Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues
Investment banking		$ 57,383	$ 36,722	$ 158,082	$ 98,156
Brokerage		84,220	49,605	198,599	147,640
Management fees		8,223	10,272	25,587	31,951
Incentive income		1,945	1,284	6,217	2,823
Interest and dividends		14,318	3,906	27,324	11,664
Reimbursement from affiliates		484	2,140	2,631	8,268
Aircraft lease revenue		934	1,089	3,036	3,071
Reinsurance premiums		7,186	8,905	21,957	23,243
Other revenue		3,402	16,207	6,147	17,940
Consolidated Funds
Interest and dividends		871	904	4,253	3,518
Other revenues		(136)	(7)	498	1,023
Total revenues		178,830	131,027	454,331	349,297
Expenses
Employee compensation and benefits		103,282	98,501	282,066	217,309
Floor brokerage and trade execution		25,817	8,224	48,218	23,887
Interest and dividends		15,132	7,612	37,273	21,866
Professional, advisory and other fees		7,001	5,305	23,344	16,585
Service fees		3,983	2,075	9,927	6,334
Communications		6,423	4,619	17,186	13,287
Occupancy and equipment		9,656	8,033	25,252	23,911
Depreciation and amortization		3,452	3,174	9,612	9,654
Client services and business development		5,551	6,349	20,505	20,335
Reinsurance claims, commissions and amortization of deferred acquisition costs		7,157	8,595	20,610	20,924
Restructuring Costs		222	0	8,763	0
Other Expenses		4,960	3,303	12,550	11,404
Consolidated Funds
Interest and dividends		1,234	1,665	7,325	4,292
Professional, advisory and other fees		205	337	901	959
Floor brokerage and trade execution		64	173	278	306
Other expenses		209	294	919	871
Total expenses		194,348	158,259	524,729	391,924
Other income (loss)
Net gains (losses) on securities, derivatives and other investments		18,326	26,153	63,101	9,123
Bargain purchase gain, net of tax		0	0	7,946	0
Consolidated Funds
Net realized and unrealized gains (losses) on investments and other transactions		9,073	19,755	48,154	(6,543)
Net realized and unrealized gains (losses) on derivatives		220	5,368	5,405	13,525
Net gains (losses) on foreign currency transactions		8	(26)	(299)	72
Total other income (loss)		27,627	51,250	124,307	16,177
Income (loss) before income taxes		12,109	24,018	53,909	(26,450)
Income tax expense (benefit)		2,281	8,759	3,407	(6,553)
Net income (loss)		9,828	15,259	50,502	(19,897)
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds		(5,162)	(18,478)	(35,412)	2,524
Net income (loss) attributable to Cowen Inc.		4,666	(3,219)	15,090	(17,373)
Preferred stock dividends		1,698	1,698	5,094	5,094
Net income (loss) attributable to Cowen Group, Inc. common stockholders		$ 2,968	$ (4,917)	$ 9,996	$ (22,467)
Weighted average common shares outstanding:
Basic (in shares)	[1]	31,271	26,993	29,004	26,818
Diluted (in shares)	[1]	32,246	26,993	30,011	26,818
Earnings (loss) per share:
Earnings Per Share, Basic (in dollars per share)	[1]	$ 0.09	$ (0.18)	$ 0.34	$ (0.84)
Earnings Per Share, Diluted (in dollars per share)	[1]	$ 0.09	$ (0.18)	$ 0.33	$ (0.84)

[1] Share and per share amounts have been retroactively updated to reflect the one-for-four reverse stock split effective as of December 5, 2016.