outstanding debt was as follows: As of September 30, 2020 As of December 31, 2019 (dollars in thousands) Convertible debt $ 122,485 $ 118,688 Notes payable 307,437 306,818 Term loans — 32,180 Other notes payable 73,253 2,516 Finance lease obligations 3,032 3,937 $ 506,207 $ 464,139
Direct Financing Lease, Lease Income [Table Text Block]	For the three and nine months ended September 30, 2020 and 2019, quantitative information regarding the Company's finance lease obligations reflected in the accompanying condensed consolidated statements 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, 2020 2019 2020 2019 (dollars in thousands) Lease cost Finance lease cost: Amortization of finance lease right-of-use assets $ 308 $ 299 $ 924 $ 966 Interest on lease liabilities $ 42 $ 54 $ 134 $ 172 Other information Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from finance leases $ 134 $ 172 Financing cash flows from finance leases $ 901 $ 951 Weighted average remaining lease term - operating leases (in years) 2.48 3.40 Weighted average discount rate - operating leases 4.89 % 4.93 %
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, 2020, are as follows: Convertible Debt Notes Payable Other Notes Payable Finance Lease (dollars in thousands) 2020 $ 2,025 $ 7,300 $ 933 $ 251 2021 4,050 23,548 593 1,396 2022 139,050 23,548 593 1,165 2023 — 23,548 72,593 411 2024 — 98,721 543 11 Thereafter — 334,304 — — Subtotal 145,125 510,969 75,255 3,234 Less (a) (22,640) (203,532) (2,002) (202) Total $ 122,485 $ 307,437 $ 73,253 $ 3,032

Stockholder's Equity (Tables)

Stockholder's Equity (Tables)	9 Months Ended
	Sep. 30, 2020
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, 2020: Treasury Stock Shares Cost Average Cost per Share Balance outstanding at December 31, 2019 18,605,581 $ 284,301 $ 15.28 Shares purchased for minimum tax withholding under the 2010 Equity Plan or other similar transactions 505,702 6,296 12.45 Shares of stock received in respect of indemnification claims 7,026 96 13.66 Purchase of treasury stock 2,974,711 43,442 14.60 Balance outstanding at September 30, 2020 22,093,020 $ 334,135 $ 15.12

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2020
Accumulated Other Comprehensive Income / (Loss) [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (dollars in thousands) Beginning balance $ (5) $ (3) $ (5) $ (5) Foreign currency translation (2) (2) (2) — Ending balance $ (7) $ (5) $ (7) $ (5)

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2020
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, 2020 2019 2020 2019 (dollars and share data in thousands, except per share data) Net income (loss) $ 29,516 $ 6,583 $ 104,353 26,596 Net income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds 9,232 2,770 (19,843) 7,188 Net income (loss) attributable to Cowen Inc. 20,284 3,813 124,196 19,408 Preferred stock dividends 1,698 1,698 5,094 5,094 Net income (loss) attributable to Cowen Inc. common stockholders $ 18,586 $ 2,115 $ 119,102 $ 14,314 Shares for basic and diluted calculations: Weighted average shares used in basic computation 27,663 29,529 28,078 29,687 Contingently issuable common stock in connection with an acquisition (see Note 3) 22 — 22 — Restricted stock 2,285 1,735 1,546 1,694 Weighted average shares used in diluted computation 29,970 31,264 29,646 31,381 Earnings (loss) per share: Basic $ 0.67 $ 0.07 $ 4.24 $ 0.48 Diluted $ 0.62 $ 0.07 $ 4.02 $ 0.46

Segment Reporting (Tables)

Segment Reporting (Tables)	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Segment Reporting Information, by Segment	Three Months Ended September 30, 2020 US GAAP Reclassifications and Adjustments Economic Income Net income (loss) Management Reclassifications Fund Consolidation Reclassifications (k) Income Statement Adjustments Operating Company Asset Company (dollars in thousands) Revenues Economic Proceeds Investment banking $ 194,341 $ (9,190) a, b $ — $ — Investment banking $ 185,151 $ — Brokerage 138,483 28,601 c, h — — Brokerage 167,084 — Management fees 11,954 2,519 d, e 163 — Management fees 14,374 262 Incentive income (loss) 127 (1,462) e 33 — Incentive income (loss) (2,621) 1,319 — (90,488) f — — Investment income (loss) (90,364) (124) Interest and dividends 37,552 (37,552) c — — — — Reimbursement from affiliates 269 (269) b — — — — Reinsurance premiums 2,505 (2,505) g — — — — Other revenue 1,369 (2,160) g (3) — Other revenues (796) 2 Consolidated Funds revenues 1,135 — (1,135) — — — Total revenues 387,735 (112,506) (942) — Total Economic proceeds 272,828 1,459 Interest and dividend expense 37,754 (29,467) c — (1,152) l Interest expense 6,026 1,109 Total net revenues 349,981 (83,039) (942) 1,152 Total Economic net proceeds 266,802 350 Expenses Economic Costs Compensation & benefits 153,427 359 i — — Compensation & Benefits 152,829 957 — 37,708 e, j — (3,324) m Fixed non-compensation expense 34,257 127 — 37,742 j — — Variable non-compensation expense 37,736 6 Other non-compensation expenses 89,636 (89,636) a, b, d, g, i — — — — Depreciation & amortization 5,682 — — (7) n Depreciation & Amortization 5,670 5 — 2,105 j — — Economic Non-Controlling Interest 2,105 — Consolidated Funds expenses 494 — (494) — — — Total expenses 249,239 (11,722) (494) (3,331) Total Economic costs 232,597 1,095 Other income (loss) (62,396) 64,896 e, f, h (2,500) — — — — — — 1,698 Preferred stock dividends 1,415 283 Income (loss) before income taxes $ 38,346 $ (6,421) * $ (2,948) * $ 2,785 Economic income (loss) $ 32,790 $ (1,028) Three Months Ended September 30, 2019 US GAAP Reclassifications and Adjustments Economic Income Net income (loss) Management Reclassifications Fund Consolidation Reclassifications (k) Income Statement Adjustments Operating Company Asset Company (dollars in thousands) Revenues Economic Proceeds Investment banking $ 77,292 $ (7,859) a, b $ — $ — Investment banking $ 69,433 $ — Brokerage 93,995 16,183 c, h — — Brokerage 110,178 — Management fees 7,300 3,033 d, e 574 — Management fees 10,321 586 Incentive income (loss) 701 13,675 e 13 — Incentive income (loss) 15,251 (862) — 11,735 f — — Investment income (loss) 10,913 822 Interest and dividends 60,707 (60,707) c — — — — Reimbursement from affiliates 238 (265) b 27 — — — Reinsurance premiums 8,146 (8,146) g — — — — Other revenue 1,237 (1,389) g 26 — Other revenues (132) 6 Consolidated Funds revenues 2,431 — (2,431) — — — Total revenues 252,047 (33,740) (1,791) — Total Economic proceeds 215,964 552 Interest and dividend expense 56,477 (48,238) c — (1,092) l Interest expense 5,758 1,389 Total net revenues 195,570 14,498 (1,791) 1,092 Total Economic net proceeds 210,206 (837) Expenses Economic Costs Compensation & benefits 120,320 2,299 i — — Compensation & Benefits 121,890 729 — 37,559 e, j — (476) m Fixed non-compensation expense 36,458 625 — 37,256 j — — Variable non-compensation expense 37,216 40 Other non-compensation expense 92,046 (92,046) a, b, d, g, i — — — — Depreciation & amortization 5,082 — — — Depreciation & Amortization 5,073 9 — 661 j — — Economic Non-Controlling Interest 661 — Consolidated Funds expenses 2,516 — (2,516) — — — Total expenses 219,964 (14,271) (2,516) (476) Total Economic costs 201,298 1,403 Other income (loss) 32,342 (26,721) e, f, h (5,621) — — — — — — 1,698 Preferred stock dividends 1,341 357 Income (loss) before income taxes $ 7,948 $ 2,048 * $ (4,896) * $ (130) Economic income (loss) $ 7,567 $ (2,597) Nine Months Ended September 30, 2020 US GAAP Reclassifications and Adjustments Economic Income Net income (loss) Management Reclassifications Fund Consolidation Reclassifications (k) Income Statement Adjustments Operating Company Asset Company (dollars in thousands) Revenues Economic Proceeds Investment banking $ 503,351 $ (28,573) a, b $ — $ — Investment banking $ 474,778 $ — Brokerage 425,069 41,754 c, h — — Brokerage 466,823 — Management fees 35,211 5,672 d, e 1,475 — Management fees 41,724 634 Incentive income (loss) 127 40,827 e 33 — Incentive income (loss) 40,829 158 — 18,895 f — — Investment income (loss) 32,566 (13,671) Interest and dividends 127,547 (127,547) c — — — — Reimbursement from affiliates 777 (827) b 50 — — — Reinsurance premiums 18,943 (18,943) g — — — — Other revenue 4,709 (4,982) g (21) — Other revenues (298) 4 Consolidated Funds revenues 4,650 — (4,650) — — — Total revenues 1,120,384 (73,724) (3,113) — Total Economic proceeds 1,056,422 (12,875) Interest and dividend expense 125,850 (99,971) c — (3,394) l Interest expense 18,471 4,014 Total net revenues 994,534 26,247 (3,113) 3,394 Total Economic net proceeds 1,037,951 (16,889) Expenses Economic Costs Compensation & benefits 583,137 1,436 i — — Compensation & Benefits 582,480 2,093 — 111,880 e, j — (5,152) m Fixed non-compensation expense 106,350 378 — 121,864 j — — Variable non-compensation expense 121,846 18 Other non-compensation expense 286,666 (286,666) a, b, d, g, i — — — — Depreciation & amortization 17,324 — — (551) n Depreciation & Amortization 16,756 17 — 5,584 j — — Economic Non-Controlling Interest 5,584 — Consolidated Funds expenses 4,793 — (4,793) — — — Total expenses 891,920 (45,902) (4,793) (5,703) Total Economic costs 833,016 2,506 Other income (loss) 54,328 (82,006) e, f, h 27,678 — — — — — — 5,094 Preferred stock dividends 4,160 934 Income (loss) before income taxes $ 156,942 $ (9,857) * $ 29,358 * $ 4,003 Economic income (loss) $ 200,775 $ (20,329) Nine Months Ended September 30, 2019 US GAAP Reclassifications and Adjustments Economic Income Net income (loss) Management Reclassifications Fund Consolidation Reclassifications (k) Income Statement Adjustments Operating Company Asset Company (dollars in thousands) Revenues Economic Proceeds Investment banking $ 272,103 $ (17,729) a, b $ — $ — Investment banking $ 254,374 $ — Brokerage 302,840 43,255 c, h — — Brokerage 346,095 — Management fees 21,480 8,684 d, e 1,640 — Management fees 30,016 1,788 Incentive income (loss) 724 33,479 e 557 — Incentive income (loss) 33,998 762 — 19,116 f — — Investment income (loss) 13,827 5,289 Interest and dividends 129,846 (129,846) c — — — — Reimbursement from affiliates 780 (874) b 94 — — — Reinsurance premiums 29,068 (29,068) g — — — — Other revenue 3,228 2,109 g 14 — Other revenues 5,295 56 Consolidated Funds revenues 8,239 — (8,239) — — — Total revenues 768,308 (70,874) (5,934) — Total Economic proceeds 683,605 7,895 Interest and dividend expense 125,089 (101,464) c — (3,208) l Interest expense 16,371 4,046 Total net revenues 643,219 30,590 (5,934) 3,208 Total Economic net proceeds 667,234 3,849 Expenses Economic Costs Compensation & benefits 388,611 2,365 i — — Compensation & Benefits 386,593 4,383 — 112,038 e, j — (1,664) m Fixed non-compensation expense 107,889 2,485 — 113,855 j — — Variable non-compensation expense 113,728 127 Other non-compensation expense 276,054 (276,054) a, b, d, g, i — — — — Depreciation & amortization 14,990 (3) — — Depreciation & Amortization 14,957 30 — 2,944 j — — Economic Non-Controlling Interest 2,944 — Goodwill impairment 4,100 — — (4,100) n — — Consolidated Funds expenses 6,229 — (6,229) — — — Total expenses 689,984 (44,855) (6,229) (5,764) Total Economic costs 626,111 7,025 Other income (loss) 82,976 (73,907) e, f, h (9,069) — — — — — — 5,094 Preferred stock dividends 4,058 1,036 Income (loss) before income taxes $ 36,211 $ 1,538 * $ (8,774) * $ 3,878 Economic income (loss) $ 37,065 $ (4,212) Adjustments made to US GAAP Net Income (Loss) to arrive at Economic Income (Loss) Management Reclassifications Management reclassification adjustments and fund consolidation reclassification adjustments have no effect on economic income. These adjustments are reclassifications to change the location of certain line items. a Economic Income (Loss) presents underwriting expenses net of investment banking revenues. b Economic Income (Loss) presents expenses reimbursed from clients and affiliates within their respective expense category but is included as a part of revenues under US GAAP. c 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. d Economic Income (Loss) presents revenues net of fund start-up costs and distribution fees paid to agents. e Economic Income (Loss) recognizes the Company's proportionate share of management and incentive fees and associated share of expenses on a gross basis for certain real estate operating entities, the healthcare royalty business and the activist business. Additionally, carried interest, which the Company applies an equity ownership model to, is recorded in other income (loss) for US GAAP and is shown as incentive income for Economic Income (Loss). f Economic Income (Loss) recognizes Company income from proprietary trading (including interest and dividends) for which the majority of this activity is shown in other income (loss) for US GAAP reporting. g Economic Income (Loss) recognizes underwriting income from the Company's insurance related activities, net of expenses, within other revenue. The costs are recorded within expenses for US GAAP reporting. h Economic Income (Loss) recognizes gains and losses on investments held as part of the Company's facilitation and trading business within brokerage revenues as these investments are directly related to the markets business activities. i Economic Income (Loss) presents certain payments to associated banking partners as compensation rather than non-compensation expenses. j Economic Income (Loss) presents US GAAP expenses as either Fixed non-compensation or Variable non-compensation expenses. The Company also presents US GAAP Income (loss) attributable to non-controlling interests within total other expenses for Economic Income (Loss). * The remainder primarily represents non-controlling interest which is excluded from this reconciliation to income (loss) before income taxes. Fund Consolidation Reclassifications k 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). * The remainder primarily represents non-controlling interest which is excluded from this reconciliation to income (loss) before income taxes. Income Statement Adjustments l Economic Income (Loss) excludes the amortization of discount on convertible debt. m Economic Income (Loss) excludes acquisition related adjustments as management does not consider these items when evaluating the performance of the Company. n Economic Income (Loss) excludes goodwill and intangible impairment.

Regulatory Requirements Regulat

Regulatory Requirements Regulatory (Tables)	9 Months Ended
	Sep. 30, 2020
Regulatory [Abstract]
Computation of Net Capital under Securities and Exchange Commission Regulation	As of September 30, 2020, these regulated broker-dealers had regulatory net capital or financial resources, regulatory net capital requirements or minimum FCA or SFC requirement and excess as follows: Subsidiary Net Capital Minimum Net Capital Requirement Excess Net Capital (dollars in thousands) Cowen and Company $ 388,606 $ 3,043 $ 385,563 ATM Execution $ 4,015 $ 250 $ 3,765 Cowen Prime $ 19,432 $ 250 $ 19,182 Westminster $ 5,305 $ 250 $ 5,055 Cowen International Ltd $ 22,892 $ 17,882 $ 5,010 Cowen Execution Ltd $ 11,501 $ 4,333 $ 7,168 Cowen Asia $ 1,394 $ 387 $ 1,007

Guarantees and Off-Balance Sh_2

Guarantees and Off-Balance Sheet Arrangements Details (Tables)	9 Months Ended
	Sep. 30, 2020
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, 2020. 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 Spike Line BMO Harris Bank Canadian Imperial Bank of Commerce Texas Capital Bank 70,000 70,000 August 20, 2021 Unsecured committed spike line facility to cover short term increases in National Securities Clearing Corporation margin deposit requirements Revolving Credit Facility BMO Harris Bank 25,000 25,000 December 2, 2021 Unsecured Corporate Revolver Total Credit Lines $ 395,000 $ 395,000

Organization and Business (Deta

Organization and Business (Details)	9 Months Ended
	Sep. 30, 2020segmentdivision
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	9 Months Ended
	Sep. 30, 2020USD ($)cowenfund	Dec. 31, 2019USD ($)
Assets	$ 5,790,718	$ 5,162,025
Liabilities	4,609,517	3,866,575
Cumulative Effect of New Accounting Principle in Period of Adoption	10
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	(10)
Variable Interest Entity, Primary Beneficiary [Member]
Assets	449,000	685,400
Liabilities	$ 6,600	$ 24,900
Other investment companies
Number of Funds | cowenfund	5
Operating Company | Hedge Funds
Asset Management Fees, Percent Fee	2.00%
Operating Company | During investment period | Minimum
Asset Management Fees, Percent Fee	1.00%
Operating Company | During investment period | Maximum
Asset Management Fees, Percent Fee	2.00%
Operating Company | After investment period | Healthcare Royalty Partners | Minimum
Asset Management Fees, Percent Fee	1.00%
Operating Company | After investment period | Healthcare Royalty Partners | Maximum
Asset Management Fees, Percent Fee	2.00%
Operating Company | After investment period | Other Healthcare Royalty Partners | Minimum
Asset Management Fees, Percent Fee	0.20%
Operating Company | After investment period | Other Healthcare Royalty Partners | Maximum
Asset Management Fees, Percent Fee	1.00%

Significant Accounting Polici_5

Significant Accounting Policies All Other - Revenue From Contract With Customers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Organization [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 327,384	$ 175,943	$ 932,255	$ 583,682
Management Fees	11,954	7,300	35,211	21,480
Incentive income	127	701	127	724
Operating Company
Organization [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	327,151	175,695	931,536	582,680
Management Fees	11,721	7,052	34,492	20,492
Incentive income	127	701	127	710
Asset Company
Organization [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	233	248	719	1,002
Management Fees	233	248	719	988
Incentive income	0	0	0	14
Underwriting fees | Operating Company
Organization [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	121,390	38,936	318,355	162,140
Strategic/financial advisory fees | Operating Company
Organization [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	39,431	17,889	101,061	49,565
Placement and sales agent fees | Operating Company
Organization [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	28,427	15,842	71,999	48,855
Expense reimbursements from clients | Operating Company
Organization [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	5,093	4,625	11,936	11,543
Investment banking revenue | Operating Company
Organization [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	194,341	77,292	503,351	272,103
Brokerage | Operating Company
Organization [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	120,962	90,650	393,566	289,375
Commissions | Operating Company
Organization [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	112,953	82,715	367,564	263,831
Trade conversion | Operating Company
Organization [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	3,404	3,700	12,370	12,364
Equity and credit research fees | Operating Company
Organization [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 4,605	$ 4,235	$ 13,632	$ 13,180

Acquisition (Narrative) (Detail

Acquisition (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Jan. 02, 2019
Business Acquisition [Line Items]
Purchase of business			$ 0	$ 48,581,000
Revenues	$ 387,735,000	$ 252,047,000	1,120,384,000	768,308,000
Net income (loss) attributable to Cowen Inc.	20,284,000	3,813,000	124,196,000	19,408,000
Quarton
Business Acquisition [Line Items]
Total estimated purchase price				103,000,000
Purchase of business				75,300,000
Business combination, contingent consideration, liability						$ 40,000,000
Other payments to acquire businesses				600,000
Business combination, contingency liability, retention of employee, bonus pool, maximum				$ 10,000,000
Business combination, contingency liability, retention of employee, bonus pool, period				5 years
Business combination, contingency liability, retention of employee, bonus pool, annual maximum payout				$ 2,500,000
Intangible assets						22,200,000
Amortization of Intangible Assets	$ 2,200,000	6,700,000	$ 2,200,000	6,700,000
Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Cost Expensed		$ 100,000		$ 1,200,000
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						27,700,000
Minimum | Quarton
Business Acquisition [Line Items]
Business combination, contingent consideration, liability						10,000,000
Maximum | Quarton
Business Acquisition [Line Items]
Business combination, contingent consideration, liability						$ 40,000,000

Acquisition (Preliminary Purcha

Acquisition (Preliminary Purchase Price Allocation) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2020	Dec. 31, 2019	Jan. 02, 2019
Business Acquisition [Line Items]
Operating lease right-of-use assets		$ 80,805	$ 92,852
Operating lease liabilities		84,044	97,581
Goodwill		$ 137,728	$ 137,728
Quarton
Business Acquisition [Line Items]
Intangible assets				$ 22,200
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
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

Acquisition (Intangible Assets)

Acquisition (Intangible Assets) (Details) - Quarton - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jan. 02, 2019
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross					$ 22,200
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				2 years 9 months 18 days
Amortization of Intangible Assets	$ 2,200	$ 6,700	$ 2,200	$ 6,700
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 (Amortization Expen

Acquisition (Amortization Expense) (Details) - Quarton - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Business Acquisition [Line Items]
Amortization of Intangible Assets	$ 2,200	$ 6,700	$ 2,200	$ 6,700
Scenario, Plan
Business Acquisition [Line Items]
2020	2,227		2,227
2021	2,608		2,608
2022	1,775		1,775
2023	0		0
2024	0		0
Thereafter	0		0
Finite-Lived Intangible Assets, Net	$ 6,610		$ 6,610

Cash Collateral Pledged (Detail

Cash Collateral Pledged (Details) - USD ($)	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Cash collateral pledged	$ 110,666,000	$ 6,563,000	$ 18,609,000
Letter of credit, borrowing capacity	395,000,000
Letter of Credit | Letter of Credit, NY Office 1, Expires April 2021
Letter of credit, borrowing capacity	358,000
Letter of Credit | Letter of Credit, NY Office 3, Expires October 2020
Letter of credit, borrowing capacity	1,424,000
Letter of Credit | Letter of Credit, NY Office 5, Expires November 2020
Letter of credit, borrowing capacity	1,637,000
Letter of Credit | Letter of Credit, Boston Office, Expires March 2021
Letter of credit, borrowing capacity	386,000
Letter of Credit | Letter of Credit, San Francisco Office, Expires October 2025
Letter of credit, borrowing capacity	712,000
Facility Leases
Cash collateral pledged	4,517,000	4,600,000
Collateral Reinsurance Agreement
Cash collateral pledged	$ 106,100,000	$ 2,000,000

Segregated Cash (Details)

Segregated Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Segregated Cash [Abstract]
Segregated cash	$ 139,152	$ 107,328	$ 128,782

Investments of Operating Enti_3

Investments of Operating Entities and Consolidated Funds - Operating Entities - Securities Owned at Fair Value (Details) - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
Investment Holdings [Line Items]
Securities owned, at fair value ($254,383 and $941,595 were pledged to various parties)		$ 1,088,566	$ 1,633,552
Estimate of Fair Value Measurement [Member]
Investment Holdings [Line Items]
Securities owned, at fair value ($254,383 and $941,595 were pledged to various parties)		9,000	8,400
Common Stock
Investment Holdings [Line Items]
Trading Securities, Equity		920,849	1,546,484
Preferred Stock
Investment Holdings [Line Items]
Trading Securities, Equity		63,605	12,656
Warrants and Rights [Member]
Investment Holdings [Line Items]
Trading Securities, Equity		20,505	22,109
Government Securities
Investment Holdings [Line Items]
Debt Securities, Trading		20,324	15,916
Corporate Bonds
Investment Holdings [Line Items]
Debt Securities, Trading		36,701	25,500
Convertible Bonds
Investment Holdings [Line Items]
Debt Securities, Trading		5,081	2,500
Loans
Investment Holdings [Line Items]
Debt Securities, Trading	[1]	12,111	1,067
Trade Claims
Investment Holdings [Line Items]
Debt Securities, Trading	[1]	$ 9,390	$ 7,320
[1]	The Company has elected the fair value option for securities owned, at fair value with a fair value of $9.0 million and $8.4 million, respectively, at September 30, 2020 and December 31, 2019.

Investments Of Operating Enti_4

Investments Of Operating Entities And Consolidated Funds - Operating Entities - Receivable On And Payable For Derivative Contracts, At Fair Value (Details)		Sep. 30, 2020USD ($)contract	Dec. 31, 2019USD ($)contract
Derivative [Line Items]
Receivable on derivative contracts, at fair value		$ 58,194,000	$ 62,977,000
Payable for derivative contracts, at fair value		62,054,000	60,761,000
Futures
Derivative [Line Items]
Derivative Liability, Notional Amount		9,895,000	10,224,000
Payable for derivative contracts, at fair value		123,000	217,000
Currency Forwards
Derivative [Line Items]
Derivative Asset, Notional Amount		82,100,000	0
Receivable on derivative contracts, at fair value		870,000	0
Derivative Liability, Notional Amount		103,500,000	77,790,000
Payable for derivative contracts, at fair value		717,000	851,000
Swaps
Derivative [Line Items]
Derivative Asset, Notional Amount		244,090,000	383,752,000
Receivable on derivative contracts, at fair value		4,644,000	2,911,000
Derivative Liability, Notional Amount		376,331,000	607,717,000
Payable for derivative contracts, at fair value		$ 7,514,000	$ 23,169,000
Options
Derivative [Line Items]
Derivative Asset, Number of Instruments Held | contract	[1]	256,841	550,188
Receivable on derivative contracts, at fair value	[1]	$ 52,680,000	$ 60,066,000
Option
Derivative [Line Items]
Derivative Liability, Number of Instruments Held | contract	[2]	252,576	306,306
Payable for derivative contracts, at fair value	[2]	$ 53,700,000	$ 36,524,000
[1]	Includes the volume of contracts for index, equity, commodity future and cash conversion options.
[2]	Includes the volume of contracts for index, equity, commodity future and cash conversion options.

Investments Of Operating Enti_5

Investments Of Operating Entities And Consolidated Funds - Operating Entities - Gross And Net Derivative Positions And The Related Offsetting Amount (Details) - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
Derivative [Line Items]
Receivable on derivative contracts, at fair value		$ 58,194	$ 62,977
Payable for derivative contracts, at fair value		62,054	60,761
Receivable on derivatives contracts, at fair value [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset		80,780	66,217
Derivative Asset, Fair Value, Amount Offset Against Collateral	[1]	22,586	3,240
Receivable on derivative contracts, at fair value		58,194	62,977
Financial Instruments, Owned and Pledged as Collateral, at Fair Value		3,631	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral		60	2,911
Derivative asset, net of offset		54,503	60,066
Payable for derivatives contracts, at fair value [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability		67,295	64,001
Derivative Liability, Fair Value, Amount Offset Against Collateral	[1]	5,241	3,240
Payable for derivative contracts, at fair value		62,054	60,761
Financial Instruments, Owned and Pledged as Collateral, at Fair Value		3,631	0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral		2,777	24,020
Derivative Liability, net of offset		$ 55,646	$ 36,741
[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

Investments Of Operating Enti_6

Investments Of Operating Entities And Consolidated Funds - Operating Entities - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Derivative [Line Items]
Receivable from brokers, dealers and clearing organizations, net of allowance of $730 and $721, respectively	$ 1,390,821		$ 1,390,821		$ 681,695
Payables to brokers, dealers and clearing organizations	312,850		312,850		$ 271,018
Other Income [Member]
Derivative [Line Items]
Realized and unrealized gains/(losses) related to derivatives trading activities	$ (53,900)	$ 7,100	$ (63,200)	$ 2,300

Investments Of Operating Enti_7

Investments Of Operating Entities And Consolidated Funds - Operating Entities - Other Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2020		Dec. 31, 2019
Investment Holdings [Line Items]
Other investments	$ 204,610		$ 185,722
Portfolio Funds
Investment Holdings [Line Items]
Other investments	123,787	[1]	114,504
Carried interest
Investment Holdings [Line Items]
Other investments	47,343	[1]	30,360
Equity Method Investments
Investment Holdings [Line Items]
Other investments	$ 33,480		$ 40,858
[1]	In accordance with US GAAP, certain investments are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient. 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_8

Investments Of Operating Entities And Consolidated Funds - Operating Entities - Portfolio Funds (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2020		Dec. 31, 2019
Investment Holdings [Line Items]
Other investments		$ 204,610		$ 185,722
Portfolio Funds
Investment Holdings [Line Items]
Other investments		123,787	[1]	114,504
Starboard Value and Opportunity Fund LP | Portfolio Funds | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[2],[3]	$ 41,354		37,895
Required notice period, withdrawal		90 days
Formation 8 Partners Fund I LP | Portfolio Funds
Investment Holdings [Line Items]
Other investments	[4]	$ 31,916		33,613
RCGLongview Debt Fund V, L.P. | Portfolio Funds | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[3],[5]	1,232		1,732
Cowen Healthcare Investments II LP | Portfolio Funds | Affiliated Entity
Investment Holdings [Line Items]
Other investments		20,691	[3],[6]	14,652
Eclipse Ventures Fund I, L.P. | Portfolio Funds
Investment Holdings [Line Items]
Other investments	[7]	4,464		3,960
Healthcare Royalty Partners | Portfolio Funds | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[3],[8]	1,157		1,326
Lagunita Biosciences, LLC | Portfolio Funds
Investment Holdings [Line Items]
Other investments	[9]	4,124		4,802
Starboard Leaders Fund LP | Portfolio Funds | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[3],[10]	$ 1,656		1,560
Unfunded Commitment cancellation		30 days
Elipse SPV I,LP | Portfolio Funds | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[11]	$ 1,680	[3]	1,447
Triartisan ES Partners, LLC | Portfolio Funds | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[12]	1,342		1,082
Triartisan PFC Partners, LLC | Portfolio Funds | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[3],[13]	628		909
RCG Longview Equity Fund, LP | Portfolio Funds | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[5]	445	[3]	835
Healthcare Royalty Partners II | Portfolio Funds | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[3],[8]	1,627		1,781
Cowen Healthcare Investments III LP | Portfolio Funds | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[3],[6]	4,346		1,398
Difesa Partners LP [Member] | Portfolio Funds | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[3],[14]	681		508
Other Private Investment | Portfolio Funds | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[3],[15]	315		4,448
BDC Fund I Coinvest 1, L.P. | Portfolio Funds | Affiliated Entity
Investment Holdings [Line Items]
Other investments		1,250	[3],[16]	0
Other Funds | Portfolio Funds | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[3],[17]	2,927		2,556
Merger Fund | Portfolio Funds | Affiliated Entity
Investment Holdings [Line Items]
Other investments		$ 1,952	[3],[18]	$ 0
[1]	In accordance with US GAAP, certain investments are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient. 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]	Starboard Value and Opportunity Fund permits quarterly withdrawals upon 90 days' notice.
[3]	These Portfolio Funds are affiliates of the Company.
[4]	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.
[5]	RCG Longview Debt Fund V, L.P. and RCG Longview Equity Fund, 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.
[6]	Cowen Healthcare Investments II LP and Cowen Healthcare Investments III LP are private equity funds.  Distributions are made from the fund when cash flows or securities are received from the underlying investments. Investors do not have redemption rights
[7]	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.
[8]	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.
[9]	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.
[10]	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.
[11]	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.
[12]	TriArtisan ES Partners LLC is a co-investment vehicle organized to invest in a privately held nuclear services company. Distributions will be made when the underlying investment is liquidated.
[13]	TriArtisan PFC Partners LLC is a co-investment vehicle organized to invest in a privately held casual dining restaurant chain. Distributions will be made when the underlying investment in liquidated.
[14]	Difesa Partners, LP permits semi-annual withdrawals occurring on or after the anniversary of initial contribution upon 90 days written notice.
[15]	Other private investment represents the Company's closed end investment in a Portfolio Fund that invests in a wireless broadband communication provider in Italy.
[16]	BDC Fund I Coinvest 1, L.P. is a private equity fund focused on investing in growth companies in industries disrupted by digitization. Distributions will be made when the underlying investments are liquidated.
[17]	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.
[18]	Ramius Merger Fund LLC permits monthly withdrawals on 45 days prior notice.

Investments of Operating Enti_9

Investments of Operating Entities and Consolidated Funds - Operating Entities - Carried Interest (Details) - USD ($) $ in Thousands		Sep. 30, 2020		Dec. 31, 2019
Investment Holdings [Line Items]
Other investments		$ 204,610		$ 185,722
Carried interest
Investment Holdings [Line Items]
Other investments		47,343	[1]	30,360
Cowen Healthcare Investments II LP | Carried interest | Affiliated Entity
Investment Holdings [Line Items]
Other investments		35,829		23,759
Cowen Healthcare Investments III LP | Carried interest | Affiliated Entity
Investment Holdings [Line Items]
Other investments		5,357		0
Triartisan TGIF Partners LLC | Carried interest | Affiliated Entity
Investment Holdings [Line Items]
Other investments		2,881		0
Triartisan ES Partners, LLC | Carried interest | Affiliated Entity
Investment Holdings [Line Items]
Other investments		1,354		0
Triartisan PFC Partners, LLC | Carried interest | Affiliated Entity
Investment Holdings [Line Items]
Other investments		1,116		0
Ramius Multi-Strategy Fund LP | Carried interest | Affiliated Entity
Investment Holdings [Line Items]
Other investments		612		0
Merger Fund | Carried interest | Affiliated Entity
Investment Holdings [Line Items]
Other investments		13		0
Other Private Investment | Carried interest | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[2]	0		4,737
RCG IO Renergys Sarl | Carried interest | Affiliated Entity
Investment Holdings [Line Items]
Other investments		181		1,251
Ramius Mutli-Strategy Fund LP | Carried interest | Affiliated Entity
Investment Holdings [Line Items]
Other investments		$ 0		$ 613
[1]	In accordance with US GAAP, certain investments are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient. 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]	Other private investment represents the Company's closed end investment in a Portfolio Fund that invests in a wireless broadband communication provider in Italy.

Investments of Operating Ent_10

Investments of Operating Entities and Consolidated Funds - Operating Entities - Equity Method Investment - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Schedule of Equity Method Investments [Line Items]
Other than Temporary Impairment Losses, Investments				$ 0
Surf House Ocean Views Holdings, LLC
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	40.00%		40.00%
Other than Temporary Impairment Losses, Investments			$ 11,300
Net Gains (Losses) on Securities, Derivatives and Other Investments
Schedule of Equity Method Investments [Line Items]
Income (Loss) from Equity Method Investments	$ 4,000	$ 2,700	$ 10,500	$ 23,100
Minimum
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	15.00%		15.00%
Maximum
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	55.00%		55.00%

Investments of Operating Ent_11

Investments of Operating Entities and Consolidated Funds - Operating Entities - Equity Method Investment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 33,480		$ 33,480		$ 40,858
Net Gains (Losses) on Securities, Derivatives and Other Investments
Schedule of Equity Method Investments [Line Items]
Income (Loss) from Equity Method Investments	4,000	$ 2,700	10,500	$ 23,100
Surf House Ocean Views Holdings, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	0		0		7,804
Starboard Value LP
Schedule of Equity Method Investments [Line Items]
Equity method investments	25,392		25,392		24,292
RCG Longview Debt Fund V Partners, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	1,721		1,721		2,889
RCG Longview Management, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	253		253		583
Healthcare Royalty GP, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	675		675		108
Healthcare Royalty GP II, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	276		276		302
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	2,198		2,198		2,230
RCG Longview Equity Management, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	105		105		105
HCR Stafford Fund GP, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments	850		850		880
Liberty Harbor North
Schedule of Equity Method Investments [Line Items]
Equity method investments	292		292		292
Equity Method Investee, Other
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 1,387		$ 1,387		$ 1,042

Investments of Operating Ent_12

Investments of Operating Entities and Consolidated Funds - Operating Entities - Regulation S-X (Details) - Equity Method Investee, Exceeded Threshold for Income Test [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Summarized Financial Information, Assets	$ 59,379		$ 59,379		$ 95,825
Liabilities	0		0		82,482
Equity	59,379		59,379		$ 13,343
Revenue	274	$ 4,564	54,717	$ 83,287
Expenses	0	0	0	0
Net realized and unrealized gain (loss)	77	55	412	717
Net Income	$ 351	$ 4,619	$ 55,129	$ 84,004

Investments of Operating Ent_13

Investments of Operating Entities and Consolidated Funds - Operating Entities - Securities Sold, Not Yet Purchased (Details) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, at fair value	$ 440,930,000	$ 451,836,000
Common Stock
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, at fair value	404,409,000	425,448,000
Corporate Bonds
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, at fair value	15,324,000	5,933,000
US Government Debt Securities
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, at fair value	1,500,000	1,950,000
Preferred Stock
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, at fair value	10,767,000	3,686,000
Warrants and Rights [Member]
Investments Sold, Not yet Purchased [Line Items]
Securities sold, not yet purchased, at fair value	$ 8,930,000	$ 14,819,000

Investments of Operating Ent_14

Investments of Operating Entities and Consolidated Funds - Operating Entities - Securities Sold Under Agreements To Repurchase And Securities Lending And Borrowing Transactions (Details) - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Securities borrowed		$ 1,272,428	$ 754,441
Securities Borrowed, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election	[1]	0	0
Securities Borrowed		1,272,428	754,441
Securities borrowed, additional amounts, asset		0	0
Securities Borrowed, Not Offset, Policy Election Deduction		1,213,253	751,913
Securities Borrowed, Collateral, Obligation to Return Cash	[2]	0	0
Securities Borrowed, Amount Offset Against Collateral		59,175	2,528
Securities Loaned		1,326,917	1,601,866
Securities Loaned, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election	[1]	0	0
Securities Loaned, Gross amounts recognized		1,326,917	1,601,866
Securities Loaned, Additional Amounts Available		0	0
Securities Loaned, Not Offset, Policy Election Deduction		1,278,129	1,585,036
Securities Loaned, Collateral, Right to Reclaim Cash	[2]	0	0
Securities Loaned, Amount Offset Against Collateral		48,788	16,830
Securities Sold under Agreements to Repurchase, Asset		6,218	23,244
Securities Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement		0	0
Securities Sold under Agreements to Repurchase		6,218	23,244
Securities sold under agreements to repurchase, additional amounts		0	0
Securities sold under agreements to repurchase		7,587	27,384
Securities borrowed, cash collateral pledged		0	0
Securities Loaned, Net amounts		$ (1,369)	$ (4,140)
[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_15

Investments of Operating Entities and Consolidated Funds - Operating Entities - Gross Obligations For Securities Loaned And Securities Sold Under Agreements To Repurchase (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Common stock	$ 1,326,917	$ 1,601,866
Securities sold, not yet purchased, at fair value	440,930	451,836
Common stock
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Common stock	933,956	1,343,478
Common stock | Open and Overnight
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Common stock	933,956	1,343,478
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	392,961	258,388
Securities sold, not yet purchased, at fair value	6,218	23,244
Corporate Bonds | Open and Overnight
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Common stock	392,961	258,388
Securities sold, not yet purchased, at fair value	0	0
Corporate Bonds | Up to 30 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Common stock	0	0
Securities sold, not yet purchased, at fair value	0	0
Corporate Bonds | 31 - 90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Common stock	0	0
Securities sold, not yet purchased, at fair value	6,218	23,244
Corporate Bonds | Greater than 90 days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Common stock	0	0
Securities sold, not yet purchased, at fair value	$ 0	$ 0

Investments of Operating Ent_16

Investments of Operating Entities and Consolidated Funds - Operating Entities - Variable Interest Entities (Details) - Variable Interest Entity, Not Primary Beneficiary - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Total assets of nonconsolidated variable interest entities	$ 7,100	$ 6,100
Total liabilities of nonconsolidated variable interest entities	1,100	617.5
Variable Interest Entity, Nonconsolidated, Comparison of Carrying Amount of Assets and Liabilities to Maximum Loss Exposure	127.6	241.2
Maximum exposure regarding nonconsolidated variable interest entities	$ 244.5	$ 261.7

Investments of Operating Ent_17

Investments of Operating Entities and Consolidated Funds - Consolidated Funds - Securities Owned at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Investment Holdings [Line Items]
Securities owned, at fair value	$ 187,991	$ 375,278
Preferred Stock
Investment Holdings [Line Items]
Securities owned, at fair value	0	4,393
Common Stock
Investment Holdings [Line Items]
Securities owned, at fair value	106,549	200,306
Government Securities
Investment Holdings [Line Items]
Securities owned, at fair value	0	161,607
Corporate Bonds
Investment Holdings [Line Items]
Securities owned, at fair value	0	3,405
Warrants and Rights [Member]
Investment Holdings [Line Items]
Securities owned, at fair value	5,904	5,567
Convertible Bonds
Investment Holdings [Line Items]
Securities owned, at fair value	$ 75,538	$ 0

Investments Of Operating Ent_18

Investments Of Operating Entities And Consolidated Funds - Consolidated Funds - Receivable On And Payable For Derivative Contracts, At Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Derivative [Line Items]
Receivable on derivative contracts, at fair value, Consolidated Funds	$ 0	$ 5,833
Payable for derivative contracts, at fair value, Consolidated Funds	0	4,769
Currency Forwards
Derivative [Line Items]
Receivable on derivative contracts, at fair value, Consolidated Funds	0	3,302
Payable for derivative contracts, at fair value, Consolidated Funds	0	88
Equity Swap
Derivative [Line Items]
Receivable on derivative contracts, at fair value, Consolidated Funds	0	927
Payable for derivative contracts, at fair value, Consolidated Funds	0	3,931
Options
Derivative [Line Items]
Receivable on derivative contracts, at fair value, Consolidated Funds	0	1,604
Payable for derivative contracts, at fair value, Consolidated Funds	$ 0	$ 750

Investments Of Operating Ent_19

Investments Of Operating Entities And Consolidated Funds - Consolidated Funds - Other Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Investment Holdings [Line Items]
Portfolio Funds, Consolidated Funds	$ 98,267	$ 175,769
Enterprise LP [Member]
Investment Holdings [Line Items]
Portfolio Funds, Consolidated Funds	98,016	99,153
Merger Fund
Investment Holdings [Line Items]
Portfolio Funds, Consolidated Funds	0	76,616
Prodigy HoldCo
Investment Holdings [Line Items]
Portfolio Funds, Consolidated Funds	$ 251	$ 0

Investments Of Operating Ent_20

Investments Of Operating Entities And Consolidated Funds - Consolidated Funds - Indirect Concentration of the Underlying Investments Held by Consolidated Funds (Details) - Equity Securities - Linkem - ITALY - Wireless Broadband - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Investment Holdings [Line Items]
Percentage of Stockholders' Equity	9.01%	9.53%
Market Value	$ 82,074	$ 77,142

Investments Of Operating Ent_21

Investments Of Operating Entities And Consolidated Funds - Consolidated Funds - Securities Owned By Enterprise Master (Details) - USD ($) $ in Thousands		Sep. 30, 2020		Dec. 31, 2019
Investment Holdings [Line Items]
Securities owned, at fair value ($254,383 and $941,595 were pledged to various parties)		$ 1,088,566		$ 1,633,552
Other investments		204,610		185,722
Portfolio Funds
Investment Holdings [Line Items]
Other investments		123,787	[1]	114,504
Portfolio Funds | Other Private Investment | Affiliated Entity
Investment Holdings [Line Items]
Other investments	[2],[3]	$ 315		$ 4,448
[1]	In accordance with US GAAP, certain investments are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient. 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]	Other private investment represents the Company's closed end investment in a Portfolio Fund that invests in a wireless broadband communication provider in Italy.
[3]	These Portfolio Funds are affiliates of the Company.

Investments of Operating Ent_22

Investments of Operating Entities and Consolidated Funds - Consolidated Funds - Securities Owned and Sold By Merger Master (Details) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Investment Holdings [Line Items]
Securities owned, at fair value ($254,383 and $941,595 were pledged to various parties)	$ 1,088,566,000	$ 1,633,552,000
Securities sold, not yet purchased, at fair value	440,930,000	451,836,000
Portfolio Funds, Consolidated Funds	98,267,000	175,769,000
Merger Master
Investment Holdings [Line Items]
Securities owned, at fair value ($254,383 and $941,595 were pledged to various parties)		79,353,000
Securities sold, not yet purchased, at fair value		68,150,000
Merger Fund
Investment Holdings [Line Items]
Portfolio Funds, Consolidated Funds	0	76,616,000
Common Stock
Investment Holdings [Line Items]
Securities sold, not yet purchased, at fair value	404,409,000	425,448,000
Common Stock | Merger Master
Investment Holdings [Line Items]
Securities owned, at fair value ($254,383 and $941,595 were pledged to various parties)		76,531,000
Securities sold, not yet purchased, at fair value		29,623,000
Warrants and Rights [Member]
Investment Holdings [Line Items]
Securities sold, not yet purchased, at fair value	8,930,000	14,819,000
Warrants and Rights [Member] | Merger Master
Investment Holdings [Line Items]
Securities owned, at fair value ($254,383 and $941,595 were pledged to various parties)		748,000
Corporate Bonds
Investment Holdings [Line Items]
Securities sold, not yet purchased, at fair value	$ 15,324,000	5,933,000
Corporate Bonds | Merger Master
Investment Holdings [Line Items]
Securities owned, at fair value ($254,383 and $941,595 were pledged to various parties)		2,074,000
Exchange Traded Funds | Merger Master
Investment Holdings [Line Items]
Securities sold, not yet purchased, at fair value		$ 38,527,000

Investments of Operating Ent_23

Investments of Operating Entities and Consolidated Funds - Consolidated Funds - Receivable on/Payable For Derivative Contracts (Details) - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
Derivative [Line Items]
Receivable on derivative contracts, at fair value		$ 58,194	$ 62,977
Payable for derivative contracts, at fair value		62,054	60,761
Merger Master
Derivative [Line Items]
Receivable on derivative contracts, at fair value			2,453
Payable for derivative contracts, at fair value			1,426
Options
Derivative [Line Items]
Receivable on derivative contracts, at fair value	[1]	52,680	60,066
Options | Merger Master
Derivative [Line Items]
Receivable on derivative contracts, at fair value			2,047
Option
Derivative [Line Items]
Payable for derivative contracts, at fair value	[2]	53,700	36,524
Option | Merger Master
Derivative [Line Items]
Payable for derivative contracts, at fair value			1,158
Currency Forwards
Derivative [Line Items]
Receivable on derivative contracts, at fair value		870	0
Payable for derivative contracts, at fair value		717	851
Swaps
Derivative [Line Items]
Receivable on derivative contracts, at fair value		4,644	2,911
Payable for derivative contracts, at fair value		$ 7,514	23,169
Swaps | Merger Master
Derivative [Line Items]
Receivable on derivative contracts, at fair value			406
Payable for derivative contracts, at fair value			$ 268
[1]	Includes the volume of contracts for index, equity, commodity future and cash conversion options.
[2]	Includes the volume of contracts for index, equity, commodity future and cash conversion options.

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, 2020		Jun. 30, 2020	Dec. 31, 2019		Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value		$ 58,194			$ 62,977
Other investments		204,610			185,722
Other Investments, Consolidated Funds		98,267			175,769
Investments		1,637,628			2,439,131
Securities sold, not yet purchased, at fair value		440,930			451,836
Securities sold, not yet purchased, at fair value		440,930			451,836
Payable for derivative contracts, at fair value		62,054			60,761
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, Low		900			1,300
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High		$ 35,100			$ 40,000
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of Total Assets at Fair Value		75.10%			95.90%
Percentage of Total Liabilities at Fair Value		89.10%			87.30%
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of Total Assets at Fair Value		3.20%			1.70%
Percentage of Total Liabilities at Fair Value		4.30%			6.00%
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of Total Assets at Fair Value		21.70%			2.30%
Balance Liability Value		$ 35,278			$ 36,766
Percentage of Total Liabilities at Fair Value		6.60%			6.70%
Contingent liability payable
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance Liability Value		$ 30,024		$ 27,001	$ 30,896		$ 29,834	$ 29,536	$ 3,070
Futures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value		123			217
Swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value		4,644			2,911
Payable for derivative contracts, at fair value		7,514			23,169
Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value	[1]	52,680			60,066
Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance Liability Value		800		$ 800
Portfolio Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments		123,787	[2]		114,504
Other Investments, Consolidated Funds		98,267	[2]		175,769
Carried interest
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments		47,343	[2]		30,360
Equity Method Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments		33,480			40,858
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Recurring		1,334,751			2,077,640
Investment Sold, Not yet Purchased and Derivative Liability, at Fair Value		533,008			548,262
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Recurring		1,002,845			1,993,268
Investment Sold, Not yet Purchased and Derivative Liability, at Fair Value		474,975			478,524
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Recurring		42,203			35,940
Investment Sold, Not yet Purchased and Derivative Liability, at Fair Value		22,755			32,972
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Recurring		289,703			48,432
Investment Sold, Not yet Purchased and Derivative Liability, at Fair Value		35,278			36,766
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		404,409			425,448
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		404,409			425,448
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		15,324			5,933
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		14,524			4,933
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		800			1,000
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		10,767			3,686
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		10,767			3,686
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 | Warrants and Rights [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		8,930			14,819
Fair Value, Measurements, Recurring | Warrants and Rights [Member] | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities sold, not yet purchased, at fair value		8,930			14,819
Fair Value, Measurements, Recurring | Warrants and Rights [Member] | 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 [Member] | 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		30,024	[3]		30,896
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	[3]		0	[4]
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	[3]		0	[4]
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	[4]				30,896
Fair Value, Measurements, Recurring | Futures | Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value		123			217
Fair Value, Measurements, Recurring | Futures | Options | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value		123			217
Fair Value, Measurements, Recurring | Futures | Options | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value		0			0
Fair Value, Measurements, Recurring | Futures | Options | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value		0			0
Fair Value, Measurements, Recurring | Currency forward | Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value		717			851
Fair Value, Measurements, Recurring | Currency forward | Options | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value		0			0
Fair Value, Measurements, Recurring | Currency forward | Options | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value		717			851
Fair Value, Measurements, Recurring | Currency forward | Options | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value		0			0
Fair Value, Measurements, Recurring | Swaps | Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value		7,514			23,169
Fair Value, Measurements, Recurring | Swaps | Options | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value		0			0
Fair Value, Measurements, Recurring | Swaps | Options | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value		7,514			23,169
Fair Value, Measurements, Recurring | Swaps | Options | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value		0			0
Fair Value, Measurements, Recurring | Options | Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value		53,700			36,524
Fair Value, Measurements, Recurring | Options | Options | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value		50,746			33,604
Fair Value, Measurements, Recurring | Options | Options | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value		0			0
Fair Value, Measurements, Recurring | Options | Options | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value					2,920
Fair Value, Measurements, Recurring | Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		20,324			15,916
Fair Value, Measurements, Recurring | Government Securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		20,324			15,916
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		63,605			12,656
Fair Value, Measurements, Recurring | Preferred Stock | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		10,187			4,821
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		53,418			7,835
Fair Value, Measurements, Recurring | Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		920,849			1,546,484
Fair Value, Measurements, Recurring | Common Stock | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		900,885			1,527,769
Fair Value, Measurements, Recurring | Common Stock | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		508			1,249
Fair Value, Measurements, Recurring | Common Stock | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		19,456			17,466
Fair Value, Measurements, Recurring | Convertible Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		5,081			2,500
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		5,081			2,500
Fair Value, Measurements, Recurring | Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		36,701			25,500
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		36,181			23,079
Fair Value, Measurements, Recurring | Corporate Bonds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		520			2,421
Fair Value, Measurements, Recurring | Trade Claims
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		9,390			7,320
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		9,390			7,320
Fair Value, Measurements, Recurring | Warrants and Rights [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		20,505			22,109
Fair Value, Measurements, Recurring | Warrants and Rights [Member] | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		15,522			21,515
Fair Value, Measurements, Recurring | Warrants and Rights [Member] | 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 [Member] | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		4,983			594
Fair Value, Measurements, Recurring | Derivative Assets | Currency forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value		870
Fair Value, Measurements, Recurring | Derivative Assets | Currency forward | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value		0
Fair Value, Measurements, Recurring | Derivative Assets | Currency forward | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value		870
Fair Value, Measurements, Recurring | Derivative Assets | Currency forward | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value		0
Fair Value, Measurements, Recurring | Derivative Assets | Swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value		4,644			2,911
Fair Value, Measurements, Recurring | Derivative Assets | Swaps | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value		0			0
Fair Value, Measurements, Recurring | Derivative Assets | Swaps | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value		4,644			2,911
Fair Value, Measurements, Recurring | Derivative Assets | Swaps | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value		0			0
Fair Value, Measurements, Recurring | Derivative Assets | Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value		52,680			60,066
Fair Value, Measurements, Recurring | Derivative Assets | Options | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value		52,329			59,730
Fair Value, Measurements, Recurring | Derivative Assets | Options | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value		0			0
Fair Value, Measurements, Recurring | Derivative Assets | Options | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value		351			336
Fair Value, Measurements, Recurring | Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		12,111			1,067
Fair Value, Measurements, Recurring | Loans | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		0			0
Fair Value, Measurements, Recurring | Loans | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		0			1,067
Fair Value, Measurements, Recurring | Loans | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		12,111			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		1,500			1,950
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			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			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		1,500			1,950
Fair Value, Measurements, Recurring | Consolidated Funds | Currency forward | Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value					88
Fair Value, Measurements, Recurring | Consolidated Funds | Currency forward | Options | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value					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]
Payable for derivative contracts, at fair value					88
Fair Value, Measurements, Recurring | Consolidated Funds | Currency forward | Options | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value					0
Fair Value, Measurements, Recurring | Consolidated Funds | Options | Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value					750
Fair Value, Measurements, Recurring | Consolidated Funds | Options | Options | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value					750
Fair Value, Measurements, Recurring | Consolidated Funds | Options | Options | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value					0
Fair Value, Measurements, Recurring | Consolidated Funds | Options | Options | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value					0
Fair Value, Measurements, Recurring | Consolidated Funds | Equity Swap | Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value					3,931
Fair Value, Measurements, Recurring | Consolidated Funds | Equity Swap | Options | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value					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]
Payable for derivative contracts, at fair value					3,931
Fair Value, Measurements, Recurring | Consolidated Funds | Equity Swap | Options | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payable for derivative contracts, at fair value					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					161,607
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					161,607
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
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
Fair Value, Measurements, Recurring | Consolidated Funds | Preferred Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity					4,393
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					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
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
Fair Value, Measurements, Recurring | Consolidated Funds | Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		106,549			200,306
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		3,598			200,306
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		102,951			0
Fair Value, Measurements, Recurring | Consolidated Funds | Convertible Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		75,538
Fair Value, Measurements, Recurring | Consolidated Funds | Convertible Bonds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		0
Fair Value, Measurements, Recurring | Consolidated Funds | Convertible Bonds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		0
Fair Value, Measurements, Recurring | Consolidated Funds | Convertible Bonds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading		75,538
Fair Value, Measurements, Recurring | Consolidated Funds | Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Trading					3,405
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
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					3,405
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
Fair Value, Measurements, Recurring | Consolidated Funds | Warrants and Rights [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		5,904			5,567
Fair Value, Measurements, Recurring | Consolidated Funds | Warrants and Rights [Member] | 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 [Member] | 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 [Member] | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		$ 5,904			5,567
Fair Value, Measurements, Recurring | Consolidated Funds | Derivative Assets | Currency forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value					3,302
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]
Receivable on derivative contracts, at fair value					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]
Receivable on derivative contracts, at fair value					3,302
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]
Receivable on derivative contracts, at fair value					0
Fair Value, Measurements, Recurring | Consolidated Funds | Derivative Assets | Options
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value					1,604
Fair Value, Measurements, Recurring | Consolidated Funds | Derivative Assets | Options | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value					1,604
Fair Value, Measurements, Recurring | Consolidated Funds | Derivative Assets | Options | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value					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]
Receivable on derivative contracts, at fair value					0
Fair Value, Measurements, Recurring | Consolidated Funds | Derivative Assets | Equity Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Receivable on derivative contracts, at fair value					927
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]
Receivable on derivative contracts, at fair value					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]
Receivable on derivative contracts, at fair value					927
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]
Receivable on derivative contracts, at fair value					$ 0
[1]	Includes the volume of contracts for index, equity, commodity future and cash conversion options.
[2]	In accordance with US GAAP, certain investments are measured at fair value using the net asset value per share (or its equivalent) as a practical expedient. 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 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 31, 2019 and December 31, 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, 2020 can range from $0.9 million to $35.1 million.
[4]	The undiscounted amounts as of December 31, 2019 can range from $1.3 million to $40.0 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, 2020		Sep. 30, 2019		Sep. 30, 2020		Sep. 30, 2019		Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Preferred Stock
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value	$ 53,418,000		$ 7,835,000		$ 53,418,000		$ 7,835,000		$ 51,480,000	$ 7,835,000	$ 7,401,000	$ 5,168,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0		0		45,530,000	[1]	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	7,744,000	[2]	1,000,000	[3]	7,744,000	[2]	1,000,000	[3]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	5,282,000		0		5,647,000		3,243,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	3,770,000		0		5,870,000		1,000,000
Realized and unrealized gains (losses), asset	8,170,000		1,434,000		8,020,000		1,424,000
Change in Unrealized Gain (Loss), instruments still held, asset	2,926,000		2,295,000		5,337,000		2,285,000
Common Stock
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value	19,456,000		13,313,000		19,456,000		13,313,000		14,816,000	17,466,000	11,006,000	9,850,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	3,000	[4]	0		29,000	[4],[5]	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	4,000,000		2,579,000		5,798,000		16,737,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0		480,000		3,712,000		12,952,000
Realized and unrealized gains (losses), asset	643,000		208,000		(67,000)		(322,000)
Change in Unrealized Gain (Loss), instruments still held, asset	562,000		210,000		(1,023,000)		(122,000)
Convertible Bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value	5,081,000		2,541,000		5,081,000		2,541,000		5,081,000	2,500,000	6,318,000	3,000,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0		2,801,000	[3]	0		4,826,000	[2],[3]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0		1,049,000		2,581,000		16,021,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0		2,072,000		0		11,764,000
Realized and unrealized gains (losses), asset	0		47,000		0		110,000
Change in Unrealized Gain (Loss), instruments still held, asset	0		4,000		0		41,000
Corporate Bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value	520,000		2,073,000		520,000		2,073,000		758,000	2,421,000	775,000	0
Balance Liability Value	800,000				800,000				800,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0		20,000	[4]	0		20,000	[4]
Liability, Transfers In	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	312,000	[2]	0		312,000	[2]	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	72,000		1,117,000		592,000		1,892,000
Liability, Purchases	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0		0		1,938,000		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales	0
Realized and unrealized gains (losses), asset	2,000		161,000		(243,000)		161,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	0
Change in Unrealized Gain (Loss), instruments still held, asset	22,000		161,000		(180,000)		161,000
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss)	0
Options
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value	351,000				351,000				337,000	336,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0				0
Realized and unrealized gains (losses), asset	14,000				15,000
Change in Unrealized Gain (Loss), instruments still held, asset	14,000				15,000
Warrants and Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value	4,983,000		584,000		4,983,000		584,000		4,625,000	594,000	595,000	1,666,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	3,000	[4]	0		3,636,000	[1],[5]	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0		72,000		0		188,000
Realized and unrealized gains (losses), asset	355,000		61,000		753,000		(894,000)
Change in Unrealized Gain (Loss), instruments still held, asset	337,000		(12,000)		753,000		20,000
Trade Claims
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value	9,390,000		7,062,000		9,390,000		7,062,000		7,587,000	7,320,000	10,488,000	5,543,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0		0		1,044,000	[4],[5]	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	2,690,000		1,871,000		4,663,000		6,965,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	648,000		5,354,000		2,863,000		5,506,000
Realized and unrealized gains (losses), asset	(239,000)		57,000		(774,000)		60,000
Change in Unrealized Gain (Loss), instruments still held, asset	(239,000)		57,000		(795,000)		57,000
US Government Debt Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Liability Value	1,500,000				1,500,000				1,500,000
Liability, Transfers In	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3	0
Liability, Purchases	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	0
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss)	0
Loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value	12,111,000				12,111,000				11,359,000	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0				11,149,000	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	245,000				245,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0				0
Realized and unrealized gains (losses), asset	507,000				717,000
Change in Unrealized Gain (Loss), instruments still held, asset	506,000				717,000
Consolidated Funds | Preferred Stock
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value	0		4,393,000		0		4,393,000			4,393,000	24,322,000	24,314,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3			0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3			19,929,000	[3]	4,000,000	[6]	19,929,000	[3]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases			0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales			0		0		0
Realized and unrealized gains (losses), asset			0		(393,000)		8,000
Change in Unrealized Gain (Loss), instruments still held, asset			0		0		8,000
Consolidated Funds | Common Stock
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value	102,951,000		0		102,951,000		0		102,951,000	0	1,017,000	94,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0		0		4,000,000	[6]	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0		94,000	[3]	0		94,000	[3]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0		0		100,000,000		407,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0		957,000		0		958,000
Realized and unrealized gains (losses), asset	0		34,000		(1,049,000)		551,000
Change in Unrealized Gain (Loss), instruments still held, asset	0		0		(1,049,000)		0
Consolidated Funds | Convertible Bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value	75,538,000				75,538,000				0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0				0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	75,000,000				75,000,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0				0
Realized and unrealized gains (losses), asset	538,000				538,000
Change in Unrealized Gain (Loss), instruments still held, asset	538,000				538,000
Consolidated Funds | Warrants and Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value	5,904,000		5,465,000		5,904,000		5,465,000		5,858,000	5,567,000	6,274,000	5,279,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0		670,000		0		1,758,000
Realized and unrealized gains (losses), asset	46,000		(139,000)		337,000		1,944,000
Change in Unrealized Gain (Loss), instruments still held, asset	46,000		(809,000)		337,000		190,000
Option
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Liability Value	2,954,000		2,500,000		2,954,000		2,500,000		2,177,000	2,920,000	2,779,000	2,096,000
Liability, Transfers In	0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3	0		0		0		0
Liability, Purchases	0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales	0		0		0		4,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	(777,000)		279,000		(34,000)		(408,000)
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss)	777,000		(279,000)		35,000		408,000
Contingent liability payable
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Liability Value	30,024,000		29,834,000		30,024,000		29,834,000		$ 27,001,000	30,896,000	29,536,000	3,070,000
Liability, Transfers In	0		0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3	0		0		0		0
Liability, Purchases	0		0		0		27,700,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales	0		0		5,653,000		1,234,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	(3,023,000)		(298,000)		(4,781,000)		(298,000)
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss)	3,023,000		298,000		4,781,000		298,000
Corporate Bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value	800,000		1,200,000		800,000		1,200,000			1,000,000	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3			2,525,000	[4]	0		2,525,000	[4]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3			0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases			0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales			0		0		0
Realized and unrealized gains (losses), asset			(1,325,000)		(200,000)		(1,325,000)
Change in Unrealized Gain (Loss), instruments still held, asset			(1,325,000)		(200,000)
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss)							(1,325,000)
US Government Debt Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance Asset Value	$ 1,500,000		2,250,000		1,500,000		2,250,000			$ 1,950,000	$ 0	$ 0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3			4,681,000	[4]	0		4,681,000	[4]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3			0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases			0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales			0		0		0
Realized and unrealized gains (losses), asset			(2,431,000)		(450,000)		(2,431,000)
Change in Unrealized Gain (Loss), instruments still held, asset			$ (2,431,000)		$ (450,000)
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss)							$ (2,431,000)
[1]	The Company consolidated an operating entity which holds preferred stock, loans and warrants.
[2]	The investments were converted to common stock.
[3]	The entity in which the Company is invested completed an initial public offering
[4]	The transfers between level 1 and level 3 are due to the change in the availability of observable inputs.
[5]	The security stopped trading on an open market.
[6]	The investment was involved in a reverse merger and preferred stock was converted to common shares.

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, 2020		Dec. 31, 2019	Jun. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Contingent liability payable
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Liability Value		$ 30,024		$ 30,896	$ 27,001	$ 29,834	$ 29,536	$ 3,070
Options
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		351		336	337
Trade Claims
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		9,390		7,320	7,587	7,062	10,488	5,543
Warrants and Rights [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		4,983		594	4,625	584	595	1,666
Corporate Bonds
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		520		2,421	758	$ 2,073	$ 775	$ 0
Balance Liability Value		800			$ 800
Level 3
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		289,703		48,432
Balance Liability Value		35,278		36,766
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		$ 30,024	[1]	$ 30,896
Level 3 | Contingent liability payable | Valuation Technique, Discounted Cash Flow
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Weighted average percent Fair Value technique		15.00%		15.00%
Level 3 | Contingent liability payable | Valuation Technique, Discounted Cash Flow | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		15.00%		15.00%
Level 3 | Contingent liability payable | Valuation Technique, Discounted Cash Flow | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		22.00%		22.00%
Level 3 | Contingent liability payable | Monte Carlo [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		22.00%		17.00%
Weighted average percent Fair Value technique		22.00%		17.00%
Level 3 | Other Liabilities [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Liability Value		$ 2,300	[2]	$ 2,950
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		$ 61,220		$ 10,876
Level 3 | Common and Preferred Stock | Valuation Technique, Discounted Cash Flow
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Weighted average percent Fair Value technique		11.00%		10.40%
Level 3 | Common and Preferred Stock | Valuation Technique, Discounted Cash Flow | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		10.00%		8.00%
Level 3 | Common and Preferred Stock | Valuation Technique, Discounted Cash Flow | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		12.00%		11.25%
Level 3 | Common and Preferred Stock | Valuation, Market Approach
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Weighted average percent Fair Value technique		650.00%		675.00%
Level 3 | Common and Preferred Stock | Valuation, Market Approach | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		625.00%		650.00%
Level 3 | Common and Preferred Stock | Valuation, Market Approach | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		675.00%		700.00%
Level 3 | Options | Market Approach, Income Approach and Replacement Cost Valuation Techniques [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		$ 352		$ 336
Level 3 | Options | Valuation Technique, Discounted Cash Flow
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Weighted average percent Fair Value technique		11.00%		10.50%
Level 3 | Options | Valuation Technique, Discounted Cash Flow | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		10.00%		9.75%
Level 3 | Options | Valuation Technique, Discounted Cash Flow | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		12.00%		11.25%
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		$ 3,446		$ 24
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				$ 6,162
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		$ 10,865
Level 3 | Warrants and Rights [Member] | Valuation Technique, Discounted Cash Flow
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Weighted average percent Fair Value technique		7.00%		6.10%
Level 3 | Warrants and Rights [Member] | Valuation Technique, Discounted Cash Flow | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		4.00%		6.00%
Level 3 | Warrants and Rights [Member] | Valuation Technique, Discounted Cash Flow | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		11.00%		7.00%
Level 3 | Warrants and Rights [Member] | Valuation, Market Approach
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Weighted average percent Fair Value technique		6.50%
Level 3 | Warrants and Rights [Member] | Valuation, Market Approach | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		6.25%
Level 3 | Warrants and Rights [Member] | Valuation, Market Approach | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		6.75%
Level 3 | Corporate Bonds | Income Approach and Market Approach Valuation Techniques
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value		$ 12,110		$ 311
Level 3 | Bonds | Valuation Technique, Discounted Cash Flow
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs				20.00%
Weighted average percent Fair Value technique		11.00%		20.00%
Level 3 | Bonds | Valuation Technique, Discounted Cash Flow | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		10.00%
Level 3 | Bonds | Valuation Technique, Discounted Cash Flow | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		12.00%
Level 3 | Bonds | Valuation, Market Approach
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Weighted average percent Fair Value technique		650.00%
Level 3 | Bonds | Valuation, Market Approach | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		625.00%
Level 3 | Bonds | Valuation, Market Approach | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		675.00%
Level 3 | Bonds | Probability of recovery valuation technique
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Weighted average percent Fair Value technique				2.30%
Level 3 | Bonds | Probability of recovery valuation technique | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs				1.00%
Level 3 | Bonds | Probability of recovery valuation technique | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs				3.00%
Level 3 | Other Investments
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Balance Asset Value	[2]	$ 201,710		$ 30,723
Level 3 | Options | Valuation, Market Approach
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Weighted average percent Fair Value technique		650.00%		675.00%
Level 3 | Options | Valuation, Market Approach | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		625.00%		650.00%
Level 3 | Options | Valuation, Market Approach | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		675.00%		700.00%
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		$ 2,954		$ 2,920
Discount rate | Level 3 | Trade Claims | Valuation Technique, Discounted Cash Flow
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		15.00%		20.00%
Weighted average percent Fair Value technique		15.00%		20.00%
Volatility | Level 3 | Warrants and Rights [Member] | Market Approach Valuation Technique
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs				30.00%
Weighted average percent Fair Value technique				0.00%
Volatility | Level 3 | Option | Market Approach Valuation Technique
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs		35.00%
Weighted average percent Fair Value technique		35.00%		35.00%
Volatility | Level 3 | Option | Market Approach Valuation Technique | Minimum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs				35.00%
Volatility | Level 3 | Option | Market Approach Valuation Technique | Maximum
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value inputs				40.00%
[1]	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 31, 2019 and December 31, 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, 2020 can range from $0.9 million to $35.1 million.
[2]	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, 2020		Dec. 31, 2019	Sep. 30, 2019
Cash and cash equivalents		$ 539,733	[1]	$ 301,123	$ 260,994
Cash collateral pledged		110,666		6,563	18,609
Segregated cash		139,152		107,328	$ 128,782
Securities borrowed		1,272,428		754,441
Loans Receivable, Net		9,045		42,830
Cash and cash equivalents, Consolidated Funds		946		30,874
Securities Sold under Agreements to Repurchase, Asset		6,218		23,244
Securities sold under agreements to repurchase		7,587		27,384
Securities Loaned		1,326,917		1,601,866
Convertible debt	[2]	122,485		118,688
Long-term Debt	[3]	383,722		345,451
Convertible Debt
Convertible debt		122,485
Convertible debt, unamortized discount		11,400		14,900
Notes Payable, Other Payables [Member]
Debt Instrument, Unamortized Premium		400		500
Level 1
Cash and cash equivalents, Fair Value		479,700		301,123
Segregated cash fair value disclosures		139,152		107,328
Cash and cash equivalents, Consolidated Funds, Fair Value		946		30,874
Level 2
Cash collateral pledged, Fair Value		110,666		6,563
Securities Borrowed, Fair Value Disclosure		1,272,428		754,441
Securities sold under agreements to repurchase		7,587		27,384
Securities loaned, fair value disclosure		1,326,917		1,601,866
Convertible debt, Fair Value	[4]	147,166		148,786
Notes payable and other debt, Fair Value	[5]	406,309		372,591
Certificates of Deposit, at Carrying Value		60,000
Level 3
Loans Receivable, Fair Value Disclosure	[6]	9,045		$ 42,830
Fair Value, Inputs, Level 1 & 2
Cash and cash equivalents, Fair Value	[1]	$ 539,733
[1]	As of September 30, 2020, cash and cash equivalents include Level 1 cash in the amount of $479.7 million and Level 2 certificates of deposit of $60.0 million.
[2]	The carrying amount of the convertible debt includes an unamortized discount of $11.4 million and $14.9 million as of September 30, 2020 and December 31, 2019, respectively.
[3]	The carrying amount of the notes payable and other debt includes an unamortized premium of $0.4 million and $0.5 million as of September 30, 2020 and December 31, 2019, respectively.
[4]	The convertible debt includes the conversion option and is based on the last broker quote available.
[5]	Notes payable and other debt are based on the last broker quote available.
[6]	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, 2020	Dec. 31, 2019
Deposits with Clearing Organizations, Brokers and Banks [Abstract]
Deposits with clearing organizations, brokers and banks	$ 90,075	$ 91,755

Receivables from and payables_3

Receivables from and payables to brokers, dealers and clearing organizations (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Brokers and Dealers [Abstract]
Receivable from Broker-dealers	$ 1,263,635	$ 623,523
Securities Failed-to-Deliver	71,280	45,673
Clearing organizations	49,978	3,180
Securities borrowed interest receivable	5,928	9,319
Receivable from brokers, dealers and clearing organizations	1,390,821	681,695
Payable to Broker-Dealers	228,628	185,838
Securities Failed-to-Receive	39,496	57,580
Clearing organizations	39,077	18,063
Securities loaned interest payable	5,649	9,537
Payables to brokers, dealers and clearing organizations	$ 312,850	$ 271,018

Receivable from and Payable t_2

Receivable from and Payable to Customers (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Receivables and Payable to Customers [Abstract]
Receivable from customers	$ 83,208	$ 105,647
Payable to customers	$ 1,151,139	$ 430,224

Commission Management Payable (

Commission Management Payable (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Commission Management Payable [Abstract]
Commission management payable	$ 117,778	$ 71,620

Non-Controlling Interests in _3

Non-Controlling Interests in Consolidated Subsidiaries and Funds (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Noncontrolling Interest [Line Items]
Redeemable non-controlling interests in consolidated subsidiaries and funds	$ 0		$ 0		$ 391,275
Nonredeemable Noncontrolling Interest	270,021		270,021		485,595
Net Income (Loss) Attributable to Noncontrolling Interest	9,232	$ 2,770	(19,843)	$ 7,188
Operating Entities
Noncontrolling Interest [Line Items]
Nonredeemable Noncontrolling Interest	72,569		72,569		11,513
Net Income (Loss) Attributable to Noncontrolling Interest	6,283	(2,126)	9,514	(1,586)
Consolidated Funds
Noncontrolling Interest [Line Items]
Redeemable non-controlling interests in consolidated subsidiaries and funds	0		0		391,275
Nonredeemable Noncontrolling Interest	197,452		197,452		$ 82,807
Net Income (Loss) Attributable to Noncontrolling Interest	$ 2,949	$ 4,896	$ (29,357)	$ 8,774

Revenue from Contracts with C_3

Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 327,384	$ 175,943	$ 932,255	$ 583,682
Management Fees	11,954	7,300	35,211	21,480
Incentive income	127	701	127	724
Operating Company
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	327,151	175,695	931,536	582,680
Management Fees	11,721	7,052	34,492	20,492
Incentive income	127	701	127	710
Asset Company
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	233	248	719	1,002
Management Fees	233	248	719	988
Incentive income	0	0	0	14
Underwriting fees | Operating Company
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	121,390	38,936	318,355	162,140
Strategic/financial advisory fees | Operating Company
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	39,431	17,889	101,061	49,565
Placement and sales agent fees | Operating Company
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	28,427	15,842	71,999	48,855
Expense reimbursements from clients | Operating Company
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	5,093	4,625	11,936	11,543
Investment banking revenue | Operating Company
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	194,341	77,292	503,351	272,103
Commissions | Operating Company
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	112,953	82,715	367,564	263,831
Trade conversion | Operating Company
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	3,404	3,700	12,370	12,364
Equity and credit research fees | Operating Company
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	4,605	4,235	13,632	13,180
Brokerage | Operating Company
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 120,962	$ 90,650	$ 393,566	$ 289,375

Reinsurance (Details)

Reinsurance (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Cash collateral pledged	$ 110,666	$ 18,609	$ 110,666	$ 18,609	$ 6,563
Total collateral posted for reinsurance business	120,500		120,500		15,000
Cash and Cash Equivalents [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Total collateral posted for reinsurance business	106,100		106,100		2,000
US Treasury Bond Securities [Member]
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Total collateral posted for reinsurance business	14,400		14,400		13,000
Collateral Reinsurance Agreement
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Cash collateral pledged	106,100		106,100		2,000
Collateral Reinsurance Agreement, Released September 30, 2030
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Cash collateral pledged	101,200		101,200		$ 0
Collateral Reinsurance Agreement, Released March 31, 2021
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Cash collateral pledged	4,900		4,900
Hollenfels
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Incurred and paid claims	2,570,000	126,000	10,498,000	7,046,000
Claims IBNR	$ 2,722,000	$ 833,000	$ 26,638,000	$ 11,724,000
Historical Average Claims Ratios, Period, Maximum			10 years

Share-Based Compensation and _3

Share-Based Compensation and Employee Ownership Plans Narrative (Details) - USD ($) $ in Millions	1 Months Ended			3 Months Ended		9 Months Ended
	Jul. 30, 2020	Apr. 30, 2019	Mar. 31, 2016	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted				2,500,000		2,500,000
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of RSU's earned						0.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of RSU's earned						200.00%
Equity Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-compensation expense recognized in connection with compensation plan				$ 11.6	$ 10	$ 35.2	$ 27.2
Tax benefit of stock-compensation expense recognized in connection with compensation plan				3.1	$ 2.6	$ 8.4	$ 6.8
Equity Plans | Restricted Shares and Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares						2,638,544	2,322,996
Vested, shares						1,320,318	1,545,850
Forfeited, shares						111,212	156,528
Unrecognized compensation expense				$ 81.8		$ 81.8
Period for recognition						2 years 2 months 26 days
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				90,645	0	90,645	0
Delivered, shares				48,021		48,021
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period							120,430
Equity Plans | Performance based restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares	1,366,666	1,366,666	1,366,666
Vested, shares						145,986
Forfeited, shares						320,681
Equity Plans | Employee Stock | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation award, vesting period						2 years
Equity Plans | Employee Stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation award, vesting period						5 years
Expiration period						7 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 awards granted				$ 0.1		$ 50.3
Deferred cash award, interest rate						0.70%
Deferred cash awards, unrecognized compensation expense				$ 79.4		$ 79.4

Share-Based Compensation and _4

Share-Based Compensation and Employee Ownership Restricted Stock Units Granted to Employees (Details) - Equity Plans - $ / shares	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Restricted Shares and Restricted Stock Units (RSUs)
Nonvested Restricted Shares and Restricted Stock Units
Balance outstanding, beginning of period, shares	5,364,486	5,962,295
Granted, shares	2,638,544	2,322,996
Vested, shares	(1,320,318)	(1,545,850)
Canceled, shares	(87,348)	(584,333)
Forfeited, shares	(111,212)	(156,528)
Balance outstanding, end of period, shares	6,484,152	5,998,580
Weighted-Average Grant Date Fair Value
Balance outstanding, beginning of period, in dollars per share	$ 16.67	$ 15.73
Granted, in dollars per share	17.14	16.62
Vested, in dollars per share	15.20	16.26
Canceled, in dollars per share	14.80	11.49
Forfeited, in dollars per share	15.55	13.97
Balance outstanding, end of period, in dollars per share	$ 17.20	$ 16.40
Restricted Stock Units (RSUs) | Non-employee Director
Weighted-Average Grant Date Fair Value
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	259,536		216,912
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period		120,430

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Effective income tax rate, percent	33.51%	26.55%
Statutory rate, percent	21.00%	21.00%
Unrecognized Tax Benefits	$ 0.3		$ 0.3

Commitments and Contingencies O

Commitments and Contingencies Operating Lease Obligations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020		Sep. 30, 2019
Contractual Commitments, Commitment [Line Items]
Lease cost	$ 5,687	$ 5,748	$ 17,044		$ 17,690
Variable lease cost	829	1,156	2,431		2,668
Sublease income	(190)	(232)	(623)		(739)
Total lease costs	6,378	6,695	19,007		19,732
Facility Leases
Contractual Commitments, Commitment [Line Items]
Short-term lease cost	$ 52	$ 23	$ 155	[1],[2]	$ 113
[1]	During the nine months ended September 30, 2020, the Company recognized $0.3 operating right-of-use assets and leases liabilities increases for facility leases.
[2]	The Company has entered into various agreements to sublease certain of its premises.

Commitments and Contingencies S

Commitments and Contingencies Supplemental Cash Flow Information And Certain Other Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Operating Lease, Payments	$ 20,228	$ 19,103
Weighted average remaining lease term - operating leases (in years)	4 years 9 months 10 days	5 years 6 months 7 days
Weighted average discount rate - operating leases	3.69%	4.14%

Commitments and Contingencies_2

Commitments and Contingencies Outstanding Operating Lease Liabilities (Details) - USD ($)		9 Months Ended
		Sep. 30, 2020	Dec. 31, 2019
Future minimum annual lease and service payments
Total lease liability		$ 84,044,000	$ 97,581,000
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability		300,000
Equipment Leases
Future minimum annual lease and service payments
2020		90,000
2021		223,000
2022		91,000
2023		3,000
2024		0
Thereafter		0
Future minimum annual lease and service payments		407,000
Less discount		25,000
Less short-term leases		0
Total lease liability		382,000
Facility Leases
Future minimum annual lease and service payments
2020	[1],[2]	4,302,000
2021	[1],[2]	24,723,000
2022	[1],[2]	21,484,000
2023	[1],[2]	18,095,000
2024	[1],[2]	14,784,000
Thereafter	[1],[2]	10,166,000
Future minimum annual lease and service payments	[1],[2]	93,554,000
Less discount	[1],[2]	9,816,000
Less short-term leases		76,000
Total lease liability	[1],[2]	$ 83,662,000
[1]	During the nine months ended September 30, 2020, the Company recognized $0.3 operating right-of-use assets and leases liabilities increases for facility leases.
[2]	The Company has entered into various agreements to sublease certain of its premises.

Commitments and Contingencies_3

Commitments and Contingencies Service Payments (Details) - Service Payments $ in Thousands	Sep. 30, 2020USD ($)
Other Commitments [Line Items]
2020	$ 8,262
2021	23,563
2022	14,295
2023	7,188
2024	4,351
Thereafter	13,201
Total service payment commitments	$ 70,860

Commitments and Contingencies_4

Commitments and Contingencies Schedules of Unfunded Commitments (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)
Healthcare Royalty Partners | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 7,816	[1]
Healthcare Royalty Partners | Commitment to Invest
Other Commitments [Line Items]
Commitments term	4 years 3 months 18 days
Eclipse Ventures Fund I, L.P. | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 59
Eclipse Ventures Fund I, L.P. | Commitment to Invest
Other Commitments [Line Items]
Commitments term	4 years 3 months 18 days
Lagunita Biosciences, LLC | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 250
Lagunita Biosciences, LLC | Commitment to Invest
Other Commitments [Line Items]
Commitments term	3 years 1 month 6 days
Eclipse Fund II, L.P. | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 110
Eclipse Fund II, L.P. | Commitment to Invest
Other Commitments [Line Items]
Commitments term	5 years 3 months 18 days
Eclipse Continuity Fund I, L.P. | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 58
Eclipse Continuity Fund I, L.P. | Commitment to Invest
Other Commitments [Line Items]
Commitments term	6 years 3 months 18 days
Cowen Healthcare Investments II LP | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 1,201
Cowen Healthcare Investments II LP | Commitment to Invest
Other Commitments [Line Items]
Commitments term	1 year 3 months 18 days
Cowen Healthcare Investments III LP | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 6,164
Cowen Healthcare Investments III LP | Commitment to Invest
Other Commitments [Line Items]
Commitments term	6 years 3 months 18 days
Cowen Sustainable Investments I LP | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 3,926
Cowen Sustainable Investments I LP | Commitment to Invest
Other Commitments [Line Items]
Commitments term	9 years 3 months 18 days
[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 - Outstanding Debt (Details) - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
Debt and Capital Lease Obligations [Line Items]
Convertible debt	[1]	$ 122,485	$ 118,688
Note payable		307,437	306,818
Loans Payable to Bank		0	32,180
Other Notes Payable		73,253	2,516
Capital lease obligations		3,032	3,937
Debt, Long-term and Short-term, Combined Amount		$ 506,207	$ 464,139
[1]	The carrying amount of the convertible debt includes an unamortized discount of $11.4 million and $14.9 million as of September 30, 2020 and December 31, 2019, respectively.

Convertible Debt and Notes Pa_4

Convertible Debt and Notes Payable - Convertible Debt (Details) - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 14, 2017
Debt and Capital Lease Obligations [Line Items]
Purchase of treasury stock, cost				$ 43,400,000
Convertible debt	[1]	$ 122,485,000		122,485,000		$ 118,688,000
Amortization of debt discount				3,393,000	$ 3,511,000
Convertible Debt
Debt and Capital Lease Obligations [Line Items]
Convertible debt		122,485,000		122,485,000
Convertible debt, unamortized discount		11,400,000		11,400,000		$ 14,900,000
2022 convertible note | Convertible Debt
Debt and Capital Lease Obligations [Line Items]
Debt Instrument, Face Amount							$ 135,000,000
Debt Instrument, Convertible, Conversion Price							$ 17.375
Convertible debt		135,000,000		135,000,000
Interest on Convertible Debt, Net of Tax		1,000,000	$ 1,000,000	3,000,000	3,000,000
Convertible debt, unamortized discount							$ 23,400,000
Amortization of debt discount		$ 1,200,000	$ 1,100,000	$ 3,500,000	$ 3,200,000
Debt Instrument, Interest Rate, Effective Percentage							7.13%
Debt Issuance Costs, Gross							$ 2,200,000
[1]	The carrying amount of the convertible debt includes an unamortized discount of $11.4 million and $14.9 million as of September 30, 2020 and December 31, 2019, respectively.

Convertible Debt and Notes Pa_5

Convertible Debt and Notes Payable - Notes Payable (Details) - Senior Notes - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	May 07, 2019	Mar. 31, 2019	Jun. 11, 2018	Dec. 14, 2017	Dec. 08, 2017
2024 Notes
Debt and Capital Lease Obligations [Line Items]
Debt Instrument, Face Amount						$ 53,000,000
Interest rate						7.25%
Debt Instrument, Additional amount issued		$ 25,000,000		$ 25,000,000
Debt Instrument, Unamortized Premium	$ 500,000		$ 500,000
Interest Expense, Debt, Excluding Amortization	1,400,000	900,000	4,200,000	1,500,000
Debt Issuance Costs, Gross					$ 600,000	$ 1,500,000
2033 Notes
Debt and Capital Lease Obligations [Line Items]
Debt Instrument, Face Amount							$ 10,000,000	$ 90,000,000
Interest rate								7.75%
Interest Expense, Debt, Excluding Amortization	1,900,000	1,900,000	5,800,000	5,800,000
Debt Issuance Costs, Gross								$ 3,600,000
2027 Notes
Debt and Capital Lease Obligations [Line Items]
Debt Instrument, Face Amount									$ 18,000,000	$ 120,000,000
Interest rate										7.35%
Interest Expense, Debt, Excluding Amortization	$ 2,500,000	$ 2,500,000	$ 7,600,000	$ 7,600,000
Debt Issuance Costs, Gross										$ 5,000,000

Convertible Debt and Notes Pa_6

Convertible Debt and Notes Payable - Term Loans, Other Notes Payable and Revolver (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2020	Jan. 31, 2020	Dec. 31, 2019	Nov. 01, 2019	Jul. 01, 2019	Dec. 14, 2017	Dec. 08, 2017	Jun. 30, 2017
Debt and Capital Lease Obligations [Line Items]
Letter of credit, borrowing capacity	$ 395,000,000		$ 395,000,000
Other Notes Payable	73,253,000		73,253,000				$ 2,516,000
The Military Mutual Ltd [Member]
Debt and Capital Lease Obligations [Line Items]
Other Receivables	$ 28,400,000		$ 28,400,000
Notes Payable to Banks
Debt and Capital Lease Obligations [Line Items]
Debt Instrument, Face Amount									$ 4,000,000			$ 28,200,000
Short-term Debt, Percentage Bearing Variable Interest Rate	3.75%		3.75%
Interest Expense, Debt, Excluding Amortization		$ 500,000	$ 800,000	$ 1,400,000
Insurance Note
Debt and Capital Lease Obligations [Line Items]
Interest rate	2.01%		2.01%
Debt Instrument, Periodic Payment, Principal			$ 300,000
Other Notes Payable	$ 800,000		800,000			$ 2,900,000
Revolving Credit Facility | BMO Harris Bank
Debt and Capital Lease Obligations [Line Items]
Letter of credit, borrowing capacity	$ 25,000,000		25,000,000
Corporate Debt
Debt and Capital Lease Obligations [Line Items]
Interest Expense, Debt, Excluding Amortization			$ 100,000
Interest rate	6.00%		6.00%
Debt Instrument, Periodic Payment, Principal			$ 100,000
Other Long-term Debt	$ 2,200,000		2,200,000					$ 2,600,000
Purple Protect Asset S-91
Debt and Capital Lease Obligations [Line Items]
Interest Expense, Debt, Excluding Amortization			$ 0
Interest rate	6.07%		6.07%
Other Notes Payable	$ 72,000,000		$ 72,000,000
Debt Issuance Costs, Gross	1,700,000		1,700,000
Purple Protect Asset S-91 | Forecast
Debt and Capital Lease Obligations [Line Items]
Interest rate					5.80%
2027 Notes | Senior Notes
Debt and Capital Lease Obligations [Line Items]
Debt Instrument, Face Amount										$ 18,000,000	$ 120,000,000
Interest Expense, Debt, Excluding Amortization	2,500,000	$ 2,500,000	7,600,000	$ 7,600,000
Interest rate											7.35%
Debt Issuance Costs, Gross											$ 5,000,000
Spike Line
Debt and Capital Lease Obligations [Line Items]
Interest Expense, Debt, Excluding Amortization	0		200,000
Revolving Credit Facility
Debt and Capital Lease Obligations [Line Items]
Interest Expense, Debt, Excluding Amortization			300,000
Maximum | Spike Line
Debt and Capital Lease Obligations [Line Items]
Line of Credit, Current	$ 70,000,000		$ 70,000,000

Convertible Debt and Notes Pa_7

Convertible Debt and Notes Payable - Finance Lease Obligations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Debt Disclosure [Abstract]
Finance Lease, Right-of-Use Asset, Amortization	$ 308	$ 299	$ 924	$ 966
Finance Lease, Interest Expense	$ 42	$ 54	134	172
Finance Lease, Interest Payment on Liability			134	172
Finance Lease, Principal Payments			$ 901	$ 951
Finance Lease, Weighted Average Remaining Lease Term	2 years 5 months 23 days	3 years 4 months 24 days	2 years 5 months 23 days	3 years 4 months 24 days
Finance Lease, Weighted Average Discount Rate, Percent	4.89%	4.93%	4.89%	4.93%

Convertible Debt and Notes Pa_8

Convertible Debt and Notes Payable - Scheduled Maturities (Details) - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
Repayments on long-term and short-term borrowings
Convertible debt	[1]	$ 122,485	$ 118,688
Note payable		307,437	306,818
Other Notes Payable		73,253	2,516
Future minimum lease payments for finance lease obligations
2020		251
2021		1,396
2022		1,165
2023		411
2024		11
Thereafter		0
Subtotal		3,234
Capital Leases, Future Minimum Payments, Interest Included in Payments	[2]	202
Capital lease obligations		3,032	$ 3,937
Convertible Debt
Repayments on long-term and short-term borrowings
2020		2,025
2021		4,050
2022		139,050
2023		0
2024		0
Thereafter		0
Subtotal		145,125
Long-term Debt and Short-term Borrowings, Amount Representing Interest	[2]	22,640
Convertible debt		122,485
Senior Notes
Repayments on long-term and short-term borrowings
2020		7,300
2021		23,548
2022		23,548
2023		23,548
2024		98,721
Thereafter		334,304
Subtotal		510,969
Long-term Debt and Short-term Borrowings, Amount Representing Interest	[2]	203,532
Note payable		307,437
Insurance Note and Aircraft
Repayments on long-term and short-term borrowings
2020		933
2021		593
2022		593
2023		72,593
2024		543
Thereafter		0
Subtotal		75,255
Long-term Debt and Short-term Borrowings, Amount Representing Interest	[2]	2,002
Other Notes Payable		$ 73,253
[1]	The carrying amount of the convertible debt includes an unamortized discount of $11.4 million and $14.9 million as of September 30, 2020 and December 31, 2019, 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 Company's convertible debt.

Convertible Debt and Notes Pa_9

Convertible Debt and Notes Payable - Letters of Credit (Details) - USD ($)	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Debt and Capital Lease Obligations [Line Items]
Cash collateral pledged	$ 110,666,000	$ 6,563,000	$ 18,609,000
Letter of credit, borrowing capacity	395,000,000
Letter of Credit, Boston Office, Expires March 2021 | Letter of Credit
Debt and Capital Lease Obligations [Line Items]
Letter of credit, borrowing capacity	386,000
Letter of Credit, NY Office 1, Expires April 2021 | Letter of Credit
Debt and Capital Lease Obligations [Line Items]
Letter of credit, borrowing capacity	358,000
Letter of Credit, NY Office 3, Expires October 2020 | Letter of Credit
Debt and Capital Lease Obligations [Line Items]
Letter of credit, borrowing capacity	1,424,000
Letter of Credit, NY Office 5, Expires November 2020 | Letter of Credit
Debt and Capital Lease Obligations [Line Items]
Letter of credit, borrowing capacity	1,637,000
Letter of Credit, San Francisco Office, Expires October 2025 | Letter of Credit
Debt and Capital Lease Obligations [Line Items]
Letter of credit, borrowing capacity	712,000
Collateral Reinsurance Agreement
Debt and Capital Lease Obligations [Line Items]
Cash collateral pledged	$ 106,100,000	$ 2,000,000

Stockholder's Equity - Quarterl

Stockholder's Equity - Quarterly (Details) - USD ($) $ / shares in Units, $ in Thousands	May 19, 2015	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Jun. 26, 2018	Dec. 14, 2017
Equity, Class of Stock [Line Items]
Preferred stock dividends declared		$ 1,698	$ 1,698	$ 5,094	$ 5,094
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, cost, beginning of period				$ 284,300
Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions				6,296	22,420
Purchase of treasury stock, cost				43,400
Treasury stock, cost, end of period		334,100		334,100
Dividends, Cash		1,632		4,144
Dividend Paid
Treasury Stock, Shares [Roll Forward]
Dividends, Cash		$ 1,100		$ 3,400
Treasury Stock
Treasury Stock, Shares [Roll Forward]
Treasury stock, shares, beginning of period				18,605,581
Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions				505,702
Treasury stock shares received, other				7,026
Purchase of treasury stock, shares				2,974,711
Treasury stock, shares, end of period		22,093,020		22,093,020
Treasury stock, cost, beginning of period				$ 284,301
Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions				6,296
Treasury stock received, value, other				96
Purchase of treasury stock, cost				43,442
Treasury stock, cost, end of period		$ 334,135		$ 334,135
Treasury stock, average cost per share, beginning of period, in dollars per share				$ 15.28
Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions, Average Cost Per Share				12.45
Treasury stock received, per share, other				13.66
Purchase of treasury stock, average cost per share, in dollars per share				14.60
Treasury stock, average cost per share, end of period, in dollars per share		$ 15.12		$ 15.12
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
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
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	$ 3,600
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	$ 1,698	$ 5,094	$ 5,094
Convertible Debt
Treasury Stock, Shares [Roll Forward]
Convertible debt, unamortized discount		$ 11,400		$ 11,400		$ 14,900
2022 convertible note | Convertible Debt
Treasury Stock, Shares [Roll Forward]
Convertible debt, unamortized discount								$ 23,400
Option Indexed to Issuer's Equity, Settlement Alternatives, Cash, at Fair Value							$ 29,000

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income / (Loss) [Abstract]
Beginning balance	$ (5)	$ (3)	$ (5)	$ (5)
Foreign currency translation	(2)	(2)	(2)	0
Ending balance	$ (7)	$ (5)	$ (7)	$ (5)

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Computation of earnings per share:
Net income (loss)	$ 29,516	$ 6,583	$ 104,353	$ 26,596
Net Income (Loss) Attributable to Noncontrolling Interest	9,232	2,770	(19,843)	7,188
Net income (loss) attributable to Cowen Inc.	20,284	3,813	124,196	19,408
Preferred stock dividends	1,698	1,698	5,094	5,094
Net income (loss) attributable to Cowen Inc. common stockholders	$ 18,586	$ 2,115	$ 119,102	$ 14,314
Shares for basic and diluted calculations:
Weighted average shares used in basic computation, shares	27,663,000	29,529,000	28,078,000	29,687,000
Weighted average shares used in diluted computation, shares	29,970,000	31,264,000	29,646,000	31,381,000
Earnings (loss) per share:
Earnings Per Share, Basic (in dollars per share)	$ 0.67	$ 0.07	$ 4.24	$ 0.48
Earnings Per Share, Diluted (in dollars per share)	$ 0.62	$ 0.07	$ 4.02	$ 0.46
Restricted Stock
Shares for basic and diluted calculations:
Shares attributable to share-based payment awards, shares	2,285,000	1,735,000	1,546,000	1,694,000
Restricted Stock | Quarton
Shares for basic and diluted calculations:
Shares attributable to share-based payment awards, shares	22,000	0	22,000	0
Restricted Stock Units (RSUs) | Non-employee Director | Equity Plans
Earnings (loss) per share:
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	259,536		259,536			216,912
Common Stock Class A
Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]
Common stock, shares outstanding, shares	26,569,335	29,013,137	26,569,335	29,013,137	27,641,600	28,610,357	29,480,287	28,437,860
Common stock, restricted shares, shares	334,230		334,230			216,912

Segment Reporting (Details)

Segment Reporting (Details)		3 Months Ended				9 Months Ended
		Sep. 30, 2020USD ($)		Sep. 30, 2019USD ($)		Sep. 30, 2020USD ($)segment		Sep. 30, 2019USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment						2
Revenues
Investment banking		$ 194,341,000		$ 77,292,000		$ 503,351,000		$ 272,103,000
Brokerage		138,483,000		93,995,000		425,069,000		302,840,000
Management fees		11,954,000		7,300,000		35,211,000		21,480,000
Incentive income		127,000		701,000		127,000		724,000
Investment Income		0		0		0		0
Interest and dividends		37,552,000		60,707,000		127,547,000		129,846,000
Reimbursement from affiliates		269,000		238,000		777,000		780,000
Reinsurance premiums		2,505,000		8,146,000		18,943,000		29,068,000
Other revenues		1,369,000		1,237,000		4,709,000		3,228,000
Total revenues		387,735,000		252,047,000		1,120,384,000		768,308,000
Interest expense		37,754,000		56,477,000		125,850,000		125,089,000
Total net revenues		349,981,000		195,570,000		994,534,000		643,219,000
Expenses
Employee compensation and benefits		153,427,000		120,320,000		583,137,000		388,611,000
Other non-compensation expense		89,636,000		92,046,000		286,666,000		276,054,000
Depreciation and amortization		5,682,000		5,082,000		17,324,000		14,990,000
Goodwill Impairment		0		0		0		4,100,000
Total expenses		249,239,000		219,964,000		891,920,000		689,984,000
Other income (loss)
Total other income (loss)		(62,396,000)		32,342,000		54,328,000		82,976,000
Preferred stock dividends		1,698,000		1,698,000		5,094,000		5,094,000
Income (Loss) before income taxes / Economic income (loss)		38,346,000		7,948,000		156,942,000		36,211,000
Consolidated Funds
Revenues
Total revenues		1,135,000		2,431,000		4,650,000		8,239,000
Expenses
Total expenses		494,000		2,516,000		4,793,000		6,229,000
Operating Company
Revenues
Management fees		11,721,000		7,052,000		34,492,000		20,492,000
Incentive income		127,000		701,000		127,000		710,000
Asset Company
Revenues
Management fees		233,000		248,000		719,000		988,000
Incentive income		0		0		0		14,000
Operating Segments | Operating Company
Revenues
Investment banking		185,151,000		69,433,000		474,778,000		254,374,000
Brokerage		167,084,000		110,178,000		466,823,000		346,095,000
Management fees		14,374,000		10,321,000		41,724,000		30,016,000
Incentive income		(2,621,000)		15,251,000		40,829,000		33,998,000
Investment Income		(90,364,000)		10,913,000		32,566,000		13,827,000
Interest and dividends		0		0		0		0
Reimbursement from affiliates		0		0		0		0
Reinsurance premiums		0		0		0		0
Other revenues		(796,000)		(132,000)		(298,000)		5,295,000
Total revenues		272,828,000		215,964,000		1,056,422,000		683,605,000
Interest expense		6,026,000		5,758,000		18,471,000		16,371,000
Total net revenues		266,802,000		210,206,000		1,037,951,000		667,234,000
Expenses
Employee compensation and benefits		152,829,000		121,890,000		582,480,000		386,593,000
Fixed expenses		34,257,000		36,458,000		106,350,000		107,889,000
Variable expenses		37,736,000		37,216,000		121,846,000		113,728,000
Other non-compensation expense		0		0		0		0
Depreciation and amortization		5,670,000		5,073,000		16,756,000		14,957,000
Economic Non-Controlling Interest		2,105,000		661,000		5,584,000		2,944,000
Goodwill Impairment								0
Total expenses		232,597,000		201,298,000		833,016,000		626,111,000
Other income (loss)
Total other income (loss)		0		0		0		0
Preferred stock dividends		1,415,000		1,341,000		4,160,000		4,058,000
Income (Loss) before income taxes / Economic income (loss)		32,790,000		7,567,000		200,775,000		37,065,000
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		262,000		586,000		634,000		1,788,000
Incentive income		1,319,000		(862,000)		158,000		762,000
Investment Income		(124,000)		822,000		(13,671,000)		5,289,000
Interest and dividends		0		0		0		0
Reimbursement from affiliates		0		0		0		0
Reinsurance premiums		0		0		0		0
Other revenues		2,000		6,000		4,000		56,000
Total revenues		1,459,000		552,000		(12,875,000)		7,895,000
Interest expense		1,109,000		1,389,000		4,014,000		4,046,000
Total net revenues		350,000		(837,000)		(16,889,000)		3,849,000
Expenses
Employee compensation and benefits		957,000		729,000		2,093,000		4,383,000
Fixed expenses		127,000		625,000		378,000		2,485,000
Variable expenses		6,000		40,000		18,000		127,000
Other non-compensation expense		0		0		0		0
Depreciation and amortization		5,000		9,000		17,000		30,000
Economic Non-Controlling Interest		0		0		0		0
Goodwill Impairment								0
Total expenses		1,095,000		1,403,000		2,506,000		7,025,000
Other income (loss)
Total other income (loss)		0		0		0		0
Preferred stock dividends		283,000		357,000		934,000		1,036,000
Income (Loss) before income taxes / Economic income (loss)		(1,028,000)		(2,597,000)		(20,329,000)		(4,212,000)
Operating Segments | Asset Company | Consolidated Funds
Revenues
Total revenues		0		0		0		0
Expenses
Total expenses		0		0		0		0
Adjustments | Management Reclassifications
Revenues
Investment banking	[1],[2]	(9,190,000)		(7,859,000)		(28,573,000)		(17,729,000)
Brokerage	[3],[4]	28,601,000		16,183,000		41,754,000		43,255,000
Management fees	[5],[6]	2,519,000		3,033,000		5,672,000		8,684,000
Incentive income	[6]	(1,462,000)		13,675,000		40,827,000		33,479,000
Investment Income	[7]	(90,488,000)		11,735,000		18,895,000		19,116,000
Interest and dividends	[3]	(37,552,000)		(60,707,000)		(127,547,000)		(129,846,000)
Reimbursement from affiliates	[1]	(269,000)		(265,000)		(827,000)		(874,000)
Reinsurance premiums	[8]	(2,505,000)		(8,146,000)		(18,943,000)		(29,068,000)
Other revenues	[8]	(2,160,000)		(1,389,000)		(4,982,000)		2,109,000
Total revenues		(112,506,000)		(33,740,000)		(73,724,000)		(70,874,000)
Interest expense	[3]	(29,467,000)		(48,238,000)		(99,971,000)		(101,464,000)
Total net revenues		(83,039,000)		14,498,000		26,247,000		30,590,000
Expenses
Employee compensation and benefits	[9]	359,000		2,299,000		1,436,000		2,365,000
Fixed expenses	[6],[10]	37,708,000		37,559,000		111,880,000		112,038,000
Variable expenses	[10]	37,742,000		37,256,000		121,864,000		113,855,000
Other non-compensation expense	[1],[2],[5],[8],[9]	(89,636,000)		(92,046,000)		(286,666,000)		(276,054,000)
Depreciation and amortization		0		0		0		(3,000)
Economic Non-Controlling Interest	[10]	2,105,000		661,000		5,584,000		2,944,000
Goodwill Impairment								0
Total expenses		(11,722,000)		(14,271,000)		(45,902,000)		(44,855,000)
Other income (loss)
Total other income (loss)	[4],[6],[7]	64,896,000		(26,721,000)		(82,006,000)		(73,907,000)
Preferred stock dividends		0		0		0		0
Income (Loss) before income taxes / Economic income (loss)		(6,421,000)		2,048,000		(9,857,000)		1,538,000
Adjustments | Management Reclassifications | Consolidated Funds
Revenues
Total revenues		0		0		0		0
Expenses
Total expenses		0		0		0		0
Adjustments | Income statement adjustments
Revenues
Investment banking		0		0		0		0
Brokerage		0		0		0		0
Management fees		0		0		0		0
Incentive income		0		0		0		0
Investment Income		0		0		0		0
Interest and dividends		0		0		0		0
Reimbursement from affiliates		0		0		0		0
Reinsurance premiums		0		0		0		0
Other revenues		0		0		0		0
Total revenues		0		0		0		0
Interest expense	[11]	(1,152,000)		(1,092,000)		(3,394,000)		(3,208,000)
Total net revenues		1,152,000		1,092,000		3,394,000		3,208,000
Expenses
Employee compensation and benefits		0		0		0		0
Fixed expenses	[12]	(3,324,000)		(476,000)		(5,152,000)		(1,664,000)
Variable expenses		0		0		0		0
Other non-compensation expense		0		0		0		0
Depreciation and amortization		(7,000)	[13]	0		(551,000)	[13]	0
Economic Non-Controlling Interest		0		0		0		0
Goodwill Impairment	[13]							(4,100,000)
Total expenses		(3,331,000)		(476,000)		(5,703,000)		(5,764,000)
Other income (loss)
Total other income (loss)		0		0		0		0
Preferred stock dividends		1,698,000		1,698,000		5,094,000		5,094,000
Income (Loss) before income taxes / Economic income (loss)		2,785,000		(130,000)		4,003,000		3,878,000
Adjustments | Income statement adjustments | Consolidated Funds
Revenues
Total revenues		0		0		0		0
Expenses
Total expenses		0		0		0		0
Adjustments | Funds Consolidation
Revenues
Investment banking	[14]	0		0		0		0
Brokerage	[14]	0		0		0		0
Management fees	[14]	163,000		574,000		1,475,000		1,640,000
Incentive income	[14]	33,000		13,000		33,000		557,000
Investment Income	[14]	0		0		0		0
Interest and dividends	[14]	0		0		0		0
Reimbursement from affiliates	[14]	0		27,000		50,000		94,000
Reinsurance premiums	[14]	0		0		0		0
Other revenues	[14]	(3,000)		26,000		(21,000)		14,000
Total revenues	[14]	(942,000)		(1,791,000)		(3,113,000)		(5,934,000)
Interest expense	[14]	0		0		0		0
Total net revenues	[14]	(942,000)		(1,791,000)		(3,113,000)		(5,934,000)
Expenses
Employee compensation and benefits	[14]	0		0		0		0
Fixed expenses		0	[14]	0	[14]	0	[14]	0
Variable expenses	[14]	0		0		0		0
Other non-compensation expense	[14]	0		0		0		0
Depreciation and amortization	[14]	0		0		0		0
Economic Non-Controlling Interest	[14]	0		0		0		0
Goodwill Impairment	[14]							0
Total expenses	[14]	(494,000)		(2,516,000)		(4,793,000)		(6,229,000)
Other income (loss)
Total other income (loss)	[14]	(2,500,000)		(5,621,000)		27,678,000		(9,069,000)
Preferred stock dividends	[14]	0		0		0		0
Income (Loss) before income taxes / Economic income (loss)		(2,948,000)	[14]	(4,896,000)		29,358,000	[14]	(8,774,000)	[14]
Adjustments | Funds Consolidation | Consolidated Funds
Revenues
Total revenues	[14]	(1,135,000)		(2,431,000)		(4,650,000)		(8,239,000)
Expenses
Total expenses	[14]	$ (494,000)		$ (2,516,000)		$ (4,793,000)		$ (6,229,000)
[1]	Economic Income (Loss) presents expenses reimbursed from clients and affiliates within their respective expense category but is included as a part of revenues under US GAAP.
[2]	Economic Income (Loss) presents underwriting expenses net of investment banking revenues.
[3]	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.
[4]	Economic Income (Loss) recognizes gains and losses on investments held as part of the Company's facilitation and trading business within brokerage revenues as these investments are directly related to the markets business activities.
[5]	Economic Income (Loss) presents revenues net of fund start-up costs and distribution fees paid to agents.
[6]	Economic Income (Loss) recognizes the Company's proportionate share of management and incentive fees and associated share of expenses on a gross basis for certain real estate operating entities, the healthcare royalty business and the activist business. Additionally, carried interest, which the Company applies an equity ownership model to, is recorded in other income (loss) for US GAAP and is shown as incentive income for Economic Income (Loss).
[7]	Economic Income (Loss) recognizes Company income from proprietary trading (including interest and dividends) for which the majority of this activity is shown in other income (loss) for US GAAP reporting.
[8]	Economic Income (Loss) recognizes underwriting income from the Company's insurance related activities, net of expenses, within other revenue. The costs are recorded within expenses for US GAAP reporting.
[9]	Economic Income (Loss) presents certain payments to associated banking partners as compensation rather than non-compensation expenses.
[10]	Economic Income (Loss) presents US GAAP expenses as either Fixed non-compensation or Variable non-compensation expenses. The Company also presents US GAAP Income (loss) attributable to non-controlling interests within total other expenses for Economic Income (Loss).
[11]	Economic Income (Loss) excludes the amortization of discount on convertible debt.
[12]	Economic Income (Loss) excludes acquisition related adjustments as management does not consider these items when evaluating the performance of the Company.
[13]	Economic Income (Loss) excludes goodwill and intangible impairment.
[14]	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).

Regulatory Requirements (Detail

Regulatory Requirements (Details)	9 Months Ended
	Sep. 30, 2020USD ($)
Regulatory Requirements for Broker-Dealers [Line Items]
Minimum net capital required	$ 250,000
Cowen and Company
Regulatory Requirements for Broker-Dealers [Line Items]
Net capital requirement under alternative method	3,043,000
Minimum net capital required	1,000,000
Required net capital under commodity exchange act	385,600,000
Cash and securities segregated under securities exchange commission regulation	43,900,000
Net capital	388,606,000
Excess capital	385,563,000
Cowen and Company (Asia) Limited [Member]
Regulatory Requirements for Broker-Dealers [Line Items]
Financial resources	1,394,000
Financial resources requirement	387,000
Excess financial resources	1,007,000
ATM Execution LLC
Regulatory Requirements for Broker-Dealers [Line Items]
Net capital requirement under alternative method	250,000
Net capital	4,015,000
Excess capital	3,765,000
Cowen Prime
Regulatory Requirements for Broker-Dealers [Line Items]
Net capital requirement under alternative method	250,000
Net capital	19,432,000
Excess capital	19,182,000
Westminster Research
Regulatory Requirements for Broker-Dealers [Line Items]
Net capital requirement under alternative method	250,000
Net capital	5,305,000
Excess capital	5,055,000
RCG Insurance Company
Regulatory Requirements for Broker-Dealers [Line Items]
Minimum net capital required	300,000
Net capital	6,100,000
Options Clearing Corporation | Cowen and Company
Regulatory Requirements for Broker-Dealers [Line Items]
Minimum net capital required	$ 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	$ 22,892,000
Financial resources requirement	17,882,000
Excess financial resources	5,010,000
U.K. Financial Services Authority | Cowen Execution Services Ltd
Regulatory Requirements for Broker-Dealers [Line Items]
Financial resources	11,501,000
Financial resources requirement	4,333,000
Excess financial resources	7,168,000
Minimum | Cowen and Company
Regulatory Requirements for Broker-Dealers [Line Items]
Cash and securities segregated under securities exchange commission regulation	20,500,000
Minimum | Cowen Prime
Regulatory Requirements for Broker-Dealers [Line Items]
Required net capital under commodity exchange act	45,000
Special Reserve Accounts | Cowen and Company
Regulatory Requirements for Broker-Dealers [Line Items]
Cash and securities segregated under securities exchange commission regulation	35,200,000
Special Reserve Accounts | Minimum | Cowen and Company
Regulatory Requirements for Broker-Dealers [Line Items]
Cash and securities segregated under securities exchange commission regulation	$ 16,600,000

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Related Party Transaction [Line Items]
Fees receivable		$ 138,234		$ 138,234		$ 126,358
Interest Income, Related Party			$ 100	100	$ 100
Due from related parties		23,480		23,480		26,749
Redeemable non-controlling interests, Related Party		0		0		391,275
Net income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds		0	(6,848)	(32,924)	(4,187)
Investment banking		194,341	77,292	503,351	272,103
Adjustments | Management Reclassifications
Related Party Transaction [Line Items]
Investment banking	[1],[2]	(9,190)	(7,859)	(28,573)	(17,729)
Employees
Related Party Transaction [Line Items]
Redeemable non-controlling interests, Related Party		192,000		192,000		36,000
Net income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds		6,700	3,600	10,700	4,700
Employee Loans
Related Party Transaction [Line Items]
Due from employees		11,300		11,300		14,900
Forgivable Loan Balances		4,900		4,900		7,100
Amortization on Forgivable Loans		800	1,000	$ 2,800	$ 2,800
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		22,600		$ 22,600		20,500
Investor
Related Party Transaction [Line Items]
Due to Affiliate		200		200		300
Other Funds
Related Party Transaction [Line Items]
Due from related parties		7,400		7,400		5,300
Starboard Value LP
Related Party Transaction [Line Items]
Effective interest rate					5.00%
Interest Income, Related Party		100	$ 100	200	$ 300
Due from related parties		$ 4,800		$ 4,800		$ 6,500
Finance Period				5 years
[1]	Economic Income (Loss) presents expenses reimbursed from clients and affiliates within their respective expense category but is included as a part of revenues under US GAAP.
[2]	Economic Income (Loss) presents underwriting expenses net of investment banking revenues.

Guarantees and Off-Balance Sh_3

Guarantees and Off-Balance Sheet Arrangements (Details)	Sep. 30, 2020USD ($)
Debt Instrument [Line Items]
Letter of credit, borrowing capacity	$ 395,000,000
Line of credit facility, remaining borrowing capacity	395,000,000
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 | Spike Line
Debt Instrument [Line Items]
Letter of credit, borrowing capacity	70,000,000
Line of credit facility, remaining borrowing capacity	70,000,000
BMO Harris Bank | Revolving Credit Facility
Debt Instrument [Line Items]
Letter of credit, borrowing capacity	25,000,000
Line of credit facility, remaining borrowing capacity	$ 25,000,000

Subsequent Events - Narrative (

Subsequent Events - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	9 Months Ended
	Oct. 31, 2020	Sep. 30, 2020	Oct. 21, 2020
Subsequent Event [Line Items]
Common Stock, Dividends, Per Share, Declared		$ 0.04
Subsequent Event
Subsequent Event [Line Items]
Common Stock, Dividends, Per Share, Declared	$ 0.08
Stock Repurchase Program Additional Authorized Amount			$ 19,700
Stock Repurchase Program, Remaining Authorized Repurchase Amount			$ 25,000