Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues
Investment banking	$ 222,781	$ 170,506	$ 105,333
Brokerage	157,722	140,132	114,593
Management fees	41,906	40,627	37,303
Incentive income	1,466	2,785	12,586
Interest and dividends	13,796	48,870	39,454
Reimbursement from affiliates	21,557	12,495	10,434
Other revenue	3,726	9,446	5,418
Consolidated Funds
Interest and dividends	1,086	2,189	1,185
Other revenues	527	726	2,213
Total revenues	464,567	427,776	328,519
Expenses
Employee compensation and benefits	321,386	305,483	207,248
Floor brokerage and trade execution	27,460	23,425	22,709
Interest and dividends	26,220	42,752	27,299
Professional, advisory and other fees	25,578	18,724	14,625
Service fees	7,535	8,071	9,768
Communications	14,325	13,449	13,434
Occupancy and equipment	29,055	26,025	24,729
Depreciation and amortization	9,498	10,188	10,227
Client services and business development	25,413	22,897	17,353
Goodwill Impairment	0	2,334	0
Other expenses	15,594	15,209	11,486
Consolidated Funds
Interest and dividends	1,104	788	345
Professional, advisory and other fees	654	620	1,157
Floor brokerage and trade execution	51	16	285
Other expenses	501	210	252
Total expenses	504,374	490,191	360,917
Other income (loss)
Net gains (losses) on securities, derivatives and other investments	36,789	104,928	39,651
Consolidated Funds
Net realized and unrealized gains (losses) on investments and other transactions	12,517	12,890	10,678
Net realized and unrealized gains (losses) on derivatives	2,071	2,451	365
Net gains (losses) on foreign currency transactions	(91)	(18)	1
Total other income (loss)	51,286	120,251	50,695
Income (loss) before income taxes	11,479	57,836	18,297
Income tax expense (benefit)	(47,496)	(124,944)	457
Net income (loss)	58,975	182,780	17,840
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	15,246	15,564	13,193
Net income (loss) attributable to Cowen Group, Inc.	43,729	167,216	4,647
Preferred Stock Dividends	4,075	0	0
Net income (loss) attributable to Cowen Group, Inc. common stockholders	$ 39,654	$ 167,216	$ 4,647
Weighted average common shares outstanding:
Basic (in shares)	110,090	114,926	116,703
Diluted (in shares)	116,174	119,486	121,117
Earnings (loss) per share:
Earnings Per Share, Basic (in dollars per share)	$ 0.36	$ 1.45	$ 0.04
Earnings Per Share, Diluted (in dollars per share)	$ 0.34	$ 1.40	$ 0.04