Cowen (COWN) 10-K 3 Mar 14 2013 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2013	Feb. 28, 2014	Jun. 30, 2013
Document and Entity Information [Abstract]	'	'	'
Entity Registrant Name	'Cowen Group, Inc.	'	'
Entity Central Index Key	'0001466538	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Filer Category	'Accelerated Filer	'	'
Document Type	'10-K	'	'
Document Period End Date	31-Dec-13	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
Amendment Flag	'false	'	'
Entity Common Stock, Shares Outstanding	'	115,042,048	'
Entity Well-known Seasoned Issuer	'No	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Public Float	'	'	$311,324,854

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Financial Condition (USD $)	Dec. 31, 2013	Dec. 31, 2012
Assets	'	'
Cash and cash equivalents	$54,720,000	$83,538,000
Cash collateral pledged	10,907,000	9,160,000
Securities owned, at fair value	320,737,000	624,127,000
Securities borrowed	927,773,000	406,326,000
Other investments	99,483,000	84,930,000
Receivable from brokers	66,980,000	71,306,000
Fees receivable, net of allowance	45,067,000	34,707,000
Due from related parties	26,910,000	21,022,000
Fixed assets, net of accumulated depreciation and amortization of $21,853 and $30,003, respectively	26,999,000	32,202,000
Goodwill	37,240,000	28,545,000
Intangible assets, net of accumulated amortization of $26,610 and $22,945, respectively	12,094,000	12,984,000
Other assets	17,938,000	18,048,000
Consolidated Funds	'	'
Cash and cash equivalents	2,048,000	3,559,000
Securities owned, at fair value	0	3,525,000
Other investments, at fair value	187,480,000	204,205,000
Other assets	5,624,000	292,000
Total Assets	1,842,000,000	1,638,476,000
Liabilities	'	'
Securities sold, not yet purchased, at fair value	137,527,000	177,937,000
Securities sold under agreement to repurchase	3,657,000	165,945,000
Securities loaned	918,577,000	408,972,000
Payable to brokers	75,420,000	188,788,000
Compensation payable	51,807,000	45,752,000
Short-term borrowings and other debt	2,564,000	4,132,000
Fees payable	6,324,000	5,277,000
Due to related parties	382,000	662,000
Accounts Payable, Accrued Expenses and Other Liabilities	46,391,000	56,894,000
Consolidated Funds	'	'
Capital withdrawals payable	5,222,000	2,891,000
Accounts payable, accrued expenses and other liabilities	549,000	414,000
Total Liabilities	1,248,420,000	1,057,664,000
Commitments and Contingencies (Note 19)	'	'
Redeemable non-controlling interests	85,814,000	85,703,000
Stockholders' equity	'	'
Preferred stock, par value $0.01 per share; 10,000,000 shares authorized, no shares issued and outstanding	0	0
Additional paid-in capital	737,341,000	713,211,000
(Accumulated deficit) retained earnings	-183,243,000	-187,865,000
Accumulated other comprehensive income (loss)	592,000	356,000
Less: Class A common stock held in treasury, at cost, 15,873,549 and 11,292,220 shares as of December 31, 2013 and December 31, 2012, respectively.	-48,100,000	-31,728,000
Total Stockholders' Equity	507,766,000	495,109,000
Total Liabilities and Stockholders' Equity	1,842,000,000	1,638,476,000
Common Stock Class A	'	'
Stockholders' equity	'	'
Common stock	1,160,000	1,135,000
Less: Class A common stock held in treasury, at cost, 15,873,549 and 11,292,220 shares as of December 31, 2013 and December 31, 2012, respectively.	-48,084,000	-31,728,000
Common Stock Class B	'	'
Stockholders' equity	'	'
Common stock	$0	$0

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Financial Condition (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified
Assets	'	'
Fixed assets, accumulated depreciation and amortization (in dollars)	$21,853	$30,003
Intangible assets, accumulated amortization (in dollars)	$26,610	$22,945
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	0	0
Preferred stock, shares outstanding	0	0
Common stock, shares authorized	500,000,000	'
Common Stock Class A	'	'
Stockholders' equity	'	'
Treasury stock, shares	15,873,549	11,292,220
Common stock, par value (in dollars per share)	$0.01	$0.01
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	130,900,182	123,740,112
Common stock, shares outstanding	115,026,633	112,447,892
Common stock, restricted shares	482,522	336,895
Common Stock Class B	'	'
Stockholders' equity	'	'
Common stock, par value (in dollars per share)	$0.01	$0.01
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	0	0
Common stock, shares outstanding	0	0

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Operations (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues	'	'	'
Investment banking	$105,333	$71,762	$50,976
Brokerage	114,593	91,167	99,611
Management fees	37,303	38,116	52,466
Incentive income	12,586	5,411	3,265
Interest and dividends	39,454	24,608	22,306
Reimbursement from affiliates	9,161	5,239	4,322
Other revenues	5,418	3,668	1,583
Consolidated Funds	'	'	'
Interest and dividends	1,185	136	569
Other revenues	2,213	373	180
Total revenues	327,246	240,480	235,278
Expenses	'	'	'
Employee compensation and benefits	207,248	194,034	203,767
Floor brokerage and trade execution	16,935	14,684	16,475
Interest and dividends	27,299	12,137	9,233
Professional, advisory and other fees	14,625	16,339	33,702
Service fees	9,768	11,281	16,365
Communications	18,078	15,704	16,350
Occupancy and equipment	24,729	22,087	27,887
Depreciation and amortization	10,227	9,437	15,472
Client services and business development	17,353	14,069	16,725
Goodwill impairment	0	0	7,151
Other expenses	12,616	15,452	9,746
Consolidated Funds	'	'	'
Interest and dividends	345	22	147
Professional, advisory and other fees	1,157	1,361	2,136
Floor brokerage and trade execution	285	0	0
Other expenses	252	293	499
Total expenses	360,917	326,900	375,655
Other income (loss)	'	'	'
Net gains (losses) on securities, derivatives and other investments	40,924	55,665	15,128
Bargain purchase gain	0	0	22,244
Consolidated Funds	'	'	'
Net realized and unrealized gains (losses) on investments and other transactions	10,678	6,376	4,925
Net realized and unrealized gains (losses) on derivatives	365	877	-583
Net gains (losses) on foreign currency transactions	1	-7	53
Total other income (loss)	51,968	62,911	41,767
Income (loss) before income taxes	18,297	-23,509	-98,610
Income tax expense (benefit)	457	448	-20,073
Net income (loss) from continuing operations	17,840	-23,957	-78,537
Net income (loss) from discontinued operations, net of tax	0	0	-23,646
Net income (loss)	17,840	-23,957	-102,183
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	13,193	-72	5,827
Net income (loss) attributable to Cowen Group, Inc. stockholders	$4,647	($23,885)	($108,010)
Weighted average common shares outstanding:	'	'	'
Basic (in shares)	116,703	114,400	95,532
Diluted (in shares)	121,117	114,400	95,532
Earnings (loss) per share:	'	'	'
Income (loss) from continuing operations, basic (in dollars per share)	$0.04	($0.21)	($0.88)
Income (loss) from discontinued operations, basic (in dollars per share)	$0	$0	($0.25)
Income (loss) from continuing operations, diluted (in dollars per share)	$0.04	($0.21)	($0.88)
Income (loss) from discontinued operations, diluted (in dollars per share)	$0	$0	($0.25)

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Comprehensive Income (Loss) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Statement of Comprehensive Income [Abstract]	'		'		'
Net income (loss)	$17,840		($23,957)		($102,183)
Other comprehensive income (loss), net of tax:	'		'		'
Foreign currency translation	-10	[1]	148	[1]	-260	[1]
Defined benefit pension plans:	'		'		'
Net gain/(loss) arising during the period	-137		459		2
Effect of Curtailment	360		-59		0
Amortization of prior service cost	23		23		23
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent	246	[1]	423	[1]	25	[1]
Total other comprehensive income, net of tax	236		571		-235
Comprehensive income (loss)	$18,076		($23,386)		($102,418)
[1]	(a) During the periods presented, the Company did not have material reclassifications out of other comprehensive income.

Condensed_Consolidated_Stateme4

Condensed Consolidated Statements of Changes in Equity (USD $)	Total		Common Stock	Treasury Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings/(Accumulated deficit)	Redeemable Non-controlling Interest	LaBranche and Co Inc. [Member]
	USD ($)		USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	Common Stock
Balance at Dec. 31, 2010	$449,256,000		$726,000	$0	$504,480,000	$20,000	($55,970,000)	$144,346,000	'
Balance, shares at Dec. 31, 2010	'		75,490,209	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'		'	'	'	'	'	'	'
Net income (loss) attributable to Cowen Group, Inc. stockholders	-108,010,000		'	'	'	'	-108,010,000	'	'
Net income (loss) attributable to redeemable non-controlling interests	5,827,000		'	'	'	'	'	5,827,000	'
Defined benefit plans	25,000	[1]	'	'	'	25,000	'	'	'
Foreign currency translation	-260,000	[1]	'	'	'	-260,000	'	'	'
Capital contributions	'		'	'	'	'	'	4,038,000	'
Capital withdrawals	'		'	'	'	'	'	-53,094,000	'
Consolidation of funds	'		'	'	'	'	'	3,470,000	'
Restricted stock awards issued, shares	'		3,053,298	'	'	'	'	'	'
Common stock issued upon acquisition (See Note 2)	156,048,000		409,000	'	155,639,000	'	'	'	'
Common stock issued upon acquisition (See Note 2), shares	'		'	'	'	'	'	'	40,850,133
Treasury stock re-issuance	0		'	'	'	'	'	'	'
Purchase of treasury stock, at cost	-16,902,000		'	-16,902,000	'	'	'	'	'
Purchase of treasury stock, at cost, shares	'		'	-5,346,003	'	'	'	'	'
Amortization of share based compensation	28,308,000		'	'	28,308,000	'	'	'	'
Balance at Dec. 31, 2011	508,465,000		1,135,000	-16,902,000	688,427,000	-215,000	-163,980,000	104,587,000	'
Balance, shares at Dec. 31, 2011	'		114,047,637	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'		'	'	'	'	'	'	'
Net income (loss) attributable to Cowen Group, Inc. stockholders	-23,885,000		'	'	'	'	-23,885,000	'	'
Net income (loss) attributable to redeemable non-controlling interests	-72,000		'	'	'	'	'	-72,000	'
Defined benefit plans	423,000	[1]	'	'	'	423,000	'	'	'
Foreign currency translation	148,000	[1]	'	'	'	148,000	'	'	'
Capital contributions	'		'	'	'	'	'	500,000	'
Capital withdrawals	'		'	'	'	'	'	-20,729,000	'
Deconsolidation of funds	'		'	'	'	'	'	-17,104,000	'
Consolidation of funds	'		'	'	'	'	'	18,521,000	'
Restricted stock awards issued, shares	'		4,346,472	'	'	'	'	'	'
Common stock issued upon acquisition (See Note 2)	0		'	'	'	'	'	'	'
Purchase of treasury stock, at cost	-14,826,000		'	-14,826,000	'	'	'	'	'
Purchase of treasury stock, at cost, shares	'		'	-5,946,217	'	'	'	'	'
Amortization of share based compensation	24,784,000		'	'	24,784,000	'	'	'	'
Balance at Dec. 31, 2012	495,109,000		1,135,000	-31,728,000	713,211,000	356,000	-187,865,000	85,703,000	'
Balance, shares at Dec. 31, 2012	'		112,447,892	'	'	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'		'	'	'	'	'	'	'
Net income (loss) attributable to Cowen Group, Inc. stockholders	4,647,000		'	'	'	'	4,647,000	'	'
Net income (loss) attributable to redeemable non-controlling interests	13,193,000		'	'	'	'	'	13,193,000	'
Defined benefit plans	246,000	[1]	'	'	'	246,000	'	'	'
Foreign currency translation	-10,000	[1]	'	'	'	-10,000	'	'	'
Capital contributions	'		'	'	'	'	'	15,181,000	'
Capital withdrawals	'		'	'	'	'	'	-28,263,000	'
Restricted stock awards issued, shares	'		4,668,423	'	'	'	'	'	'
Common stock issued upon acquisition (See Note 2)	6,240,000		25,000	'	6,215,000	'	'	'	'
Common stock issued upon acquisition (See Note 2), shares	'		2,491,647	'	'	'	'	'	'
Treasury stock re-issuance	90,000		'	90,000	'	'	'	'	'
Treasury Stock Reissued at Lower than Repurchase Price	'		'	-25,000	'	'	'	'	'
Treasury stock reissued during the period net of gain(loss)	65,000		'	'	'	'	'	'	'
Treasury stock re-issuance, shares	'		'	24,744	'	'	'	'	'
Purchase of treasury stock, at cost	-16,446,000		'	-16,446,000	'	'	'	'	'
Purchase of treasury stock, at cost, shares	'		'	-4,606,073	'	'	'	'	'
Amortization of share based compensation	17,915,000		'	'	17,915,000	'	'	'	'
Balance at Dec. 31, 2013	$507,766,000		$1,160,000	($48,084,000)	$737,341,000	$592,000	($183,243,000)	$85,814,000	'
Balance, shares at Dec. 31, 2013	'		115,026,633	'	'	'	'	'	'
[1]	(a) During the periods presented, the Company did not have material reclassifications out of other comprehensive income.

Condensed_Consolidated_Stateme5

Condensed Consolidated Statements of Cash Flows (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:	'	'	'
Net income (loss) from continuing operations	$17,840,000	($23,957,000)	($78,537,000)
Net income (loss) from discontinued operations, net of tax	0	0	-23,646,000
Adjustments to reconcile net income (loss) to net cash provided by / (used in) operating activities:	'	'	'
Bargain purchase gain	0	0	22,244,000
Depreciation and amortization	10,227,000	9,437,000	26,864,000
Share-based compensation	17,915,000	24,784,000	28,308,000
Deferred rent obligations	-268,000	-1,938,000	-4,061,000
Net loss on disposal of fixed assets	410,000	30,000	103,000
Goodwill impairment	0	0	7,151,000
Purchases of securities owned, at fair value	-6,821,969,000	-6,257,362,000	-8,953,879,000
Proceeds from sales of securities owend, at fair value	7,106,181,000	6,328,288,000	8,726,114,000
Proceeds from sales of securities sold, not yet purchased, at fair value	2,767,452,000	4,327,700,000	4,690,844,000
Payments to cover securities sold, not yet purchased, at fair value	-2,789,081,000	-4,456,056,000	-4,553,832,000
Net (gains) losses on securities, derivatives and other investments	-40,510,000	-43,872,000	-3,128,000
Consolidated Funds	'	'	'
Purchases of securities owned, at fair value	-298,220,000	-366,388,000	-480,251,000
Proceeds from sales of securities owned, at fair value	287,412,000	369,209,000	482,630,000
Proceeds from sales of securities sold, not yet purchased, at fair value	42,701,000	0	0
Payments to cover securities sold, not yet purchased, at fair value	-42,387,000	0	0
Purchases of other investments	-4,497,000	-9,785,000	-18,356,000
Proceeds from sales of other investments	56,873,000	42,071,000	127,664,000
Net realized and unrealized (gains) losses on investments and other transactions	-14,153,000	-8,608,000	-4,746,000
(Increase) decrease in operating assets:	'	'	'
Cash acquired upon transaction	10,747,000	290,000	117,496,000
Cash collateral pledged	135,000	625,000	-25,000
Securities owned, at fair value, held at broker dealer	20,434,000	43,657,000	152,080,000
Securities borrowed	-521,447,000	119,758,000	0
Receivable from brokers	5,614,000	405,000	127,995,000
Fees receivable, net of allowance	-9,975,000	-5,642,000	9,041,000
Due from related parties	-5,888,000	-3,570,000	2,388,000
Other assets	1,304,000	10,661,000	-1,388,000
Consolidated Funds	'	'	'
Cash and cash equivalents	1,511,000	-2,326,000	6,913,000
Other assets	-5,528,000	1,370,000	469,000
Increase (decrease) in operating liabilities:	'	'	'
Securities sold, not yet purchased, at fair value, held at broker dealer	-11,898,000	-1,301,000	-157,134,000
Securities loaned	509,605,000	-132,927,000	0
Payable to brokers	-113,368,000	-24,572,000	46,169,000
Compensation payable	-13,036,000	-29,047,000	-12,107,000
Fees payable	1,047,000	-985,000	-3,772,000
Due to related parties	-280,000	-1,252,000	-7,273,000
Accounts payable, accrued expenses and other liabilities	-15,490,000	-12,737,000	6,652,000
Consolidated Funds	'	'	'
Payable to brokers	1,030,000	0	0
Due to related parties	0	25,000	0
Accounts payable, accrued expenses and other liabilities	146,000	149,000	-1,582,000
Net cash provided by / (used in) operating activities	150,589,000	-103,866,000	232,920,000
Cash flows from investing activities:	'	'	'
Securities purchased under agreement to resell	0	166,260,000	-68,505,000
Purchases of other investments	-20,048,000	-14,848,000	-61,364,000
Proceeds from sales of other investments	29,900,000	13,298,000	53,317,000
Purchase of business, net of cash acquired (Note 2)	0	-10,853,000	0
Cash paid to acquire net assets (contingent payable)	-779,000	0	0
Purchase of fixed assets	-1,141,000	-1,902,000	-6,539,000
Net cash provided by / (used in) investing activities	7,932,000	151,955,000	-83,091,000
Cash flows from financing activities:	'	'	'
Securities sold under agreement to repurchase	-162,288,000	-62,838,000	36,618,000
Borrowings on short-term borrowings and other debt	2,044,000	0	493,000
Repayments on short-term borrowings and other debt	-3,613,000	-1,518,000	-26,576,000
Purchase of treasury stock	-12,732,000	-10,838,000	-11,365,000
Capital contributions by non-controlling interests in operating entities	501,000	0	0
Capital withdrawals to non-controlling interests in operating entities	-3,058,000	-3,167,000	-5,009,000
Consolidated Funds	'	'	'
Capital contributions by non-controlling interests in Consolidated Funds	14,680,000	0	4,038,000
Capital withdrawals to non-controlling interests in Consolidated Funds	-22,873,000	-15,065,000	-55,507,000
Net cash provided by / (used in) financing activities	-187,339,000	-93,426,000	-57,308,000
Change in cash and cash equivalents	-28,818,000	-45,337,000	92,521,000
Cash and cash equivalents at beginning of period	83,538,000	128,875,000	36,354,000
Cash and cash equivalents at end of period	54,720,000	83,538,000	128,875,000
Supplemental information	'	'	'
Cash paid during the year for interest	24,644,000	9,419,000	9,007,000
Cash paid during the year for taxes	72,000	611,000	871,000
Purchase of treasury stock, at cost, upon close of acquisition (see Note 2)	0	0	1,906,000
Net assets (liabilities) acquired upon acquisition (net of cash) (See Note 2)	0	9,995,000	58,486,000
Non compete agreements and covenants with limiting conditions acquired (see Note 2)	460,000	167,000	2,310,000
Common stock issuance upon close of acquisition (see Note 2)	6,240,000	0	156,048,000
Purchase of treasury stock, at cost, through net settlement (see Note 21)	3,649,000	3,988,000	3,631,000
Re-issuance of treasury stock for services provided	65,000	'	'
Re-issuance of treasury stock for services provided	90,000	'	0
Net assets transferred to Merger Master (see Note 6)	22,152,000	0	0
Net assets of consolidated entities	0	18,521,000	3,470,000
Net assets of deconsolidated entities	$0	$17,104,000	$0

Organization_and_Business

Organization and Business	12 Months Ended
	Dec. 31, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Organization and Business	'
	Organization and Business
	Cowen Group, Inc., a Delaware corporation formed in 2009, is a diversified financial services firm and, together with its consolidated subsidiaries (collectively, “Cowen,” “Cowen Group” or the “Company”), provides alternative investment management, investment banking, research, market-making and sales and trading and securities lending services through its two business segments: alternative investment and broker-dealer. The Company's alternative investment segment includes hedge funds, replication products, liquid alternative risk premia products, customized solutions, mutual funds, managed futures funds, funds of funds, real estate and healthcare royalty funds, offered primarily under the Ramius name. The broker-dealer segment offers research, brokerage and investment banking services to companies and institutional investor clients primarily in the healthcare, technology, media and telecommunications, consumer, aerospace and defense, industrials, real estate investment trusts ("REITs"), clean technology, energy, metals and mining, transportation, chemicals and agriculture sectors, primarily under the Cowen name.

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2013
Business Combinations [Abstract]	'
Acquisitions	'
	Acquisitions
	Dahlman Rose & Company, LLC
	On March 11, 2013, the Company completed its acquisition of all of the outstanding interests in Dahlman Rose & Company, LLC ("Dahlman"), a privately-held investment bank specializing in the energy, metals and mining, transportation, chemicals and agriculture sectors. This acquisition was an all-stock transaction. In the aggregate, the purchase price, assets acquired and liabilities assumed were not significant and the near term impact to the Company and its consolidated results of operations and cash flows is not expected to be significant. Dahlman was subsequently renamed to Cowen Securities LLC ("Cowen Securities"). Following the acquisition, Cowen Securities is included in the broker-dealer segment (See Note 24).
	During the fourth quarter of 2013, the Company finalized its purchase price allocation with insignificant adjustments to the recognized amounts on the consolidated statements of financial condition. The purchase price allocation of Cowen Securities is based upon all information available to us at the present time, and is based upon management's estimates of the fair values using valuation techniques including income, cost and market approaches.
	The acquisition was accounted for under the acquisition method of accounting in accordance with accounting principles generally accepted in the United States of America ("US GAAP"). As such, results of operations for the Cowen Securities are included in the accompanying consolidated statements of operations since the date of the acquisition, and the assets acquired, liabilities assumed and the resulting goodwill were recorded at their fair values within their respective line items on the accompanying consolidated statement of financial condition. The goodwill is fully deductible for tax purposes. During the year ended December 31, 2013, the business was fully integrated within the broker dealer segment.
	ATM USA, LLC and KDC Securities, LP
	During the year ended December 31, 2012, the Company completed two acquisitions that were not individually material but were material in the aggregate. On April 5, 2012, the Company completed its acquisition of all of the outstanding interests in ATM USA, LLC ("ATM USA"), Algorithmic Trading Management, LLC ("ATM LLC") and Algo Trading Management Inc. ("ATM INC") (collectively the “ATM Group”), a provider of global, multi-asset class algorithmic execution trading models. On November 1, 2012, the Company also completed the acquisition of all of the outstanding interests in KDC Securities, LP (renamed subsequent to the acquisition to "Cowen Equity Finance LP"), a securities lending business. KDC Securities, LP was the broker-dealer subsidiary of Kellner Capital, LLC, an alternative investment manager. Post acquisition, the ATM Group and Cowen Equity Finance LP are integrated in to the broker-dealer segment.
	These acquisitions were completed in accordance with their respective agreements for cash of $10.9 million and contingent consideration of $8.1 million in the aggregate. In accordance with the terms of the purchase agreements, the Company is required to pay to the sellers a portion of future net profits of the businesses, if certain revenue targets are achieved over the period through October 2016. The Company estimated the contingent consideration using the income approach (discounted cash flow method) which requires the Company to make estimates and assumptions regarding the future cash flows and profits. Changes in these estimates and assumptions could have a significant impact on the amounts recognized. The undiscounted amounts can range from $3.5 million to $13.8 million.
	The acquisitions were accounted for under the acquisition method of accounting in accordance with accounting principles generally accepted in the United States of America ("US GAAP"). As such, results of operations for the ATM Group and Cowen Equity Finance LP are included in the accompanying consolidated statements of operations since the dates of the respective acquisitions, and the assets acquired, liabilities assumed and the resulting goodwill were recorded at their fair values within their respective line items on the accompanying consolidated statement of financial condition (see Note 10). Goodwill in the amount of $2.2 million is deductible for tax purposes.
	The following table summarizes the aggregate purchase price allocation of net tangible and intangible assets acquired during the year ended December 31, 2012:
		(dollars in thousands)
	Cash and cash equivalents	$	290
	Securities owned, at fair value	17
	Securities borrowed	527,854
	Receivable from brokers	15,682
	Fees receivable	751
	Intangibles	9,782
	Other assets	136
	Securities loaned	(543,369		)
	Compensation payable	(11		)
	Fees payable	(56		)
	Unfavorable lease liability	(91		)
	Accounts payable, accrued expenses and other liabilities	(700		)
	Total net assets acquired	10,285
	Non compete agreements	167
	Goodwill/(Bargain purchase gain) on transactions	8,517
	Total purchase price	$	18,969
	The Company believes that all of the acquired receivables as reflected above in the allocation of the purchase price are recorded at fair value.
	The Company recognized approximately $0.3 million of acquisition-related costs, including legal, accounting, and valuation services, for the year ended December 31, 2012. These costs are included in professional, advisory and other fees and other expenses in the accompanying consolidated statements of operations.
	Included in the accompanying consolidated statements of operations for the year ended December 31, 2012 are revenues of $6.2 million and net loss of $1.6 million related to the combined ATM Group and Cowen Equity Finance LP results of operations. During the year ended December 31, 2013, these businesses were fully integrated into the current business lines of the Company and the revenues and net income/(loss) are included in the respective line items.
	LaBranche & Co Inc.
	The acquisition of LaBranche & Co Inc. ("LaBranche") by the Company was consummated pursuant to the terms of the Agreement and Plan of Merger, dated as of February 16, 2011, after the market close on June 28, 2011. LaBranche Capital, LLC ("LCAP"). LCAP was a registered broker-dealer and Financial Industry Regulatory Authority ("FINRA") member firm that operated as a market-maker in ETFs, engaged in hedging activities in options, exchange traded funds ("ETFs"), structured notes, foreign currency securities and futures related to its market-making operations and also conducted principal trading activities in these securities. Prior to the acquisition, LaBranche discontinued certain operations in its market-making segment, including upstairs options market-making on various exchanges and electronic market-making in the International Securities Exchange. As of the close of market on June 28, 2011, LaBranche stock was delisted and no longer trades on the New York Stock Exchange.
	The acquisition was accounted for under the acquisition method of accounting in accordance with US GAAP. In this case, the acquisition was accounted for as an acquisition by Cowen of LaBranche. As such, results of operations for LaBranche are included in the accompanying consolidated statements of operations since the date of acquisition, and the assets acquired and liabilities assumed were recorded at their estimated fair values. The fair value of Cowen shares issued to LaBranche shareholders was the purchase consideration for the acquisition. Based on the June 28, 2011 purchase price allocation, the fair value of the net identifiable assets acquired and liabilities assumed amounted to $176.0 million (excluding $2.3 million non-compete agreements and covenants with limiting conditions acquired), exceeding the fair value of the purchase price of $156.0 million. As a result, the Company recognized a nonrecurring bargain purchase gain of approximately $22.2 million in the second quarter of 2011, which is included in other income in the accompanying consolidated statements of operations for the twelve months ended December 31, 2011.
	The Company recognized approximately $3.3 million of acquisition-related costs, including legal, accounting, and valuation services, for the year ended December 31, 2011. These costs are included in professional, advisory and other fees and other expenses in the accompanying consolidated statements of operations.
	During the fourth quarter of 2011, the subsidiaries acquired through the LaBranche acquisition were discontinued (See Note 4). As a result, no unaudited supplemental proforma information is presented.

Significant_Accounting_Policie

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Significant Accounting Policies	'
	Significant Accounting Policies
	a.	Basis of presentation
	These consolidated financial statements are prepared in accordance with US GAAP as promulgated by the Financial Accounting Standards Board ("FASB") through Accounting Standards Codification 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 substantive, controlling general partner interest. All material intercompany transactions and balances have been eliminated on consolidation. Certain fund entities that are consolidated in these accompanying consolidated financial statements, as further discussed below, are not subject to the consolidation provisions with respect to their own controlled investments pursuant to their specialized accounting.
	The Company serves as the managing member/general partner and/or investment manager to affiliated fund entities which it sponsors and manages. Funds in which the Company has a controlling financial interest are consolidated with the Company pursuant to US GAAP as described below. Consequently, the Company's consolidated financial statements reflect the assets, liabilities, income and expenses of these funds on a gross basis. The ownership interests in these funds that are not owned by the Company are reflected as redeemable non-controlling interests in consolidated subsidiaries in the accompanying consolidated financial statements. The management fees and incentive income earned by the Company from these funds are eliminated in consolidation.
	b.	Principles of consolidation
	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 and (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. VOEs are consolidated in accordance with US GAAP.
	Under US GAAP, the usual condition for a controlling financial interest in a VOE is ownership of a majority voting interest. Accordingly, the Company consolidates VOEs in which it owns a majority of the entity's voting shares or units. US GAAP also provides that a general partner of a limited partnership (or a managing member, in the case of a limited liability company) is presumed to control the partnership, and thus should consolidate it, unless a simple majority of the limited partners has the right to remove the general partner without cause or to terminate the partnership. In accordance with these standards, the Company presently consolidates eight entities deemed to be VOEs for which it acts as the general partner and investment manager.
	As of December 31, 2013 and 2012, the Company consolidates the following funds: Ramius Enterprise LP (“Enterprise LP”), Ramius Multi‑Strategy Master FOF LP (“Multi‑Strat Master FOF”), Ramius Vintage Multi‑Strategy Master FOF LP (“Vintage Master FOF”), Ramius Levered Multi‑Strategy FOF LP (“Levered FOF”), and (effective May 1, 2013) Ramius Merger Fund LLC (the "Merger Fund") (collectively the "Consolidated Funds"). RTS Global 3X was consolidated as of December 31, 2012 but was liquidated on March 31, 2013.
	The Company also consolidates three investment companies; RCG Linkem II LLC, formed to make an investment in a wireless broadband communication provider in Italy, Ramius Co-Investment I LLC and Ramius Co-Investment II LLC, which were both formed to make investments in biomedical companies that develop innovative gene therapies for severe genetic disorders. The Company determined that RCG Linkem II, LLC, Ramius Co-Investment I LLC and Ramius Co-Investment II LLC are VOE's due to its controlling equity interests held through the managing member and/or affiliates and control exercised by the managing member who is not subject to substantive removal rights.
	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.
	However, the FASB has deferred the application of the revised consolidation model for VIEs that meet the following conditions: (a) the entity has all the attributes of an investment company as defined under AICPA Audit and Accounting Guide, Investment Companies, or does not have all the attributes of an investment company but is an entity for which it is acceptable based on industry practice to apply measurement principles that are consistent with investment companies, (b) the reporting entity does not have explicit or implicit obligations to fund any losses of the entity that could potentially be significant to the entity, and (c) the entity is not a securitization entity, asset‑backed financing entity or an entity that was formerly considered a qualifying special‑purpose entity. The Company's involvement with its funds is such that all three of the above conditions are met for substantially all of the funds managed by the Company. Where the VIEs have qualified for the deferral, the analysis is based on previous consolidation rules. These rules require an analysis to (a) determine whether an entity in which the Company holds a variable interest is a variable interest entity and (b) whether the Company's involvement, through holding interests directly or indirectly in the entity or contractually through other variable interests (e.g., management and performance related fees), would be expected to absorb a majority of the VIE's expected losses, receive a majority of the VIEs expected residual returns, or both. If these conditions are met, the Company is considered to be the primary beneficiary of the VIE and thus is required to consolidate it.
	The Company reconsiders whether it is the primary beneficiary of a VIE by performing a periodic qualitative and/or quantitative analysis of the VIE that includes a review of, among other things, its capital structure, contractual agreements between the Company and the VIE, the economic interests that create or absorb variability, related party relationships and the design of the VIE. As of December 31, 2013, the Company consolidates three VIEs and as of December 31, 2012 the Company does not consolidate any VIEs. As of December 31, 2013, the total net assets of the consolidated VIEs are $8.2 million. The VIEs act as managing members/general partners and/or investment managers to affiliated fund entities which they sponsor and/or manage. The VIEs are financed through their operations and/or loan agreements with the Company.
	As of December 31, 2013 and December 31, 2012, the Company holds a variable interest in Ramius Enterprise Master Fund Ltd (“Enterprise Master”) through one of its Consolidated Funds, Enterprise LP and as of December 31, 2013 the Company holds a variable interest in Ramius Merger Master Fund Ltd through one of its Consolidated Funds, Merger Fund, (the “Unconsolidated Master Funds”). Investment companies, which account for their investments under the specialized industry accounting guidance for investment companies prescribed under US GAAP, are not subject to the consolidation provisions for their investments. Therefore, the Company has not consolidated the Unconsolidated Master Funds.
	In the ordinary course of business, the Company also sponsors various other entities that it has determined to be VIEs. These VIEs are primarily funds and real estate entities for which the Company serves as the general partner, managing member and/or investment manager with decision-making rights.
	The Company does not consolidate any of these funds or real estate entities that are VIEs as it has concluded that it is not the primary beneficiary in each instance. 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's involvement with funds and real estate entities that are unconsolidated VIEs is limited to providing investment management services in exchange for management fees and incentive income. Although the Company may advance amounts and pay certain expenses on behalf of the funds and real estate entities 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 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 consolidated statements of operations.
	The Company evaluates for impairment its equity method investments 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, apply the equity method of accounting or account for an investment under the cost method, the Company accounts for all securities which are bought and held principally for the purpose of selling them in the near term as trading securities in accordance with US GAAP, at fair value with unrealized gains (losses) resulting from changes in fair value reflected within net gains (losses) on securities, derivatives and other investments in the consolidated statements of operations.
	Retention of Specialized Accounting—The Consolidated Funds are investment companies and apply specialized industry accounting for investment companies. The Company has retained this specialized accounting for these funds pursuant to US GAAP. The Company reports its investments on the 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 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”), ATM Execution (formerly known as Cowen Capital LLC), ATM USA, LLC, and Cowen Equity Finance LP, apply the specialized industry accounting for brokers and dealers in securities also prescribed under US GAAP. The Company also retains specialized accounting in consolidation.
	c.	Use of estimates
	The preparation of the accompanying 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 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. Certain reclassifications have been made to prior period amounts in order to conform with current period presentation.
	d.	Cash and cash equivalents
	The Company considers investments in money market funds and other highly liquid investments with original maturities of three months or less which are deposited with a bank or prime broker to be cash equivalents. Cash and cash equivalents held at Consolidated Funds, although not legally restricted, are not available to fund the general liquidity needs of the Company. The Company is also exposed to credit risk as a result of cash being held at several banks.
	e.	Valuation of investments and derivative contracts
	US GAAP establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (level 1 measurements) and the lowest priority to unobservable inputs (level 3 measurements). The three levels of the fair value hierarchy are as follows:
	Level 1 Inputs that reflect unadjusted quoted prices in active markets for identical assets or liabilities that the Company has
	the ability to access at the measurement date;
	Level 2     Inputs other than quoted prices that are observable for the asset or liability either directly or indirectly, including
	inputs in markets that are not considered to be active; and
	Level 3 Fair value is determined based on pricing inputs that are unobservable and includes situations where there is little,
	if any, market activity for the asset or liability. The determination of fair value for assets and liabilities in this
	category requires significant management judgment or estimation.
	Inputs are used in applying the various valuation techniques and broadly refer to the assumptions that market participants use to make valuation decisions, including assumptions about risk. Inputs may include price information, volatility statistics, specific and broad credit data, liquidity statistics, and other factors. A financial instrument's level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. However, the determination of what constitutes “observable” requires significant judgment by the Company. The Company considers observable data to be that market data which is readily available, regularly distributed or updated, reliable and verifiable, not proprietary, and provided by independent sources that are actively involved in the relevant market. The categorization of a financial instrument within the hierarchy is based upon the pricing transparency of the instrument and does not necessarily correspond to the Company's perceived risk of that instrument.
	The Company and its operating subsidiaries act as the manager for the Consolidated Funds. Both the Company and the Consolidated Funds hold certain investments which are valued by the Company, acting as the investment manager. The fair value of these investments is generally estimated based on proprietary models developed by the Company, which include discounted cash flow analysis, public market comparables, and other techniques and may be based, at least in part, on independently sourced market information. The material estimates and assumptions used in these models include the timing and expected amount of cash flows, the appropriateness of discount rates used, and, in some cases, the ability to execute, timing of, and estimated proceeds from expected financings. Significant judgment and estimation goes into 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 its investments through Ramius Co-Investment I LLC (formerly known as Cowen Bluebird LLC), Ramius Co-Investment II LLC (formerly known as RCG Ultragenex Holdings LLC) and certain investments it holds though 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 whose values are based on quoted market prices in active markets for identical assets, and are therefore classified in level 1 of the fair value hierarchy, include active listed equities, certain U.S. government and sovereign obligations, ETF's and certain money market securities. The Company does not adjust the quoted price for such instruments, even in situations where the Company holds a large position and a sale could reasonably impact the quoted price.
	Certain positions for which trading activity may not be readily visible, consisting primarily of convertible debt, corporate debt and loans, are stated at fair value and classified within level 2. The estimated fair values assigned by management are determined in good faith and are based on available information considering, trading activity, broker quotes, quotations provided by published pricing services, counterparties and other market participants, and pricing models using quoted inputs, and do not necessarily represent the amounts which might ultimately be realized. As level 2 investments include positions that are not always traded in active markets and/or are subject to transfer restrictions, valuations may be adjusted to reflect illiquidity and/or non-transferability.
	Derivative contracts—Derivative contracts can be exchange-traded or privately negotiated over-the-counter (“OTC”). Exchange-traded derivatives, such as futures contracts and exchange-traded option contracts, are typically classified within level 1 or level 2 of the fair value hierarchy depending on whether or not they are deemed to be actively traded. OTC derivatives, such as generic forwards, swaps and options, have inputs which can generally be corroborated by market data and are therefore classified within level 2. Futures and currency forwards are included within other assets on the accompanying consolidated statements of financial condition and all other derivatives are included within securities owned, at fair value on the accompanying consolidated statements of financial condition.
	Other investments—Other investments consist primarily of portfolio funds, real estate investments and equity method investments, which are valued as follows:
	i.	Portfolio funds—Portfolio funds (“Portfolio Funds”) include interests in funds and investment companies managed by the Company or its affiliates. The Company follows US GAAP regarding fair value measurements and disclosures relating to investments in certain entities that calculate net asset value (“NAV”) per share (or its equivalent). The guidance permits, as a practical expedient, an entity holding investments in certain entities that either are investment companies as defined by the AICPA Audit and Accounting Guide, Investment Companies, or have attributes similar to an investment company, and calculate net asset value 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.
	The Company categorizes its investments in Portfolio Funds within the fair value hierarchy dependent on its ability to redeem the investment. If the Company has the ability to redeem its investment at NAV at the measurement date or within the near term, the Portfolio Fund is categorized as a level 2 investment within the fair value hierarchy. If the Company does not know when it will have the ability to redeem its investment or cannot do so in the near term, the Portfolio Fund is categorized as a level 3 investment within the fair value hierarchy. See Notes 6 and 7 for further details of the Company's investments in Portfolio Funds.
	ii.	Real estate investments—Real estate investments are valued at fair value. The fair value of real estate investments are 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.
	The Company also reflects its real estate equity investments net of investment level financing. Valuation adjustments attributable to underlying financing arrangements are considered in the real estate equity valuation based on amounts at which the financing liabilities could be transferred to market participants at the measurement date.
	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 a level 3 investment within the fair value hierarchy as management uses significant unobservable inputs in determining their estimated fair value.
	See Notes 6 and 7 for further information regarding the Company's investments, including equity method investments, and fair value measurements.
	f.	Due from/due to related parties
	The Company may advance amounts and pay certain expenses on behalf of employees of the Company or other affiliates of the Company. These amounts settle in the ordinary course of business. Such amounts are included in due from and due to related parties, respectively, on the accompanying consolidated statements of financial condition.
	g.	Receivable from and payable to brokers
	Receivable from and payable to brokers, includes cash held at clearing brokers, amounts receivable or payable for unsettled transactions, monies borrowed and proceeds from short sales equal to the fair value of securities sold, but not yet purchased. Pursuant to the Company's prime broker agreements, these balances are presented net (assets less liabilities) across balances with the same broker.
	h.	Securities borrowed and securities loaned
	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 statement of operations as interest income and interest expense. Securities borrowed transactions require the Company to deposit cash collateral with the lender. With respect to securities loaned, the Company receives cash collateral from the borrower. The initial collateral advanced or received approximates or is greater than the market value of securities borrowed or loaned. The Company monitors the market value of securities borrowed and loaned on a daily basis, with additional collateral obtained or returned, as necessary. Securities borrowed and loaned may also result in credit exposures for the Company in an event that the counterparties are unable to fulfill their contractual obligations. The Company minimizes its credit risk by continuously monitoring  its credit exposure and collateral values by demanding additional or returning excess collateral in accordance with the netting provisions available in the master securities lending contracts in place with the counterparties.
	Fees and interest received or paid are recorded in interest and dividend income and interest expense, respectively, on an accrual basis. In the case where the fair value basis of accounting is elected, any resulting change in fair value is reported in trading revenues. Accrued interest income and expense are recorded in the same manner as under the accrual method. At December 31, 2013 and 2012, the Company does not have any securities lending transactions for which fair value basis of accounting was elected.
	i.	Securities purchased under agreements to resell and securities sold under agreements to repurchase
	The Company uses securities purchased under agreements to resell and securities sold under agreements to repurchase (“Repurchase Agreements”) as part of its liquidity management activities and to support its trading and risk management activities. In particular, securities purchased and sold under Repurchase Agreements are used for short-term liquidity purposes. As of December 31, 2013 and 2012, Repurchase Agreements are secured predominantly by liquid corporate credit and/or government issued securities. The use of Repurchase Agreements will fluctuate with the Company's need to fund short term credit or obtain competitive short term credit financing. The Company's securities purchased under agreements to resell and securities sold under agreements to repurchase were transacted pursuant to agreements with one counterparty as of December 31, 2013 and multiple counterparties as of December 31, 2012.
	Collateral is valued daily and the Company and its counterparties may adjust the collateral or require additional collateral to be deposited when appropriate. Collateral held by counterparties may be sold or re-hypothecated by such counterparties, subject to certain limitations sometimes imposed by the Company and in accordance with the master netting agreements in place with the counterparty. Collateralized Repurchase Agreements may result in credit exposure in the event the counterparties to the transactions are unable to fulfill their contractual obligations. The Company minimizes the credit risk associated with this activity by monitoring credit exposure and collateral values, and by requiring additional collateral to be promptly deposited with or returned to the Company when deemed necessary.
	j.    Fixed Assets
	Fixed assets are stated at cost less accumulated depreciation or amortization. Leasehold improvements are amortized on a straight-line basis over the lesser of their useful life or lease term. When the Company commits to a plan to abandon fixed assets or leasehold improvements before the end of its original useful life, the estimated depreciation or amortization period is revised to reflect the shortened useful life of the asset. Other fixed assets are depreciated on a straight-line basis over their estimated useful lives.
	Asset	Depreciable Lives	Principal Method
	Telephone and computer equipment	3-5 years	Straight-line
	Computer software	3-5 years	Straight-line
Furniture and fixtures	3-8 years	Straight-line
Leasehold improvements	1-10 years	Straight-line
Capitalized lease asset	5 years	Straight-line
k.	Goodwill and intangible assets
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, the Company tests goodwill for impairment on an annual basis, at December 31st each year, or at an interim period if events or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount. Under US GAAP, the Company tests goodwill for impairment by assessing the qualitative factors including, macroeconomic environment, industry and market specific conditions, financial performance and events specific to the reporting unit to determine whether it is more likely than not that the fair value of the reporting unit is less than its carrying amount. Based on the results of the qualitative assessment the Company performs the two-step goodwill impairment test. The first step 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 the fair value, there is an indication that the related goodwill might be impaired and the step two is performed to measure the amount of impairment, if any.
The second step of the goodwill impairment test compares the implied fair value of the reporting unit's goodwill with its carrying amount to measure the amount of impairment, if any. The implied fair value of goodwill is determined in the same manner as the amount of goodwill recognized in a business combination. In other words, the estimated fair value of the reporting unit is allocated to all of its assets and liabilities (including any unrecognized intangible assets) as if the reporting unit had been acquired in a business combination and the fair value of the reporting unit was the purchase price paid. If the carrying amount of the reporting unit goodwill exceeds the implied fair value of that goodwill, an impairment is recognized in an amount equal to that excess. Goodwill impairment tests involve significant judgment in determining the estimates of future cash flows, discount rates, economic forecast and other assumptions which are then used in acceptable valuation techniques, such as the market approach (earning and or transactions multiples) and / or income approach (discounted cash flow method). Changes in these estimates and assumptions could have a significant impact on the fair value and any resulting impairment of goodwill. See Note 10 for further discussion.
Intangible assets with finite lives are amortized over their estimated average useful lives. The Company does not have any intangible assets deemed to have indefinite lives. Intangible assets are tested for potential impairment whenever events or changes in circumstances suggest that an asset or asset group's carrying value may not be fully recoverable. Similar to goodwill impairment test, an impairment loss, calculated as the difference between the estimated fair value and the carrying value of an asset or asset group, is recognized in the accompanying consolidated statements of operations if the sum of the estimated undiscounted cash flows relating to the asset or asset group is less than the corresponding carrying value.
l.    Deferred rent
Deferred rent primarily consists of step rent, allowances from landlords and valuing the Company's lease properties in accordance with US GAAP. Step rent represents the difference between actual operating lease payments due and straight-line rent expense, which is recorded by the Company over the term of the lease, including the build-out period. This amount is recorded as deferred rent in the early years of the lease, when cash payments are generally lower than straight-line rent expense, and reduced in the later years of the lease when payments begin to exceed the straight-line expense. Landlord allowances are generally comprised of amounts received and/or promised to the Company by landlords and may be received in the form of cash or free rent. These allowances are part of the negotiated terms of the lease. The Company records a receivable from the landlord and a deferred rent liability when the allowances are earned. This deferred rent is amortized into income (through lower rent expense) over the term (including the pre-opening build-out period) of the applicable lease, and the receivable is reduced as amounts are received from the landlord. Liabilities resulting from valuing the Company's leased properties acquired through business combinations are quantified by comparing the current fair value of the leased space to the current rental payments on the date of acquisition. Deferred rent, included in accounts payable, accrued expenses and other liabilities in the accompanying consolidated statements of financial condition, as of December 31, 2013 and 2012 is $14.6 million and $13.8 million, respectively.
m.    Legal reserves
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 reserve nor disclosure is required for losses that are deemed remote.
n.	Capital withdrawals payable
Capital withdrawals from the Consolidated Funds are recognized as liabilities, net of any incentive income, when the amount requested in the withdrawal notice represents an unconditional obligation at a specified or determined date (or dates) or upon an event certain to occur. This generally may occur either at the time of the receipt of the notice, or on the last day of a reporting period, depending on the nature of the request. As a result, withdrawals paid after the end of the year, but based upon year-end capital balances are reflected as liabilities at the balance sheet date.
o.	Redeemable non-controlling interests in consolidated subsidiaries
Redeemable non-controlling interests represent the pro rata share of the book value of the financial positions and results of operations attributable to the other owners of the consolidated subsidiaries. Redeemable non-controlling interests related to Consolidated Funds are generally subject to annual, semi-annual or quarterly withdrawals or redemptions by investors in these funds, sometimes following the expiration of a specified period of time (generally one year), or may only be withdrawn subject to a redemption fee (generally ranging from 1% to 5%). Likewise, non-controlling interests related to certain other consolidated entities are generally subject to withdrawal, redemption, transfer or put/call rights that permit such non-controlling investors to withdraw from the entities on varying terms and conditions. Because these non-controlling interests are redeemable at the option of the non-controlling interests, they have been classified as temporary equity in the accompanying consolidated statements of financial condition. When redeemed amounts become legally payable to investors on a current basis, they are reclassified as a liability.
p.	Treasury stock
In accordance with the US GAAP relating to repurchases of an entity's own outstanding common stock, the Company records the purchases of stock held in treasury at cost and reports them separately as a deduction from total stockholders' equity on the accompanying consolidated statements of financial condition and changes in equity.
q.	Comprehensive income (loss)
Comprehensive income (loss) consists of net income and other comprehensive income (loss). The Company's other comprehensive income (loss) is comprised of valuation adjustments to the Company's defined benefit plans and foreign currency cumulative translation adjustments.
r.	Revenue recognition
The Company's principal sources of revenue are derived from two segments: an alternative investment segment and a broker-dealer segment, as more fully described below.
Our alternative investment segment generates revenue through three principal sources: management fees, incentive income and investment income from the Company's own capital.
Our broker-dealer segment generates revenue through two principal sources: investment banking and brokerage.
Management fees
The Company earns management fees from affiliated funds and certain managed accounts that it serves as the investment manager based on assets under management. The actual management fees received vary depending on distribution fees or fee splits paid to third parties either in connection with raising the assets or structuring the investment.
Management fees are generally paid on a quarterly basis at the beginning of each quarter in arrears and are prorated for capital inflows and redemptions. While some investors may have separately negotiated fees, in general the management fees are as follows:
•	Hedge Funds. Management fees for the Company's hedge funds are generally charged at an annual rate of up to 2% of assets under management. Management fees are generally calculated monthly based on assets under management at the end of each month before incentive income.
•	Mutual Funds. Management fees for the Company’s mutual funds (Ramius Trading Strategies Managed Futures Fund, Ramius Event Driven Equity Fund, Ramius Dynamic Replication Fund and Ramius Strategic Volatility Fund) are generally charged at an annual rate of up to 1.60% of assets under management (subject to an overall expense cap of up to 2%).
•	Alternative Solutions. Management fees for the Alternative Solutions business are generally charged at an annual rate of up to 2% of assets under management. Management fees are generally calculated monthly based on assets under management at the end of each month before incentive income or based on assets under management at the beginning of the month. Management fees earned from the Alternative Solutions business are based and initially calculated on estimated net asset values and actual fees ultimately earned could be impacted to the extent of any changes in these estimates.
•	Real Estate. Management fees from the Company's real estate business are generally charged by their general partners at an annual rate from 0.75% to 1.50% of total capital commitments during the investment period and of invested capital or net asset value of the applicable fund after the investment period has ended. Management fees are typically paid to the general partners on a quarterly basis, at the beginning of the quarter in arrears, and are prorated for changes in capital commitments throughout the investment period and invested capital after the investment period. The general partners of the funds on the RCG Longview platform are owned jointly by the Company and third parties. Accordingly, the management fees (in addition to incentive income and investment income) generated by these real estate funds are split between the Company and the other general partners. Pursuant to US GAAP, these fees and other income received by the general partners that are accounted for under the equity method of accounting and are reflected under net gains (losses) on securities, derivatives and other investments in the consolidated statements of operations.
•	HealthCare Royalty Partners. During the investment period (as defined in the management agreement of the HealthCare Royalty Partners funds), management fees for the funds advised by HealthCare Royalty Partners are generally charged at an annual rate of up to 2% of committed capital. After the investment period, management fees are generally charged at an annual rate of up to 2% of net asset value. Management fees for the HealthCare Royalty Partners funds are calculated on a quarterly basis. Accordingly, the management fees (in addition to incentive income and investment income) generated by these real estate funds are split between the Company and the other general partners. Pursuant to US GAAP, these fees and other income received by the general partners that are accounted for under the equity method of accounting and are reflected under net gains (losses) on securities, derivatives and other investments in the consolidated statements of operations.
•	Ramius Trading Strategies. Management fees and platform fees for the Company's private commodity trading advisory business are generally charged at an annual rate of up to 1%. Management and platform fees are generally calculated monthly based on assets under management at the end of each month.
•	Other. Prior to 2013, the Company also provided other investment advisory services. Other management fees were primarily earned from the Company's cash management business and ranged from annual rates of up to 0.20% of assets, based on the average daily balances of the assets under management. Since November 2012, the Company no longer offer cash management services.
Incentive income
The Company earns incentive income based on net profits (as defined in the respective investment management agreements) with respect to certain of the Company's funds and managed accounts, allocable for each fiscal year that exceeds cumulative unrecovered net losses, if any, that have been carried forward from prior years. For the products the Company offers, incentive income earned is typically up to 20% for hedge funds and up to 10% for alternative solutions products (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. Generally, incentive income on real estate funds is earned after the investor has received a full return of their invested capital, plus a preferred return. However, for certain real estate funds, the Company is entitled to receive incentive fees earlier, provided that the investors have received their preferred return on a current basis. These funds are subject to a potential clawback of these incentive fees upon the liquidation of the fund if the investor has not received a full return of its invested capital plus the preferred return thereon. Incentive income in the HealthCare Royalty Partners funds is earned only after investors receive a full return of their capital plus a preferred return.
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 that investor until the accumulated net loss from prior periods is recovered, an arrangement commonly referred to as a “high-water mark.” The Company has elected to record incentive income revenue in accordance with “Method 2” of US GAAP. Under Method 2, the incentive income from the Company's funds and managed accounts for any period is based upon the net profits of those funds and managed accounts at the reporting date. Any incentive income recognized in the consolidated statement of operations may be subject to future reversal based on subsequent negative performance prior to the conclusion of the fiscal year, when all contingencies have been resolved.
Carried interest in the real estate funds is subject to clawback to the extent that the carried interest actually distributed to date exceeds the amount due to the Company based on cumulative results. As such, the accrual for potential repayment of previously received carried interest, which is a component of accounts payable, accrued expenses and other liabilities, represents all amounts previously distributed to the Company, less an assumed tax liability, that would need to be repaid to certain real estate funds if these funds were to be liquidated based on the current fair value of the underlying funds' investments as of the reporting date. The actual clawback liability does not become realized until the end of a fund's life.
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 small and mid-capitalization companies within the Company's target sectors of healthcare, technology, media and telecommunications, consumer, aerospace and defense, industrials, REITs and clean technology.
Investment banking revenue consists of underwriting fees, strategic/financial advisory fees and private placement fees.
•	Underwriting fees. The Company earns underwriting revenues in securities offerings in which the Company acts as an underwriter, such as initial public offerings, follow-on equity offerings, debt offerings, and convertible security offerings. Underwriting revenues include management fees, selling concessions and underwriting fees. Fee revenue relating to underwriting commitments is recorded 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; and (iii) the Company has been informed of the number of securities that it has been allotted.
When the Company is not the lead manager for an underwriting transaction, management must estimate the Company's share of transaction-related expenses incurred by the lead manager in order to recognize revenue. Transaction-related expenses are deducted from the underwriting fee and therefore reduce the revenue the Company recognizes as co-manager. 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 revenues include success fees earned in connection with advising companies, principally in mergers and acquisitions and liability management transactions. The Company also earns fees for related advisory work such as providing fairness opinions. The Company records strategic advisory revenues when the services for the transactions are completed under the terms of each assignment or engagement and collection is reasonably assured. Expenses associated with such transactions are deferred until the related revenue is recognized or the engagement is otherwise concluded.
•	Private placement fees. The Company earns agency placement fees in non-underwritten transactions such as private placements of debt and equity securities, including, private investment in public equity transactions (“PIPEs”) and registered direct offerings. The Company records private placement revenues when the services for the transactions are completed under the terms of each assignment or engagement and collection is reasonably assured. Expenses associated with such transactions are deferred until the related revenue is recognized or the engagement is otherwise concluded.
Brokerage
Brokerage revenue consists of commissions, principal transactions, net and equity research fees.
•	Commissions. Commission revenue includes fees from executing client transactions. These fees are recognized on a trade date basis. 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. Commissions on soft dollar brokerage are recorded net of the related expenditures on an accrual basis. Commission revenues also includes fees from making algorithms available to clients. During the years ended December, 2013, 2012, and 2011, the Company earned $79.7 million, $63.0 million and $66.0 million of revenues from commissions, respectively.
•	Principal transactions, net. Principal transaction, net revenue includes net trading gains and losses from the Company's market-making activities in over-the-counter equity securities, trading of convertible securities, and trading gains and losses on inventory and other firm positions, which include warrants previously received as part of investment banking transactions. Commissions associated with these transactions are also included herein. In certain cases, the Company provides liquidity to clients 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 very short duration. During the years ended December, 2013, 2012, and 2011, the Company earned $28.1 million, $22.5 million and $27.1 million of revenues from principal transactions, net, respectively.
•	Equity research fees. Equity research fees are paid to the Company for providing equity research. Revenue is recognized once an arrangement exists, access to research has been provided, the fee amount is fixed or determinable, and collection is reasonably assured. During the years ended December, 2013, 2012, and 2011, the Company earned $6.8 million, $5.7 million and $6.5 million of revenues from equity research fees, respectively.
Interest and dividends
Interest and dividends are earned by the Company from various sources. The Company receives interest and dividends primarily from investments held by its Consolidated Funds and its brokerage balances from invested capital and from its security lending program. Interest is recognized on an accrual basis and interest income is recognized on the debt of those issuers that is deemed collectible. Interest income and expense includes premiums and discounts amortized and accreted on debt investments based on criteria determined by the Company using the effective yield method, which assumes the reinvestment of all interest payments. Dividends are recognized on the ex-dividend date.
Reimbursement from affiliates
The Company allocates, at its discretion, certain expenses incurred on behalf of its hedge fund, fund of funds and real estate businesses. These expenses relate to the administration of such subsidiaries and assets that the Company manages for its funds. In addition, pursuant to the funds' offering documents, the Company charges certain allowable expenses to the 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 funds. Such expenses that have been reimbursed at their actual costs are included in the accompanying 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.
s.	Investments transactions and related income/expenses
Purchases and sales of securities, net of commissions, and 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, in the accompanying consolidated statements of operations.
t.	Share-based compensation
The Company accounts for its share-based awards granted to individuals as payment for employee services in accordance with US GAAP and values such awards based on grant date fair value. Unearned compensation associated with share-based awards is amortized over the vesting period of the option or award. The Company estimates forfeiture for equity-based awards that are not expected to vest. See Note 15 for further information regarding the Company's share-based compensation plans.
u.	Employee benefit plans
The Company recognizes, in its accompanying consolidated statements of financial condition, the funded status of its defined benefit plans, measured as the difference between the fair value of the plan assets and the benefit obligation The Company recognizes changes in the funded status of a defined benefit plan within accumulated other comprehensive income (loss), net of tax, to the extent such changes are not recognized in earnings as components of periodic net benefit cost. See Note 16 for further information regarding the Company's defined benefit plans.
v.	Leases
The Company leases certain facilities and equipment used in its operations. The Company evaluates and classifies its leases as operating or capital leases for financial reporting purposes. Assets held under capital leases are included in fixed assets. Operating lease expense is recorded on a straight-line basis over the lease term. Landlord incentives are recorded as deferred rent and amortized, as reductions to lease expense, on a straight-line basis over the life of the applicable lease.
w.	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 bases 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.
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 resident in foreign countries where tax filings generally have to be submitted on a stand‑alone basis. These subsidiaries are subject to tax in their respective countries and the Company is responsible for and, thus, reports all taxes incurred by these subsidiaries in the consolidated statement of operations. The countries where the Company owns subsidiaries and has tax filing obligations are the United Kingdom, Luxembourg, and Hong Kong. Income tax expense/(benefit) for the years ended December 31, 2011 includes deferred tax benefits following acquisitions of Luxembourg reinsurance companies (See Note 18).
x.	Foreign currency transactions
The Company consolidates certain foreign subsidiaries that have designated a foreign currency as their functional currency. For entities that have designated a foreign currency as their functional currency, assets and liabilities are translated into U.S. dollars based on current rates, which are the spot rates prevailing at the end of each statement of financial condition date, and revenues and expenses are translated at historical rates, which are the average rates for the relevant periods. The resulting translation gains and losses, and the tax effects of such gains and losses, are recorded in accumulated other comprehensive income (loss), a separate component of stockholders' equity.
For subsidiaries that have designated the U.S. Dollar as their functional currency, securities and other assets and liabilities denominated in foreign currencies are translated into U.S. Dollar amounts at the date of valuation. Purchases and sales of securities and other assets and liabilities and the related income and expenses denominated in foreign currencies are translated into U.S. Dollar amounts on the respective dates of the transactions. The Company does not isolate that portion of the results of operations resulting from changes in foreign exchange rates on these balances from fluctuations arising from changes in market prices of securities and other assets/liabilities held or sold. Such fluctuations are included in the accompanying consolidated statements of operations as a component of net gains (losses) on securities, derivatives and other investments. Gains and losses primarily relating to foreign currency broker balances are included in net gains (losses) on foreign currency transactions in the accompanying consolidated statements of operations.
y.    New accounting pronouncements
Recently issued accounting pronouncements
In July 2013, the FASB issued guidance which was directed to eliminate the disparity in practice for the financial statement presentation of an unrecognized tax benefit when a net operating loss carry-forward, a similar tax loss, or a tax credit carry-forward exist. The guidance requires an entity to present the unrecognized tax benefit as a reduction to the deferred tax asset for a net operating loss carry-forward, a similar tax loss, or a tax credit carry-forward with certain exceptions. The guidance is effective prospectively for reporting periods beginning after December 15, 2013 for all unrecognized tax benefits that exist at the effective date. Early adoption and retrospective application is also permitted. The Company is currently evaluating the impact of this guidance on the Company's financial condition and results of operations.
In June 2013, the FASB issued guidance which amended the scope, measurement and disclosure requirements for Financial Services - Investment Companies. The guidance among other things changed the definition and criteria used for the investment company assessment. The guidance also require investment companies to measure non-controlling ownership interest in other investment companies at fair value rather than using equity method of accounting and requires certain additional disclosures. The guidance is effective for reporting periods beginning after December 15, 2013. The Company is currently evaluating the impact of this guidance on the Company's financial condition and results of operations.
In April 2013, the FASB issued guidance which improved and clarified the requirements as to when an entity should apply the liquidation basis of accounting and provides principles for the recognition and measurement of assets and liabilities. The guidance requires an entity to prepare its financial statements using liquidation basis of accounting when the liquidation is imminent and to present relevant information about entity's resources by measuring and presenting assets and liabilities at the amount of expected cash proceeds and / or settlement amounts. The guidance is effective prospectively for reporting periods beginning after December 15, 2013. The Company is currently evaluating the impact of this guidance on the Company's financial condition and the results of operations and its applicability on certain of its affiliated entities.

Discontinued_Operations

Discontinued Operations	12 Months Ended
	Dec. 31, 2013
Discontinued Operations and Disposal Groups [Abstract]	'
Discontinued Operations	'
	Discontinued Operations
	During the fourth quarter of 2011, the Company discontinued the operations of subsidiaries acquired through the LaBranche acquisition (See Note 2). These subsidiaries were not meeting the Company's expectations as to their results of operations and not generating positive cash flows. The subsidiaries comprised of market making operations for exchange traded funds in the US, Europe and Asia which were included in the broker-dealer segment. The results of operations and cash flows for these subsidiaries were eliminated from the Company's ongoing operations and the Company has no continuing involvement in these operations. In accordance with US GAAP, the Company reclassified and reported the results of operations related to these subsidiaries in discontinued operations for the year ended December 31, 2011.
	The results of operations related to the Company's discontinued operations for the year ended December 31, 2011 are summarized below:
		For the Period June 28, 2011 through December 31, 2011
		(dollars in thousands)
	Total revenues, net of interest expense	$	2,899
	Loss from discontinued operations	(24,075		)
	Income tax expense/(benefit)	(429		)
	Loss from discontinued operations, net of taxes	(23,646		)

Cash_collateral_pledged

Cash collateral pledged	12 Months Ended
	Dec. 31, 2013
Cash and Cash Equivalents [Abstract]	'
Cash collateral pledged	'
	Cash collateral pledged
	As of December 31, 2013 and 2012, the Company pledged cash collateral in the amount of $10.9 million and $9.2 million, respectively, which relates to letters of credit issued to the landlords of the Company's premises in New York City and San Francisco (see Note 20).

Investments_of_Operating_Entit

Investments of Operating Entities and Consolidated Funds	12 Months Ended
	Dec. 31, 2013
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 and options are pledged to the clearing broker under terms which permit the clearing broker to sell or re-pledge the securities to others subject to certain limitations.
	As of December 31, 2013 and 2012, securities owned, at fair value consisted of the following:
		As of December 31,
		2013				2012
		(dollars in thousands)
	U.S. Government securities (a)	$	9			$	137,478
	Preferred stock	324				2,332
	Common stocks	176,939				259,292
	Convertible bonds (b)	5,958				6,202
	Corporate bonds (c)	121,372				193,078
	Options	9,698				20,546
	Warrants and rights	5,912				2,354
	Mutual funds	525				2,845
		$	320,737			$	624,127
	(a)	As of December 31, 2013, the maturity was April 2016 with an interest rate of 5.95%. As of December 31, 2012, maturities ranged from November 2013 to November 2022 and interest rates ranged between 0.25% and 5.95%.
	(b)	As of December 31, 2013, maturities ranged from May 2014 to October 2014 and interest rates ranged between 5.00% to 10.00%. As of December 31, 2012, maturities ranged from May 2014 to July 2014 with an interest rate of 5.00%.
	(c)	As of December 31, 2013, maturities ranged from January 2014 to February 2046 and interest rates ranged between 3.38% and 11.75%. As of December 31, 2012, maturities ranged from January 2013 to February 2041 and interest rates ranged between 3.09% and 12.50%.
	The Company's direct involvement with derivative financial instruments includes futures, currency forwards, equity swaps and warrants and rights. Open equity positions in futures transactions are recorded as receivables from and payables to broker-dealers or clearing brokers, as applicable. The Company's derivatives trading activities exposes the Company to certain risks, such as price and interest rate fluctuations, volatility risk, credit risk, counterparty risk, foreign currency movements and changes in the liquidity of markets. The Company's overall exposure to financial derivatives is limited. The Company's long exposure to futures, currency forwards and equity swaps, at fair value, as of December 31, 2013 and 2012 of $0.4 million and $0.2 million, respectively, is included in other assets in the accompanying consolidated statements of financial condition. The Company's short exposure to futures, currency forwards and equity swaps, at fair value, as of December 31, 2013 and 2012 of $1.1 million and $1.0 million, respectively, is included in accounts payable, accrued expenses and other liabilities in the accompanying consolidated statements of financial condition. The realized and unrealized gains/(losses) related to derivatives trading activities for the years ended December 31, 2013, 2012, and 2011, were $4.4 million, $7.8 million and $7.0 million, respectively, and are included in other income in the accompanying consolidated statements of operations. As of December 31, 2013, The Company's long exposure to options of $9.7 million (71,129 contracts held) and short exposure of $6.6 million (38,221 contracts held) are included in Securities owned, at fair value and in Securities sold, not yet purchased, at fair value respectively in the accompanying statement of financial condition. As of December 31, 2012, The Company's long exposure to options of $20.5 million (28,133,185 contracts held) and short exposure of $9.1 million (10,070,267 contracts held) are included in Securities owned, at fair value and in Securities sold, not yet purchased, at fair value respectively in the accompanying statement of financial condition.
	Pursuant to the various derivatives transactions discussed above, the Company is required to post collateral for its obligations or potential obligations. As of December 31, 2013 and 2012, collateral consisting of $10.0 million and $6.7 million of cash, respectively, is included in receivable from brokers on the accompanying consolidated statements of financial condition. As of December 31, 2013 and 2012 all derivative contracts were with multiple major financial institutions.
	Other investments
	As of December 31, 2013 and 2012, other investments consisted of the following:
		As of December 31,
		2013				2012
		(dollars in thousands)
	(1) Portfolio Funds, at fair value	$	71,051			$	55,898
	(2) Real estate investments, at fair value	2,088				1,864
	(3) Equity method investments	25,966				26,462
	(4) Lehman claims, at fair value	378				706
		$	99,483			$	84,930
	-1	Portfolio Funds, at fair value
	The Portfolio Funds, at fair value as of December 31, 2013 and 2012, included the following:
		As of December 31,
		2013				2012
		(dollars in thousands)
	HealthCare Royalty Partners (a)(*)	$	9,741			$	7,866
	HealthCare Royalty Partners II (a)(*)	4,961				6,415
	Orchard Square Partners Credit Fund LP (b)(*)	12,674				14,196
	Tapestry Investment Co PCC Ltd (c)	—				194
	Starboard Value and Opportunity Fund LP (d)(*)	17,495				15,706
	Formation 8 Partners Fund I (e)	2,788				1,500
	RCG LV Park Lane LLC (f)	678				708
	RCGL 12E13th LLC (g)	558				—
	RCG Longview Debt Fund V, L.P. (g)	11,979				—
	Other private investment (h)	7,772				7,826
	Other affiliated funds (i)(*)	2,405				1,487
		$	71,051			$	55,898
	* 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 19.
	(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)	Orchard Square Partners Credit Fund LP (formerly known as Ramius Global Credit Fund LP) has a quarterly redemption policy with a 60 day notice period and a 4% penalty on redemptions of investments of less than a year in duration.
	(c)	Tapestry Investment Company PCC Ltd had been fully liquidated at the manager's discretion.
	(d)	Starboard Value and Opportunity Fund LP permits quarterly withdrawals upon 90 days notice.
	(e)	Formation 8 Partners Fund I is a private equity fund which invests in equity of early stage and growth transformational information and energy technology companies. Distributions will be made when the underlying investments are liquidated.
	(f)	RCG LV Park Lane LLC  is a single purpose entity formed to participate in a joint venture which acquired, at a discount, the mortgage notes on a portfolio of multifamily real estate properties located in Birmingham, Alabama.  RCG LV Park Lane LLC is a private equity structure and therefore distributions will be made when the underlying investments are liquidated.
	(g)	RCGL 12E13th LLC and RCG Longview Debt Fund V, L.P. are real estate private equity structures and therefore distributions will be made when the underlying investments are liquidated.
	(h)	Other private investment represents the Company's closed end investment in a wireless broadband communication provider in Italy.
	(i)	The majority of these 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	Real estate investments, at fair value
	Real estate investments as of December 31, 2013 and 2012 are carried at fair value and include real estate equity investments held by RCG RE Manager, LLC (“RE Manager”), a real estate operating subsidiary of the Company, of $2.1 million and $1.9 million, respectively.
	-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 30% to 55%. The Company holds a majority of the outstanding ownership interest (i.e., more than 50%) in three of these entities: RCG Longview Debt Fund IV Management, LLC, RCG Longview Debt Fund IV Partners, LLC and RCG Longview Partners II, LLC. The operating agreements that govern the management of day-to-day operations and affairs of each of these three entities stipulate 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 three entities require 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 is the investment in (a) HealthCare Royalty Partners General Partners (b) an investment in the CBOE (Chicago Board Options Exchange) Stock Exchange LLC representing a 9.7% stake in the exchange service provider for which the Company exercises significant influence over through representation on the CBOE Board of Directors, and (c) 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 a deep value small cap hedge fund and related managed accounts.
The Company does not hold significant financial interest in Starboard Value entities. The independent portfolio managers are responsible for activities which are significant to the overall business and hold the majority of the equity interest. The Starboard Value entities were formed to provide a full range of investment advisory and management services and act as a general partner, investment advisor, and pension advisor or in similar capacity to clients. In accordance with the respective offering documents of the underlying funds, Starboard Value entities are entitled to a fixed percentage of management fee and performance fees.
The following table summarizes equity method investments held by the Company:
	As of December 31,
	2013				2012
	(dollars in thousands)
RCG Longview Debt Fund IV Management, LLC	$	1,533			$	1,954
RCG Longview Debt Fund V Partners, LLC	1,497				—
HealthCare Royalty GP, LLC	794				642
HealthCare Royalty GP II, LLC	840				1,086
HealthCare Royalty GP III, LLC	47				—
CBOE Stock Exchange, LLC	1,351				2,058
Starboard Value LP	14,263				12,757
RCG Longview Partners, LLC	1,839				1,535
RCG Longview Louisiana Manager, LLC	—				1,866
RCG Urban American, LLC	316				1,380
RCG Urban American Management, LLC	238				545
RCG Longview Equity Management, LLC	292				285
Urban American Real Estate Fund II, LLC	1,785				1,636
RCG Kennedy House, LLC	502				377
Other	669				341
	$	25,966			$	26,462
For the period ended December 31, 2013, certain of the Company's equity method investments have met the significance criteria as defined under SEC guidance. As such, the Company is required to present summarized financial information for equity method investees for the years ended December 31, 2013, 2012, and 2011. The summarized financial information for the Company's investments in investees is as follows:
Other equity method investments	As of December 31,
	2013				2012
	(dollars in thousands)
Assets	$	626,866			$	498,557
Liabilities	226,138				20,170
Equity	$	400,728			$	478,387
	Year Ended December 31,
	2013				2012				2011
	(dollars in thousands)
Revenues	$	75,429			$	77,502			$	33,061
Expenses	(69,893		)		(60,093		)		(45,335		)
Net realized and unrealized gains (losses)	77,042				5,575				9,365
Net Income	$	82,578			$	22,984			$	(2,909	)
For the year ended December 31, 2013, Starboard Value A LP has met the significance criteria as defined under Regulation S-X Rule 4-08(g) of the SEC guidance. As such, the Company is presenting the following summarized financial information:
Starboard Value A LP	As of December 31,
	2013				2012
	(dollars in thousands)
Assets
Cash	$	14			$	—
Performance fee receivable	25,214				20,448
Investments in Portfolio Funds, at fair value	2,201				1,380
Liabilities	—				—
Equity	$	27,429			$	21,828
	Year Ended December 31,
	2013				2012				2011
	(dollars in thousands)
Performance fee revenues	$	23,098			$	20,448			$	4,750
Net realized and unrealized gains (losses)	283				254				18
Net Income	$	23,381			$	20,702			$	4,768
As of December 31, 2013 and 2012, the Company's share of losses in its equity method investment in RCG Longview Partners II, LLC has exceeded the carrying amount recorded in this investee. These amounts are included in accounts payable, accrued expenses and other liabilities in the accompanying consolidated statements of financial condition. RCG Longview Partners II, LLC, as general partner to a real estate fund, has reversed previously recorded incentive income allocations and has recorded a current clawback obligation to the limited partners in the fund. This obligation is due to a change in unrealized value of the fund on which there have previously been distributed carried interest realizations; however, the settlement of a potential obligation is not due until the end of the life of the respective fund. As the Company is obligated to return previous distributions it received from RCG Longview Partners II, LLC, it has continued to record its share of gains/losses in the investee including reflecting its share of the clawback obligation in the amount of $6.2 million.
The Company's income (loss) from equity method investments was $16.1 million, $15.6 million, and $5.4 million for the years ended December 31, 2013, 2012 and 2011, respectively, and is included in net gains (losses) on securities, derivatives and other investments on the accompanying consolidated statements of operations. In addition, the Company recorded no impairment charges in relation to its equity method investments for the years ended December 31, 2013, 2012, and 2011, respectively.
-4	Lehman Claims, at fair value
Lehman Brothers International (Europe) (“LBIE”), through certain affiliates, was a prime broker to the Company, and the Company held cash and cash equivalent balances with LBIE. On September 15, 2008, LBIE was placed into administration (the “Administration”) in the United Kingdom and, as a result, the assets held by the Company in its LBIE accounts were frozen at LBIE. The assets which the Company believed were held at LBIE at the time of Administration (the “Total Net Equity Claim”) consisted of $1.0 million, which the Company believed would represent an unsecured claim against LBIE. On November 2, 2012, the Company executed a Claims Determination Deed with respect to this claim.  By entering into this deed, the Company and LBIE reached agreement on the amount of the Company's unsecured claim, which was agreed to be approximately $0.9 million.  As a result of entering into this deed, the Company is entitled to participate in dividends to unsecured creditors of LBIE. At the end of November 2012 the Company received its first dividend in an amount equal to 25.2% of its agreed claim, or approximately $0.2 million, at the end of June 2013 the Company received its second dividend in an amount equal to 43.3% of its agreed claim, or approximately $0.4 million, and at the end of November 2013 the Company received its third dividend in an amount equal to 23.7% of its agreed claim, or approximately $0.2 million. The total amounts received to date in respect of the Company’s unsecured claim against LBIE are approximately $0.9 million, representing 92.2% of its agreed claim. This does not include claims held by the Company against LBIE through its investment in Enterprise Master discussed in Note 5b(2). The Company does not know the timing with respect to future dividends to unsecured creditors or the ultimate value that will be received, with respect to its claim.
Given the fact that LBIE has made multiple distributions to unsecured creditors and the increased trading levels for unsecured claims of LBIE, the Company decided to record the estimated fair value of the Total Net Equity Claim at 131.5% as of December 31, 2013 and at par as of December 31, 2012, which represented management's best estimate at the respective dates of the value that ultimately may be recovered with respect to the Total Net Equity Claim (the “Estimated Recoverable Lehman Claim”). The Estimated Recoverable Lehman Claim was recorded at estimated fair value considering a number of factors including the status of the assets under U.K. insolvency laws and the trading levels of LBIE unsecured debt. In determining the estimated value of the Total Net Equity Claim, the Company was required to use considerable judgment and is based on the facts currently available. As additional information on the LBIE proceeding becomes available, the Company may need to adjust the valuation of the Estimated Recoverable Lehman Claim. The actual recovery that may ultimately be received by the Company with respect to the pending LBIE claim is not known and could be different from the estimated value assigned by the Company. (See Note 6b(2)).
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 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 consolidated statements of financial condition. Substantially all equity securities and options are pledged to the clearing broker under terms which permit the clearing broker to sell or re-pledge the securities to others subject to certain limitations. As of December 31, 2013 and 2012, securities sold, not yet purchased, at fair value consisted of the following:
	As of December 31,
	2013				2012
	(dollars in thousands)
Common stocks	$	130,899			$	168,797
Corporate bonds (a)	55				61
Options	6,573				9,076
Warrants and rights	—				3
	$	137,527			$	177,937
(a)	As of December 31, 2013 and 2012, the maturity was January 2026 with an interest rate of 5.55%.
Securities purchased under agreements to resell and securities sold under agreements to repurchase
The following table represents the Company's securities purchased under agreements to resell and securities sold under agreements to repurchase as of December 31, 2013 and 2012:
	As of December 31, 2013
	(dollars in thousands)
Securities sold under agreements to repurchase
Agreements with Royal Bank of Canada bearing interest of 1.75% due June 2015 to November 2015	$	3,657
	$	3,657
	As of December 31, 2012
	(dollars in thousands)
Securities sold under agreements to repurchase
Agreements with Royal Bank of Canada bearing interest of 2.12% - 2.2% due January 31, 2013 to June 25, 2013	$	29,039
Agreements with Barclays Capital Inc bearing interest of (0.05%) - 0.23% due January 1, 2013	136,906
	$	165,945
The following tables present the gross and net repurchase agreements and the related offsetting amount, as of December 31, 2013 and 2012.
As of December 31, 2013
	Gross amounts recognized				Gross amounts offset on the Consolidated Statements of Financial Condition				Net amounts included on the Consolidated Statements of Financial Condition				Amounts not offset on the consolidated balance sheet but eligible for offsetting upon counterparty default (b)				Net amounts
					(a)
	(dollars in thousands)
Securities sold under agreements to repurchase	$	3,657			$	—			$	3,657			$	3,657			$	—
As of December 31, 2012
	Gross amounts recognized				Gross amounts offset on the Consolidated Statements of Financial Condition				Net amounts included on the Consolidated Statements of Financial Condition				Amounts not offset on the consolidated balance sheet but eligible for offsetting upon counterparty default (b)				Net amounts
					(a)
	(dollars in thousands)
Securities sold under agreements to repurchase	$	165,945			$	—			$	165,945			$	165,945			$	—
(a)	Includes financial instruments subject to enforceable master netting provisions that are permitted to be offset to the extent an event of default has occurred.
(b)	Includes the amount of collateral held/posted.
For all of the Company's holdings of repurchase agreements as of December 31, 2013, the repurchase dates are open and the agreement can be terminated by either party at any time. The agreements rolls over on a day-to-day basis.
Transactions involving the sale of securities under repurchase agreements are carried at their contract value, which approximates fair value, and are accounted for as collateralized financings. In connection with these financings, as of December 31, 2013 and 2012, the Company had pledged collateral of $4.6 million (consisting of corporate bonds) and $173.7 million (consisting of $137.5 million of government bonds and $36.2 million of corporate bonds), respectively, which is included in securities owned, at fair value in the accompanying consolidated statements of financial condition.
Securities lending and borrowing transactions
As of December 31, 2013 and 2012, the Company has loaned to brokers and dealers, securities having a market value of $881.7 million and $388.4 million, respectively.  In addition, as of December 31, 2013, the Company has borrowed from brokers and dealers, securities having a market value of $892.8 million and $391.6 million, respectively.
The following tables present the gross and net securities borrowing and lending agreements and the related offsetting amount, as of December 31, 2013 and 2012.
As of December 31, 2013
	Gross amounts recognized				Gross amounts offset on the Consolidated Statements of Financial Condition				Net amounts included on the Consolidated Statements of Financial Condition				Amounts not offset on the consolidated balance sheet but eligible for offsetting upon counterparty default (b)				Net amounts
					(a)
	(dollars in thousands)
Securities borrowed	$	927,773			$	—			$	927,773			$	927,773			$	—
Securities loaned	918,577				—				918,577				918,577				—
As of December 31, 2012
	Gross amounts recognized				Gross amounts offset on the Consolidated Statements of Financial Condition				Net amounts included on the Consolidated Statements of Financial Condition				Amounts not offset on the consolidated balance sheet but eligible for offsetting upon counterparty default (b)				Net amounts
					(a)
	(dollars in thousands)
Securities borrowed	$	406,326			$	—			$	406,326			$	406,326			$	—
Securities loaned	408,972				—				408,972				408,972				—
(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.
Variable Interest Entities
The total assets and liabilities of the variable interest entities for which the Company has concluded that it holds a variable interest, but for which it is not the primary beneficiary, are $1.7 billion and $242.5 million as of December 31, 2013 and $1.4 billion and $22.8 million as of December 31, 2012, respectively. In addition, the maximum exposure relating to these variable interest entities as of December 31, 2013 was $193.9 million, and as of December 31, 2012 was $208.4 million, all of which is included in other investments, at fair value in the Company's consolidated statements of financial condition. The exposure to loss primarily relates to the Consolidated Feeder Funds' investment in their Unconsolidated Master Funds as of December 31, 2013 and 2012.
b.	Consolidated Funds
Securities owned, at fair value
As of December 31, 2013 the Company held no securities owned, at fair value, held by the Consolidated Funds. As of December 31, 2012 securities owned, at fair value, held by the Consolidated Funds are comprised of:
	As of December 31, 2012
	(dollars in thousands)
Government sponsored securities (a)	$	1,911
Commercial paper (b)	1,614
	$	3,525
(a)	As of December 31, 2012, maturities ranged from August 2013 to December 2014 and interest rates ranged between 0.28% and 4.00%.
(b)	As of December 31, 2012, commercial paper was purchased at a discount and matures on January 2, 2013.
Other investments, at fair value
As of December 31, 2013 and 2012 other investments, at fair value, held by the Consolidated Funds are comprised of:
	As of December 31,
	2013				2012
	(dollars in thousands)
(1) Portfolio Funds	$	182,638			$	190,081
(2) Lehman claims	4,842				14,124
	$	187,480			$	204,205
-1	Investments in Portfolio Funds, at fair value
As of December 31, 2013 and 2012, investments in Portfolio Funds, at fair value, included the following:
	As of December 31,
	2013				2012
	(dollars in thousands)
Investments of Enterprise LP	$	155,530			$	173,348
Investments of Merger Fund	26,963				—
Investments of consolidated fund of funds	145				16,733
	$	182,638			$	190,081
Consolidated investments of Enterprise LP
Enterprise LP operates under a “master-feeder” structure, whereby Enterprise Master's shareholders are Enterprise LP and RCG II Intermediate Fund, L.P. The consolidated investments in Portfolio Funds include Enterprise LP's investment of $155.5 million and $173.3 million in Enterprise Master as of December 31, 2013 and 2012, respectively. On May 12, 2010, the Company announced its intention to close Enterprise Master. Prior to this announcement, strategies utilized by Enterprise Master included merger arbitrage and activist investing, investments in distressed securities, convertible hedging, capital structure arbitrage, equity market neutral, investments in private placements of convertible securities, proprietary mortgages, structured credit investments, investments in mortgage backed securities and other structured finance products, investments in real estate and real property interests, structured private placements and other relative value strategies. Enterprise Master had broad investment powers and maximum flexibility in seeking to achieve its investment objective. Enterprise Master was permitted to invest in equity securities, debt instruments, options, futures, swaps, credit default swaps and other derivatives. Enterprise Master has been selling, and will continue to sell, its positions and return capital to its investors. There are no unfunded commitments at Enterprise LP.
Consolidated investments of Merger Fund
Effective August 1, 2013, the Merger Fund operates under a “master-feeder” structure, whereby Ramius Merger Master Ltd's ("Merger Master") shareholders are Merger Fund and Ramius Merger Fund Ltd. The consolidated investments in Portfolio Funds include Merger Fund's investment of $27.0 million in Merger Master as of December 31, 2013. 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 markets conditions, generally focus the majority of its investment program on announced transactions. If the investment manager of Merger Master considers it necessary, it may either alone or as part of a group, also initiate shareholder actions seeking to maximize value. Such shareholder actions may include, but are not limited to, re-orienting management’s focus or initiating the sale of the company (or one or more of its divisions) to a third party. There are no unfunded commitments at Merger Fund.
Investments of consolidated fund of funds investment companies
The investments of the consolidated fund of funds investment companies are $0.1 million and $16.7 million as of December 31, 2013 and 2012, respectively. As of December 31, 2013, Levered FOF, Multi-Strat Master FOF and Vintage Master FOF, all of which are investment companies managed by Ramius Alternative Solutions LLC, have been fully liquidated via secondary market transactions. The investments held at December 31, 2013 include the remaining investments of Vintage Master FOF which were transferred to an external party subsequent to year end. Multi-Strat Master FOF's investment objective was to invest discrete pools of their capital among portfolio managers that invest through Portfolio Funds, forming a multi-strategy, diversified investment portfolio designed to achieve returns with low to moderate volatility. Levered FOF had a similar strategy, but on a levered basis, prior to the fund winding down. Levered FOF was no longer levered. Vintage Master FOF's investment objective was to allocate its capital among portfolio managers that invest through investment pools or managed accounts thereby forming concentrated investments in high conviction managers designed to achieve attractive risk adjusted returns with moderate relative volatility. RTS Global 3X, which was managed by Ramius Trading Strategies LLC, was consolidated as of December 31, 2012 but was liquidated on March 31, 2013. As such it holds no investments as of December 31, 2013. RTS Global 3X's investment objective was to achieve attractive investment returns on a risk-adjusted basis that are non-correlated with the traditional equity and bond markets by investing substantially all of its capital in managed futures and global macro‑based investment strategies. RTS Global 3X sought to achieve its objective through a multi‑advisor investment approach by allocating its capital among third‑party trading advisors that are unaffiliated with RTS Global 3X. However, unlike a traditional “fund of funds” that invests with advisors through entities controlled by third‑parties, RTS Global 3X allocated its capital among a number of different trading accounts organized and managed by the general partner.
The following is a summary of the investments held by the consolidated fund of funds, at fair value, as of December 31, 2013 and 2012:
			Fair Value as of December 31, 2013
	Strategy		Ramius Levered Multi-Strategy FOF LP				Ramius Multi-Strategy Master FOF LP				Ramius Vintage Multi-Strategy Master FOF LP				RTS Global 3X Fund LP				Total
			(dollars in thousands)
Tapestry Pooled Account V LLC*	Credit-Based		$	—			$	—			$	—			$	—			$	—	(a)
Externally Managed Portfolio Funds	Event Driven		—				—				—				—				—		(c)
Externally Managed Portfolio Funds	Hedged Equity		—				—				145				—				145		(d)
			$	—			$	—			$	145			$	—			$	145
			Fair value as of December 31, 2012
	Strategy		Ramius Levered Multi-Strategy FOF LP				Ramius Multi-Strategy Master FOF LP				Ramius Vintage Multi-Strategy Master FOF LP				RTS Global 3X Fund LP				Total
			(dollars in thousands)
Tapestry Pooled Account V LLC*	Credit-Based		$	315			$	649			$	693			$	—			$	1,657	(a)
Independently Advised Portfolio Funds*	Futures & Global Macro		—				—				—				7,161				7,161		(b)
Externally Managed Portfolio Funds	Event Driven		1,545				2,316				3,264				—				7,125		(c)
Externally Managed Portfolio Funds	Hedged Equity		—				—				790				—				790		(d)
			$	1,860			$	2,965			$	4,747			$	7,161			$	16,733
*    These Portfolio Funds are affiliates of the Company.
As of December 31, 2013, the Company has no unfunded commitments regarding investments held by the three consolidated fund of funds.
(a)	The Credit-Based strategy aims to generate returns via positions in the credit sensitive sphere of the fixed income markets. The strategy generally involves the purchase of corporate bonds with hedging of the interest exposure. The investments held in Tapestry Pooled Account V LLC, a related fund, are held solely in a credit based fund which the underlying fund's manager has placed in a side-pocket. The remaining amount of the investments within this category represents an investment in a fund that is in the process of liquidating. Distributions from this fund will be received as underlying investments are liquidated.
(b)	The Futures and Global Macro strategy was comprised of several portfolio accounts, each of which was advised independently by a commodity trading advisor implementing primarily managed futures or global macro-based investment strategies. The trading advisors (through their respective portfolio accounts) traded independently of each other and, as a group, employed a wide variety of systematic, relative value and discretionary trading programs in the global currency, fixed income, commodities and equity futures markets. In implementing their trading programs, the trading advisors traded primarily in the futures and forward markets (as well as in related options). Although certain trading advisors were permitted to use total return swaps and trade other financial instruments from time to time on an interim basis, the primary focus was on the futures and forward markets. Redemption frequency of these portfolio accounts were monthly (and intra month for a $10,000 fee) and the notification period for redemptions was 5 business days (or 3 business days for intra month redemptions).
(c)	The Event Driven strategy is generally implemented through various combinations and permutations of merger arbitrage, restructuring and distressed instruments. The investments in this category are primarily in a side pocket or suspended with undetermined payout dates.
(d)	The Hedged Equity strategy focuses on equity strategies with some directional market exposure. The strategy attempts to profit from market efficiencies and direction. The investee fund manager has side-pocketed investments.
-2	Lehman Claims, at fair value
With respect to the aforementioned Lehman claims, the Total Net Equity Claim of Enterprise Master based on the value of assets at the time of Lehman's insolvency held directly by Enterprise Master and through Enterprise Master's ownership interest in affiliated funds consisted of $24.3 million. Included in this claim were assets with a value of $9.5 million at the time LBIE entered Administration that were returned to Enterprise Master and its affiliated funds in June 2010. Enterprise Master and its affiliated funds sold the returned assets for an aggregate $10.7 million, and distributed this amount to Enterprise Master's investors in July 2010. In December 2011, Enterprise Master received an aggregate of approximately $2.4 million relating to securities, interest and dividends earned with respect to securities held by LBIE on behalf of Enterprise Master and its affiliated funds. A distribution of $2.9 million occurred in February of 2012. On November 2, 2012, Enterprise Master executed a Claims Determination Deed with respect to the unsecured portion of its direct claim against LBIE.  By entering into this deed, Enterprise Master and LBIE reached agreement on the amount of Enterprise Master's unsecured claim, which was agreed to be approximately $1.3 million.  As a result of entering into this deed, Enterprise Master was entitled to participate in dividends to unsecured creditors of LBIE and at the end of November 2012 Enterprise Master received its first dividend in an amount equal to 25.2% of its agreed claim, or approximately $0.3 million. In February 2013, Enterprise Master sold its unsecured claim, including the amount received in connection with the first dividend, for $1.3 million, or par. Enterprise Master distributed the proceeds of the sale to the Company in March 2013. Of the original remaining - net equity claim, $10.6 million represented claims to trust assets that the Company believes were held by LBIE through Lehman Brothers, Inc. (“LBI”). LBIE made a corresponding claim for these assets and other trust assets held at LBI by LBIE on behalf of other prime brokerage clients pursuant to an omnibus customer claim (the “LBIE Omnibus Customer Claim”). LBIE was only going to be able to return trust assets held at LBI to Enterprise Master once LBIE received a distribution from LBI in respect of the LBIE Omnibus Customer Claim. In February 2013, LBIE, Lehman Brothers Holdings, Inc. and LBI announced that they entered into two separate agreements settling all intercompany claims between LBI on the one part, and LBHI and LBIE on the other part. The settlement agreements were subject to the approval by the U.S. Bankruptcy Judge in the LBI Securities Investor Protection Act (SIPA) proceeding and, in the case of the agreement between LBI and LBIE, an order of the English High Court. The U.S. Banking Judge approved the settlement agreement in April 2013 and the English High Court issued an order approving the settlement in May 2013. The settlements allowed the trustee appointed under SIPA (the “SIPA Trustee”) to proceed with plans to allocate and distribute sufficient cash and securities to LBI's customer claimants, including LBIE with respect to the LBIE Omnibus Customer Claim, to enable the SIPA Trustee to satisfy valid customer claims in full. In March 2013, LBIE made a consensual proposal to the clients holding trust assets pursuant to the LBIE Omnibus Customer Claim to facilitate the return of the amounts recovered from LBI with respect to the LBIE Omnibus Customer Claim. Under the consensual proposal, LBIE indicated that it intended to liquidate any securities received from LBI with respect to the LBIE Omnibus Customer Claim and then allocate the value received from LBI among all of the LBIE clients who had trust assets held at LBI under the LBIE Omnibus Customer Claim. In allocating the amounts received from LBI, LBIE indicated that it intended to allow clients to determine their entitlements on a portfolio basis based on the higher of (i) the market value of the portfolio as of September 19, 2008 or (ii) the market value of the portfolio together with accrued income thereon as of November 30, 2012 (the “Best Claim”). LBIE's purpose in seeking a consensual arrangement with its clients relating to the liquidation and allocation described above was to ensure that a distribution could be made without having to seek UK court direction on these issues, which would otherwise have substantially delayed any distribution. On April 2, 2013, LBIE announced that the consensual proposal had been accepted by a sufficient number of clients to satisfy the acceptance threshold and would therefore become effective. The settlement agreement between LBI and LBIE also became effective and LBIE announced in June 2013 that it had recovered the majority of the cash and securities from LBI and that it had liquidated approximately 90% of the aggregate value of securities received or to be received from LBI and that it intended to make its first distribution to trust asset claimants at the end of September 2013. On September 26, 2013, LBIE announced that it had made a first interim distribution to trust claimants of 100% of the claimant's Best Claim amount. As previously announced by LBIE, LBIE has requested guidance from the US Internal Revenue Service ("IRS") with regard to the character and source of the settlement payments. In order to balance LBIE's objective of making a significant distribution to claimants with the requirement to pay the appropriate US withholding tax in respect of distributions, as an interim solution LBIE deposited 30% of the gross distribution to claimants with the IRS as a reserve, except with respect to claimants who provided LBIE with validly executed Form W-9. Once the appropriate US withholding tax treatment of the distributions is finally determined by the IRS, LBIE expects to be in a position to promptly receive back funds and release any excess reserves back to the appropriate claimants. The amount of the distribution received by Enterprise Master on September 26, 2013 was $14.9 million, with $1 million reserved by LBIE in respect of the withholding described above. As of December 31, 2013, after giving effect to the receipt of the distribution described above, the Company is valuing Enterprise Master's remaining trust asset claim at 105% of its Best Claim, or $0.8 million. After giving effect to all of these distributions, the remaining Net Equity Claim for Enterprise Master held directly and through its ownership interest in affiliated funds was $7.0 million as of December 31, 2013. Of the $7.0 million current valuation of Enterprise Master's claim, $4.8 million was attributable to Enterprise LP based on its ownership percentage in Enterprise Master at the time of the Administration.
In addition to Enterprise Master's claims against LBIE, LBI was a prime broker to Enterprise Master and Enterprise Master held cash balances of $4.9 million at LBI. These are not part of the LBIE Omnibus Customer Claim. On September 19, 2008, LBI was placed in a Securities Investor Protection Corporation (“SIPC”) liquidation proceeding after the filing for bankruptcy of its parent Lehman Brothers Holdings, Inc. The settlement agreements between LBI, LBHI and LBIE discussed above have permitted the trustee appointed under the Securities Investor Protection Act (the “SIPA Trustee”) to make distributions to LBI customers and the SIPA Trustee announced that it expected to be able to make 100% distributions to its customers. In July 2013, Enterprise Master received a distribution of $4.9 million from LBI in respect of this claim.
The remaining components of the LBIE claims included within the $7.0 million value as of December 31, 2013 consist of several components valued as follows: (a) the trust assets that the Company was informed were within the control of LBIE and were expected to be returned in the relatively near term were valued at market less a 1% discount that corresponds to the fee to be charged under the Claim Resolution Agreement (“CRA”) and (b) the foreign denominated trust assets that are not within the control of LBIE (which the Company does not believe are held through LBI), were valued at $5.0 million, which represents the market value of those assets less a 1% discount that corresponds to the fee charged under the CRA, which represented the Company's estimate of potential recovery rates. The estimated final recoverable amount by Enterprise Master may differ from the actual recoverable amount of the pending LBIE and LBI claims, and the differences may be significant.
As a result of Enterprise Master and certain of the funds managed by the Company having assets held at LBIE frozen in their LBIE prime brokerage account and the degree of uncertainty as to the status of those assets and the process and prospects of the return of those assets, Enterprise Master and the funds managed by the Company decided that only the investors who were invested at the time of the Administration should participate in any profit or loss relating to the Estimated Recoverable Lehman Claim. As a result, Enterprise Master and certain of the funds managed by the Company with assets held at LBIE granted a 100% participation in the Estimated Recoverable Lehman Claims to Special Purpose Vehicles (the “SPVs” or “Lehman Segregated Funds”) incorporated under the laws of the Cayman Islands on September 29, 2008, whose shares were distributed to each of their investor funds. Fully redeeming investors of Enterprise LP will not be paid out on the balance invested in the SPV until the claim with LBIE is settled and assets are returned by LBIE.
Indirect Concentration of the Underlying Investments Held by Consolidated Funds
From time to time, through its investments in the Consolidated Funds, the Company may indirectly maintain exposure to a particular issue or issuer (both long and/or short) which may account for 5% or more of the Consolidated Funds' net assets (on an aggregated basis). Based on information that is available to the Company as of December 31, 2013 and 2012, the Company assessed whether or not its Consolidated Funds had interests in an issuer for which the Company's pro-rata share exceeds 5% of the Consolidated Funds' net assets (on an aggregated basis). There were no indirect concentrations that exceed 5% of the Consolidated Funds' net assets held by the Company as of December 31, 2013 or 2012.
Net realized and unrealized gains (losses)
Net realized gains (losses) and net unrealized gains (losses) on investments and other transactions and on derivatives for Consolidated Funds for the years ended December 31, 2012, 2011 and 2010 were as follows:
	Year Ended December 31,
	2013				2012				2011
	(dollars in thousands)
Consolidated Funds net gains (losses) on investments and other transactions:
Net realized gains (losses) on investments and other transactions	$	6,050			$	(8,121	)		$	4,959
Net unrealized gains (losses) on investments and other transactions	4,628				14,497				(34		)
Consolidated Funds net gains (losses) on derivatives:
Net realized gains (losses) on derivatives	$	521			$	915			$	(651	)
Net unrealized gains (losses) on derivatives	(156		)		(38		)		68
Underlying Investments of Unconsolidated Funds Held by Consolidated Funds
Enterprise Master
Enterprise LP's investment in Enterprise Master represents Enterprise LP's proportionate share of Enterprise Master's net assets; as a result, the investment balances of Enterprise Master reflected below may exceed the net investment which Enterprise LP has recorded. The following tables present summarized investment information for the underlying investments and derivatives held by Enterprise Master as of December 31, 2013 and 2012:
Securities owned and securities sold, but not yet purchased by Enterprise Master, at fair value
	As of December 31,
	2013				2012
	(dollars in thousands)
Bank debt	$	5			$	79
Common stock	2,677				2,680
Preferred stock	973				997
Private equity	406				297
Restricted stock	124				26
Rights	2,528				1,714
Trade claims	128				128
Warrants	—				2
	$	6,841			$	5,923
Derivative contracts, at fair value, owned by Enterprise Master, net
	As of December 31,
	2013				2012
Description	(dollars in thousands)
Currency forwards	$	(21	)		$	6
	$	(21	)		$	6
Portfolio Funds, owned by Enterprise Master, at fair value
			As of December 31,
			2013				2012
	Strategy		(dollars in thousands)
RCG Longview Equity Fund, LP*	Real Estate		$	8,470			$	11,027
RCG Longview II, LP*	Real Estate		800				970
RCG Longview Debt Fund IV, LP*	Real Estate		17,641				30,572
RCG Longview, LP*	Real Estate		319				265
RCG Soundview, LLC*	Real Estate		442				2,374
RCG Urban American Real Estate Fund, L.P.*	Real Estate		1,812				1,987
RCG International Sarl*	Multi-Strategy		1,795				752
RCG Special Opportunities Fund, Ltd*	Multi-Strategy		82,119				80,166
RCG Endeavour, LLC*	Multi-Strategy		6				43
RCG Energy, LLC *	Energy		2,842				14,239
RCG Renergys, LLC*	Energy		1				1
Other Private Investments	Various		12,952				12,430
Real Estate Investments	Real Estate		15,024				12,321
			$	144,223			$	167,147
*	These Portfolio Funds are affiliates of the Company.
Merger Master
Securities owned by Merger Master, at fair value
	As of December 31, 2013
	(dollars in thousands)
Common stocks	$	33,901
Corporate bond (a)	14,444
Options	200
	$	48,545
(a)	As of December 31, 2013, maturities ranged from April 2016 to October 2020 and interest rates ranged between 7.00% and 10.88%.
Derivative contracts, at fair value, owned by Merger Master, net
	As of December 31, 2013
Description	(dollars in thousands)
Currency forwards	$	(10	)
Cross rate	(92		)
	$	(102	)
RTS Global 3X Fund LP's Portfolio Fund investments
RTS Global 3X invested over half of its equity in six externally managed portfolio funds which primarily concentrated on futures and global macro strategies. RTS Global 3X's investments in the portfolio funds represented its proportionate share of the portfolio funds net assets; as a result, the portfolio funds' investments reflected below may exceed the net investment which RTS Global 3X had recorded. RTS Global 3X was consolidated as of December 31, 2012 but was liquidated on March 31, 2013. As such it holds no investments as of December 31, 2013. The following table presents the summarized investment information, which primarily consisted of receivables/(payables) on derivatives, for the underlying Portfolio Funds held by RTS Global 3X, at fair value, as of December 31, 2012:
	As of December 31, 2012
	(dollars in thousands)
Bond futures	$	489
Commodity forwards	(659		)
Commodity futures	47
Currency forwards	202
Currency futures	264
Energy futures	239
Equity future	(27		)
Index futures	(257		)
Interest rate futures	40
	$	338

Fair_Value_Measurements_for_Op

Fair Value Measurements for Operating Entities and Consolidated Funds	12 Months Ended
	Dec. 31, 2013
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 consolidated statements of financial condition by caption and by level within the valuation hierarchy as of December 31, 2013 and 2012:
	Operating Entities
		Assets at Fair Value as of December 31, 2013
		Level 1		Level 2				Level 3				Total
				(dollars in thousands)
	Securities owned and derivatives
	US Government securities	$	9	$	—			$	—			$	9
	Preferred stock	—		—				324				324
	Common stocks	171,277		2,103				3,559				176,939
	Convertible bonds	—		4,008				1,950				5,958
	Corporate bonds	—		121,372				—				121,372
	Futures	285		—				—				285
	Currency forwards	—		22				—				22
	Equity swaps	—		70				—				70
	Options	9,698		—				—				9,698
	Warrants and rights	107		—				5,805				5,912
	Mutual funds	525		—				—				525
	Other investments
	Portfolio Funds	—		19,402				51,649				71,051
	Real estate investments	—		—				2,088				2,088
	Lehman claim	—		—				378				378
		$	181,901	$	146,977			$	65,753			$	394,631
		Liabilities at Fair Value as of December 31, 2013
		Level 1		Level 2				Level 3				Total
		(dollars in thousands)
	Securities sold, not yet purchased and derivatives
	Common stocks	$	130,899	$	—			$	—			$	130,899
	Corporate bonds	—		55				—				55
	Futures	275		—				—				275
	Currency forwards	—		301				—				301
	Equity swaps	—		525				—				525
	Options	6,573		—				—				6,573
	Accounts payable, accrued expenses and other liabilities
	Contingent consideration liability (See Note 2)							$	6,937			$	6,937
		$	137,747	$	881			$	6,937			$	145,565
		Assets at Fair Value as of December 31, 2012
		Level 1		Level 2				Level 3				Total
				(dollars in thousands)
	Securities owned and derivatives
	US Government securities	$	137,478	$	—			$	—			$	137,478
	Preferred stock	—		—				2,332				2,332
	Common stocks	254,606		2,137				2,549				259,292
	Convertible bonds	—		6,202				—				6,202
	Corporate bonds	—		192,563				515				193,078
	Currency forwards	—		202				—				202
	Options	18,273		2,273				—				20,546
	Warrants and rights	641		—				1,713				2,354
	Mutual funds	2,845		—				—				2,845
	Other investments
	Portfolio Funds	—		30,228				25,670				55,898
	Real estate investments	—		—				1,864				1,864
	Lehman claim	—		—				706				706
		$	413,843	$	233,605			$	35,349			$	682,797
		Liabilities at Fair Value as of December 31, 2012
		Level 1		Level 2				Level 3				Total
		(dollars in thousands)
	Securities sold, not yet purchased and derivatives
	Common stocks	$	168,797	$	—			$	—			$	168,797
	Corporate bonds	—		61				—				61
	Futures	370		—				—				370
	Currency forwards	—		603				—				603
	Options	8,990		86				—				9,076
Warrants and rights	—		—				3				3
Accounts payable, accrued expenses and other liabilities
Contingent consideration liability (See Note 2)	—		—				8,116				8,116
	$	178,157	$	750			$	8,119			$	187,026
Consolidated Funds' investments
	Assets at Fair Value as of December 31, 2013
	Level 1		Level 2				Level 3				Total
			(dollars in thousands)
Other investments
Portfolio Funds	$	—	$	26,964			$	155,674			$	182,638
Lehman claims	—		—				4,842				4,842
	$	—	$	26,964			$	160,516			$	187,480
	Assets at Fair Value as of December 31, 2012
	Level 1		Level 2				Level 3				Total
			(dollars in thousands)
Securities owned
US Government securities	$	1,911	$	—			$	—			$	1,911
Commercial paper	—		1,614				—				1,614
Other investments
Portfolio Funds	—		7,161				182,920				190,081
Lehman claims	—		—				14,124				14,124
	$	1,911	$	8,775			$	197,044			$	207,730
The following table includes a rollforward of the amounts for the years ended December 31, 2013, 2012, and 2011, 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.
	Year Ended December 31, 2013
	Balance at December 31, 2012		Transfers in				Transfers out				Purchases/(covers)				(Sales)/shorts				Realized gains (losses)				Unrealized gains or losses				Balance at December 31, 2013
	(dollars in thousands)
Operating Entities
Preferred stock	$	2,332	$	—			$	(2,000	)	(e)	$	—			$	—			$	—			$	(8	)		$	324
Common stocks	2,549		—				—				4				(275		)		260				1,021				3,559
Convertible bonds	—		—				—				3,938				(1,988		)		—				—				1,950
Corporate Bond	515		—				—				2,735				(3,346		)		(914		)		1,010				—
Warrants and Rights	1,713		291			(c)	—				166				(110		)		(1		)		3,746				5,805
Warrants and Rights, sold not yet purchased	3		—				—				—				—				(4		)		1				—
Portfolio Funds	25,670		13,128			(f)	—				16,932				(9,012		)		(366		)		5,297				51,649
Real estate	1,864		—				—				—				(124		)		—				348				2,088
Lehman claim	706		—				—				—				(607		)		—				279				378
Contingent consideration liability	8,116		—				—				(779		)		—				—				(400		)		6,937
Consolidated Funds
Portfolio Funds	182,920		—				—				—				(33,504		)		211				6,047				155,674
Lehman claim	14,124		—				—				—				(13,377		)		8,597				(4,502		)		4,842
	Year Ended December 31, 2012
	Balance at December 31, 2011		Transfers in					Transfers out					Purchases/(covers)				(Sales)/shorts				Realized gains (losses)				Unrealized gains or losses				Balance at December 31, 2012
	(dollars in thousands)
Operating Entities
Preferred stock	$	250	$	—				$	—				$	2,000			$	—			$	—			$	82			$	2,332
Common stocks	819		—					—					1,789				(6		)		6				(59		)		2,549
Corporate Bond	—		—					—					4,600				(3,050		)		—				(1,035		)		515
Warrants and Rights	1,534		—					(89		)	(b)		632				(212		)		56				(208		)		1,713
Warrants and Rights, sold not yet purchased	—		—					(1,004		)	(d)		(297		)		977				(37		)		364				3
Portfolio Funds	16,919		—					—					10,116				(3,482		)		(41		)		2,158				25,670
Real estate	2,353		—					—					153				(781		)		—				139				1,864
Lehman claim	553		—					—					—				(234		)		—				387				706
Contingent consideration liability	—		—					—					(64		)		8,180				—				—				8,116
Consolidated Funds
Portfolio Funds	213,402		16,227			(a)		(17,151		)	(a)		434				(28,892		)		(3,823		)		2,723				182,920
Lehman claim	7,340		—					—					—				(2,292		)		1,914				7,162				14,124
(a) Change in consolidated funds (from master-feeder to stand alone funds).
(b) The security was listed on an exchange subsequent to a private funding.
(c) The security was acquired through an acquisition (See Note 2).
(d) The security began trading on an exchange due to a business combination.
(e) The company completed an initial public offering.
(f) The investment was transferred into level 3 due to Company’s commitment as part of its long term extension of its
partnership with credit funds.
All realized and unrealized gains (losses) in the table above are reflected in other income (loss) in the accompanying consolidated statements of operations.
Certain assets and liabilities are measured at fair value on a nonrecurring basis and therefore are not included in the tables above.
The Company recognizes all transfers and the related unrealized gain (loss) at the beginning of the reporting period.
Transfers between level 1 and 2 generally relate to whether the principal market for the security becomes active or inactive. Transfers between level 2 and 3 generally relate to whether significant relevant observable inputs are available for the fair value measurements or due to change in liquidity restrictions for the investments.
During the years ended December 31, 2013, 2012 and 2011, there were no transfers between level 1 and level 2 assets and liabilities.
The following table includes quantitative information as of December 31, 2013 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 at December 31, 2013		Valuation techniques		Unobservable Inputs		Range
Common and preferred stocks	$	3,474	Discounted cash flows, market multiples, recent transactions, bid levels, and comparable transactions		Market multiples		2x to 3x
Warrants and rights, net	5,805		Model based		Volatility		20% to 100% (weighted average 37%)
Contingent consideration	6,937		Discounted cash flows		Projected Cash Flow and DCF rate		0% to 15%
	$	16,216
Other level 3 assets and liabilities (a)	216,990
Total level 3 assets and liabilities	$	233,206
(a)	Quantitative disclosures of unobservable inputs and assumptions are not required for investments for which NAV per share is used as a practical expedient to determine fair value, as their redemption features rather than observability of inputs cause them to be classified as a level 3 type asset within the fair value hierarchy. In addition, the fair value of the Consolidated Funds' investments are determined based on net asset value and therefore quantitative disclosures are not included in the table above. The quantitative disclosures also exclude financial instruments for which the determination of fair value is based on prices from prior transactions.
The Company has established valuation policies and procedures and an internal control infrastructure over its fair value measurement of financial instruments which includes ongoing oversight by the valuation committee as well as periodic audits performed by the Company's internal audit group. The valuation committee is comprised of senior management, including non-investment professionals, who are responsible for overseeing and monitoring the pricing of the Company's investments, including the review of the results of the independent price verification process, approval of new trading asset classes and use of applicable pricing models and approaches.
The US GAAP fair value leveling hierarchy is designated and monitored on an ongoing basis. In determining the designation, the Company takes into consideration a number of factors including the observability of inputs, liquidity of the investment and the significance of a particular input to the fair value measurement. Designations, models, pricing vendors, third party valuation providers and inputs used to derive fair market value are subject to review by the valuation committee and the internal audit group. The Company reviews its valuation policy guidelines on an ongoing basis and may adjust them in light of, improved valuation metrics and models, the availability of reliable inputs and information, and prevailing market conditions. The Company reviews a daily profit and loss report, as well as other periodic reports, and analyzes material changes from period-to-period in the valuation of its investments as part of its control procedures. The Company also performs back testing on a regular basis by comparing prices observed in executed transactions to previous valuations.
The fair market value for level 3 securities may be highly sensitive to the use of industry standard models, unobservable inputs and subjective assumptions. The degree of fair market value sensitivity is also contingent upon the subjective weight given to specific inputs and valuation metrics. The Company holds various equity and debt instruments where different weight may be applied to industry standard models representing standard valuation metrics such as: discounted cash flows, market multiples, comparative transactions, capital rates, recovery rates and timing, and bid levels. Generally, changes in the weights ascribed to the various valuation metrics and the significant unobservable inputs in isolation may result in significantly lower or higher fair value measurements. Volatility levels for warrants and options are not readily observable and subject to interpretation. Changes in capital rates, discount rates and replacement costs could significantly increase or decrease the valuation of the real estate investments. The interrelationship between unobservable inputs may vary significantly amongst level 3 securities as they are generally highly idiosyncratic. Significant increases (decreases) in any of those inputs in isolation can result in a significantly lower (higher) fair value measurement.

Receivables_from_and_Payable_t

Receivables from and Payable to Brokers	12 Months Ended
	Dec. 31, 2013
Brokers and Dealers [Abstract]	'
Receivables from and Payable to Brokers	'
	Receivables from and Payable to Brokers
	Receivables from and payable to brokers includes cash held at the clearing brokers, amounts receivable or payable for unsettled transactions, monies borrowed and proceeds from short sales (including commissions and fees related to securities transactions) equal to the fair value of securities sold, not yet purchased, which are restricted until the Company purchases the securities sold short. Pursuant to the master netting agreements the Company entered into with its brokers, these balances are presented net (assets less liabilities) across balances with the same broker. As of December 31, 2013 and 2012, receivable from brokers was $67.0 million and $71.3 million, respectively. Payable to brokers was $75.4 million and $188.8 million as of December 31, 2013 and 2012, respectively. The Company's receivables from and payable to brokers balances are held at multiple reputable financial institutions.

Fixed_Assets

Fixed Assets	12 Months Ended
	Dec. 31, 2013
Fixed assets [Abstract]	'
Fixed Assets	'
	Fixed Assets
	As of December 31, 2013 and 2012, fixed assets consisted of the following:
		As of December 31,
		2013			2012
		(dollars in thousands)
	Telephone and computer equipment	$	5,923		$	13,215
	Computer software	2,079			5,928
	Furniture and fixtures	5,418			6,265
	Leasehold improvements	29,047			30,412
	Assets acquired under capital leases—equipment	6,337			6,337
	Other	48			48
		48,852			62,205
	Less: Accumulated depreciation and amortization	(21,853		)	(30,003		)
		$	26,999		$	32,202
	Depreciation and amortization expense related to fixed assets was $6.5 million, $6.7 million and $7.4 million for the years ended December 31, 2013, 2012, and 2011, respectively and are included in depreciation and amortization expense in the accompanying consolidated statements of operations.
	During the fourth quarter of 2011, the Company recognized an impairment charge for certain fixed assets relating to the discontinued operations and accordingly accelerated depreciation and amortization of the leasehold improvements and related fixed assets for the total amount of $8.8 million. Of this amount, $7.5 million was directly attributable to discontinued operations since this location was used for the former LaBranche business (see Note 4) and was recorded within net income (loss) from discontinued operations, net of taxes in the accompanying consolidated statements of operations for the twelve months ended December 31, 2011. The remaining $1.3 million was not attributable to discontinued operations and therefore recorded within depreciation and amortization expense in the accompanying consolidated statements of operations.
	Assets acquired under capital leases were $6.3 million as of December 31, 2013 and 2012. If the assets acquired under capital leases transfer title at the end of the lease term or contain a bargain purchase option, the assets are amortized over their estimated useful lives; otherwise, the assets are amortized over the respective lease term. The depreciation of assets capitalized under capital leases is included in depreciation and amortization expenses and was $1.3 million, $1.3 million, and $0.5 million for the year ended December 31, 2013, 2012, and 2011.
	During the year, the Company reviewed its records relating to fixed assets and removed fully depreciated fixed assets, which were either no longer in service or the assets for which the Company could not determine an alternative use, with the cost and accumulated depreciation of $13.7 million. The removal of these assets had no impact on current or prior periods of reported income / (loss).

Goodwill_and_Intangible_Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Goodwill and Intangible Assets	'
	Goodwill and Intangible Assets
	In accordance with US GAAP, the Company tests goodwill for impairment on an annual basis or at an interim period if events or changed circumstances would more likely than not reduce the fair value of a reporting unit below its carrying amount. Under US GAAP, the Company first assesses the qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amounts as a basis for determining if it is necessary to perform the two-step approach. Periodically estimating the fair value of a reporting unit requires significant judgment and often involves the use of significant estimates and assumptions. These estimates and assumptions could have a significant effect on whether or not an impairment charge is recorded and the magnitude of such a charge.
	As a result of the Company's transactions in prior years, goodwill of $30.2 million was recognized. This goodwill was recorded within the alternative investment reporting unit.
	As a result of the Cowen and Ramius transactions in November 2009, the Company recognized additional goodwill of $7.2 million during the year ended December 31, 2009. This goodwill is recorded within the broker-dealer reporting unit.
	As a result of the two acquisitions during the period ended December 31, 2012, (see Note 2) the Company recognized goodwill in the amount of $8.5 million The goodwill primarily relates to the expected synergies from the acquisitions and has been assigned to the broker-dealer reporting unit of the Company.
	As a result of the Company's acquisition of Dahlman, during the first quarter of 2013, the Company recognized goodwill in the amount of $8.7 million within the broker dealer reporting unit (See Note 2).
	For the year ended December, 31, 2013, for alternative investment reporting unit, the Company assessed the qualitative factors ("Step 0") to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. This assessment serves as a basis for determining whether it is necessary to perform the two-step goodwill impairment test. For the broker dealer reporting unit, the Company elected to bypass Step 0 and perform Step 1 of the goodwill impairment analysis, which includes determining whether the carrying amount of a reporting unit, including goodwill, exceeds its estimated fair value.
	A significant amount of judgment is required in performing goodwill impairment analysis. When using the qualitative approach, the Company considered macroeconomic factors such as industry and market conditions, and reporting unit-specific events, actual financial performance versus expectations and management's future business expectations. For reporting units for which the Company performed the step 1, the Company estimated the fair value primarily using an income approach based on a discounted cash flow model. The cash flow projections used in the discounted cash flow model included management's best estimate of future growth and margins. The discount rates used to determine the fair value estimates were developed based on the capital asset pricing model using market-based inputs as well as an assessment of the inherent risk in projected future cash flows.
	The Company believes that the fair value of broker-dealer reporting unit exceeded their respective carrying amounts as of December 31, 2013.
	For the year ended December 31, 2011, the Company engaged an independent valuation specialist to assist with the goodwill impairment analysis. The independent valuation specialist employed industry standard tools and methodology which incorporated both market and income approach. Based on the results of the impairment analysis as of December 31, 2011, it had been determined that no impairment loss would need to be recognized relating to the goodwill recorded within the alternative investment reporting unit.
	However, the Company recognized an impairment charge for the entire amount of goodwill related to the broker-dealer reporting unit amounting to $7.2 million.  This was primarily due to the effects of global and macro-economic conditions that prevailed throughout the year. Specifically, the adverse investment climate coupled with the European Debt crises, resulted in declining trading volumes and increased volatility. These developments negatively affected the Company's revenues in particular the broker-dealer reporting unit and caused the per share price to decline below a tangible book value.
	The following table presents the changes in the Company's goodwill balance, by reporting unit for the years ended December 31, 2013 and 2012:
		Alternative Investment				Broker-				Total
						Dealer
		(dollars in thousands)
	Beginning balance - December 31, 2011
	Goodwill	$	30,228			$	7,151			$	37,379
	Accumulated impairment charges	(10,200		)		(7,151		)		(17,351		)
	Net	20,028				—				20,028
	Activity: 2012
	Recognized goodwill	—				8,517				8,517
	Goodwill impairment charges	—				—				—
	Ending balance: December 31, 2012
	Goodwill	30,228				15,668				45,896
	Accumulated impairment charges	(10,200		)		(7,151		)		(17,351		)
	Net	20,028				8,517				28,545
	Activity: 2013
	Recognized goodwill	—				8,695				8,695
	Goodwill impairment charges	—				—				—
	Ending balance: December 31, 2013
	Goodwill	30,228				24,363				54,591
	Accumulated impairment charges	(10,200		)		(7,151		)		(17,351		)
	Net	$	20,028			$	17,212			$	37,240
	Intangible assets
	Information for the Company's intangible assets that are subject to amortization is presented below as of December 31, 2013 and 2012. The Company recognized trade name, customer relationships, and customer contracts in connection with the transactions in prior years. As a result of the acquisition of Dahlman Rose during the period ending December 31, 2013 (see Note 2) the Company recognized intangible assets in the amount of $2.8 million. These intangibles include trade name and customer relationships with weighted average useful lives of 4.7 years. As a result of the two acquisitions during the period ending December 31, 2012 (see Note 2) the Company recognized intangible assets in the amount of $9.9 million. These intangibles include trade name, customer relationship, intellectual properties and non-compete agreements with weighted average useful lives of 8.5 years.
					December 31, 2013										December 31, 2012
		Amortization			Gross				Accumulated				Net		Gross		Accumulated			Net
		Period			Carrying				Amortization				Carrying		Carrying		Amortization (1)			Carrying
					Amount								Amount		Amount					Amount
		(in years)			(in thousands)										(in thousands)
	Investment contracts	5			$	3,900			$	(3,900	)		$	—	$	3,900	$	(3,900	)	$	—
	Trade names	5 - 7.5			9,612				(7,747		)		1,865		9,572		(7,190		)	2,382
	Customer relationships	10-Apr			14,744				(8,375		)		6,369		11,974		(6,284		)	5,690
	Customer contracts	1.2			800				(800		)		—		800		(800		)	—
	Non compete agreements and covenants with limiting conditions acquired	10-Jan			2,697				(2,583		)		114		2,732		(2,576		)	156
	Intellectual property	10-Mar			6,951				(3,205		)		3,746		6,951		(2,195		)	4,756
					$	38,704			$	(26,610	)		$	12,094	$	35,929	$	(22,945	)	$	12,984
	The Company tests intangible assets for impairment if events or circumstances suggest that the asset groups carrying value may not be fully recoverable. For the years ended December 31, 2013 and 2012, no impairment charge for intangible assets was recognized.
	Intangibles acquired upon acquisition of LaBranche in the second quarter of 2011 (See Note 2) are covenants to not compete, covenants with limiting conditions and intellectual property of $5.1 million. These intangibles were assessed for impairment when the Company discontinued the operations of the LaBranche subsidiaries (See Note 4) and an impairment charge of $2.9 million (in addition to the $1.0 million of amortization recorded during the year) was recognized as the Company will no longer derive future benefits from these intangibles. This amount was recorded in net income (loss) from discontinued operations, net of tax in the accompanying consolidated statements of operations for the year ended December 31, 2011.
	The Company recorded an impairment charge of $5.2 million related to the trade name and customer relationships acquired, during the Cowen and Ramius transaction in November 2009, which is attributable to the broker-dealer reporting unit. The impairment charge recognized is primarily attributable to the lower customer trading volumes and is recorded in depreciation and amortization expense within the accompanying consolidated statements of operations for the year ended December 31, 2011. The Company used the discounted cash flow approach to determine the future benefits expected to be derived from the trade name and customer relationships.
	Amortization expense related to intangible assets was $3.7 million, $2.7 million and $8.1 million (including impairment charges of $5.2 million relating to the broker-dealer reporting unit) for the years ended December 31, 2013, 2012 and 2011, respectively, which is included in depreciation and amortization expense in the accompanying consolidated statements of operations. All of the Company's intangible assets have finite lives.
	The estimated future amortization expense for the Company's intangible assets as of December 31, 2013 is as follows:
		(dollars in thousands)
	2014	$	2,737
	2015	2,483
	2016	2,144
	2017	1,411
	2018	849
	Thereafter	2,470
		$	12,094

Other_Assets

Other Assets	12 Months Ended
	Dec. 31, 2013
Other Assets [Abstract]	'
Other Assets	'
	Other Assets
	Other assets in Operating Entities are as follows:
		As of December 31,
		2013		2012
		(dollars in thousands)
	Deposits	$	683	$	769
	Prepaid expenses	5,097		5,100
	Taxes receivable	1,911		2,105
	Derivative contracts, at fair value	377		202
	Deferred rent asset	897		433
	Interest and dividends receivable	4,716		6,031
	Other	4,257		3,408
		$	17,938	$	18,048

Accounts_Payable_Accrued_Expen

Accounts Payable Accrued Expenses and Other Liabilities	12 Months Ended
	Dec. 31, 2013
Accounts Payable, Accrued Expenses and Other Liabilities [Abstract]	'
Accounts Payable and Accrued Liabilities Disclosure [Text Block]	'
	Accounts Payable, Accrued Expenses and Other Liabilities
	Accounts payable, accrued expenses and other liabilities in Operating Entities are as follows:
		As of December 31,
		2013		2012
		(dollars in thousands)
	Deferred rent obligations (see Note 3(l))	$	14,554	$	13,822
	Deferred income	1,147		540
	Equity in RCG Longview Partners II, LLC (see Note 6a(3))	5,938		5,970
	Legal and regulatory reserve (see Note 19)	—		3,337
	Contingent consideration payable (see Note 2)	6,937		8,116
	Liability for future rent payments (see Note 19)	—		2,775
	Termination of service contracts	259		465
	Derivative contracts, at fair value	1,101		973
	Interest and dividends payable	2,073		2,324
	Accrued expenses and accounts payable	11,879		16,142
	Accrued tax liabilities	2,503		2,430
		$	46,391	$	56,894

Redeemable_NonControlling_Inte

Redeemable Non-Controlling Interests in Consolidated Subsidiaries	12 Months Ended
	Dec. 31, 2013
Noncontrolling Interest [Abstract]	'
Redeemable Non-Controlling Interests in Consolidated Subsidiaries	'
	Redeemable Non-Controlling Interests in Consolidated Subsidiaries and Funds
	Redeemable non-controlling interests in consolidated subsidiaries and funds and the related net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds are comprised as follows:
		As of December 31,
		2013		2012
		(dollars in thousands)
	Redeemable non-controlling interests in consolidated subsidiaries and funds
	Operating companies	$	12,009	$	4,106
	Consolidated funds	73,805		81,597
		$	85,814	$	85,703
		Year Ended December 31,
		2013		2012			2011
		(dollars in thousands)
	Income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds
	Operating companies	$	10,461	$	301		$	7,002
	Consolidated funds	2,732		(373		)	(1,175		)
		$	13,193	$	(72	)	$	5,827

Other_Revenues_and_Expenses

Other Revenues and Expenses	12 Months Ended
	Dec. 31, 2013
Other Revenues and Expenses [Abstract]	'
Other Revenues and Expenses	'
	Other Revenues and Expenses
	Included within other revenues in the accompanying consolidated statements of operations for the year ended December 31, 2011, are gross insurance premium income of $35.0 million , which is offset by gross reinsurance premium expense of $35.0 million related to the Luxembourg reinsurance companies.
	During June 2008, the Company sold its fractional share ownership of a business aircraft for a net gain of $0.5 million. In the same month, October LLC, a wholly owned subsidiary of the Company, also sold an aircraft through a sale-leaseback transaction. The Company recognized a deferred net gain of $2.8 million and amortized it over a period of sixty-seven months, the term of the lease. During the years ended December 31, 2013, 2012, and 2011, the amount of the gain recognized in other revenue in the accompanying consolidated statements of operations was $0.5 million each year, respectively. The lease will expire on January 31, 2014 and the associated net gain of $2.8 million will be fully recognized. In connection with this transaction, the Company was required to maintain minimum assets under management at all times of not less than$6.5 billion. In the event that the Company does not maintain this minimum, the Company shall immediately either a) deposit collateral with a perfected security interest to secure the next twelve months' lease payments (approximately $0.1 million) or b) provide a letter of credit in the same amount. As of and during the years ended December 31, 2013 and 2012 the Company was in compliance with this minimum requirement.
	Other expenses, during the years ended December 31, 2013, 2012, and 2011, are primarily the general administrative expenses of the various operating company subsidiaries or the Consolidated Funds.

ShareBased_Compensation_and_Em

Share-Based Compensation and Employee Ownership Plans	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Share-Based Compensation and Employee Ownership Plans	'
	Share-Based and Deferred Compensation and Employee Ownership Plans
	The Company issues share based compensation under the 2006 Equity and Incentive Plan, the 2007 Equity and Incentive Plan (both established prior to the November 2009 transaction between Ramius and Cowen) and the Cowen Group, Inc. 2010 Equity and Incentive Plan (collectively, the “Equity Plans”). The Equity Plans permit the grant of options, restricted shares, restricted stock units, stock appreciation rights ("SAR's") and other equity based awards to the Company's employees, consultants and directors for up to 17,725,000 shares of common stock plus any approved additional shares in accordance with the Equity Plans. Stock options granted generally vest over two-to-five-year periods and expire seven years from the date of grant. Restricted shares and restricted share units issued may be immediately vested or may generally vest over a two-to-five-year period. SAR's vest and expire after 5 years from grant date. As of December 31, 2013, there were approximately 0.7 million shares available for future issuance under the Equity Plans.
	Under the 2010 Equity Plan, the Company awarded $29.0 million of deferred cash awards to its employees during 2013 in addition to awards granted during 2012. These awards vest over a period of five years and accrue interest between 0.70% to 0.75% per year. As of December 31, 2013, the Company had unrecognized compensation expense related to these awards of $24.7 million.
	In addition to the Equity Plans, certain employees of the Company, in November 2009, were issued membership interests in RCG Holdings LLC ("RCG") by RCG, a related party of the Company (the “RCG Grants”). Substantially all of the assets owned by RCG consist of shares of common stock of the Company. Accordingly, upon withdrawal of capital from RCG, members receive either distributions in kind of shares of common stock of the Company, or the proceeds from the sale of shares of the Company's common stock attributable to their capital accounts. The RCG Grants are subject to a service condition and vest to each employee over a period of approximately three years. Any RCG Grants forfeited are redistributed to the remaining stakeholders in RCG, which includes both employees and non-employees. The RCG Grants represent awards to employees of the Company by a related party, as compensation for services provided to the Company. As such, the expense related to these grants is included in the compensation expense of the Company, with a corresponding credit to stockholders equity.
	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. In relation to awards under the Equity Plans, the Company recognized expense of $17.9 million, $19.9 million and $22.9 million for the years ended December 31, 2013, 2012 and 2011, respectively. The income tax effect recognized for the Equity Plans was a benefit of $9.7 million, $11.3 million and $11.5 million for the years ended December 31, 2013, 2012, and 2011 respectively; however, these benefits were offset by a valuation allowance.
	In relation to awards under the RCG Grants, the Company recognized expense of $4.9 million and $5.4 million for the years ended December 31, 2012 and 2011, respectively. The income tax effect recognized for the RCG Grants was a benefit of $1.9 million and $2.1 million for the years ended December 31, 2012 and 2011, respectively; however, these benefits were offset by valuation allowances. As of December 31, 2012 the Company's RCG Grants were fully vested and expensed.
	Stock Options and Stock Appreciation Rights
	The Company values options and SAR's on grant date using the Black-Scholes option valuation model which requires the Company to make assumptions regarding the expected term, volatility, risk-free rate and dividend yield:
	Expected term.    Expected term represents the period of time that awards granted are expected to be outstanding. The Company elected to use the "simplified" calculation method, as applicable to companies that lack extensive historical data. The mid-point between the vesting date and the contractual expiration date is used as the expected term under this method.
	Expected volatility.    The Company bases its expected volatility on its own stock price history.
	Risk free rate.    The risk-free rate for periods within the expected term of the award is based on the interest rate of a traded zero-coupon U.S. Treasury bond with a term equal to the awards' expected term on the date of grant.
	Dividend yield.    The Company has not paid and does not expect to pay dividends in the foreseeable future. Accordingly, the assumed dividend yield is zero.
	The following table summarizes the Company's stock option activity for the year ended December 31, 2013:
		Shares Subject		Weighted Average		Weighted Average	Aggregate Intrinsic
		to Option		Exercise Price/Share		Remaining Term	Value(1)
						(in years)	(dollars in thousands)
	Balance outstanding at December 31, 2011	866,428		$	12.95	2.5	$	—
	Options granted	—		—		—	—
	Options acquired	—		—		—	—
	Options exercised	—		—		—	—
	Options forfeited	—		—		—	—
	Options expired	(92,665	)	16		—	—
	Balance outstanding at December 31, 2012	773,763		$	12.58	1.6	$	—
	Options granted	—		—		—	—
	Options acquired	—		—		—	—
	Options expired	(473,757	)	16		—	—
	Balance outstanding at December 31, 2013	300,006		$	7.19	2.4	$	—
	Options exercisable at December 31, 2012	623,760		$	14.66	0.9	$	—
	Options exercisable at December 31, 2013	300,006		$	7.19	2.4	$	—
	-1	Based on the Company's closing stock price of $3.91 on December 31, 2013 and $2.45 on December 31, 2012.
	As of December 31, 2013, the unrecognized compensation expense related to the Company's grant of stock options was insignificant.
	The following table summarizes the Company's SAR's for the year ended December 31, 2013:
		Shares Subject		Weighted Average		Weighted Average	Aggregate Intrinsic
		to Option		Exercise Price/Share		Remaining Term	Value(1)
						(in years)	(dollars in thousands)
	Balance outstanding at December 31, 2012	—		$	—	—	$	—
	SAR's granted	400,000		2.9		—
	SAR's acquired	—		—		—
	SAR's expired	—		—		—
	Balance outstanding at December 31, 2013	400,000		$	2.9	4.21	$	608
	SAR's exercisable at December 31, 2013	—		$	—	—
	-1	Based on the Company's closing stock price of $3.91 on December 31, 2013.
	As of December 31, 2013, the unrecognized compensation expense related to the Company's grant of SAR's was $0.3 million.
	Restricted Shares and 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 year ended December 31, 2013:
		Nonvested Restricted Shares and Restricted Stock Units		Weighted-Average
				Grant Date
				Fair Value
	Balance outstanding at December 31, 2011	7,517,682		$	5.57
	Granted	8,381,939		2.82
	Vested	(4,855,489	)	4.16
	Canceled	—		—
	Forfeited	(792,109	)	3.51
	Balance outstanding at December 31, 2012	10,252,023		$	4.15
	Granted (1)	7,939,924		2.63
	Vested	(4,463,990	)	3.86
	Canceled	—		—
	Forfeited	(176,413	)	3.15
	Balance outstanding at December 31, 2013	13,551,544		$	3.37
	(1) On December 30, 2013, the Company awarded 705,000 performance linked restricted stock units to employees of the Company. The awards will vest on June 10, 2019 and will be earned only to the extent that the Company attains specified performance goals relating its volume-weighted average share price and the aggregate net income for the years from 2014 to 2018. The actual number of RSUs ultimately earned could vary from zero, if performance goals are not met, to as much as 100% of award. Each RSU is equal to the one share of the Company’s common stock. The value of the award will fluctuate with changes in Company’s share price and the attainment of the specified performance goals, until the RSUs are settled solely in shares after the end of the performance period.
	The fair value of restricted stock 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 December 31, 2013, there was $27.7 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 1.59 years.
	Restricted Shares and Restricted Stock Units Granted to Non-employee Board Members
There were 257,947 restricted stock units awarded, which were immediately vested and expensed, during the year ended December 31, 2013. Vested awards of 112,320 were delivered during the year ended December 31, 2013. As of December 31, 2013 there were 482,522 restricted stock units outstanding.

Defined_Benefit_Plans

Defined Benefit Plans	12 Months Ended
	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]	'
Defined Benefit Plans	'
	Defined Benefit Plan
	On December 1, 2005, the Company adopted a defined benefit plan ("Cash Balance Plan") to provide retirement income to all eligible employees of the Company and its subsidiaries in accordance with the terms and conditions in the plan document. The Plan blends the features of a traditional defined benefit plan with the features of a defined contribution plan.  In this plan, hypothetical individual accounts periodically receive a contribution credit and an interest credit.  The contribution credits are a flat dollar amount that vary with age. Investment policies and strategies of the Cash Balance Plan are set by the Retirement Plan Committee and approved by the plan  trustees. The plan trustee will oversee the actual investment of plan assets into permitted asset classes to achieve targeted plan returns. There were net assets of $4.4 million and $5.2 million in the Cash Balance Plan as of December 31, 2013 and 2012, respectively. Hypothetical participant balances are vested at all times. The method of payment for Cash Balance Plan is an annuity unless the participant elects an alternate choice of payment.  The Cash Balance Plan is developed to meet the requirements of Section 401(a) and Section 501(a) of the Internal Revenue Code.
	During the fourth quarter of 2013, the Company made the decision to terminate the Cash Balance Plan, effective December 31, 2013.  To ensure all qualified requirements have been met at the time of the plan termination, the Company has requested a “favorable determination letter” from the IRS.  As a result, the Company anticipates that this process could take twelve to eighteen months to complete. Once all of the necessary approvals are received, the Cash Balance Plan will start making distributions to the participants either in the form of annuities or contributions to other retirement plans elected by the participants.
	In addition, Ramius Japan Ltd. also established a defined benefit plan (the "Retirement Allowance Plan") covering its employees. There are no plan assets associated with this plan and the benefits were based on years of credited service and a percentage of the employees' compensation. This plan was liquidated during the fourth quarter of 2012.
	The estimated future benefits for the above plans are an actuarial estimate of the benefits that the Company will be required to pay. A measurement date of December 31 was used for each of the actuarial calculations.
	The amounts contained in the following table relate to the Company's defined benefit plan(s) for the years ended December 31, 2013, 2012, and 2011:
		As of December 31,
		2013			2012
		(dollars in thousands)
	Projected benefit obligation
	Benefit obligation at beginning of year	$	4,436		$	5,591
	Service cost	—			53
	Interest cost	207			216
	Actuarial loss (gain)	(93		)	(50		)
	Benefits paid	(48		)	—
	Curtailments	—			(98		)
	Lump sum settlement	(910		)	(1,269		)
	Effect of change in currency conversion	—			(7		)
	Benefit obligation at end of year	$	3,592		$	4,436
	Change in plan assets
	Fair value of plan assets at beginning of year	$	5,230		$	5,639
	Actual return on plan assets	153			676
	Employer contributions	1			—
	Benefits paid	(956		)	(1,085		)
	Expenses paid from the plan	(39		)	—
	Fair value of plan assets at the end of year	$	4,389		$	5,230
	Funded balance at end of year	$	797		$	794
	Amounts recognized in the consolidated statement of financial condition
	Asset	$	797		$	794
	Accumulated benefit obligation	$	3,592		$	4,436
		Year Ended December 31,
		2013			2012			2011
		(dollars in thousands)
	Components of net periodic benefit cost included in employee compensation and benefits
	Service cost	$	—		$	53		$	50
	Interest cost	207			216			264
	Expected return on plan assets	(251		)	(235		)	(276		)
	Amortization of (loss) / gain	—			—			—
	Amortization of prior service cost	21			20			21
	Effect of curtailment	360			(59		)	—
	Effect of special termination benefits	—			6			—
	Effect of settlement	(95		)	(95		)	(29		)
	Net periodic benefit cost	$	242		$	(94	)	$	30
	Other changes in plan assets and benefit obligations recognized in other comprehensive loss
	Net loss (gain)	$	137		$	(557	)	$	(33	)
	Effect of curtailment	(360		)	59			—
	Effect of settlement	—			98			31
	Amortization of loss / (gain)	—			—			—
	Amortization of prior service cost	(23		)	(23		)	(23		)
	Total recognized in other comprehensive income (loss)	$	(246	)	$	(423	)	$	(25	)
	Total recognized in net periodic benefit cost and other comprehensive loss	$	(4	)	$	(517	)	$	5
	Amounts recognized in accumulated other comprehensive loss
	Net gain (loss)	$	344		$	479		$	116
	Prior service cost	—			(381		)	(441		)
	Effect of change in currency conversion	—			—			—
	Total recognized in accumulated other comprehensive income (loss)	$	344		$	98		$	(325	)
	Estimated amounts to be amortized from accumulated other comprehensive loss into net periodic benefit cost over the next fiscal year
	Prior service cost	$	—		$	19		$	19
	Net gain (loss)	$	—		$	—		$	—
	The assumed long term rate of return on the Cash Balance Plan assets was 6% as of December 31, 2013, 2012 and 2011. The Company's approach in determining the long-term rate of return for plan assets is based upon historical financial market relationships that have existed over time with the presumption that this trend will generally remain constant in the future.
	The composition of plan assets by asset category for the Cash Balance Plan are set forth below:
		As of December 31,
		2013			2012
	(dollars in thousands)
Ramius Multi-Strategy Fund Ltd(a)	$	390		$	513
Ramius Merger Fund Ltd	2,279			—
Orchard Square Partners Credit Fund Ltd(b)	1,640			1,304
External Mutual Funds—Total return(c)	7			1,358
External Mutual Funds—Real Return(d)	34			1,019
External Mutual Funds—Conservative(e)	39			1,036
	$	4,389		$	5,230
(a)	Ramius Multi-Strategy Fund Ltd invests substantially all of its capital through a "master feeder" structure in Ramius Intermediate Fund, L.P. which invests in funds that employ a variety of diversified, non-directional investment strategies that seek to achieve, over the long term, a target return with low volatility.
(b)	Orchard Square Partners Credit Fund Ltd invests substantially all of its capital through a "master-feeder" structure in Orchard Square Partners Credit Intermediate Fund, LP which invests in a fund whose objective is to seek to achieve superior returns.
(c)	External Mutual Funds—Total Return's main objective is to achieve maximum total return by investing assets in a diversified portfolio of fixed income instruments of varying maturities which may be represented by derivatives.
(d)	External Mutual Funds—Real Return's main objective is to seek to achieve maximum total return after inflation consistent with preservation of real capital and prudent investment management.
(e)	External Mutual Funds—Conservative's main objective is to seek to achieve a high level of current income with some consideration given to the growth of capital by investing in fixed-income securities.
The investment approach of the Cash Balance Plan is to generate a return equal to or greater than the 30-year treasury rate with relatively low risk by investing in a variety of vehicles. The Company has valued the assets in the Cash Balance Plan at fair value in accordance with the Company's investment policies (see Note 3e). The assets in the Cash Balance Plan are categorized in level 2 of the fair value hierarchy. Investment risk is measured and monitored on an ongoing basis through semi-annual retirement committee meetings and annual liability measurements.
Estimated future benefits payments
Benefit payments, which reflect future service, as appropriate, of $3.7 million are expected to be paid in full during 2014.

Defined_Contribution_Plans

Defined Contribution Plans	12 Months Ended
	Dec. 31, 2013
Defined Contribution Plans [Abstract]	'
Defined Contribution Plans	'
	Defined Contribution Plans
	The Company sponsors a Retirement and Savings Plan which is defined contribution plans pursuant to Section 401(k) of the Internal Revenue Code (the "401k Plans"). All full-time employees of the Company can contribute on a tax deferred basis to the 401k Plans up to 100% of their annual compensation, subject to certain limitations. The Company provides matching contributions for certain employees that are equal to a specified percentage of the eligible participant's contribution as defined by the 401k Plans. For the years ended December 31, 2013, 2012, and 2011, the Company's contributions to the Plans were $0.4 million, $1.4 million and $1.5 million, respectively.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
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 Group, Inc. as well as stand‑alone state and local tax returns. The Company has subsidiaries that are resident in foreign countries where tax filings have to be submitted on a stand‑alone basis. These subsidiaries are subject to tax in their respective countries and the Company is responsible for and, thus, reports all taxes incurred by these subsidiaries. The countries where the Company owns subsidiaries that file tax returns are United Kingdom, Luxembourg, Gibraltar, and Hong Kong.
	The components of the Company's income tax expense for the years ended December 31, 2013 , 2012 and 2011 are as follows:
		Year ended December 31,
		2013				2012				2011
		(dollars in thousands)
	Continued Operations
	Current tax expense/(benefit)
	Federal	$	—			$	—			$	—
	State and local	241				(133		)		560
	Foreign	188				569				897
	Total	$	429			$	436			$	1,457
	Deferred tax expense/(benefit)
	Federal	$	—			$	8			$	2
	State and local	—				2				(6		)
	Foreign	28				2				(21,526		)
	Total	28				12				(21,530		)
	Total Tax expense/(benefit)	$	457			$	448			$	(20,073	)
	Discontinued Operations
	Current tax expense/(benefit)
	Federal	$	—			$	—			$	—
	State and local	—				—				(5		)
	Foreign	—				—				(424		)
	Total	$	—			$	—			$	(429	)
	Deferred tax expense/(benefit)
	Federal	$	—			$	—			$	—
	State and local	—				—				—
	Foreign	—				—				—
	Total	—				—				—
	Total Tax expense/(benefit)	$	—			$	—			$	(429	)
	Total
	Current tax expense/(benefit)
	Federal	$	—			$	—			$	—
	State and local	241				(133		)		555
	Foreign	188				569				473
	Total	$	429			$	436			$	1,028
	Deferred tax expense/(benefit)
	Federal	$	—			$	8			$	2
	State and local	—				2				(6		)
	Foreign	28				2				(21,526		)
	Total	28				12				(21,530		)
	Total Tax expense/(benefit)	$	457			$	448			$	(20,502	)
	Consolidated U.S. income/(loss) before income taxes was $11.9 million in 2013, $(25.9) million in 2012, and $(122.2) million in 2011 . The corresponding amounts for non-U.S.-based income/(loss) were $6.4 million in 2013, $2.4 million in 2012, and $(0.5) million in 2011.
	The reconciliations of the Company's federal statutory rate to the effective income tax rate for the years ended December 31, 2013, 2012, and 2011 are as follows:
		2013			2012			2011
	Pre-tax loss at U.S. statutory rate	35	%		35	%		35	%
	Stock compensation	12.6			(28.1	)		—
	Change in valuation allowance	(27.2	)		(7.6	)		(33.3	)
	Deferred asset recognition	—			—			11.5
	Bargain purchase price	—			—			6.3
	Minority interest reversal	(25.2	)		(0.1	)		1.7
	Other, net	7.3			(1.1	)		(4.5	)
	Total	2.5	%		(1.9	)%		16.7	%
	As of December 31, 2013, the Company has net income taxes receivable of approximately $1.9 million representing a federal refund claim resulting from carrying back net operating losses and state tax overpayments, which is included in other assets on the consolidated statements of financial condition. The Company also has foreign income taxes payable of $0.4 million, which is included in other liabilities on the consolidated statements of financial condition.
	The components of the Company's deferred tax assets and liabilities as of December 31, 2013 and 2012 are as follows:
		2013				2012
		(dollars in thousands)
	Deferred tax assets, net of valuation allowance
	Net operating loss	$	130,562			$	135,108
	Deferred compensation	22,538				23,373
	Unrealized losses on investments	—				4,450
	Goodwill	9,937				10,885
	Legal reserves	—				803
Foreign tax credits	1,820				1,756
Acquired lease liability	3,336				1,036
Other	4,842				3,532
Total deferred tax assets	173,035				180,943
Valuation allowance	(148,816		)		(161,181		)
Deferred tax assets, net of valuation allowance	24,219				19,762
Deferred tax liabilities
Basis difference on investments	(15,352		)		(15,351		)
Unrealized gains on investments	(6,354		)		—
Fixed assets	(761		)		(1,405		)
Intangible assets	(1,177		)		(1,230		)
Other	(602		)		(1,766		)
Total deferred tax liabilities	(24,246		)		(19,752		)
Deferred tax assets, net	$	(27	)		$	10
Deferred tax assets, net of valuation allowance, are reported in other assets in the accompanying consolidated statements of financial condition. In addition to the deferred tax balances in the table above, the Company records balances related to its operating losses in Luxembourg, which are discussed below.
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. The Company recorded a valuation allowance of approximately $148.8 million against its deferred tax assets as of December 31, 2013 and approximately $161.2 million as of December 31, 2012 as management believes it is more likely than not that the deferred tax assets will not be realized. Separately, the Company has deferred tax liabilities of $24.2 million as of December 31, 2013, and $19.8 million as of December 31, 2012.
The Company’s acquisition of Dahlman on March 11, 2013 did not have a material impact on the Company’s tax balances.
The deferred tax expense recorded during the year ended December 31, 2013 and 2012 was insignificant. The deferred tax benefit of $21.7 million recorded in 2011, represented the deferred tax benefits generated by a local subsidiary upon acquisition of two reinsurance companies, respectively, in Luxembourg from third parties offering a service program that provides reinsurance coverage to the Company against certain risks. These reinsurance companies carried deferred tax liabilities and upon their purchase, pursuant to an Advance Tax Agreement, the local subsidiary generated deferred tax assets that fully offset these liabilities, resulting in the recognition of the deferred tax benefits.
The Company has the following net operating loss carryforwards at December 31, 2013:
	Federal				New York				Hong Kong
Jurisdiction:
Net operating loss (in millions)	$	323			$	390			$	14
Year of expiration	2033				2033				Indefinite
In addition to the net operating loss carryforwards in the table above, the Company also has net operating loss carryforwards in Luxembourg. These loss carryforwards are only accessible to the extent of taxable income generated by the Luxembourg reinsurance companies, including any deferred income that will be generated in the future. Consequently, the Company recorded a deferred tax asset of $160.1 million, net of deferred tax liabilities of $193.4 million in connection with future taxable income, and an offsetting valuation allowance of $160.1 million against its Luxembourg net operating loss carryforwards that are in excess of such taxable income.
As of December 31, 2013, the Company has foreign tax credit carryovers of $1.8 million which will expire by 2019. The Company underwent a change of control under Section 382 of the Internal Revenue Code on November 2, 2009 (“Section 382”). Accordingly, a portion of the Company's deferred tax assets, in particular a portion of its net operating loss and foreign tax credit carryovers, are subject to an annual limitation. The deduction limitation is approximately $2.4 million annually and applies to approximately $13.7 million of pre-transaction losses. Further, the acquisition of LaBranche by the Company on June 28, 2011 caused an ownership change of LaBranche under Section 382. As such, the portion of the Company's deferred tax assets representing net operating losses from LaBranche as of the date of its acquisition is subject to a separate annual limitation. The limitation is approximately $6.7 million annually and applies to approximately $87.4 million of net operating losses. The Company is not expected to lose any deferred tax assets as a result of these limitations.
The Company adopted the accounting guidance for accounting for uncertainty in income taxes as which clarifies the criteria that must be met prior to recognition of the financial statement benefit of a position taken in a tax return. The Company does not have any uncertain tax positions recorded for the years ended December 31, 2013, 2012, and 2011. Further, the Company did not record any additions to its unrecognized tax benefit balances as a result of current or prior year tax positions or reductions due to expired statute of limitations during the years ended December 31, 2013, 2012, and 2011.
The Company is subject to examination by the United States Internal Revenue Service, the United Kingdom HM Revenue and Customs as well as state, local and foreign tax authorities in jurisdictions where the Company has significant business operations, such as New York. Currently, the Company is under audit by New York State for the 2009 tax year. Management is not expecting a material tax liability from this audit.
The Company intends to permanently reinvest the capital and accumulated earnings of its foreign subsidiaries in the respective subsidiary, but remits the current earnings of its foreign subsidiaries to the United States to the extent permissible under local regulatory rules. The undistributed earnings of the Company’s foreign subsidiaries totaled $1.1 million and $3.5 million as of December 31, 2013 and 2012, respectively, and the tax liability that would arise if these earnings were remitted to the United States would be approximately $0.2 million and $0.3 million, respectively.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Commitments and Contingencies
	Lease Obligations
	The Company has entered into non-cancellable leases for office space and equipment. These leases contain rent escalation clauses. The Company records rent expense on a straight-line basis over the lease term, including any rent holiday periods. Rent expense was $15.6 million, $14.3 million, and $16.7 million for the years ended December 31, 2013, 2012, and 2011, respectively.
	On August 20, 2010, the Company entered into an amendment to the Company's original lease for offices located at 1221 Avenue of Americas, New York, to surrender a portion of the office space as of January 1, 2011. As of December 31, 2011, the Company vacated the remaining portion of the leased premises located at 1221 Avenue of Americas. As a result, the Company recognized a liability in the amount of $5.7 million relating to future rent payments and other monthly amounts associated with the lease through its expiration in September 2013. The liability relating to future rent payments and other monthly amounts associated with vacating the remaining portion of the Company's leased premises, located at 1221 Avenue of Americas, was $2.8 million as of December 31, 2012.
	As of December 31, 2013, future minimum annual lease and service payments for the Company were as follows:
		Equipment Leases (a)		Service Payments		Facility Leases (b)
		(dollars in thousands)
	2014	$	810	$	11,970	$	17,862
	2015	405		5,499		17,375
	2016	86		1,634		14,283
	2017	—		1,133		11,174
	2018	—		1,049		10,885
	Thereafter	—		22		39,594
		$	1,301	$	21,307	$	111,173
	(a)	Equipment Leases include the Company's commitments relating to operating and capital leases. See Note 20 for further information on the capital lease minimum payments which are included in the table. See Note 28 regarding a new lease for data storage and data backup equipment entered into in January 2014.
	(b)	The Company has entered into various agreements to sublease certain of its premises. The Company recorded sublease income related to these leases of $1.5 million, $1.2 million, and $0.3 million for the years ended December 31, 2013, 2012, and 2011, respectively.
	Clawback Obligations
	For financial reporting purposes, the general partners have recorded a liability for potential clawback obligations to the limited partners of a real estate fund, due to changes in the unrealized value of the fund's remaining investments and where the fund's general partner has previously received carried interest distributions.
	For financial reporting purposes, the general partners have recorded a liability for potential clawback obligations to the limited partners of a real estate fund, due to changes in the unrealized value of the fund's remaining investments and where the fund's general partner has previously received carried interest distributions. The actual clawback liability, however, does not become realized until the end of the fund's life. The fund is currently in winding-down mode and as of December 31, 2013 and December 31, 2012, the clawback obligations were $6.2 million, respectively.
	The Company serves as the general partner/managing member and/or investment manager to various affiliated and sponsored funds. As such, the Company is contingently liable for obligations for those entities. These amounts are not included above as the Company believes that the assets in these funds are sufficient to discharge any liabilities.
	Unfunded Commitments
	As of December 31, 2013, the Company had unfunded commitments of $13.2 million pertaining to capital commitments in four real estate investments held by the Company, all of which pertain to related party investments. Such commitments can be called at any time, subject to advance notice. The Company, as a limited partner of the HealthCare Royalty Partners funds and also as a member of HealthCare Royalty Partners General Partner, has committed to invest $42.4 million in the Healthcare Royalty Partners funds which are managed by Healthcare Royalty Management. This commitment is expected to be called over a two to five year period. The Company will make its pro-rata investment in the HealthCare Royalty Partners funds along with the other limited partners. Through December 31, 2013, the Company has funded $29.9 million towards these commitments. In April 2011, the Company committed $15.0 million to Starboard Value and Opportunity Fund LP, which may increase or decrease over time with the performance of Starboard Value and Opportunity Fund LP. As of December 31, 2013, the Company has fully funded this commitment. In April 2013, the Company committed $1.0 million to Starboard Leaders Fund LP, which may increase or decrease over time dependent on the performance of the fund, and, as of December 31, 2013, has funded $0.5 million towards this commitment. In January 2013, the Company committed $10.0 million to Orchard Square Partners Credit Fund LP (formerly known as Ramius Global Credit Fund LP). As of March 31, 2013, the Company has fully funded this commitment. In September 2012, the Company committed $10.0 million to Formation 8 Partners Fund I LP as a limited partner and funded $3.0 million through December 31, 2013. The remaining capital commitment is expected to be called over a five year period.
	Litigation
	In the ordinary course of business, the Company and its affiliates and 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 affiliates and subsidiaries of the Company are investment banks, 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 and such affiliates and subsidiaries receive requests, and orders seeking documents and other information in connection with various aspects of their 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, and 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 the Company and Related Parties are subject to 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 the US GAAP, the Company establishes reserves for contingencies when the Company believes that it is probable that a loss has been incurred and the amount of loss can be reasonably estimated. The Company discloses a contingency if there is at least a reasonable possibility that a loss may have been incurred and there is no reserve for the loss because the conditions above are not met. The Company's disclosure includes an estimate of the reasonably possible loss or range of loss for those matters, for which an estimate can be made. Neither a reserve nor disclosure is required for losses that are deemed remote.
	The Company appropriately reserves for certain matters where, in the opinion of management, the likelihood of liability is probable and the extent of such liability is reasonably estimable. Such amounts are included within accounts payable, accrued expenses and other liabilities in the consolidated statements of financial condition. Estimates, by their nature, are based on judgment and currently available information and involve a variety of factors, including, but not limited to, the type and nature of the litigation, claim or proceeding, the progress of the matter, the advice of legal counsel, the Company's defenses and its experience in similar cases or proceedings as well as its assessment of matters, including settlements, involving other defendants in similar or related cases or proceedings. The Company may increase or decrease its legal reserves in the future, on a matter-by-matter basis, to account for developments in such matters. The Company accrues legal fees as incurred.

ShortTerm_Borrowings_and_Other

Short-Term Borrowings and Other Debt	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Short-Term Borrowings and Other Debt	'
	Short-Term Borrowings and Other Debt
	As of December 31, 2013 and 2012, short term borrowings and other debt of the Company were as follows:
		As of December 31,
		2013			2012
		(dollars in thousands)
	Notes payable	$	41		$	206
	Capital lease obligations	2,523			3,926
		$	2,564		$	4,132
	In January 2013, the Company borrowed $2.0 million to fund insurance premium payments. This note bears interest at 2.22% and was due on December 1, 2013, with monthly payment requirements of $0.2 million. As of December 31, 2013, the outstanding balance on this note payable was fully repaid. Interest expense for the year ended December 31, 2013 was insignificant.
	The Company entered into several capital leases for computer equipment during the fourth quarter of 2010. These leases amount to $6.3 million and are recorded in fixed assets and as capital lease obligations, which are included in short-term borrowings and other debt in the accompanying consolidated statements of financial condition, and have lease terms that range from 48 to 60 months and interest rates that range from 0.60% to 6.14%. As of December 31, 2013, the remaining balance on these capital leases was $2.5 million. Approximately $0.9 million of capital lease obligations held at December 31, 2013 were terminated in January 2014 (See Note 28). Interest expense was $0.1 million, $0.2 million, and $0.2 million for the years ended December 31, 2013, 2012, and 2011, respectively.
	As of December 31, 2013, the Company has the following five 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.
	Location		Amount			Maturity
			(dollars in thousands)
	San Francisco		$	82		May-14
	New York		$	1,191		Sep-14
	New York		$	6,746		Dec-14
	New York		$	1,000		Feb-14
	New York		$	1,861		Mar-14
	To the extent any letter of credit is drawn upon, interest will be assessed at the prime commercial lending rate. As of December 31, 2013 and 2012, there were no amounts due related to these letters of credit.
	Annual scheduled maturities of debt and minimum lease payments for capital lease obligation and short term borrowings and other debt outstanding as of December 31, 2013, are as follows:
		Capital Lease			Notes payable
		Obligation
		(dollars in thousands)
	2014	$	1,402		$	46
	2015	1,051			—
	2016	194			—
	2017	—			—
	2018	—			—
	Thereafter	—			—
	Subtotal	2,647			46
	Less: Amount representing interest (a)	(124		)	(5		)
	Total	$	2,523		$	41
	(a)	Amount necessary to reduce net minimum lease payments to present value calculated at the Company's implicit rate at lease inception.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Stockholders' Equity	'
	Stockholders' Equity
	The Company is authorized to issue 500,000,000 shares of common stock, which shall consist of 250,000,000 shares of Class A common stock, par value $0.01 per share, and 250,000,000 shares of Class B common stock, par value $0.01 per share. The Company is also authorized to issue 10,000,000 shares of preferred stock, par value $0.01 per share. Subject to the rights of holders of any outstanding preferred stock, the number of authorized shares of common stock or preferred stock may be increased or decreased by the affirmative vote of the holders of a majority of the shares entitled to vote on such matters, but in no instance can the number of authorized shares be reduced below the number of shares then outstanding.
	Common stock
	The certificate of incorporation of the Company provides for two classes of common stock, and for the conversion of each class into the other, to provide a mechanism by which holders of Class A common stock of the Company who may be limited in the amount of voting common stock of the Company they can hold pursuant to federal, state or foreign bank laws, to convert their shares into non-voting Class B common stock to prevent being in violation of such laws. Each holder of Class A common stock is entitled to one vote per share in connection with the election of directors and on all other matters submitted to a stockholder vote, provided, however, that, except as otherwise required by law, holders of Class A common stock are not entitled to vote on any amendment to the Company 's amended and restated certificate of incorporation that relates solely to the terms of one or more outstanding series of the Company's preferred stock, if holders of the preferred stock series are entitled to vote on the amendment under the Company's certificate of incorporation or Delaware law. No holder of Class A common stock may accumulate votes in voting for directors of the Company.
	Each holder of Class B common stock is not entitled to vote except as otherwise provided by law, provided however that the Company must obtain the consent of a majority of the holders of Class B common stock to effect any amendment, alteration or repeal of any provision of the Company's amended and restated certificate of incorporation or amended and restated by-laws that would adversely affect the voting powers, preferences or rights of holders of Class B common stock. Except as otherwise provided by law, Class B common stock shares will not be counted as shares held by stockholders for purposes of determining whether a vote or consent has been approved or given by the requisite percentage of shares.
	Each share of Class A common stock is convertible at the option of the holder and at no cost into one share of Class B common stock, and each share of Class B common stock is convertible at the option of the holder and at no cost into one share of Class A common stock. The conversion ratios will be adjusted proportionally to reflect any stock split, stock dividend, merger, reorganization, recapitalization or other change in the Class A common stock and Class B common stock. Upon conversion, converted shares resume the status of authorized and unissued shares.
	Subject to the preferences of the holders of any of the Company's preferred stock that may be outstanding from time to time, each share of Class A common stock and Class B common stock will have an equal and ratable right to receive dividends and other distributions in cash, property or shares of stock as may be declared by the Company's board of directors out of assets or funds legally available for the payment of dividends and other distributions.
	In the event of the liquidation, dissolution or winding up of the Company, subject to the preferences of the holders of any preferred stock of the Company that may be outstanding from time to time, holders of Class A common stock and Class B common stock will be entitled to share equally and ratably in the assets available for distribution to the Company's stockholders. There are no redemption or sinking fund provisions applicable to the Class A or the Class B common stock.
	On November 2, 2009, in connection with the Cowen and Ramius transaction, the Company issued of 37,536,826 shares of Class A common stock to RCG and 2,713,882 shares of Class A common stock to HVB. In addition, 15,042,290 shares of Cowen Holdings's stock were converted into an equivalent number of the Company's Class A common stock.
	In December 2009, the Company completed a public offering of 17,292,698 shares of Class A common stock, resulting in approximately $82 million of additional equity. An additional 284,655 shares were sold in connection with this offering. These shares were held by RCG and attributable to certain of its non-affiliate members who withdrew one-third of their capital in RCG as of December 31, 2009. RCG distributed the net proceeds from the sale of these shares to those members to satisfy such withdrawals. As of December 31, 2010, RCG held 33,576,099 shares of the Company's Class A common stock. During 2012 and 2013, 9,054,175 and 16,045,865 shares were transferred to member's ownership, respectively. The Company's Class A common stock held by RCG Holdings as of December 31, 2012 was 16,135,162 and after all 2013 distributions were completed it holds no common stock in the Company as of December 31, 2013.
	Under the terms of the Merger Agreement, each outstanding share of LaBranche was converted into 0.9980 shares of Cowen Class A common stock (or 40,850,133 shares) which were issued on the date of the completion of the acquisition (See Note 2).
	Preferred stock
	The Company's amended and restated certificate of incorporation permits the Company to issue up to 10,000,000 shares of preferred stock in one or more series with such designations, titles, voting powers, preferences and rights and such qualifications, limitations and restrictions as may be fixed by the board of directors of the Company without any further action by the Company's stockholders. The Company's board of directors may increase or decrease the number of shares of any series of preferred stock following the issuance of that series of preferred stock, but in no instance can the number of shares of a series of preferred stock be reduced below the number of shares of the series then outstanding.
	Treasury stock
	Treasury stock of $48.1 million as of December 31, 2013, compared to $31.7 million as of December 31, 2012, resulted from $3.6 million acquired through repurchases of shares to cover employee minimum tax withholding obligations related to stock compensation vesting events under the Company's Equity Plan or other similar transactions, $12.8 million purchased in connection with a share repurchase program and $0.1 million of treasury stock re-issued.
	The following represents the activity relating to the treasury stock held by the Company during the year ended December 31, 2013:
		Treasury stock shares		Cost			Average cost
							per share
		(dollars in thousands)
	Balance outstanding at December 31, 2012	11,292,220		$	31,728		$	2.81
	Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions	1,203,454		3,649			3.03
	Treasury stock reissued	(24,744	)	(90		)	3.64
	Purchase of treasury stock	3,402,619		12,797			3.76
	Balance outstanding at December 31, 2013	15,873,549		$	48,084		$	3.03

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income (Loss) (Notes)	12 Months Ended
	Dec. 31, 2013
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 and net gain / (loss) and amortization of prior service costs related to the Company's defined benefit plans.
		Foreign currency translation (a)			Defined benefit plans (a)			Total
		(dollars in thousands)
	Balance at January 1, 2011	$	370		$	(350	)	$	20
	Net change	(260		)	25			(235		)
	Balance at December 31, 2011	110			(325		)	(215		)
	Net change	148			423			571
	Balance at December 31, 2012	258			98			356
	Net change	(10		)	246			236
	Balance at December 31, 2013	$	248		$	344		$	592
	(a) During the periods presented, the Company did not have material reclassifications out of other comprehensive income.

Earnings_Per_Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Earnings Per Share	'
	Earnings Per Share
	The Company calculates its basic and diluted earnings per share in accordance with US GAAP. Basic earnings per common share is calculated by dividing net income attributable to the Company's stockholders by the weighted average number of common shares outstanding for the period. As of December 31, 2013, there were 115,026,633 shares outstanding. The Company has included 482,522 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 nonvested restricted stock and stock options. The Company uses the treasury stock method to reflect the potential dilutive effect of the unvested restricted shares, restricted stock units and unexercised stock options and SAR's. In calculating the number of dilutive shares outstanding, the shares of common stock underlying unvested restricted shares and restricted stock units are assumed to have been delivered, and options are assumed to have been exercised, on the grant date. The assumed proceeds from the assumed vesting, delivery and exercising were calculated as the sum of (a) the amount of compensation cost attributed to future services and not yet recognized and (b) the amount of tax benefit that would be credited to additional paid-in capital assuming vesting and delivery of the restricted stock. The tax benefit is the amount resulting from a tax deduction for compensation in excess of compensation expense recognized for financial statement reporting purposes. All outstanding stock options were not included in the computation of diluted net income (loss) per common share for the years ended December 31, 2013, 2012 and 2011, respectively, as their inclusion would have been anti-dilutive.
	The computation of earnings per share is as follows:
		Year Ended December 31,
		2013		2012			2011
		(dollars in thousands, except per share data)
	Net income (loss)	$	17,840	$	(23,957	)	$	(78,537	)
	Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	13,193		(72		)	5,827
	Net income (loss) attributable to Cowen Group, Inc. stockholders	4,647		(23,885		)	(84,364		)
	Net income (loss) from discontinued operations, net of tax	—		—			(23,646		)
	Shares for basic and diluted calculations:
	Weighted average shares used in basic computation	116,703		114,400			95,532
	Stock options	—		—			—
	Stock appreciation rights	306		—			—
	Restricted stock	4,108		—			—
	Weighted average shares used in diluted computation	121,117		114,400			95,532
	Earnings (loss) per share:
	Basic
	Income (loss) from continued operations	$	0.04	$	(0.21	)	$	(0.88	)
	Income (loss) from discontinued operations	—		—			(0.25		)
	Diluted
	Income (loss) from continued operations	$	0.04	$	(0.21	)	$	(0.88	)
	Income (loss) from discontinued operations	—		—			(0.25		)

Segment_Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Segment Reporting	'
	Segment Reporting
	The Company conducts its operations through two segments: the alternative investment segment and the broker‑dealer segment. These activities are conducted primarily in the United States and substantially all of its revenues are generated domestically. 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.
	In general, Economic Income (Loss) is a pre-tax measure that (i) eliminates the impact of consolidation for consolidated funds, (ii) excludes equity award expense related to the November 2009 Ramius/Cowen transaction, and (iii) excludes certain other acquisition-related and/or reorganization expenses (See Note 2). In addition, Economic Income (Loss) revenues include investment income that represents the income the Company has earned in investing its own capital, including realized and unrealized gains and losses, interest and dividends, net of associated investment related expenses. For US GAAP purposes, these items are included in each of their respective line items. Economic Income (Loss) revenues also include management fees, incentive income and investment income earned through the Company's investment as a general partner in certain real estate entities and the Company's investment in the Value and Opportunity business. For US GAAP purposes, all of these items are recorded in other income (loss). In addition, Economic Income (Loss) expenses are reduced by reimbursement from affiliates, which for US GAAP purposes is presented gross as part of revenue.
	As further stated below, one major difference between Economic Income (Loss) and US GAAP net income (loss) is that Economic Income (Loss) presents the segments' results of operations without the impact resulting from the full consolidation of any of the Consolidated Funds. Consolidation of these funds results in including in income the pro rata share of the income or loss attributable to other owners of such entities which is reflected in net income (loss) attributable to redeemable non-controlling interest in consolidated subsidiaries in the accompanying consolidated statements of operations. This pro rata share has no effect on the overall financial performance for the alternative investment segment, as ultimately, this income or loss is not income or loss for the alternative investment segment itself. Included in Economic Income (Loss) is the actual pro rata share of the income or loss attributable to the Company as an investor in such entities, which is relevant in management making operating decisions and evaluating financial performance.
	The following tables set forth operating results for the Company's alternative investment and broker dealer segments and related adjustments necessary to reconcile the Company's Economic Income (Loss) measure to arrive at the Company's consolidated US GAAP net income (loss):
		Year Ended December 31, 2013
											Adjustments
		Alternative			Broker-Dealer (1)			Total Economic Income/(Loss)			Funds			Other				US GAAP
		Investment									Consolidation			Adjustments
		(dollars in thousands)
	Revenues
	Investment banking	$	—		$	105,333		$	105,333		$	—		$	—			$	105,333
	Brokerage	—			121,065			121,065			—			(6,472		)	(e)	114,593
	Management fees	56,984			—			56,984			(1,146		)	(18,535		)	(a)	37,303
	Incentive income	21,933			—			21,933			—			(9,347		)	(a)	12,586
	Investment Income	30,713			5,947			36,660			—			(36,660		)	(c)	—
	Interest and dividends	—			—			—			—			39,454			(c)	39,454
	Reimbursement from affiliates	—			—			—			(99		)	9,260			(b)	9,161
	Other revenue	524			2,010			2,534			—			2,884			(c)	5,418
	Consolidated Funds revenues	—			—			—			3,398			—				3,398
	Total revenues	110,154			234,355			344,509			2,153			(19,416		)		327,246
	Expenses
	Employee compensation and benefits	54,656			150,180			204,836			—			2,412				207,248
	Interest and dividends	231			119			350			—			26,949			(c)	27,299
	Non-compensation expenses—Fixed	33,986			61,538			95,524			—			(95,524		)	(c)(d)	—
	Non-compensation expenses—Variable	4,520			26,123			30,643			—			(30,643		)	(c)(d)	—
	Non-compensation expenses	—			—			—			—			124,331			(c)(d)	124,331
	Reimbursement from affiliates	(6,380		)	—			(6,380		)	—			6,380			(b)	—
	Consolidated Funds expenses	—			—			—			2,039			—				2,039
	Total expenses	87,013			237,960			324,973			2,039			33,905				360,917
	Other income (loss)
	Net gains (losses) on securities, derivatives and other investments	—			—			—			—			40,924			(c)	40,924
	Consolidated Funds net gains (losses)	—			—			—			2,618			8,426				11,044
	Total other income (loss)	—			—			—			2,618			49,350				51,968
	Income (loss) before income taxes and non-controlling interests	23,141			(3,605		)	19,536			2,732			(3,971		)		18,297
	Income taxes expense / (benefit)	—			—			—			—			457			(b)	457
	Economic Income (Loss) / Net income (loss) before non-controlling interests	23,141			(3,605		)	19,536			2,732			(4,428		)		17,840
	(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	(12,995		)	—			(12,995		)	(2,732		)	2,534				(13,193		)
	Economic Income (Loss) / Net Income (loss) attributable to Cowen Group, Inc. stockholders	$	10,146		$	(3,605	)	$	6,541		$	—		$	(1,894	)		$	4,647
	(1) For the year ended December 31, 2013, the Company has reflected $7.6 million of investment income and related compensation expense of $2.5 million within the broker-dealer segment in proportion to its capital.
		Year Ended December 31, 2012
											Adjustments
		Alternative			Broker-Dealer (1)			Total Economic Income/(Loss)			Funds			Other				US GAAP
		Investment									Consolidation			Adjustments
		(dollars in thousands)
	Revenues
	Investment banking	$	—		$	71,762		$	71,762		$	—		$	—			$	71,762
	Brokerage	—			93,903			93,903			—			(2,736		)	(e)	91,167
	Management fees	56,381			—			56,381			(1,474		)	(16,791		)	(a)	38,116
	Incentive income	15,205			—			15,205			—			(9,794		)	(a)	5,411
	Investment Income	40,374			9,742			50,116			—			(50,116		)	(c)	—
	Interest and dividends	—			—			—			—			24,608			(c)	24,608
	Reimbursement from affiliates	—			—			—			(288		)	5,527			(b)	5,239
	Other revenue	844			404			1,248			—			2,420			(c)	3,668
	Consolidated Funds revenues	—			—			—			509			—				509
	Total revenues	112,804			175,811			288,615			(1,253		)	(46,882		)		240,480
	Expenses
	Employee compensation and benefits	59,647			128,508			188,155			—			5,879				194,034
	Interest and dividends	151			188			339			—			11,798			(c)	12,137
	Non-compensation expenses—Fixed	32,575			62,887			95,462			—			(95,462		)	(c)(d)	—
	Non-compensation expenses—Variable	4,941			20,334			25,275			—			(25,275		)	(c)(d)	—
	Non-compensation expenses	—			—			—			—			119,053			(c)(d)	119,053
	Reimbursement from affiliates	(5,527		)	—			(5,527		)	—			5,527			(b)	—
Consolidated Funds expenses	—			—			—			1,676			—				1,676
Total expenses	91,787			211,917			303,704			1,676			21,520				326,900
Other income (loss)
Net gains (losses) on securities, derivatives and other investments	—			—			—			—			55,665			(c)	55,665
Consolidated Funds net gains (losses)	—			—			—			2,556			4,690				7,246
Total other income (loss)	—			—			—			2,556			60,355				62,911
Income (loss) before income taxes and non-controlling interests	21,017			(36,106		)	(15,089		)	(373		)	(8,047		)		(23,509		)
Income taxes expense / (benefit)	—			—			—			—			448			(b)	448
Economic Income (Loss) / Net income (loss) before non-controlling interests	21,017			(36,106		)	(15,089		)	(373		)	(8,495		)		(23,957		)
(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	(2,480		)	—			(2,480		)	373			2,179				72
Economic Income (Loss) / Net Income (loss) attributable to Cowen Group, Inc. stockholders	$	18,537		$	(36,106	)	$	(17,569	)	$	—		$	(6,316	)		$	(23,885	)
(1) For the year ended December 31, 2012, the Company has reflected $10.2 million of investment income and related compensation expense of $3.4 million within the broker-dealer segment in proportion to its capital.
	Year Ended December 31, 2011
										Adjustments
	Alternative			Broker-Dealer (1)			Total			Funds			Other				US GAAP
	Investment						Economic Income/(Loss)			Consolidation			Adjustments
	(dollars in thousands)
Revenues
Investment banking	$	—		$	50,976		$	50,976		$	—		$	—			$	50,976
Brokerage	—			99,611			99,611			—			—				99,611
Management fees	67,309			—			67,309			(1,809		)	(13,034		)	(a)	52,466
Incentive income	10,366			—			10,366			—			(7,101		)	(a)	3,265
Investment Income	33,599			7,748			41,347			—			(41,347		)	(c)	—
Interest and dividends	—			—			—			—			22,306			(c)	22,306
Reimbursement from affiliates	—			—			—			(280		)	4,602			(b)	4,322
Other revenue	622			(7		)	615			—			968			(c)	1,583
Consolidated Funds revenues	—			—			—			749			—				749
Total revenues	111,896			158,328			270,224			(1,340		)	(33,606		)		235,278
Expenses
Employee compensation and benefits	46,757			145,801			192,558			—			11,209				203,767
Interest and dividends	184			551			735			—			8,498			(c)	9,233
Non-compensation expenses—Fixed	33,954			69,227			103,181			—			(103,181		)	(c)(d)	—
Non-compensation expenses—Variable	17,085			24,412			41,497			—			(41,497		)	(c)(d)	—
Non-compensation expenses	—			—			—			—			152,722			(c)(d)	152,722
Goodwill impairment	—			—			—			—			7,151			(h)	7,151
Reimbursement from affiliates	(4,602		)	—			(4,602		)	—			4,602			(b)	—
Consolidated Funds expenses	—			—			—			2,782			—				2,782
Total expenses	93,378			239,991			333,369			2,782			39,504				375,655
Other income (loss)
Net gains (losses) on securities, derivatives and other investments	—			—			—			—			15,128			(c)	15,128
Bargain purchase gain	—			—			—			—			22,244			(f)	22,244
Consolidated Funds net gains (losses)	—			—			—			2,947			1,448				4,395
Total other income (loss)	—			—			—			2,947			38,820				41,767
Income (loss) before income taxes and non-controlling interests	18,518			(81,663		)	(63,145		)	(1,175		)	(34,290		)		(98,610		)
Income taxes expense / (benefit)	—			—			—			—			(20,073		)	(b)	(20,073		)
Economic Income (Loss) / Net income (loss) before non-controlling interests	18,518			(81,663		)	(63,145		)	(1,175		)	(14,217		)		(78,537		)
Net income (loss) from discontinued operations, net of tax	—			—			—			—			(23,646		)	(g)	(23,646		)
(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	(8,292		)	—			(8,292		)	1,175			1,290				(5,827		)
Economic Income (Loss) / Net income (loss) attributable to Cowen Group, Inc. stockholders	$	10,226		$	(81,663	)	$	(71,437	)	$	—		$	(36,573	)		$	(108,010	)
(1) For the year ended December 31, 2011, the Company has reflected $5.6 million of investment income and related compensation expense of $1.8 million within the broker-dealer segment in proportion to its capital.
The following is a summary of the adjustments made to US GAAP net income (loss) for the segment to arrive at
Economic Income (Loss):
Funds Consolidation: The impacts of consolidation and the related elimination entries of the Consolidated Funds are not included in Economic Income (Loss). Adjustments to reconcile to US GAAP net income (loss) include elimination of incentive income and management fees earned from the Consolidated Funds and addition of fund expenses excluding management fees paid, fund revenues and investment income (loss).
Other Adjustments:
(a)     Economic Income (Loss) recognizes revenues (i) net of distribution fees paid to agents and (ii) our proportionate share
of management and incentive fees of certain real estate operating entities and the activist business.
(b)    Economic Income (Loss) excludes income taxes as management does not consider this item when evaluating the
performance of the segment. Also, reimbursement from affiliates is shown as a reduction of Economic Income
expenses, but is included as a part of revenues under US GAAP.
(c)     Economic Income (Loss) recognizes Company income from proprietary trading net of related expenses.
(d)     Economic Income (Loss) recognizes the Company's proportionate share of expenses for certain real estate and other
operating entities for which the investments are recorded under the equity method of accounting for investments.
(e)    Economic Income (Loss) recognizes stock borrow/loan activity and other brokerage dividends as brokerage revenue.
(f)    Economic Income (Loss) excludes the bargain purchase gain which resulted from the LaBranche acquisition.
(g)    Economic Income (Loss) excludes discontinued operations.
(h)    Economic Income (Loss) excludes goodwill impairment.
For the years ended December 31, 2013, 2012, and 2011, there was no one fund or other customer which represented more than 10% of the Company's total revenues.

Regulatory_Requirements

Regulatory Requirements	12 Months Ended
	Dec. 31, 2013
Brokers and Dealers [Abstract]	'
Regulatory Requirements	'
	Regulatory Requirements
	As registered broker-dealers, Cowen and Company, ATM Execution (formerly known as Cowen Capital LLC), ATM USA, and Cowen Equity Finance are subject to the SEC's Uniform Net Capital Rule 15c3-1 (the “Rule”), which requires the maintenance of minimum net capital. Under the alternative method permitted by the Rule, Cowen and Company's minimum net capital requirement, as defined, is $1.0 million. Under the alternative method, ATM Execution, ATM USA and Cowen Equity Finance are each required to maintain minimum net capital, as defined, equal to $250,000. The broker-dealers are not permitted to withdraw equity if certain minimum net capital requirements are not met. As of December 31, 2013, Cowen and Company had total net capital of approximately $36.4 million, which was approximately $35.4 million in excess of its minimum net capital requirement of $1.0 million. As of December 31, 2013, ATM Execution had total net capital of approximately $2.7 million, which was approximately $2.4 million in excess of its minimum net capital requirement of $250,000. As of December 31, 2013, ATM USA had total net capital of approximately $1.2 million, which was approximately $0.9 million in excess of its minimum net capital requirement of $250,000. As of December 31, 2013, Cowen Equity Finance had total net capital of approximately $12.0 million which was approximately $11.7 million in excess of its minimum net capital requirement of $250,000.
	Cowen and Company and ATM Execution are exempt from the provisions of Rule 15c3-3 under the Securities Exchange Act of 1934 as their activities are limited to those set forth in the conditions for exemption appearing in paragraph (k)(2)(ii) of the Rule. Similarly, ATM USA and Cowen Equity Finance are exempt from the provisions of Rule 15c3-3 under (k)(2)(i).
	Proprietary accounts of introducing brokers (“PAIB”) held at the clearing broker are considered allowable assets for net capital purposes, pursuant to agreements between Cowen and Company and ATM Execution and the clearing broker, which require, among other things, that the clearing broker performs computations for PAIB and segregates certain balances on behalf of Cowen and Company and ATM Execution, if applicable.
	Ramius UK Ltd. ("Ramius UK") and Cowen International Limited ("CIL") are subject to the capital requirements of the Financial Conduct Authority (“FCA”) of the UK. Financial Resources, as defined, must exceed the requirement of the FCA. As of December 31, 2013, Ramius UK's Financial Resources of $0.35 million exceeded its minimum requirement of $0.18 million by $0.17 million. As of December 31, 2013, CIL's Financial Resources of $4.4 million exceeded its minimum requirement of $2.2 million by $2.2 million.
	Cowen and Company (Asia) Limited (“CCAL”) is subject to the financial resources requirements of the Securities and Futures Commission (“SFC”) of Hong Kong. Financial Resources, as defined, must exceed the Total Financial Resources requirement of the SFC. As of December 31, 2013, CCAL's Financial Resources of $1.1 million exceeded the minimum requirement of $0.4 million by $0.7 million.

Related_Party_Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2013
Related Party Transactions [Abstract]	'
Related Party Transactions	'
	Related Party Transactions
	The Company acts as managing member, general partner and/or investment manager to most of the Company's alternative asset management products, HealthCare Royalty Management, LLC, and the HealthCare Royalty Partners funds, and certain managed accounts. Management fees and incentive income are primarily earned from affiliated entities. Fees receivable primarily represents the management fees and incentive income owed to the Company from these related funds and certain affiliated managed accounts. As of December 31, 2013 and 2012, $18.9 million and $13.6 million, respectively, included in fees receivable are earned from related parties.
	The Company may, at its discretion, reimburse certain fees charged to the funds that it manages to avoid duplication of fees when such funds have an underlying investment in another affiliated investment fund. For the years ended December 31, 2013, 2012, and 2011, the Company reimbursed the funds it manages $1.7 million, $1.5 million, and $1.6 million, respectively, which were recorded net in management fees and incentive income in the accompanying consolidated statements of operations. As of December 31, 2013 and 2012, related amounts still payable were $1.7 million and $1.7 million, respectively, and were reflected in fees payable in the accompanying consolidated statements of financial condition.
	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 consolidated statements of financial condition. As of December 31, 2013 and 2012, loans to employees of $6.0 million and $5.1 million, respectively, were included in due from related parties on the consolidated statements of financial condition. Of these amounts $3.8 million and $2.3 million, respectively, are related to forgivable loans. These forgivable loans provide for a cash payment up-front to employees, with the amount due back to the Company forgiven over a vesting period.  An employee that voluntarily ceases employment, or is terminated with cause, is generally required to pay back to the Company any unvested forgivable loans granted to them.  The forgivable loans are recorded as an asset to the Company on the date of grant and payment, and then amortized to compensation expense on a straight-line basis over the vesting period.  The vesting period on forgivable loans is generally one to three years. The Company recorded compensation expense of $3.2 million, $1.9 million, and $1.8 million, for the years ended December 31, 2013, 2012, and 2011, respectively. This expense is included in employee compensation and benefits in the consolidated statement of operations. For the years ended December 31, 2013, 2012, and 2011, the interest income was insignificant for all loans and advances. The remaining balance included in due from related parties primarily relates to amounts due to the Company from affiliated funds and real estate entities due to expenses paid on their behalf.
	In April 2011, the Company entered into a credit agreement with Starboard Value LP (see Note 6), whereby the Company can loan up to $3.0 million to Starboard Value LP at an interest rate of LIBOR plus 3.75% (payable quarterly) with a maturity of March 30, 2014. As of December 31, 2013, $1.5 million is included in due from related parties in the accompanying consolidated statement of financial condition. For the year ended December 31, 2013, interest charged for this loan was $0.1 million. For the years ended December 31, 2012 and 2011, interest charged for this loan was insignificant.
	Included in due to related parties is approximately $0.4 million and $0.4 million as of December 31, 2013 and 2012, 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.

Guarantees_and_OffBalance_Shee

Guarantees and Off-Balance Sheet Arrangements	12 Months Ended
	Dec. 31, 2013
Guarantees [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 and 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 consolidated financial statements for these indemnifications.
	The Company is a member of various securities exchanges. Under the standard membership agreements, members are required to guarantee the performance of other members and, accordingly, if another member becomes unable to satisfy its obligations to the exchange, all other members would be required to meet the shortfall. The Company's liability under these arrangements is not quantifiable and could exceed the cash and securities it has posted as collateral. However, management believes that the potential for the Company to be required to make payments under these arrangements is remote. Accordingly, no contingent liability is recorded in the accompanying consolidated statements of financial condition for these arrangements.
	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 consolidated financial statements for these indemnifications.
	Through the Company's securities lending program (see Note 6(a)), the Company can borrow and lend customers' securities, via custodial and non-custodial arrangements, to third parties. As part of this program, the Company provides a guarantee in an aggregate amount of $150.0 million to counterparties of the securities lending agreements, which protects the lender against the failure of the third-party borrower to return the lent securities in the event the Company did not obtain sufficient collateral. To minimize its liability under these indemnification agreements, the Company obtains cash collateral with a value exceeding 100% of the market value of the securities on loan from the borrower. Collateral is marked to market daily to assure that collateralization is adequate. Additional collateral is called from the borrower if a shortfall exists, or collateral may be released to the borrower in the event of overcollateralization. If a borrower defaults, the Company would use the collateral held to purchase replacement securities in the market or to credit the lending customer with the cash equivalent thereof.
	In conjunction with the acquisition of Cowen Securities (See Note 2) the Company has agreed to guarantee loans which were issued to employees of Cowen Securities by a third-party bank prior to the acquisition. The value of these loans at December 31, 2013 was $2.5 million.
	Off-Balance Sheet Arrangements
	The Company has no material off-balance sheet arrangements as of December 31, 2013 and 2012. However, through indemnification provisions in the clearing agreement, 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.
	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.

Subsequent_Events

Subsequent Events	12 Months Ended
	Dec. 31, 2013
Subsequent Events [Abstract]	'
Subsequent Events	'
	Subsequent Events
	In January 2014, the Company entered into a lease for data storage and data backup equipment with a term of 5 years and total cost of $5.0 million.
	In January 2014, the Company entered into a lease for a plane with a term of 5.5 years with a total cost of $6.9 million. The monthly payments under the new lease are approximately $40,000 less than the monthly payments for the previous lease which expired in January 2014 (See Note 14).
	On February 26 2014, the Company's Board of Directors approved a $10 million increase in the Company's share repurchase program (See Note 21).
	The Company has evaluated events through March 3, 2014 which is the date the consolidated financial statements were available to be issued and has determined that there were no additional subsequent events requiring adjustment or disclosure in the consolidated financial statements.

Supplemental_Financial_Informa

Supplemental Financial Information	12 Months Ended
	Dec. 31, 2013
Supplemental Financial Information [Abstract]	'
Quarterly Financial Information [Text Block]	'
	Supplemental Financial Information
	The following table presents unaudited quarterly results of operations for 2013 and 2012. These quarterly results reflect all normal recurring adjustments that are, in the opinion of management, necessary for a fair presentation of the results. Revenues and net income (loss) can vary significantly from quarter to quarter due to the nature of the Company's business activities.
	Cowen Group, Inc.
	Quarterly Financial Information (Unaudited)
		Quarter Ended
		March 31, 2013			June 30, 2013			September 30, 2013			December 31, 2013
		(in thousands)
	Total revenues	$	67,241		$	81,207		$	81,360		$	97,438
	Net Income (loss) before income taxes	1,095			3,506			8,324			5,372
	Income tax expense (benefit)	176			158			(46		)	169
	Net income (loss) from continuing operations	919			3,348			8,370			5,203
	Net Income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	3,495			2,255			4,759			2,684
	Net income (loss) attributable to Cowen Group, Inc. stockholders	$	(2,576	)	$	1,093		$	3,611		$	2,519
	Earnings (loss) per share:
	Basic	$	(0.02	)	$	0.01		$	0.03		$	0.02
	Diluted	$	(0.02	)	$	0.01		$	0.03		$	0.02
	Weighted average number of common shares:
	Basic	113,798			117,235			118,359			117,514
	Diluted	113,798			120,901			122,708			123,573
		Quarter Ended
		31-Mar-12			30-Jun-12			30-Sep-12			31-Dec-12
		(in thousands)
	Total revenues	$	57,480		$	59,470		$	57,598		$	65,932
	Net Income (loss) before income taxes	6,378			(10,189		)	(11,455		)	(8,243		)
	Income tax expense (benefit)	142			191			163			(48		)
	Net income (loss) from continuing operations	6,236			(10,380		)	(11,618		)	(8,195		)
	Net Income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	2,241			(2,434		)	(1,033		)	1,154
	Net income (loss) attributable to Cowen Group, Inc. stockholders	$	3,995		$	(7,946	)	$	(10,585	)	$	(9,349	)
	Earnings (loss) per share:
	Basic	$	0.03		$	(0.07	)	$	(0.09	)	$	(0.08	)
	Diluted	$	0.03		$	(0.07	)	$	(0.09	)	$	(0.08	)
	Weighted average number of common shares:
	Basic	114,281			114,561			114,989			113,939
	Diluted	115,663			114,561			114,989			113,939

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Basis of presentation	'
	Basis of presentation
	These consolidated financial statements are prepared in accordance with US GAAP as promulgated by the Financial Accounting Standards Board ("FASB") through Accounting Standards Codification 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 substantive, controlling general partner interest. All material intercompany transactions and balances have been eliminated on consolidation. Certain fund entities that are consolidated in these accompanying consolidated financial statements, as further discussed below, are not subject to the consolidation provisions with respect to their own controlled investments pursuant to their specialized accounting.
	The Company serves as the managing member/general partner and/or investment manager to affiliated fund entities which it sponsors and manages. Funds in which the Company has a controlling financial interest are consolidated with the Company pursuant to US GAAP as described below. Consequently, the Company's consolidated financial statements reflect the assets, liabilities, income and expenses of these funds on a gross basis. The ownership interests in these funds that are not owned by the Company are reflected as redeemable non-controlling interests in consolidated subsidiaries in the accompanying consolidated financial statements. The management fees and incentive income earned by the Company from these funds are eliminated in consolidation.
Principles of consolidation	'
	Principles of consolidation
	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 and (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. VOEs are consolidated in accordance with US GAAP.
	Under US GAAP, the usual condition for a controlling financial interest in a VOE is ownership of a majority voting interest. Accordingly, the Company consolidates VOEs in which it owns a majority of the entity's voting shares or units. US GAAP also provides that a general partner of a limited partnership (or a managing member, in the case of a limited liability company) is presumed to control the partnership, and thus should consolidate it, unless a simple majority of the limited partners has the right to remove the general partner without cause or to terminate the partnership. In accordance with these standards, the Company presently consolidates eight entities deemed to be VOEs for which it acts as the general partner and investment manager.
	As of December 31, 2013 and 2012, the Company consolidates the following funds: Ramius Enterprise LP (“Enterprise LP”), Ramius Multi‑Strategy Master FOF LP (“Multi‑Strat Master FOF”), Ramius Vintage Multi‑Strategy Master FOF LP (“Vintage Master FOF”), Ramius Levered Multi‑Strategy FOF LP (“Levered FOF”), and (effective May 1, 2013) Ramius Merger Fund LLC (the "Merger Fund") (collectively the "Consolidated Funds"). RTS Global 3X was consolidated as of December 31, 2012 but was liquidated on March 31, 2013.
	The Company also consolidates three investment companies; RCG Linkem II LLC, formed to make an investment in a wireless broadband communication provider in Italy, Ramius Co-Investment I LLC and Ramius Co-Investment II LLC, which were both formed to make investments in biomedical companies that develop innovative gene therapies for severe genetic disorders. The Company determined that RCG Linkem II, LLC, Ramius Co-Investment I LLC and Ramius Co-Investment II LLC are VOE's due to its controlling equity interests held through the managing member and/or affiliates and control exercised by the managing member who is not subject to substantive removal rights.
	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.
	However, the FASB has deferred the application of the revised consolidation model for VIEs that meet the following conditions: (a) the entity has all the attributes of an investment company as defined under AICPA Audit and Accounting Guide, Investment Companies, or does not have all the attributes of an investment company but is an entity for which it is acceptable based on industry practice to apply measurement principles that are consistent with investment companies, (b) the reporting entity does not have explicit or implicit obligations to fund any losses of the entity that could potentially be significant to the entity, and (c) the entity is not a securitization entity, asset‑backed financing entity or an entity that was formerly considered a qualifying special‑purpose entity. The Company's involvement with its funds is such that all three of the above conditions are met for substantially all of the funds managed by the Company. Where the VIEs have qualified for the deferral, the analysis is based on previous consolidation rules. These rules require an analysis to (a) determine whether an entity in which the Company holds a variable interest is a variable interest entity and (b) whether the Company's involvement, through holding interests directly or indirectly in the entity or contractually through other variable interests (e.g., management and performance related fees), would be expected to absorb a majority of the VIE's expected losses, receive a majority of the VIEs expected residual returns, or both. If these conditions are met, the Company is considered to be the primary beneficiary of the VIE and thus is required to consolidate it.
	The Company reconsiders whether it is the primary beneficiary of a VIE by performing a periodic qualitative and/or quantitative analysis of the VIE that includes a review of, among other things, its capital structure, contractual agreements between the Company and the VIE, the economic interests that create or absorb variability, related party relationships and the design of the VIE. As of December 31, 2013, the Company consolidates three VIEs and as of December 31, 2012 the Company does not consolidate any VIEs. As of December 31, 2013, the total net assets of the consolidated VIEs are $8.2 million. The VIEs act as managing members/general partners and/or investment managers to affiliated fund entities which they sponsor and/or manage. The VIEs are financed through their operations and/or loan agreements with the Company.
	As of December 31, 2013 and December 31, 2012, the Company holds a variable interest in Ramius Enterprise Master Fund Ltd (“Enterprise Master”) through one of its Consolidated Funds, Enterprise LP and as of December 31, 2013 the Company holds a variable interest in Ramius Merger Master Fund Ltd through one of its Consolidated Funds, Merger Fund, (the “Unconsolidated Master Funds”). Investment companies, which account for their investments under the specialized industry accounting guidance for investment companies prescribed under US GAAP, are not subject to the consolidation provisions for their investments. Therefore, the Company has not consolidated the Unconsolidated Master Funds.
	In the ordinary course of business, the Company also sponsors various other entities that it has determined to be VIEs. These VIEs are primarily funds and real estate entities for which the Company serves as the general partner, managing member and/or investment manager with decision-making rights.
	The Company does not consolidate any of these funds or real estate entities that are VIEs as it has concluded that it is not the primary beneficiary in each instance. 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's involvement with funds and real estate entities that are unconsolidated VIEs is limited to providing investment management services in exchange for management fees and incentive income. Although the Company may advance amounts and pay certain expenses on behalf of the funds and real estate entities 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 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 consolidated statements of operations.
	The Company evaluates for impairment its equity method investments 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, apply the equity method of accounting or account for an investment under the cost method, the Company accounts for all securities which are bought and held principally for the purpose of selling them in the near term as trading securities in accordance with US GAAP, at fair value with unrealized gains (losses) resulting from changes in fair value reflected within net gains (losses) on securities, derivatives and other investments in the consolidated statements of operations.
	Retention of Specialized Accounting—The Consolidated Funds are investment companies and apply specialized industry accounting for investment companies. The Company has retained this specialized accounting for these funds pursuant to US GAAP. The Company reports its investments on the 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 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”), ATM Execution (formerly known as Cowen Capital LLC), ATM USA, LLC, and Cowen Equity Finance LP, apply the specialized industry accounting for brokers and dealers in securities also prescribed under US GAAP. The Company also retains specialized accounting in consolidation.
Use of estimates	'
	Use of estimates
	The preparation of the accompanying 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 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. Certain reclassifications have been made to prior period amounts in order to conform with current period presentation.
Cash and cash equivalents	'
	Cash and cash equivalents
	The Company considers investments in money market funds and other highly liquid investments with original maturities of three months or less which are deposited with a bank or prime broker to be cash equivalents. Cash and cash equivalents held at Consolidated Funds, although not legally restricted, are not available to fund the general liquidity needs of the Company. The Company is also exposed to credit risk as a result of cash being held at several banks.
Valuation of investments and derivative contracts	'
	Valuation of investments and derivative contracts
	US GAAP establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (level 1 measurements) and the lowest priority to unobservable inputs (level 3 measurements). The three levels of the fair value hierarchy are as follows:
	Level 1 Inputs that reflect unadjusted quoted prices in active markets for identical assets or liabilities that the Company has
	the ability to access at the measurement date;
	Level 2     Inputs other than quoted prices that are observable for the asset or liability either directly or indirectly, including
	inputs in markets that are not considered to be active; and
	Level 3 Fair value is determined based on pricing inputs that are unobservable and includes situations where there is little,
	if any, market activity for the asset or liability. The determination of fair value for assets and liabilities in this
	category requires significant management judgment or estimation.
	Inputs are used in applying the various valuation techniques and broadly refer to the assumptions that market participants use to make valuation decisions, including assumptions about risk. Inputs may include price information, volatility statistics, specific and broad credit data, liquidity statistics, and other factors. A financial instrument's level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. However, the determination of what constitutes “observable” requires significant judgment by the Company. The Company considers observable data to be that market data which is readily available, regularly distributed or updated, reliable and verifiable, not proprietary, and provided by independent sources that are actively involved in the relevant market. The categorization of a financial instrument within the hierarchy is based upon the pricing transparency of the instrument and does not necessarily correspond to the Company's perceived risk of that instrument.
	The Company and its operating subsidiaries act as the manager for the Consolidated Funds. Both the Company and the Consolidated Funds hold certain investments which are valued by the Company, acting as the investment manager. The fair value of these investments is generally estimated based on proprietary models developed by the Company, which include discounted cash flow analysis, public market comparables, and other techniques and may be based, at least in part, on independently sourced market information. The material estimates and assumptions used in these models include the timing and expected amount of cash flows, the appropriateness of discount rates used, and, in some cases, the ability to execute, timing of, and estimated proceeds from expected financings. Significant judgment and estimation goes into 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 its investments through Ramius Co-Investment I LLC (formerly known as Cowen Bluebird LLC), Ramius Co-Investment II LLC (formerly known as RCG Ultragenex Holdings LLC) and certain investments it holds though 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 whose values are based on quoted market prices in active markets for identical assets, and are therefore classified in level 1 of the fair value hierarchy, include active listed equities, certain U.S. government and sovereign obligations, ETF's and certain money market securities. The Company does not adjust the quoted price for such instruments, even in situations where the Company holds a large position and a sale could reasonably impact the quoted price.
	Certain positions for which trading activity may not be readily visible, consisting primarily of convertible debt, corporate debt and loans, are stated at fair value and classified within level 2. The estimated fair values assigned by management are determined in good faith and are based on available information considering, trading activity, broker quotes, quotations provided by published pricing services, counterparties and other market participants, and pricing models using quoted inputs, and do not necessarily represent the amounts which might ultimately be realized. As level 2 investments include positions that are not always traded in active markets and/or are subject to transfer restrictions, valuations may be adjusted to reflect illiquidity and/or non-transferability.
	Derivative contracts—Derivative contracts can be exchange-traded or privately negotiated over-the-counter (“OTC”). Exchange-traded derivatives, such as futures contracts and exchange-traded option contracts, are typically classified within level 1 or level 2 of the fair value hierarchy depending on whether or not they are deemed to be actively traded. OTC derivatives, such as generic forwards, swaps and options, have inputs which can generally be corroborated by market data and are therefore classified within level 2. Futures and currency forwards are included within other assets on the accompanying consolidated statements of financial condition and all other derivatives are included within securities owned, at fair value on the accompanying consolidated statements of financial condition.
	Other investments—Other investments consist primarily of portfolio funds, real estate investments and equity method investments, which are valued as follows:
	i.	Portfolio funds—Portfolio funds (“Portfolio Funds”) include interests in funds and investment companies managed by the Company or its affiliates. The Company follows US GAAP regarding fair value measurements and disclosures relating to investments in certain entities that calculate net asset value (“NAV”) per share (or its equivalent). The guidance permits, as a practical expedient, an entity holding investments in certain entities that either are investment companies as defined by the AICPA Audit and Accounting Guide, Investment Companies, or have attributes similar to an investment company, and calculate net asset value 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.
	The Company categorizes its investments in Portfolio Funds within the fair value hierarchy dependent on its ability to redeem the investment. If the Company has the ability to redeem its investment at NAV at the measurement date or within the near term, the Portfolio Fund is categorized as a level 2 investment within the fair value hierarchy. If the Company does not know when it will have the ability to redeem its investment or cannot do so in the near term, the Portfolio Fund is categorized as a level 3 investment within the fair value hierarchy. See Notes 6 and 7 for further details of the Company's investments in Portfolio Funds.
	ii.	Real estate investments—Real estate investments are valued at fair value. The fair value of real estate investments are 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.
	The Company also reflects its real estate equity investments net of investment level financing. Valuation adjustments attributable to underlying financing arrangements are considered in the real estate equity valuation based on amounts at which the financing liabilities could be transferred to market participants at the measurement date.
	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 a level 3 investment 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.
Due from / due to related parties	'
	Due from/due to related parties
	The Company may advance amounts and pay certain expenses on behalf of employees of the Company or other affiliates of the Company. These amounts settle in the ordinary course of business. Such amounts are included in due from and due to related parties, respectively, on the accompanying consolidated statements of financial condition.
Receivable from and payable to brokers	'
	Receivable from and payable to brokers
	Receivable from and payable to brokers, includes cash held at clearing brokers, amounts receivable or payable for unsettled transactions, monies borrowed and proceeds from short sales equal to the fair value of securities sold, but not yet purchased. Pursuant to the Company's prime broker agreements, these balances are presented net (assets less liabilities) across balances with the same broker.
Securities borrowed and securities loaned and repurchase agreements	'
	Securities borrowed and securities loaned
	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 statement of operations as interest income and interest expense. Securities borrowed transactions require the Company to deposit cash collateral with the lender. With respect to securities loaned, the Company receives cash collateral from the borrower. The initial collateral advanced or received approximates or is greater than the market value of securities borrowed or loaned. The Company monitors the market value of securities borrowed and loaned on a daily basis, with additional collateral obtained or returned, as necessary. Securities borrowed and loaned may also result in credit exposures for the Company in an event that the counterparties are unable to fulfill their contractual obligations. The Company minimizes its credit risk by continuously monitoring  its credit exposure and collateral values by demanding additional or returning excess collateral in accordance with the netting provisions available in the master securities lending contracts in place with the counterparties.
	Fees and interest received or paid are recorded in interest and dividend income and interest expense, respectively, on an accrual basis. In the case where the fair value basis of accounting is elected, any resulting change in fair value is reported in trading revenues. Accrued interest income and expense are recorded in the same manner as under the accrual method. At December 31, 2013 and 2012, the Company does not have any securities lending transactions for which fair value basis of accounting was elected.
	i.	Securities purchased under agreements to resell and securities sold under agreements to repurchase
	The Company uses securities purchased under agreements to resell and securities sold under agreements to repurchase (“Repurchase Agreements”) as part of its liquidity management activities and to support its trading and risk management activities. In particular, securities purchased and sold under Repurchase Agreements are used for short-term liquidity purposes. As of December 31, 2013 and 2012, Repurchase Agreements are secured predominantly by liquid corporate credit and/or government issued securities. The use of Repurchase Agreements will fluctuate with the Company's need to fund short term credit or obtain competitive short term credit financing. The Company's securities purchased under agreements to resell and securities sold under agreements to repurchase were transacted pursuant to agreements with one counterparty as of December 31, 2013 and multiple counterparties as of December 31, 2012.
	Collateral is valued daily and the Company and its counterparties may adjust the collateral or require additional collateral to be deposited when appropriate. Collateral held by counterparties may be sold or re-hypothecated by such counterparties, subject to certain limitations sometimes imposed by the Company and in accordance with the master netting agreements in place with the counterparty. Collateralized Repurchase Agreements may result in credit exposure in the event the counterparties to the transactions are unable to fulfill their contractual obligations. The Company minimizes the credit risk associated with this activity by monitoring credit exposure and collateral values, and by requiring additional collateral to be promptly deposited with or returned to the Company when deemed necessary.
Fixed assets	'
	Fixed Assets
	Fixed assets are stated at cost less accumulated depreciation or amortization. Leasehold improvements are amortized on a straight-line basis over the lesser of their useful life or lease term. When the Company commits to a plan to abandon fixed assets or leasehold improvements before the end of its original useful life, the estimated depreciation or amortization period is revised to reflect the shortened useful life of the asset. Other fixed assets are depreciated on a straight-line basis over their estimated useful lives.
	Asset	Depreciable Lives	Principal Method
	Telephone and computer equipment	3-5 years	Straight-line
	Computer software	3-5 years	Straight-line
	Furniture and fixtures	3-8 years	Straight-line
	Leasehold improvements	1-10 years	Straight-line
	Capitalized lease asset	5 years	Straight-line
Goodwill and intangible assets	'
	Goodwill and intangible assets
	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, the Company tests goodwill for impairment on an annual basis, at December 31st each year, or at an interim period if events or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount. Under US GAAP, the Company tests goodwill for impairment by assessing the qualitative factors including, macroeconomic environment, industry and market specific conditions, financial performance and events specific to the reporting unit to determine whether it is more likely than not that the fair value of the reporting unit is less than its carrying amount. Based on the results of the qualitative assessment the Company performs the two-step goodwill impairment test. The first step 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 the fair value, there is an indication that the related goodwill might be impaired and the step two is performed to measure the amount of impairment, if any.
	The second step of the goodwill impairment test compares the implied fair value of the reporting unit's goodwill with its carrying amount to measure the amount of impairment, if any. The implied fair value of goodwill is determined in the same manner as the amount of goodwill recognized in a business combination. In other words, the estimated fair value of the reporting unit is allocated to all of its assets and liabilities (including any unrecognized intangible assets) as if the reporting unit had been acquired in a business combination and the fair value of the reporting unit was the purchase price paid. If the carrying amount of the reporting unit goodwill exceeds the implied fair value of that goodwill, an impairment is recognized in an amount equal to that excess. Goodwill impairment tests involve significant judgment in determining the estimates of future cash flows, discount rates, economic forecast and other assumptions which are then used in acceptable valuation techniques, such as the market approach (earning and or transactions multiples) and / or income approach (discounted cash flow method). Changes in these estimates and assumptions could have a significant impact on the fair value and any resulting impairment of goodwill. See Note 10 for further discussion.
	Intangible assets with finite lives are amortized over their estimated average useful lives. The Company does not have any intangible assets deemed to have indefinite lives. Intangible assets are tested for potential impairment whenever events or changes in circumstances suggest that an asset or asset group's carrying value may not be fully recoverable. Similar to goodwill impairment test, an impairment loss, calculated as the difference between the estimated fair value and the carrying value of an asset or asset group, is recognized in the accompanying consolidated statements of operations if the sum of the estimated undiscounted cash flows relating to the asset or asset group is less than the corresponding carrying value.
Deferred rent	'
	Deferred rent
	Deferred rent primarily consists of step rent, allowances from landlords and valuing the Company's lease properties in accordance with US GAAP. Step rent represents the difference between actual operating lease payments due and straight-line rent expense, which is recorded by the Company over the term of the lease, including the build-out period. This amount is recorded as deferred rent in the early years of the lease, when cash payments are generally lower than straight-line rent expense, and reduced in the later years of the lease when payments begin to exceed the straight-line expense. Landlord allowances are generally comprised of amounts received and/or promised to the Company by landlords and may be received in the form of cash or free rent. These allowances are part of the negotiated terms of the lease. The Company records a receivable from the landlord and a deferred rent liability when the allowances are earned. This deferred rent is amortized into income (through lower rent expense) over the term (including the pre-opening build-out period) of the applicable lease, and the receivable is reduced as amounts are received from the landlord. Liabilities resulting from valuing the Company's leased properties acquired through business combinations are quantified by comparing the current fair value of the leased space to the current rental payments on the date of acquisition. Deferred rent, included in accounts payable, accrued expenses and other liabilities in the accompanying consolidated statements of financial condition, as of December 31, 2013 and 2012 is $14.6 million and $13.8 million, respectively.
Legal reserves	'
	Legal reserves
	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 reserve nor disclosure is required for losses that are deemed remote.
Capital withdrawals payable	'
	Capital withdrawals payable
	Capital withdrawals from the Consolidated Funds are recognized as liabilities, net of any incentive income, when the amount requested in the withdrawal notice represents an unconditional obligation at a specified or determined date (or dates) or upon an event certain to occur. This generally may occur either at the time of the receipt of the notice, or on the last day of a reporting period, depending on the nature of the request. As a result, withdrawals paid after the end of the year, but based upon year-end capital balances are reflected as liabilities at the balance sheet date.
Redeemable non-controlling interests in consolidated subsidiaries	'
	Redeemable non-controlling interests in consolidated subsidiaries
	Redeemable non-controlling interests represent the pro rata share of the book value of the financial positions and results of operations attributable to the other owners of the consolidated subsidiaries. Redeemable non-controlling interests related to Consolidated Funds are generally subject to annual, semi-annual or quarterly withdrawals or redemptions by investors in these funds, sometimes following the expiration of a specified period of time (generally one year), or may only be withdrawn subject to a redemption fee (generally ranging from 1% to 5%). Likewise, non-controlling interests related to certain other consolidated entities are generally subject to withdrawal, redemption, transfer or put/call rights that permit such non-controlling investors to withdraw from the entities on varying terms and conditions. Because these non-controlling interests are redeemable at the option of the non-controlling interests, they have been classified as temporary equity in the accompanying consolidated statements of financial condition. When redeemed amounts become legally payable to investors on a current basis, they are reclassified as a liability.
Treasury stock	'
	Treasury stock
	In accordance with the US GAAP relating to repurchases of an entity's own outstanding common stock, the Company records the purchases of stock held in treasury at cost and reports them separately as a deduction from total stockholders' equity on the accompanying consolidated statements of financial condition and changes in equity.
Comprehensive income	'
	Comprehensive income (loss)
	Comprehensive income (loss) consists of net income and other comprehensive income (loss). The Company's other comprehensive income (loss) is comprised of valuation adjustments to the Company's defined benefit plans and foreign currency cumulative translation adjustments.
Revenue recognition	'
	Revenue recognition
	The Company's principal sources of revenue are derived from two segments: an alternative investment segment and a broker-dealer segment, as more fully described below.
	Our alternative investment segment generates revenue through three principal sources: management fees, incentive income and investment income from the Company's own capital.
	Our broker-dealer segment generates revenue through two principal sources: investment banking and brokerage.
	Management fees
	The Company earns management fees from affiliated funds and certain managed accounts that it serves as the investment manager based on assets under management. The actual management fees received vary depending on distribution fees or fee splits paid to third parties either in connection with raising the assets or structuring the investment.
	Management fees are generally paid on a quarterly basis at the beginning of each quarter in arrears and are prorated for capital inflows and redemptions. While some investors may have separately negotiated fees, in general the management fees are as follows:
	•	Hedge Funds. Management fees for the Company's hedge funds are generally charged at an annual rate of up to 2% of assets under management. Management fees are generally calculated monthly based on assets under management at the end of each month before incentive income.
	•	Mutual Funds. Management fees for the Company’s mutual funds (Ramius Trading Strategies Managed Futures Fund, Ramius Event Driven Equity Fund, Ramius Dynamic Replication Fund and Ramius Strategic Volatility Fund) are generally charged at an annual rate of up to 1.60% of assets under management (subject to an overall expense cap of up to 2%).
	•	Alternative Solutions. Management fees for the Alternative Solutions business are generally charged at an annual rate of up to 2% of assets under management. Management fees are generally calculated monthly based on assets under management at the end of each month before incentive income or based on assets under management at the beginning of the month. Management fees earned from the Alternative Solutions business are based and initially calculated on estimated net asset values and actual fees ultimately earned could be impacted to the extent of any changes in these estimates.
	•	Real Estate. Management fees from the Company's real estate business are generally charged by their general partners at an annual rate from 0.75% to 1.50% of total capital commitments during the investment period and of invested capital or net asset value of the applicable fund after the investment period has ended. Management fees are typically paid to the general partners on a quarterly basis, at the beginning of the quarter in arrears, and are prorated for changes in capital commitments throughout the investment period and invested capital after the investment period. The general partners of the funds on the RCG Longview platform are owned jointly by the Company and third parties. Accordingly, the management fees (in addition to incentive income and investment income) generated by these real estate funds are split between the Company and the other general partners. Pursuant to US GAAP, these fees and other income received by the general partners that are accounted for under the equity method of accounting and are reflected under net gains (losses) on securities, derivatives and other investments in the consolidated statements of operations.
	•	HealthCare Royalty Partners. During the investment period (as defined in the management agreement of the HealthCare Royalty Partners funds), management fees for the funds advised by HealthCare Royalty Partners are generally charged at an annual rate of up to 2% of committed capital. After the investment period, management fees are generally charged at an annual rate of up to 2% of net asset value. Management fees for the HealthCare Royalty Partners funds are calculated on a quarterly basis. Accordingly, the management fees (in addition to incentive income and investment income) generated by these real estate funds are split between the Company and the other general partners. Pursuant to US GAAP, these fees and other income received by the general partners that are accounted for under the equity method of accounting and are reflected under net gains (losses) on securities, derivatives and other investments in the consolidated statements of operations.
	•	Ramius Trading Strategies. Management fees and platform fees for the Company's private commodity trading advisory business are generally charged at an annual rate of up to 1%. Management and platform fees are generally calculated monthly based on assets under management at the end of each month.
	•	Other. Prior to 2013, the Company also provided other investment advisory services. Other management fees were primarily earned from the Company's cash management business and ranged from annual rates of up to 0.20% of assets, based on the average daily balances of the assets under management. Since November 2012, the Company no longer offer cash management services.
	Incentive income
	The Company earns incentive income based on net profits (as defined in the respective investment management agreements) with respect to certain of the Company's funds and managed accounts, allocable for each fiscal year that exceeds cumulative unrecovered net losses, if any, that have been carried forward from prior years. For the products the Company offers, incentive income earned is typically up to 20% for hedge funds and up to 10% for alternative solutions products (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. Generally, incentive income on real estate funds is earned after the investor has received a full return of their invested capital, plus a preferred return. However, for certain real estate funds, the Company is entitled to receive incentive fees earlier, provided that the investors have received their preferred return on a current basis. These funds are subject to a potential clawback of these incentive fees upon the liquidation of the fund if the investor has not received a full return of its invested capital plus the preferred return thereon. Incentive income in the HealthCare Royalty Partners funds is earned only after investors receive a full return of their capital plus a preferred return.
	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 that investor until the accumulated net loss from prior periods is recovered, an arrangement commonly referred to as a “high-water mark.” The Company has elected to record incentive income revenue in accordance with “Method 2” of US GAAP. Under Method 2, the incentive income from the Company's funds and managed accounts for any period is based upon the net profits of those funds and managed accounts at the reporting date. Any incentive income recognized in the consolidated statement of operations may be subject to future reversal based on subsequent negative performance prior to the conclusion of the fiscal year, when all contingencies have been resolved.
	Carried interest in the real estate funds is subject to clawback to the extent that the carried interest actually distributed to date exceeds the amount due to the Company based on cumulative results. As such, the accrual for potential repayment of previously received carried interest, which is a component of accounts payable, accrued expenses and other liabilities, represents all amounts previously distributed to the Company, less an assumed tax liability, that would need to be repaid to certain real estate funds if these funds were to be liquidated based on the current fair value of the underlying funds' investments as of the reporting date. The actual clawback liability does not become realized until the end of a fund's life.
	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 small and mid-capitalization companies within the Company's target sectors of healthcare, technology, media and telecommunications, consumer, aerospace and defense, industrials, REITs and clean technology.
	Investment banking revenue consists of underwriting fees, strategic/financial advisory fees and private placement fees.
	•	Underwriting fees. The Company earns underwriting revenues in securities offerings in which the Company acts as an underwriter, such as initial public offerings, follow-on equity offerings, debt offerings, and convertible security offerings. Underwriting revenues include management fees, selling concessions and underwriting fees. Fee revenue relating to underwriting commitments is recorded 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; and (iii) the Company has been informed of the number of securities that it has been allotted.
	When the Company is not the lead manager for an underwriting transaction, management must estimate the Company's share of transaction-related expenses incurred by the lead manager in order to recognize revenue. Transaction-related expenses are deducted from the underwriting fee and therefore reduce the revenue the Company recognizes as co-manager. 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 revenues include success fees earned in connection with advising companies, principally in mergers and acquisitions and liability management transactions. The Company also earns fees for related advisory work such as providing fairness opinions. The Company records strategic advisory revenues when the services for the transactions are completed under the terms of each assignment or engagement and collection is reasonably assured. Expenses associated with such transactions are deferred until the related revenue is recognized or the engagement is otherwise concluded.
	•	Private placement fees. The Company earns agency placement fees in non-underwritten transactions such as private placements of debt and equity securities, including, private investment in public equity transactions (“PIPEs”) and registered direct offerings. The Company records private placement revenues when the services for the transactions are completed under the terms of each assignment or engagement and collection is reasonably assured. Expenses associated with such transactions are deferred until the related revenue is recognized or the engagement is otherwise concluded.
	Brokerage
	Brokerage revenue consists of commissions, principal transactions, net and equity research fees.
	•	Commissions. Commission revenue includes fees from executing client transactions. These fees are recognized on a trade date basis. 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. Commissions on soft dollar brokerage are recorded net of the related expenditures on an accrual basis. Commission revenues also includes fees from making algorithms available to clients. During the years ended December, 2013, 2012, and 2011, the Company earned $79.7 million, $63.0 million and $66.0 million of revenues from commissions, respectively.
	•	Principal transactions, net. Principal transaction, net revenue includes net trading gains and losses from the Company's market-making activities in over-the-counter equity securities, trading of convertible securities, and trading gains and losses on inventory and other firm positions, which include warrants previously received as part of investment banking transactions. Commissions associated with these transactions are also included herein. In certain cases, the Company provides liquidity to clients 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 very short duration. During the years ended December, 2013, 2012, and 2011, the Company earned $28.1 million, $22.5 million and $27.1 million of revenues from principal transactions, net, respectively.
	•	Equity research fees. Equity research fees are paid to the Company for providing equity research. Revenue is recognized once an arrangement exists, access to research has been provided, the fee amount is fixed or determinable, and collection is reasonably assured. During the years ended December, 2013, 2012, and 2011, the Company earned $6.8 million, $5.7 million and $6.5 million of revenues from equity research fees, respectively.
	Interest and dividends
	Interest and dividends are earned by the Company from various sources. The Company receives interest and dividends primarily from investments held by its Consolidated Funds and its brokerage balances from invested capital and from its security lending program. Interest is recognized on an accrual basis and interest income is recognized on the debt of those issuers that is deemed collectible. Interest income and expense includes premiums and discounts amortized and accreted on debt investments based on criteria determined by the Company using the effective yield method, which assumes the reinvestment of all interest payments. Dividends are recognized on the ex-dividend date.
	Reimbursement from affiliates
	The Company allocates, at its discretion, certain expenses incurred on behalf of its hedge fund, fund of funds and real estate businesses. These expenses relate to the administration of such subsidiaries and assets that the Company manages for its funds. In addition, pursuant to the funds' offering documents, the Company charges certain allowable expenses to the 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 funds. Such expenses that have been reimbursed at their actual costs are included in the accompanying 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.
	s.	I
Investment transactions and related income / expenses	'
	Investments transactions and related income/expenses
	Purchases and sales of securities, net of commissions, and 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, in the accompanying consolidated statements of operations.
Share-based compensation	'
	Share-based compensation
	The Company accounts for its share-based awards granted to individuals as payment for employee services in accordance with US GAAP and values such awards based on grant date fair value. Unearned compensation associated with share-based awards is amortized over the vesting period of the option or award. The Company estimates forfeiture for equity-based awards that are not expected to vest. See Note 15 for further information regarding the Company's share-based compensation plans.
Employee benefit plans	'
	Employee benefit plans
	The Company recognizes, in its accompanying consolidated statements of financial condition, the funded status of its defined benefit plans, measured as the difference between the fair value of the plan assets and the benefit obligation The Company recognizes changes in the funded status of a defined benefit plan within accumulated other comprehensive income (loss), net of tax, to the extent such changes are not recognized in earnings as components of periodic net benefit cost. See Note 16 for further information regarding the Company's defined benefit plans.
Leases	'
	Leases
	The Company leases certain facilities and equipment used in its operations. The Company evaluates and classifies its leases as operating or capital leases for financial reporting purposes. Assets held under capital leases are included in fixed assets. Operating lease expense is recorded on a straight-line basis over the lease term. Landlord incentives are recorded as deferred rent and amortized, as reductions to lease expense, on a straight-line basis over the life of the applicable lease.
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 bases 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.
	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 resident in foreign countries where tax filings generally have to be submitted on a stand‑alone basis. These subsidiaries are subject to tax in their respective countries and the Company is responsible for and, thus, reports all taxes incurred by these subsidiaries in the consolidated statement of operations. The countries where the Company owns subsidiaries and has tax filing obligations are the United Kingdom, Luxembourg, and Hong Kong. Income tax expense/(benefit) for the years ended December 31, 2011 includes deferred tax benefits following acquisitions of Luxembourg reinsurance companies (See Note 18).
	The taxable results of the Company’s U.S. operations are included in the consolidated income tax returns of Cowen Group, Inc. as well as stand‑alone state and local tax returns. The Company has subsidiaries that are resident in foreign countries where tax filings have to be submitted on a stand‑alone basis. These subsidiaries are subject to tax in their respective countries and the Company is responsible for and, thus, reports all taxes incurred by these subsidiaries. The countries where the Company owns subsidiaries that file tax returns are United Kingdom, Luxembourg, Gibraltar, and Hong Kong.
Foreign currency transactions	'
	Foreign currency transactions
	The Company consolidates certain foreign subsidiaries that have designated a foreign currency as their functional currency. For entities that have designated a foreign currency as their functional currency, assets and liabilities are translated into U.S. dollars based on current rates, which are the spot rates prevailing at the end of each statement of financial condition date, and revenues and expenses are translated at historical rates, which are the average rates for the relevant periods. The resulting translation gains and losses, and the tax effects of such gains and losses, are recorded in accumulated other comprehensive income (loss), a separate component of stockholders' equity.
	For subsidiaries that have designated the U.S. Dollar as their functional currency, securities and other assets and liabilities denominated in foreign currencies are translated into U.S. Dollar amounts at the date of valuation. Purchases and sales of securities and other assets and liabilities and the related income and expenses denominated in foreign currencies are translated into U.S. Dollar amounts on the respective dates of the transactions. The Company does not isolate that portion of the results of operations resulting from changes in foreign exchange rates on these balances from fluctuations arising from changes in market prices of securities and other assets/liabilities held or sold. Such fluctuations are included in the accompanying consolidated statements of operations as a component of net gains (losses) on securities, derivatives and other investments. Gains and losses primarily relating to foreign currency broker balances are included in net gains (losses) on foreign currency transactions in the accompanying consolidated statements of operations.
New accounting pronouncements	'
	New accounting pronouncements
	Recently issued accounting pronouncements
	In July 2013, the FASB issued guidance which was directed to eliminate the disparity in practice for the financial statement presentation of an unrecognized tax benefit when a net operating loss carry-forward, a similar tax loss, or a tax credit carry-forward exist. The guidance requires an entity to present the unrecognized tax benefit as a reduction to the deferred tax asset for a net operating loss carry-forward, a similar tax loss, or a tax credit carry-forward with certain exceptions. The guidance is effective prospectively for reporting periods beginning after December 15, 2013 for all unrecognized tax benefits that exist at the effective date. Early adoption and retrospective application is also permitted. The Company is currently evaluating the impact of this guidance on the Company's financial condition and results of operations.
	In June 2013, the FASB issued guidance which amended the scope, measurement and disclosure requirements for Financial Services - Investment Companies. The guidance among other things changed the definition and criteria used for the investment company assessment. The guidance also require investment companies to measure non-controlling ownership interest in other investment companies at fair value rather than using equity method of accounting and requires certain additional disclosures. The guidance is effective for reporting periods beginning after December 15, 2013. The Company is currently evaluating the impact of this guidance on the Company's financial condition and results of operations.
	In April 2013, the FASB issued guidance which improved and clarified the requirements as to when an entity should apply the liquidation basis of accounting and provides principles for the recognition and measurement of assets and liabilities. The guidance requires an entity to prepare its financial statements using liquidation basis of accounting when the liquidation is imminent and to present relevant information about entity's resources by measuring and presenting assets and liabilities at the amount of expected cash proceeds and / or settlement amounts. The guidance is effective prospectively for reporting periods beginning after December 15, 2013. The Company is currently evaluating the impact of this guidance on the Company's financial condition and the results of operations and its applicability on certain of its affiliated entities.
Earnings Per Share	'
	Diluted earnings per common share are calculated by adjusting the weighted average outstanding shares to assume conversion of all potentially dilutive nonvested restricted stock and stock options. The Company uses the treasury stock method to reflect the potential dilutive effect of the unvested restricted shares, restricted stock units and unexercised stock options and SAR's. In calculating the number of dilutive shares outstanding, the shares of common stock underlying unvested restricted shares and restricted stock units are assumed to have been delivered, and options are assumed to have been exercised, on the grant date. The assumed proceeds from the assumed vesting, delivery and exercising were calculated as the sum of (a) the amount of compensation cost attributed to future services and not yet recognized and (b) the amount of tax benefit that would be credited to additional paid-in capital assuming vesting and delivery of the restricted stock. The tax benefit is the amount resulting from a tax deduction for compensation in excess of compensation expense recognized for financial statement reporting purposes. All outstanding stock options were not included in the computation of diluted net income (loss) per common share for the years ended December 31, 2013, 2012 and 2011, respectively, as their inclusion would have been anti-dilutive.
Segment Reporting	'
	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.
	In general, Economic Income (Loss) is a pre-tax measure that (i) eliminates the impact of consolidation for consolidated funds, (ii) excludes equity award expense related to the November 2009 Ramius/Cowen transaction, and (iii) excludes certain other acquisition-related and/or reorganization expenses (See Note 2). In addition, Economic Income (Loss) revenues include investment income that represents the income the Company has earned in investing its own capital, including realized and unrealized gains and losses, interest and dividends, net of associated investment related expenses. For US GAAP purposes, these items are included in each of their respective line items. Economic Income (Loss) revenues also include management fees, incentive income and investment income earned through the Company's investment as a general partner in certain real estate entities and the Company's investment in the Value and Opportunity business. For US GAAP purposes, all of these items are recorded in other income (loss). In addition, Economic Income (Loss) expenses are reduced by reimbursement from affiliates, which for US GAAP purposes is presented gross as part of revenue.
	As further stated below, one major difference between Economic Income (Loss) and US GAAP net income (loss) is that Economic Income (Loss) presents the segments' results of operations without the impact resulting from the full consolidation of any of the Consolidated Funds. Consolidation of these funds results in including in income the pro rata share of the income or loss attributable to other owners of such entities which is reflected in net income (loss) attributable to redeemable non-controlling interest in consolidated subsidiaries in the accompanying consolidated statements of operations. This pro rata share has no effect on the overall financial performance for the alternative investment segment, as ultimately, this income or loss is not income or loss for the alternative investment segment itself. Included in Economic Income (Loss) is the actual pro rata share of the income or loss attributable to the Company as an investor in such entities, which is relevant in management making operating decisions and evaluating financial performance.

Acquisitions_Tables

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2013
Business Combinations [Abstract]	'
Schedule of Business Acquisitions, by Acquisition [Table Text Block]	'
	The following table summarizes the aggregate purchase price allocation of net tangible and intangible assets acquired during the year ended December 31, 2012:
		(dollars in thousands)
	Cash and cash equivalents	$	290
	Securities owned, at fair value	17
	Securities borrowed	527,854
	Receivable from brokers	15,682
	Fees receivable	751
	Intangibles	9,782
	Other assets	136
	Securities loaned	(543,369		)
	Compensation payable	(11		)
	Fees payable	(56		)
	Unfavorable lease liability	(91		)
	Accounts payable, accrued expenses and other liabilities	(700		)
	Total net assets acquired	10,285
	Non compete agreements	167
	Goodwill/(Bargain purchase gain) on transactions	8,517
	Total purchase price	$	18,969

Significant_Accounting_Policie2

Significant Accounting Policies Fixed assets (Tables)	12 Months Ended
	Dec. 31, 2013
Property, Plant and Equipment Useful Lives [Abstract]	'
Fixed Assets Depreciable Lives [Table Text Block]	'
	Asset	Depreciable Lives	Principal Method
	Telephone and computer equipment	3-5 years	Straight-line
	Computer software	3-5 years	Straight-line
	Furniture and fixtures	3-8 years	Straight-line
	Leasehold improvements	1-10 years	Straight-line
	Capitalized lease asset	5 years	Straight-line

Discontinued_Operations_Tables

Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2013
Discontinued Operations and Disposal Groups [Abstract]	'
Discontinued Operations	'
	The results of operations related to the Company's discontinued operations for the year ended December 31, 2011 are summarized below:
		For the Period June 28, 2011 through December 31, 2011
		(dollars in thousands)
	Total revenues, net of interest expense	$	2,899
	Loss from discontinued operations	(24,075		)
	Income tax expense/(benefit)	(429		)
	Loss from discontinued operations, net of taxes	(23,646		)

Investments_of_Operating_Entit1

Investments of Operating Entities and Consolidated Funds (Tables)	12 Months Ended
	Dec. 31, 2013
Investment Holdings [Line Items]	'
Gain (Loss) on Investments [Table Text Block]	'
	Net realized gains (losses) and net unrealized gains (losses) on investments and other transactions and on derivatives for Consolidated Funds for the years ended December 31, 2012, 2011 and 2010 were as follows:
		Year Ended December 31,
		2013				2012				2011
		(dollars in thousands)
	Consolidated Funds net gains (losses) on investments and other transactions:
	Net realized gains (losses) on investments and other transactions	$	6,050			$	(8,121	)		$	4,959
	Net unrealized gains (losses) on investments and other transactions	4,628				14,497				(34		)
	Consolidated Funds net gains (losses) on derivatives:
	Net realized gains (losses) on derivatives	$	521			$	915			$	(651	)
	Net unrealized gains (losses) on derivatives	(156		)		(38		)		68
Securities Borrowed and Securities Loaned Disclosure [Text Block]	'
	The following tables present the gross and net securities borrowing and lending agreements and the related offsetting amount, as of December 31, 2013 and 2012.
	As of December 31, 2013
		Gross amounts recognized				Gross amounts offset on the Consolidated Statements of Financial Condition				Net amounts included on the Consolidated Statements of Financial Condition				Amounts not offset on the consolidated balance sheet but eligible for offsetting upon counterparty default (b)				Net amounts
						(a)
		(dollars in thousands)
	Securities borrowed	$	927,773			$	—			$	927,773			$	927,773			$	—
	Securities loaned	918,577				—				918,577				918,577				—
	As of December 31, 2012
		Gross amounts recognized				Gross amounts offset on the Consolidated Statements of Financial Condition				Net amounts included on the Consolidated Statements of Financial Condition				Amounts not offset on the consolidated balance sheet but eligible for offsetting upon counterparty default (b)				Net amounts
						(a)
		(dollars in thousands)
	Securities borrowed	$	406,326			$	—			$	406,326			$	406,326			$	—
	Securities loaned	408,972				—				408,972				408,972				—
	(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.
Operating Entities	'
Investment Holdings [Line Items]	'
Marketable Securities	'
	As of December 31, 2013 and 2012, securities owned, at fair value consisted of the following:
		As of December 31,
		2013				2012
		(dollars in thousands)
	U.S. Government securities (a)	$	9			$	137,478
	Preferred stock	324				2,332
	Common stocks	176,939				259,292
	Convertible bonds (b)	5,958				6,202
	Corporate bonds (c)	121,372				193,078
	Options	9,698				20,546
	Warrants and rights	5,912				2,354
	Mutual funds	525				2,845
		$	320,737			$	624,127
	(a)	As of December 31, 2013, the maturity was April 2016 with an interest rate of 5.95%. As of December 31, 2012, maturities ranged from November 2013 to November 2022 and interest rates ranged between 0.25% and 5.95%.
	(b)	As of December 31, 2013, maturities ranged from May 2014 to October 2014 and interest rates ranged between 5.00% to 10.00%. As of December 31, 2012, maturities ranged from May 2014 to July 2014 with an interest rate of 5.00%.
	(c)	As of December 31, 2013, maturities ranged from January 2014 to February 2046 and interest rates ranged between 3.38% and 11.75%. As of December 31, 2012, maturities ranged from January 2013 to February 2041 and interest rates ranged between 3.09% and 12.50%.
Schedule of Other Investments	'
	As of December 31, 2013 and 2012, other investments consisted of the following:
		As of December 31,
		2013				2012
		(dollars in thousands)
	(1) Portfolio Funds, at fair value	$	71,051			$	55,898
	(2) Real estate investments, at fair value	2,088				1,864
	(3) Equity method investments	25,966				26,462
	(4) Lehman claims, at fair value	378				706
		$	99,483			$	84,930
Schedule of Other Investments, Portfolio Funds	'
	The Portfolio Funds, at fair value as of December 31, 2013 and 2012, included the following:
		As of December 31,
		2013				2012
		(dollars in thousands)
	HealthCare Royalty Partners (a)(*)	$	9,741			$	7,866
	HealthCare Royalty Partners II (a)(*)	4,961				6,415
	Orchard Square Partners Credit Fund LP (b)(*)	12,674				14,196
	Tapestry Investment Co PCC Ltd (c)	—				194
	Starboard Value and Opportunity Fund LP (d)(*)	17,495				15,706
	Formation 8 Partners Fund I (e)	2,788				1,500
	RCG LV Park Lane LLC (f)	678				708
	RCGL 12E13th LLC (g)	558				—
	RCG Longview Debt Fund V, L.P. (g)	11,979				—
	Other private investment (h)	7,772				7,826
	Other affiliated funds (i)(*)	2,405				1,487
		$	71,051			$	55,898
	* 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 19.
	(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)	Orchard Square Partners Credit Fund LP (formerly known as Ramius Global Credit Fund LP) has a quarterly redemption policy with a 60 day notice period and a 4% penalty on redemptions of investments of less than a year in duration.
	(c)	Tapestry Investment Company PCC Ltd had been fully liquidated at the manager's discretion.
	(d)	Starboard Value and Opportunity Fund LP permits quarterly withdrawals upon 90 days notice.
	(e)	Formation 8 Partners Fund I is a private equity fund which invests in equity of early stage and growth transformational information and energy technology companies. Distributions will be made when the underlying investments are liquidated.
	(f)	RCG LV Park Lane LLC  is a single purpose entity formed to participate in a joint venture which acquired, at a discount, the mortgage notes on a portfolio of multifamily real estate properties located in Birmingham, Alabama.  RCG LV Park Lane LLC is a private equity structure and therefore distributions will be made when the underlying investments are liquidated.
	(g)	RCGL 12E13th LLC and RCG Longview Debt Fund V, L.P. are real estate private equity structures and therefore distributions will be made when the underlying investments are liquidated.
	(h)	Other private investment represents the Company's closed end investment in a wireless broadband communication provider in Italy.
	(i)	The majority of these funds are affiliates of the Company or are managed by the Company and the investors can redeem from these funds as investments are liquidated.
Schedule of Equity Method Investments	'
	The following table summarizes equity method investments held by the Company:
		As of December 31,
		2013				2012
		(dollars in thousands)
	RCG Longview Debt Fund IV Management, LLC	$	1,533			$	1,954
	RCG Longview Debt Fund V Partners, LLC	1,497				—
	HealthCare Royalty GP, LLC	794				642
	HealthCare Royalty GP II, LLC	840				1,086
	HealthCare Royalty GP III, LLC	47				—
	CBOE Stock Exchange, LLC	1,351				2,058
	Starboard Value LP	14,263				12,757
	RCG Longview Partners, LLC	1,839				1,535
	RCG Longview Louisiana Manager, LLC	—				1,866
	RCG Urban American, LLC	316				1,380
	RCG Urban American Management, LLC	238				545
	RCG Longview Equity Management, LLC	292				285
	Urban American Real Estate Fund II, LLC	1,785				1,636
	RCG Kennedy House, LLC	502				377
	Other	669				341
		$	25,966			$	26,462
Schedule of Results of Operations, Equity Method Investments	'
	The summarized financial information for the Company's investments in investees is as follows:
	Other equity method investments	As of December 31,
		2013				2012
		(dollars in thousands)
	Assets	$	626,866			$	498,557
	Liabilities	226,138				20,170
	Equity	$	400,728			$	478,387
		Year Ended December 31,
		2013				2012				2011
		(dollars in thousands)
	Revenues	$	75,429			$	77,502			$	33,061
	Expenses	(69,893		)		(60,093		)		(45,335		)
	Net realized and unrealized gains (losses)	77,042				5,575				9,365
	Net Income	$	82,578			$	22,984			$	(2,909	)
Investments Sold, Not yet Purchased	'
	As of December 31, 2013 and 2012, securities sold, not yet purchased, at fair value consisted of the following:
		As of December 31,
		2013				2012
		(dollars in thousands)
	Common stocks	$	130,899			$	168,797
	Corporate bonds (a)	55				61
	Options	6,573				9,076
	Warrants and rights	—				3
		$	137,527			$	177,937
	(a)	As of December 31, 2013 and 2012, the maturity was January 2026 with an interest rate of 5.55%
Schedule of Securities Financing Transactions	'
	The following table represents the Company's securities purchased under agreements to resell and securities sold under agreements to repurchase as of December 31, 2013 and 2012:
		As of December 31, 2013
		(dollars in thousands)
	Securities sold under agreements to repurchase
	Agreements with Royal Bank of Canada bearing interest of 1.75% due June 2015 to November 2015	$	3,657
		$	3,657
		As of December 31, 2012
		(dollars in thousands)
	Securities sold under agreements to repurchase
	Agreements with Royal Bank of Canada bearing interest of 2.12% - 2.2% due January 31, 2013 to June 25, 2013	$	29,039
	Agreements with Barclays Capital Inc bearing interest of (0.05%) - 0.23% due January 1, 2013	136,906
		$	165,945
	The following tables present the gross and net repurchase agreements and the related offsetting amount, as of December 31, 2013 and 2012.
	As of December 31, 2013
		Gross amounts recognized				Gross amounts offset on the Consolidated Statements of Financial Condition				Net amounts included on the Consolidated Statements of Financial Condition				Amounts not offset on the consolidated balance sheet but eligible for offsetting upon counterparty default (b)				Net amounts
						(a)
		(dollars in thousands)
	Securities sold under agreements to repurchase	$	3,657			$	—			$	3,657			$	3,657			$	—
	As of December 31, 2012
		Gross amounts recognized				Gross amounts offset on the Consolidated Statements of Financial Condition				Net amounts included on the Consolidated Statements of Financial Condition				Amounts not offset on the consolidated balance sheet but eligible for offsetting upon counterparty default (b)				Net amounts
						(a)
		(dollars in thousands)
	Securities sold under agreements to repurchase	$	165,945			$	—			$	165,945			$	165,945			$	—
	(a)	Includes financial instruments subject to enforceable master netting provisions that are permitted to be offset to the extent an event of default has occurred.
	(b)	Includes the amount of collateral held/posted.
Consolidated Funds	'
Investment Holdings [Line Items]	'
Marketable Securities	'
	As of December 31, 2013 the Company held no securities owned, at fair value, held by the Consolidated Funds. As of December 31, 2012 securities owned, at fair value, held by the Consolidated Funds are comprised of:
		As of December 31, 2012
		(dollars in thousands)
	Government sponsored securities (a)	$	1,911
	Commercial paper (b)	1,614
		$	3,525
	(a)	As of December 31, 2012, maturities ranged from August 2013 to December 2014 and interest rates ranged between 0.28% and 4.00%.
	(b)	As of December 31, 2012, commercial paper was purchased at a discount and matures on January 2, 2013.
Schedule of Other Investments	'
	As of December 31, 2013 and 2012 other investments, at fair value, held by the Consolidated Funds are comprised of:
		As of December 31,
		2013				2012
		(dollars in thousands)
	(1) Portfolio Funds	$	182,638			$	190,081
	(2) Lehman claims	4,842				14,124
		$	187,480			$	204,205
Schedule of Other Investments, Portfolio Funds	'
	As of December 31, 2013 and 2012, investments in Portfolio Funds, at fair value, included the following:
		As of December 31,
		2013				2012
		(dollars in thousands)
	Investments of Enterprise LP	$	155,530			$	173,348
	Investments of Merger Fund	26,963				—
	Investments of consolidated fund of funds	145				16,733
		$	182,638			$	190,081
Schedule of Other Investments, Funds Investment Companies	'
	The following is a summary of the investments held by the consolidated fund of funds, at fair value, as of December 31, 2013 and 2012:
				Fair Value as of December 31, 2013
		Strategy		Ramius Levered Multi-Strategy FOF LP				Ramius Multi-Strategy Master FOF LP				Ramius Vintage Multi-Strategy Master FOF LP				RTS Global 3X Fund LP				Total
				(dollars in thousands)
	Tapestry Pooled Account V LLC*	Credit-Based		$	—			$	—			$	—			$	—			$	—	(a)
	Externally Managed Portfolio Funds	Event Driven		—				—				—				—				—		(c)
	Externally Managed Portfolio Funds	Hedged Equity		—				—				145				—				145		(d)
				$	—			$	—			$	145			$	—			$	145
				Fair value as of December 31, 2012
		Strategy		Ramius Levered Multi-Strategy FOF LP				Ramius Multi-Strategy Master FOF LP				Ramius Vintage Multi-Strategy Master FOF LP				RTS Global 3X Fund LP				Total
				(dollars in thousands)
	Tapestry Pooled Account V LLC*	Credit-Based		$	315			$	649			$	693			$	—			$	1,657	(a)
	Independently Advised Portfolio Funds*	Futures & Global Macro		—				—				—				7,161				7,161		(b)
	Externally Managed Portfolio Funds	Event Driven		1,545				2,316				3,264				—				7,125		(c)
	Externally Managed Portfolio Funds	Hedged Equity		—				—				790				—				790		(d)
				$	1,860			$	2,965			$	4,747			$	7,161			$	16,733
	*    These Portfolio Funds are affiliates of the Company.
	As of December 31, 2013, the Company has no unfunded commitments regarding investments held by the three consolidated fund of funds.
	(a)	The Credit-Based strategy aims to generate returns via positions in the credit sensitive sphere of the fixed income markets. The strategy generally involves the purchase of corporate bonds with hedging of the interest exposure. The investments held in Tapestry Pooled Account V LLC, a related fund, are held solely in a credit based fund which the underlying fund's manager has placed in a side-pocket. The remaining amount of the investments within this category represents an investment in a fund that is in the process of liquidating. Distributions from this fund will be received as underlying investments are liquidated.
	(b)	The Futures and Global Macro strategy was comprised of several portfolio accounts, each of which was advised independently by a commodity trading advisor implementing primarily managed futures or global macro-based investment strategies. The trading advisors (through their respective portfolio accounts) traded independently of each other and, as a group, employed a wide variety of systematic, relative value and discretionary trading programs in the global currency, fixed income, commodities and equity futures markets. In implementing their trading programs, the trading advisors traded primarily in the futures and forward markets (as well as in related options). Although certain trading advisors were permitted to use total return swaps and trade other financial instruments from time to time on an interim basis, the primary focus was on the futures and forward markets. Redemption frequency of these portfolio accounts were monthly (and intra month for a $10,000 fee) and the notification period for redemptions was 5 business days (or 3 business days for intra month redemptions).
	(c)	The Event Driven strategy is generally implemented through various combinations and permutations of merger arbitrage, restructuring and distressed instruments. The investments in this category are primarily in a side pocket or suspended with undetermined payout dates.
	(d)	The Hedged Equity strategy focuses on equity strategies with some directional market exposure. The strategy attempts to profit from market efficiencies and direction. The investee fund manager has side-pocketed investments.
Enterprise Master	'
Investment Holdings [Line Items]	'
Schedule of Other Investments, Portfolio Funds	'
	Portfolio Funds, owned by Enterprise Master, at fair value
				As of December 31,
				2013				2012
		Strategy		(dollars in thousands)
	RCG Longview Equity Fund, LP*	Real Estate		$	8,470			$	11,027
	RCG Longview II, LP*	Real Estate		800				970
	RCG Longview Debt Fund IV, LP*	Real Estate		17,641				30,572
	RCG Longview, LP*	Real Estate		319				265
	RCG Soundview, LLC*	Real Estate		442				2,374
	RCG Urban American Real Estate Fund, L.P.*	Real Estate		1,812				1,987
	RCG International Sarl*	Multi-Strategy		1,795				752
	RCG Special Opportunities Fund, Ltd*	Multi-Strategy		82,119				80,166
	RCG Endeavour, LLC*	Multi-Strategy		6				43
	RCG Energy, LLC *	Energy		2,842				14,239
	RCG Renergys, LLC*	Energy		1				1
	Other Private Investments	Various		12,952				12,430
	Real Estate Investments	Real Estate		15,024				12,321
				$	144,223			$	167,147
	*	These Portfolio Funds are affiliates of the Company.
Schedule of Securities Owned and Sold, Not yet Purchased, at Fair Value	'
	Securities owned and securities sold, but not yet purchased by Enterprise Master, at fair value
		As of December 31,
		2013				2012
		(dollars in thousands)
	Bank debt	$	5			$	79
	Common stock	2,677				2,680
	Preferred stock	973				997
	Private equity	406				297
	Restricted stock	124				26
	Rights	2,528				1,714
	Trade claims	128				128
	Warrants	—				2
		$	6,841			$	5,923
Schedule of Derivative Instruments	'
	Derivative contracts, at fair value, owned by Enterprise Master, net
		As of December 31,
		2013				2012
	Description	(dollars in thousands)
	Currency forwards	$	(21	)		$	6
		$	(21	)		$	6
Merger Master	'
Investment Holdings [Line Items]	'
Schedule of Securities Owned and Sold, Not yet Purchased, at Fair Value	'
	Securities owned by Merger Master, at fair value
		As of December 31, 2013
		(dollars in thousands)
	Common stocks	$	33,901
	Corporate bond (a)	14,444
	Options	200
		$	48,545
	(a)	As of December 31, 2013, maturities ranged from April 2016 to October 2020 and interest rates ranged between 7.00% and 10.88%.
Schedule of Derivative Instruments	'
	Derivative contracts, at fair value, owned by Merger Master, net
		As of December 31, 2013
	Description	(dollars in thousands)
	Currency forwards	$	(10	)
	Cross rate	(92		)
		$	(102	)
RTS Global 3X Fund LP	'
Investment Holdings [Line Items]	'
Schedule of Derivative Instruments	'
	The following table presents the summarized investment information, which primarily consisted of receivables/(payables) on derivatives, for the underlying Portfolio Funds held by RTS Global 3X, at fair value, as of December 31, 2012:
		As of December 31, 2012
		(dollars in thousands)
	Bond futures	$	489
	Commodity forwards	(659		)
	Commodity futures	47
	Currency forwards	202
	Currency futures	264
	Energy futures	239
	Equity future	(27		)
	Index futures	(257		)
	Interest rate futures	40
		$	338
Starboard Value A LP [Member] | Operating Entities	'
Investment Holdings [Line Items]	'
Schedule of Results of Operations, Equity Method Investments	'
	For the year ended December 31, 2013, Starboard Value A LP has met the significance criteria as defined under Regulation S-X Rule 4-08(g) of the SEC guidance. As such, the Company is presenting the following summarized financial information:
	Starboard Value A LP	As of December 31,
		2013				2012
		(dollars in thousands)
	Assets
	Cash	$	14			$	—
	Performance fee receivable	25,214				20,448
	Investments in Portfolio Funds, at fair value	2,201				1,380
	Liabilities	—				—
	Equity	$	27,429			$	21,828
		Year Ended December 31,
		2013				2012				2011
		(dollars in thousands)
	Performance fee revenues	$	23,098			$	20,448			$	4,750
	Net realized and unrealized gains (losses)	283				254				18
	Net Income	$	23,381			$	20,702			$	4,768

Fair_Value_Measurements_for_Op1

Fair Value Measurements for Operating Entities and Consolidated Funds (Tables)	12 Months Ended
	Dec. 31, 2013
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 consolidated statements of financial condition by caption and by level within the valuation hierarchy as of December 31, 2013 and 2012:
	Operating Entities
		Assets at Fair Value as of December 31, 2013
		Level 1		Level 2				Level 3				Total
				(dollars in thousands)
	Securities owned and derivatives
	US Government securities	$	9	$	—			$	—			$	9
	Preferred stock	—		—				324				324
	Common stocks	171,277		2,103				3,559				176,939
	Convertible bonds	—		4,008				1,950				5,958
	Corporate bonds	—		121,372				—				121,372
	Futures	285		—				—				285
	Currency forwards	—		22				—				22
	Equity swaps	—		70				—				70
	Options	9,698		—				—				9,698
	Warrants and rights	107		—				5,805				5,912
	Mutual funds	525		—				—				525
	Other investments
	Portfolio Funds	—		19,402				51,649				71,051
	Real estate investments	—		—				2,088				2,088
	Lehman claim	—		—				378				378
		$	181,901	$	146,977			$	65,753			$	394,631
		Liabilities at Fair Value as of December 31, 2013
		Level 1		Level 2				Level 3				Total
		(dollars in thousands)
	Securities sold, not yet purchased and derivatives
	Common stocks	$	130,899	$	—			$	—			$	130,899
	Corporate bonds	—		55				—				55
	Futures	275		—				—				275
	Currency forwards	—		301				—				301
	Equity swaps	—		525				—				525
	Options	6,573		—				—				6,573
	Accounts payable, accrued expenses and other liabilities
	Contingent consideration liability (See Note 2)							$	6,937			$	6,937
		$	137,747	$	881			$	6,937			$	145,565
		Assets at Fair Value as of December 31, 2012
		Level 1		Level 2				Level 3				Total
				(dollars in thousands)
	Securities owned and derivatives
	US Government securities	$	137,478	$	—			$	—			$	137,478
	Preferred stock	—		—				2,332				2,332
	Common stocks	254,606		2,137				2,549				259,292
	Convertible bonds	—		6,202				—				6,202
	Corporate bonds	—		192,563				515				193,078
	Currency forwards	—		202				—				202
	Options	18,273		2,273				—				20,546
	Warrants and rights	641		—				1,713				2,354
	Mutual funds	2,845		—				—				2,845
	Other investments
	Portfolio Funds	—		30,228				25,670				55,898
	Real estate investments	—		—				1,864				1,864
	Lehman claim	—		—				706				706
		$	413,843	$	233,605			$	35,349			$	682,797
		Liabilities at Fair Value as of December 31, 2012
		Level 1		Level 2				Level 3				Total
		(dollars in thousands)
	Securities sold, not yet purchased and derivatives
	Common stocks	$	168,797	$	—			$	—			$	168,797
	Corporate bonds	—		61				—				61
	Futures	370		—				—				370
	Currency forwards	—		603				—				603
	Options	8,990		86				—				9,076
	Warrants and rights	—		—				3				3
Accounts payable, accrued expenses and other liabilities
Contingent consideration liability (See Note 2)	—		—				8,116				8,116
	$	178,157	$	750			$	8,119			$	187,026
Consolidated Funds' investments
	Assets at Fair Value as of December 31, 2013
	Level 1		Level 2				Level 3				Total
			(dollars in thousands)
Other investments
Portfolio Funds	$	—	$	26,964			$	155,674			$	182,638
Lehman claims	—		—				4,842				4,842
	$	—	$	26,964			$	160,516			$	187,480
	Assets at Fair Value as of December 31, 2012
	Level 1		Level 2				Level 3				Total
			(dollars in thousands)
Securities owned
US Government securities	$	1,911	$	—			$	—			$	1,911
Commercial paper	—		1,614				—				1,614
Other investments
Portfolio Funds	—		7,161				182,920				190,081
Lehman claims	—		—				14,124				14,124
	$	1,911	$	8,775			$	197,044			$	207,730
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	'
	The following table includes a rollforward of the amounts for the years ended December 31, 2013, 2012, and 2011, 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.
		Year Ended December 31, 2013
		Balance at December 31, 2012		Transfers in				Transfers out				Purchases/(covers)				(Sales)/shorts				Realized gains (losses)				Unrealized gains or losses				Balance at December 31, 2013
		(dollars in thousands)
	Operating Entities
	Preferred stock	$	2,332	$	—			$	(2,000	)	(e)	$	—			$	—			$	—			$	(8	)		$	324
	Common stocks	2,549		—				—				4				(275		)		260				1,021				3,559
	Convertible bonds	—		—				—				3,938				(1,988		)		—				—				1,950
	Corporate Bond	515		—				—				2,735				(3,346		)		(914		)		1,010				—
	Warrants and Rights	1,713		291			(c)	—				166				(110		)		(1		)		3,746				5,805
	Warrants and Rights, sold not yet purchased	3		—				—				—				—				(4		)		1				—
	Portfolio Funds	25,670		13,128			(f)	—				16,932				(9,012		)		(366		)		5,297				51,649
	Real estate	1,864		—				—				—				(124		)		—				348				2,088
	Lehman claim	706		—				—				—				(607		)		—				279				378
	Contingent consideration liability	8,116		—				—				(779		)		—				—				(400		)		6,937
	Consolidated Funds
	Portfolio Funds	182,920		—				—				—				(33,504		)		211				6,047				155,674
	Lehman claim	14,124		—				—				—				(13,377		)		8,597				(4,502		)		4,842
		Year Ended December 31, 2012
		Balance at December 31, 2011		Transfers in					Transfers out					Purchases/(covers)				(Sales)/shorts				Realized gains (losses)				Unrealized gains or losses				Balance at December 31, 2012
		(dollars in thousands)
	Operating Entities
	Preferred stock	$	250	$	—				$	—				$	2,000			$	—			$	—			$	82			$	2,332
	Common stocks	819		—					—					1,789				(6		)		6				(59		)		2,549
	Corporate Bond	—		—					—					4,600				(3,050		)		—				(1,035		)		515
	Warrants and Rights	1,534		—					(89		)	(b)		632				(212		)		56				(208		)		1,713
	Warrants and Rights, sold not yet purchased	—		—					(1,004		)	(d)		(297		)		977				(37		)		364				3
	Portfolio Funds	16,919		—					—					10,116				(3,482		)		(41		)		2,158				25,670
	Real estate	2,353		—					—					153				(781		)		—				139				1,864
	Lehman claim	553		—					—					—				(234		)		—				387				706
	Contingent consideration liability	—		—					—					(64		)		8,180				—				—				8,116
	Consolidated Funds
	Portfolio Funds	213,402		16,227			(a)		(17,151		)	(a)		434				(28,892		)		(3,823		)		2,723				182,920
	Lehman claim	7,340		—					—					—				(2,292		)		1,914				7,162				14,124
	(a) Change in consolidated funds (from master-feeder to stand alone funds).
	(b) The security was listed on an exchange subsequent to a private funding.
	(c) The security was acquired through an acquisition (See Note 2).
	(d) The security began trading on an exchange due to a business combination.
	(e) The company completed an initial public offering.
	(f) The investment was transferred into level 3 due to Company’s commitment as part of its long term extension of its
	partnership with credit funds.
Fair Value Inputs, Assets, Quantitative Information	'
	The following table includes quantitative information as of December 31, 2013 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 at December 31, 2013		Valuation techniques		Unobservable Inputs		Range
	Common and preferred stocks	$	3,474	Discounted cash flows, market multiples, recent transactions, bid levels, and comparable transactions		Market multiples		2x to 3x
	Warrants and rights, net	5,805		Model based		Volatility		20% to 100% (weighted average 37%)
	Contingent consideration	6,937		Discounted cash flows		Projected Cash Flow and DCF rate		0% to 15%
		$	16,216
	Other level 3 assets and liabilities (a)	216,990
	Total level 3 assets and liabilities	$	233,206
	(a)	Quantitative disclosures of unobservable inputs and assumptions are not required for investments for which NAV per share is used as a practical expedient to determine fair value, as their redemption features rather than observability of inputs cause them to be classified as a level 3 type asset within the fair value hierarchy. In addition, the fair value of the Consolidated Funds' investments are determined based on net asset value and therefore quantitative disclosures are not included in the table above. The quantitative disclosures also exclude financial instruments for which the determination of fair value is based on prices from prior transactions.

Fixed_Assets_Tables

Fixed Assets (Tables)	12 Months Ended
	Dec. 31, 2013
Fixed assets [Abstract]	'
Property, Plant and Equipment [Table Text Block]	'
	As of December 31, 2013 and 2012, fixed assets consisted of the following:
		As of December 31,
		2013			2012
		(dollars in thousands)
	Telephone and computer equipment	$	5,923		$	13,215
	Computer software	2,079			5,928
	Furniture and fixtures	5,418			6,265
	Leasehold improvements	29,047			30,412
	Assets acquired under capital leases—equipment	6,337			6,337
	Other	48			48
		48,852			62,205
	Less: Accumulated depreciation and amortization	(21,853		)	(30,003		)
		$	26,999		$	32,202

Goodwill_and_Intangible_Assets1

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Schedule of Goodwill [Table Text Block]	'
	The following table presents the changes in the Company's goodwill balance, by reporting unit for the years ended December 31, 2013 and 2012:
		Alternative Investment				Broker-				Total
						Dealer
		(dollars in thousands)
	Beginning balance - December 31, 2011
	Goodwill	$	30,228			$	7,151			$	37,379
	Accumulated impairment charges	(10,200		)		(7,151		)		(17,351		)
	Net	20,028				—				20,028
	Activity: 2012
	Recognized goodwill	—				8,517				8,517
	Goodwill impairment charges	—				—				—
	Ending balance: December 31, 2012
	Goodwill	30,228				15,668				45,896
	Accumulated impairment charges	(10,200		)		(7,151		)		(17,351		)
	Net	20,028				8,517				28,545
	Activity: 2013
	Recognized goodwill	—				8,695				8,695
	Goodwill impairment charges	—				—				—
	Ending balance: December 31, 2013
	Goodwill	30,228				24,363				54,591
	Accumulated impairment charges	(10,200		)		(7,151		)		(17,351		)
	Net	$	20,028			$	17,212			$	37,240
Intangible Assets Disclosure [Text Block]	'
					December 31, 2013										December 31, 2012
		Amortization			Gross				Accumulated				Net		Gross		Accumulated			Net
		Period			Carrying				Amortization				Carrying		Carrying		Amortization (1)			Carrying
					Amount								Amount		Amount					Amount
		(in years)			(in thousands)										(in thousands)
	Investment contracts	5			$	3,900			$	(3,900	)		$	—	$	3,900	$	(3,900	)	$	—
	Trade names	5 - 7.5			9,612				(7,747		)		1,865		9,572		(7,190		)	2,382
	Customer relationships	10-Apr			14,744				(8,375		)		6,369		11,974		(6,284		)	5,690
	Customer contracts	1.2			800				(800		)		—		800		(800		)	—
	Non compete agreements and covenants with limiting conditions acquired	10-Jan			2,697				(2,583		)		114		2,732		(2,576		)	156
	Intellectual property	10-Mar			6,951				(3,205		)		3,746		6,951		(2,195		)	4,756
					$	38,704			$	(26,610	)		$	12,094	$	35,929	$	(22,945	)	$	12,984
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	'
	The estimated future amortization expense for the Company's intangible assets as of December 31, 2013 is as follows:
		(dollars in thousands)
	2014	$	2,737
	2015	2,483
	2016	2,144
	2017	1,411
	2018	849
	Thereafter	2,470
		$	12,094

Other_Assets_Tables

Other Assets (Tables)	12 Months Ended
	Dec. 31, 2013
Other Assets [Abstract]	'
Other Assets [Table Text Block]	'
	Other assets in Operating Entities are as follows:
		As of December 31,
		2013		2012
		(dollars in thousands)
	Deposits	$	683	$	769
	Prepaid expenses	5,097		5,100
	Taxes receivable	1,911		2,105
	Derivative contracts, at fair value	377		202
	Deferred rent asset	897		433
	Interest and dividends receivable	4,716		6,031
	Other	4,257		3,408
		$	17,938	$	18,048

Accounts_Payable_Accrued_Expen1

Accounts Payable Accrued Expenses and Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2013
Accounts Payable, Accrued Expenses and Other Liabilities [Abstract]	'
Schedule of Accounts Payable and Accrued Liabilities [Table Text Block]	'
	Accounts payable, accrued expenses and other liabilities in Operating Entities are as follows:
		As of December 31,
		2013		2012
		(dollars in thousands)
	Deferred rent obligations (see Note 3(l))	$	14,554	$	13,822
	Deferred income	1,147		540
	Equity in RCG Longview Partners II, LLC (see Note 6a(3))	5,938		5,970
	Legal and regulatory reserve (see Note 19)	—		3,337
	Contingent consideration payable (see Note 2)	6,937		8,116
	Liability for future rent payments (see Note 19)	—		2,775
	Termination of service contracts	259		465
	Derivative contracts, at fair value	1,101		973
	Interest and dividends payable	2,073		2,324
	Accrued expenses and accounts payable	11,879		16,142
	Accrued tax liabilities	2,503		2,430
		$	46,391	$	56,894

Redeemable_NonControlling_Inte1

Redeemable Non-Controlling Interests in Consolidated Subsidiaries (Tables)	12 Months Ended
	Dec. 31, 2013
Noncontrolling Interest [Abstract]	'
Redeemable non-controlling interests in consolidated subsidiaries	'
	Redeemable non-controlling interests in consolidated subsidiaries and funds and the related net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds are comprised as follows:
		As of December 31,
		2013		2012
		(dollars in thousands)
	Redeemable non-controlling interests in consolidated subsidiaries and funds
	Operating companies	$	12,009	$	4,106
	Consolidated funds	73,805		81,597
		$	85,814	$	85,703
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries	'
		Year Ended December 31,
		2013		2012			2011
		(dollars in thousands)
	Income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds
	Operating companies	$	10,461	$	301		$	7,002
	Consolidated funds	2,732		(373		)	(1,175		)
		$	13,193	$	(72	)	$	5,827

ShareBased_Compensation_and_Em1

Share-Based Compensation and Employee Ownership Plans (Tables)	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Schedule of Share-based Compensation, Stock Options, Activity	'
	The following table summarizes the Company's stock option activity for the year ended December 31, 2013:
		Shares Subject		Weighted Average		Weighted Average	Aggregate Intrinsic
		to Option		Exercise Price/Share		Remaining Term	Value(1)
						(in years)	(dollars in thousands)
	Balance outstanding at December 31, 2011	866,428		$	12.95	2.5	$	—
	Options granted	—		—		—	—
	Options acquired	—		—		—	—
	Options exercised	—		—		—	—
	Options forfeited	—		—		—	—
	Options expired	(92,665	)	16		—	—
	Balance outstanding at December 31, 2012	773,763		$	12.58	1.6	$	—
	Options granted	—		—		—	—
	Options acquired	—		—		—	—
	Options expired	(473,757	)	16		—	—
	Balance outstanding at December 31, 2013	300,006		$	7.19	2.4	$	—
	Options exercisable at December 31, 2012	623,760		$	14.66	0.9	$	—
	Options exercisable at December 31, 2013	300,006		$	7.19	2.4	$	—
	-1	Based on the Company's closing stock price of $3.91 on December 31, 2013 and $2.45 on December 31, 2012.
Schedule of Share-based Compensation, Stock Appreciation Rights, Activity	'
	The following table summarizes the Company's SAR's for the year ended December 31, 2013:
		Shares Subject		Weighted Average		Weighted Average	Aggregate Intrinsic
		to Option		Exercise Price/Share		Remaining Term	Value(1)
						(in years)	(dollars in thousands)
	Balance outstanding at December 31, 2012	—		$	—	—	$	—
	SAR's granted	400,000		2.9		—
	SAR's acquired	—		—		—
	SAR's expired	—		—		—
	Balance outstanding at December 31, 2013	400,000		$	2.9	4.21	$	608
	SAR's exercisable at December 31, 2013	—		$	—	—
	-1	Based on the Company's closing stock price of $3.91 on December 31, 2013.
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 year ended December 31, 2013:
		Nonvested Restricted Shares and Restricted Stock Units		Weighted-Average
				Grant Date
				Fair Value
	Balance outstanding at December 31, 2011	7,517,682		$	5.57
	Granted	8,381,939		2.82
	Vested	(4,855,489	)	4.16
	Canceled	—		—
	Forfeited	(792,109	)	3.51
	Balance outstanding at December 31, 2012	10,252,023		$	4.15
	Granted (1)	7,939,924		2.63
	Vested	(4,463,990	)	3.86
	Canceled	—		—
	Forfeited	(176,413	)	3.15
	Balance outstanding at December 31, 2013	13,551,544		$	3.37

Defined_Benefit_Plans_Tables

Defined Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]	'
Schedule of Net Periodic Benefit Cost	'
	The amounts contained in the following table relate to the Company's defined benefit plan(s) for the years ended December 31, 2013, 2012, and 2011:
		As of December 31,
		2013			2012
		(dollars in thousands)
	Projected benefit obligation
	Benefit obligation at beginning of year	$	4,436		$	5,591
	Service cost	—			53
	Interest cost	207			216
	Actuarial loss (gain)	(93		)	(50		)
	Benefits paid	(48		)	—
	Curtailments	—			(98		)
	Lump sum settlement	(910		)	(1,269		)
	Effect of change in currency conversion	—			(7		)
	Benefit obligation at end of year	$	3,592		$	4,436
	Change in plan assets
	Fair value of plan assets at beginning of year	$	5,230		$	5,639
	Actual return on plan assets	153			676
	Employer contributions	1			—
	Benefits paid	(956		)	(1,085		)
	Expenses paid from the plan	(39		)	—
	Fair value of plan assets at the end of year	$	4,389		$	5,230
	Funded balance at end of year	$	797		$	794
	Amounts recognized in the consolidated statement of financial condition
	Asset	$	797		$	794
	Accumulated benefit obligation	$	3,592		$	4,436
		Year Ended December 31,
		2013			2012			2011
		(dollars in thousands)
	Components of net periodic benefit cost included in employee compensation and benefits
	Service cost	$	—		$	53		$	50
	Interest cost	207			216			264
	Expected return on plan assets	(251		)	(235		)	(276		)
	Amortization of (loss) / gain	—			—			—
	Amortization of prior service cost	21			20			21
	Effect of curtailment	360			(59		)	—
	Effect of special termination benefits	—			6			—
	Effect of settlement	(95		)	(95		)	(29		)
	Net periodic benefit cost	$	242		$	(94	)	$	30
	Other changes in plan assets and benefit obligations recognized in other comprehensive loss
	Net loss (gain)	$	137		$	(557	)	$	(33	)
	Effect of curtailment	(360		)	59			—
	Effect of settlement	—			98			31
	Amortization of loss / (gain)	—			—			—
	Amortization of prior service cost	(23		)	(23		)	(23		)
	Total recognized in other comprehensive income (loss)	$	(246	)	$	(423	)	$	(25	)
	Total recognized in net periodic benefit cost and other comprehensive loss	$	(4	)	$	(517	)	$	5
	Amounts recognized in accumulated other comprehensive loss
	Net gain (loss)	$	344		$	479		$	116
	Prior service cost	—			(381		)	(441		)
	Effect of change in currency conversion	—			—			—
	Total recognized in accumulated other comprehensive income (loss)	$	344		$	98		$	(325	)
	Estimated amounts to be amortized from accumulated other comprehensive loss into net periodic benefit cost over the next fiscal year
	Prior service cost	$	—		$	19		$	19
	Net gain (loss)	$	—		$	—		$	—
Schedule of Allocation of Plan Assets [Table Text Block]	'
	The composition of plan assets by asset category for the Cash Balance Plan are set forth below:
		As of December 31,
		2013			2012
		(dollars in thousands)
	Ramius Multi-Strategy Fund Ltd(a)	$	390		$	513
	Ramius Merger Fund Ltd	2,279			—
	Orchard Square Partners Credit Fund Ltd(b)	1,640			1,304
	External Mutual Funds—Total return(c)	7			1,358
	External Mutual Funds—Real Return(d)	34			1,019
	External Mutual Funds—Conservative(e)	39			1,036
		$	4,389		$	5,230

Income_Taxes_Income_Taxes_Tabl

Income Taxes Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	'
	The components of the Company's income tax expense for the years ended December 31, 2013 , 2012 and 2011 are as follows:
		Year ended December 31,
		2013				2012				2011
		(dollars in thousands)
	Continued Operations
	Current tax expense/(benefit)
	Federal	$	—			$	—			$	—
	State and local	241				(133		)		560
	Foreign	188				569				897
	Total	$	429			$	436			$	1,457
	Deferred tax expense/(benefit)
	Federal	$	—			$	8			$	2
	State and local	—				2				(6		)
	Foreign	28				2				(21,526		)
	Total	28				12				(21,530		)
	Total Tax expense/(benefit)	$	457			$	448			$	(20,073	)
	Discontinued Operations
	Current tax expense/(benefit)
	Federal	$	—			$	—			$	—
	State and local	—				—				(5		)
	Foreign	—				—				(424		)
	Total	$	—			$	—			$	(429	)
	Deferred tax expense/(benefit)
	Federal	$	—			$	—			$	—
	State and local	—				—				—
	Foreign	—				—				—
	Total	—				—				—
	Total Tax expense/(benefit)	$	—			$	—			$	(429	)
	Total
	Current tax expense/(benefit)
	Federal	$	—			$	—			$	—
	State and local	241				(133		)		555
	Foreign	188				569				473
	Total	$	429			$	436			$	1,028
	Deferred tax expense/(benefit)
	Federal	$	—			$	8			$	2
	State and local	—				2				(6		)
	Foreign	28				2				(21,526		)
	Total	28				12				(21,530		)
	Total Tax expense/(benefit)	$	457			$	448			$	(20,502	)
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	'
	The reconciliations of the Company's federal statutory rate to the effective income tax rate for the years ended December 31, 2013, 2012, and 2011 are as follows:
		2013			2012			2011
	Pre-tax loss at U.S. statutory rate	35	%		35	%		35	%
	Stock compensation	12.6			(28.1	)		—
	Change in valuation allowance	(27.2	)		(7.6	)		(33.3	)
	Deferred asset recognition	—			—			11.5
	Bargain purchase price	—			—			6.3
	Minority interest reversal	(25.2	)		(0.1	)		1.7
	Other, net	7.3			(1.1	)		(4.5	)
	Total	2.5	%		(1.9	)%		16.7	%
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	'
	The components of the Company's deferred tax assets and liabilities as of December 31, 2013 and 2012 are as follows:
		2013				2012
		(dollars in thousands)
	Deferred tax assets, net of valuation allowance
	Net operating loss	$	130,562			$	135,108
	Deferred compensation	22,538				23,373
	Unrealized losses on investments	—				4,450
	Goodwill	9,937				10,885
	Legal reserves	—				803
	Foreign tax credits	1,820				1,756
	Acquired lease liability	3,336				1,036
	Other	4,842				3,532
	Total deferred tax assets	173,035				180,943
	Valuation allowance	(148,816		)		(161,181		)
	Deferred tax assets, net of valuation allowance	24,219				19,762
	Deferred tax liabilities
	Basis difference on investments	(15,352		)		(15,351		)
	Unrealized gains on investments	(6,354		)		—
	Fixed assets	(761		)		(1,405		)
	Intangible assets	(1,177		)		(1,230		)
	Other	(602		)		(1,766		)
	Total deferred tax liabilities	(24,246		)		(19,752		)
	Deferred tax assets, net	$	(27	)		$	10
Summary of Operating Loss Carryforwards [Table Text Block]	'
	The Company has the following net operating loss carryforwards at December 31, 2013:
		Federal				New York				Hong Kong
	Jurisdiction:
	Net operating loss (in millions)	$	323			$	390			$	14
	Year of expiration	2033				2033				Indefinite

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Future Minimum Annual Lease and Service Payments	'
	As of December 31, 2013, future minimum annual lease and service payments for the Company were as follows:
		Equipment Leases (a)		Service Payments		Facility Leases (b)
		(dollars in thousands)
	2014	$	810	$	11,970	$	17,862
	2015	405		5,499		17,375
	2016	86		1,634		14,283
	2017	—		1,133		11,174
	2018	—		1,049		10,885
	Thereafter	—		22		39,594
		$	1,301	$	21,307	$	111,173
	(a)	Equipment Leases include the Company's commitments relating to operating and capital leases. See Note 20 for further information on the capital lease minimum payments which are included in the table. See Note 28 regarding a new lease for data storage and data backup equipment entered into in January 2014.
	(b)	The Company has entered into various agreements to sublease certain of its premises. The Company recorded sublease income related to these leases of $1.5 million, $1.2 million, and $0.3 million for the years ended December 31, 2013, 2012, and 2011, respectively.

ShortTerm_Borrowings_and_Other1

Short-Term Borrowings and Other Debt (Tables)	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Schedule of Debt	'
	As of December 31, 2013 and 2012, short term borrowings and other debt of the Company were as follows:
		As of December 31,
		2013			2012
		(dollars in thousands)
	Notes payable	$	41		$	206
	Capital lease obligations	2,523			3,926
		$	2,564		$	4,132
Schedule of Letters of Credit	'
	As of December 31, 2013, the Company has the following five 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.
	Location		Amount			Maturity
			(dollars in thousands)
	San Francisco		$	82		May-14
	New York		$	1,191		Sep-14
	New York		$	6,746		Dec-14
	New York		$	1,000		Feb-14
	New York		$	1,861		Mar-14
Schedule of Maturities of Long-term Debt and Future Minimum Lease Payments for Capital Leases	'
	Annual scheduled maturities of debt and minimum lease payments for capital lease obligation and short term borrowings and other debt outstanding as of December 31, 2013, are as follows:
		Capital Lease			Notes payable
		Obligation
		(dollars in thousands)
	2014	$	1,402		$	46
	2015	1,051			—
	2016	194			—
	2017	—			—
	2018	—			—
	Thereafter	—			—
	Subtotal	2,647			46
	Less: Amount representing interest (a)	(124		)	(5		)
	Total	$	2,523		$	41
	(a)	Amount necessary to reduce net minimum lease payments to present value calculated at the Company's implicit rate at lease inception.

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Treasury Stock Activity	'
	The following represents the activity relating to the treasury stock held by the Company during the year ended December 31, 2013:
		Treasury stock shares		Cost			Average cost
							per share
		(dollars in thousands)
	Balance outstanding at December 31, 2012	11,292,220		$	31,728		$	2.81
	Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions	1,203,454		3,649			3.03
	Treasury stock reissued	(24,744	)	(90		)	3.64
	Purchase of treasury stock	3,402,619		12,797			3.76
	Balance outstanding at December 31, 2013	15,873,549		$	48,084		$	3.03

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2013
Accumulated Other Comprehensive Income / (Loss) [Abstract]	'
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	'
		Foreign currency translation (a)			Defined benefit plans (a)			Total
		(dollars in thousands)
	Balance at January 1, 2011	$	370		$	(350	)	$	20
	Net change	(260		)	25			(235		)
	Balance at December 31, 2011	110			(325		)	(215		)
	Net change	148			423			571
	Balance at December 31, 2012	258			98			356
	Net change	(10		)	246			236
	Balance at December 31, 2013	$	248		$	344		$	592

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Earnings Per Share, Basic and Diluted	'
	The computation of earnings per share is as follows:
		Year Ended December 31,
		2013		2012			2011
		(dollars in thousands, except per share data)
	Net income (loss)	$	17,840	$	(23,957	)	$	(78,537	)
	Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	13,193		(72		)	5,827
	Net income (loss) attributable to Cowen Group, Inc. stockholders	4,647		(23,885		)	(84,364		)
	Net income (loss) from discontinued operations, net of tax	—		—			(23,646		)
	Shares for basic and diluted calculations:
	Weighted average shares used in basic computation	116,703		114,400			95,532
	Stock options	—		—			—
	Stock appreciation rights	306		—			—
	Restricted stock	4,108		—			—
	Weighted average shares used in diluted computation	121,117		114,400			95,532
	Earnings (loss) per share:
	Basic
	Income (loss) from continued operations	$	0.04	$	(0.21	)	$	(0.88	)
	Income (loss) from discontinued operations	—		—			(0.25		)
	Diluted
	Income (loss) from continued operations	$	0.04	$	(0.21	)	$	(0.88	)
	Income (loss) from discontinued operations	—		—			(0.25		)

Segment_Reporting_Tables

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Segment Reporting Information, by Segment	'
	The following tables set forth operating results for the Company's alternative investment and broker dealer segments and related adjustments necessary to reconcile the Company's Economic Income (Loss) measure to arrive at the Company's consolidated US GAAP net income (loss):
		Year Ended December 31, 2013
											Adjustments
		Alternative			Broker-Dealer (1)			Total Economic Income/(Loss)			Funds			Other				US GAAP
		Investment									Consolidation			Adjustments
		(dollars in thousands)
	Revenues
	Investment banking	$	—		$	105,333		$	105,333		$	—		$	—			$	105,333
	Brokerage	—			121,065			121,065			—			(6,472		)	(e)	114,593
	Management fees	56,984			—			56,984			(1,146		)	(18,535		)	(a)	37,303
	Incentive income	21,933			—			21,933			—			(9,347		)	(a)	12,586
	Investment Income	30,713			5,947			36,660			—			(36,660		)	(c)	—
	Interest and dividends	—			—			—			—			39,454			(c)	39,454
	Reimbursement from affiliates	—			—			—			(99		)	9,260			(b)	9,161
	Other revenue	524			2,010			2,534			—			2,884			(c)	5,418
	Consolidated Funds revenues	—			—			—			3,398			—				3,398
	Total revenues	110,154			234,355			344,509			2,153			(19,416		)		327,246
	Expenses
	Employee compensation and benefits	54,656			150,180			204,836			—			2,412				207,248
	Interest and dividends	231			119			350			—			26,949			(c)	27,299
	Non-compensation expenses—Fixed	33,986			61,538			95,524			—			(95,524		)	(c)(d)	—
	Non-compensation expenses—Variable	4,520			26,123			30,643			—			(30,643		)	(c)(d)	—
	Non-compensation expenses	—			—			—			—			124,331			(c)(d)	124,331
	Reimbursement from affiliates	(6,380		)	—			(6,380		)	—			6,380			(b)	—
	Consolidated Funds expenses	—			—			—			2,039			—				2,039
	Total expenses	87,013			237,960			324,973			2,039			33,905				360,917
	Other income (loss)
	Net gains (losses) on securities, derivatives and other investments	—			—			—			—			40,924			(c)	40,924
	Consolidated Funds net gains (losses)	—			—			—			2,618			8,426				11,044
	Total other income (loss)	—			—			—			2,618			49,350				51,968
	Income (loss) before income taxes and non-controlling interests	23,141			(3,605		)	19,536			2,732			(3,971		)		18,297
	Income taxes expense / (benefit)	—			—			—			—			457			(b)	457
	Economic Income (Loss) / Net income (loss) before non-controlling interests	23,141			(3,605		)	19,536			2,732			(4,428		)		17,840
	(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	(12,995		)	—			(12,995		)	(2,732		)	2,534				(13,193		)
	Economic Income (Loss) / Net Income (loss) attributable to Cowen Group, Inc. stockholders	$	10,146		$	(3,605	)	$	6,541		$	—		$	(1,894	)		$	4,647
	(1) For the year ended December 31, 2013, the Company has reflected $7.6 million of investment income and related compensation expense of $2.5 million within the broker-dealer segment in proportion to its capital.
		Year Ended December 31, 2012
											Adjustments
		Alternative			Broker-Dealer (1)			Total Economic Income/(Loss)			Funds			Other				US GAAP
		Investment									Consolidation			Adjustments
		(dollars in thousands)
	Revenues
	Investment banking	$	—		$	71,762		$	71,762		$	—		$	—			$	71,762
	Brokerage	—			93,903			93,903			—			(2,736		)	(e)	91,167
	Management fees	56,381			—			56,381			(1,474		)	(16,791		)	(a)	38,116
	Incentive income	15,205			—			15,205			—			(9,794		)	(a)	5,411
	Investment Income	40,374			9,742			50,116			—			(50,116		)	(c)	—
	Interest and dividends	—			—			—			—			24,608			(c)	24,608
	Reimbursement from affiliates	—			—			—			(288		)	5,527			(b)	5,239
	Other revenue	844			404			1,248			—			2,420			(c)	3,668
	Consolidated Funds revenues	—			—			—			509			—				509
	Total revenues	112,804			175,811			288,615			(1,253		)	(46,882		)		240,480
	Expenses
	Employee compensation and benefits	59,647			128,508			188,155			—			5,879				194,034
	Interest and dividends	151			188			339			—			11,798			(c)	12,137
	Non-compensation expenses—Fixed	32,575			62,887			95,462			—			(95,462		)	(c)(d)	—
	Non-compensation expenses—Variable	4,941			20,334			25,275			—			(25,275		)	(c)(d)	—
	Non-compensation expenses	—			—			—			—			119,053			(c)(d)	119,053
	Reimbursement from affiliates	(5,527		)	—			(5,527		)	—			5,527			(b)	—
	Consolidated Funds expenses	—			—			—			1,676			—				1,676
	Total expenses	91,787			211,917			303,704			1,676			21,520				326,900
	Other income (loss)
	Net gains (losses) on securities, derivatives and other investments	—			—			—			—			55,665			(c)	55,665
Consolidated Funds net gains (losses)	—			—			—			2,556			4,690				7,246
Total other income (loss)	—			—			—			2,556			60,355				62,911
Income (loss) before income taxes and non-controlling interests	21,017			(36,106		)	(15,089		)	(373		)	(8,047		)		(23,509		)
Income taxes expense / (benefit)	—			—			—			—			448			(b)	448
Economic Income (Loss) / Net income (loss) before non-controlling interests	21,017			(36,106		)	(15,089		)	(373		)	(8,495		)		(23,957		)
(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	(2,480		)	—			(2,480		)	373			2,179				72
Economic Income (Loss) / Net Income (loss) attributable to Cowen Group, Inc. stockholders	$	18,537		$	(36,106	)	$	(17,569	)	$	—		$	(6,316	)		$	(23,885	)
(1) For the year ended December 31, 2012, the Company has reflected $10.2 million of investment income and related compensation expense of $3.4 million within the broker-dealer segment in proportion to its capital.
	Year Ended December 31, 2011
										Adjustments
	Alternative			Broker-Dealer (1)			Total			Funds			Other				US GAAP
	Investment						Economic Income/(Loss)			Consolidation			Adjustments
	(dollars in thousands)
Revenues
Investment banking	$	—		$	50,976		$	50,976		$	—		$	—			$	50,976
Brokerage	—			99,611			99,611			—			—				99,611
Management fees	67,309			—			67,309			(1,809		)	(13,034		)	(a)	52,466
Incentive income	10,366			—			10,366			—			(7,101		)	(a)	3,265
Investment Income	33,599			7,748			41,347			—			(41,347		)	(c)	—
Interest and dividends	—			—			—			—			22,306			(c)	22,306
Reimbursement from affiliates	—			—			—			(280		)	4,602			(b)	4,322
Other revenue	622			(7		)	615			—			968			(c)	1,583
Consolidated Funds revenues	—			—			—			749			—				749
Total revenues	111,896			158,328			270,224			(1,340		)	(33,606		)		235,278
Expenses
Employee compensation and benefits	46,757			145,801			192,558			—			11,209				203,767
Interest and dividends	184			551			735			—			8,498			(c)	9,233
Non-compensation expenses—Fixed	33,954			69,227			103,181			—			(103,181		)	(c)(d)	—
Non-compensation expenses—Variable	17,085			24,412			41,497			—			(41,497		)	(c)(d)	—
Non-compensation expenses	—			—			—			—			152,722			(c)(d)	152,722
Goodwill impairment	—			—			—			—			7,151			(h)	7,151
Reimbursement from affiliates	(4,602		)	—			(4,602		)	—			4,602			(b)	—
Consolidated Funds expenses	—			—			—			2,782			—				2,782
Total expenses	93,378			239,991			333,369			2,782			39,504				375,655
Other income (loss)
Net gains (losses) on securities, derivatives and other investments	—			—			—			—			15,128			(c)	15,128
Bargain purchase gain	—			—			—			—			22,244			(f)	22,244
Consolidated Funds net gains (losses)	—			—			—			2,947			1,448				4,395
Total other income (loss)	—			—			—			2,947			38,820				41,767
Income (loss) before income taxes and non-controlling interests	18,518			(81,663		)	(63,145		)	(1,175		)	(34,290		)		(98,610		)
Income taxes expense / (benefit)	—			—			—			—			(20,073		)	(b)	(20,073		)
Economic Income (Loss) / Net income (loss) before non-controlling interests	18,518			(81,663		)	(63,145		)	(1,175		)	(14,217		)		(78,537		)
Net income (loss) from discontinued operations, net of tax	—			—			—			—			(23,646		)	(g)	(23,646		)
(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	(8,292		)	—			(8,292		)	1,175			1,290				(5,827		)
Economic Income (Loss) / Net income (loss) attributable to Cowen Group, Inc. stockholders	$	10,226		$	(81,663	)	$	(71,437	)	$	—		$	(36,573	)		$	(108,010	)
(1) For the year ended December 31, 2011, the Company has reflected $5.6 million of investment income and related compensation expense of $1.8 million within the broker-dealer segment in proportion to its capital.
The following is a summary of the adjustments made to US GAAP net income (loss) for the segment to arrive at
Economic Income (Loss):
Funds Consolidation: The impacts of consolidation and the related elimination entries of the Consolidated Funds are not included in Economic Income (Loss). Adjustments to reconcile to US GAAP net income (loss) include elimination of incentive income and management fees earned from the Consolidated Funds and addition of fund expenses excluding management fees paid, fund revenues and investment income (loss).
Other Adjustments:
(a)     Economic Income (Loss) recognizes revenues (i) net of distribution fees paid to agents and (ii) our proportionate share
of management and incentive fees of certain real estate operating entities and the activist business.
(b)    Economic Income (Loss) excludes income taxes as management does not consider this item when evaluating the
performance of the segment. Also, reimbursement from affiliates is shown as a reduction of Economic Income
expenses, but is included as a part of revenues under US GAAP.
(c)     Economic Income (Loss) recognizes Company income from proprietary trading net of related expenses.
(d)     Economic Income (Loss) recognizes the Company's proportionate share of expenses for certain real estate and other
operating entities for which the investments are recorded under the equity method of accounting for investments.
(e)    Economic Income (Loss) recognizes stock borrow/loan activity and other brokerage dividends as brokerage revenue.
(f)    Economic Income (Loss) excludes the bargain purchase gain which resulted from the LaBranche acquisition.
(g)    Economic Income (Loss) excludes discontinued operations.
(h)    Economic Income (Loss) excludes goodwill impairment.

Supplemental_Financial_Informa1

Supplemental Financial Information (Tables)	12 Months Ended
	Dec. 31, 2013
Supplemental Financial Information [Abstract]	'
Schedule of Quarterly Financial Information [Table Text Block]	'
		Quarter Ended
		March 31, 2013			June 30, 2013			September 30, 2013			December 31, 2013
		(in thousands)
	Total revenues	$	67,241		$	81,207		$	81,360		$	97,438
	Net Income (loss) before income taxes	1,095			3,506			8,324			5,372
	Income tax expense (benefit)	176			158			(46		)	169
	Net income (loss) from continuing operations	919			3,348			8,370			5,203
	Net Income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	3,495			2,255			4,759			2,684
	Net income (loss) attributable to Cowen Group, Inc. stockholders	$	(2,576	)	$	1,093		$	3,611		$	2,519
	Earnings (loss) per share:
	Basic	$	(0.02	)	$	0.01		$	0.03		$	0.02
	Diluted	$	(0.02	)	$	0.01		$	0.03		$	0.02
	Weighted average number of common shares:
	Basic	113,798			117,235			118,359			117,514
	Diluted	113,798			120,901			122,708			123,573
		Quarter Ended
		31-Mar-12			30-Jun-12			30-Sep-12			31-Dec-12
		(in thousands)
	Total revenues	$	57,480		$	59,470		$	57,598		$	65,932
	Net Income (loss) before income taxes	6,378			(10,189		)	(11,455		)	(8,243		)
	Income tax expense (benefit)	142			191			163			(48		)
	Net income (loss) from continuing operations	6,236			(10,380		)	(11,618		)	(8,195		)
	Net Income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	2,241			(2,434		)	(1,033		)	1,154
	Net income (loss) attributable to Cowen Group, Inc. stockholders	$	3,995		$	(7,946	)	$	(10,585	)	$	(9,349	)
	Earnings (loss) per share:
	Basic	$	0.03		$	(0.07	)	$	(0.09	)	$	(0.08	)
	Diluted	$	0.03		$	(0.07	)	$	(0.09	)	$	(0.08	)
	Weighted average number of common shares:
	Basic	114,281			114,561			114,989			113,939
	Diluted	115,663			114,561			114,989			113,939

Organization_and_Business_Deta

Organization and Business (Details)	12 Months Ended
	Dec. 31, 2013
	segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Number of business segments	2

Acquisitions_Narrative_Details

Acquisitions Narrative (Details) (USD $)

3 Months Ended

12 Months Ended

0 Months Ended

3 Months Ended

12 Months Ended

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Jun. 28, 2011

Jun. 30, 2011

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

ATM Group and Cowen Equity Finance LP [Member]

ATM Group and Cowen Equity Finance LP [Member]

LaBranche and Co Inc. [Member]

LaBranche and Co Inc. [Member]

LaBranche and Co Inc. [Member]

Minimum

Maximum

ATM Group and Cowen Equity Finance LP [Member]

ATM Group and Cowen Equity Finance LP [Member]

Business Acquisition [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Business Acquisition, Cost of Acquired Entity, Cash Paid

'

'

'

'

'

'

'

'

$779,000

$0

$0

'

$10,900,000

'

'

'

'

'

Business Acquisition, Cost of Acquired Entity, Contingent Consideration

'

'

'

'

'

'

'

'

'

'

'

'

8,100,000

'

'

'

'

'

Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, Low

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3,500,000

'

Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

13,800,000

Business Acquisition, Purchase Price Allocation, Goodwill, Expected Tax Deductible Amount

'

'

'

'

'

'

'

'

'

'

'

2,200,000

'

'

'

'

'

'

Business Combination, Acquisition Related Costs

'

'

'

'

'

'

'

'

'

'

'

'

300,000

'

'

3,300,000

'

'

Revenues

97,438,000

81,360,000

81,207,000

67,241,000

65,932,000

57,598,000

59,470,000

57,480,000

327,246,000

240,480,000

235,278,000

6,200,000

'

'

'

'

'

'

Net income (loss) attributable to Cowen Group, Inc. stockholders

2,519,000

3,611,000

1,093,000

-2,576,000

-9,349,000

-10,585,000

-7,946,000

3,995,000

4,647,000

-23,885,000

-108,010,000

1,600,000

'

'

'

'

'

'

Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net

'

'

'

'

'

'

'

'

'

'

'

'

10,285,000

176,000,000

'

'

'

'

Non compete agreements and covenants with limiting conditions acquired recognized separately

'

'

'

'

'

'

'

'

'

'

'

'

167,000

2,300,000

'

'

'

'

Business Acquisition, Cost of Acquired Entity, Purchase Price

'

'

'

'

'

'

'

'

'

'

'

'

'

156,000,000

'

'

'

'

Bargain purchase gain

'

'

'

'

'

'

'

'

$0

$0

$22,244,000

'

$8,517,000

'

$22,200,000

'

'

'

Acquisitions_Purchase_Price_Al

Acquisitions Purchase Price Allocation (Details) (USD $)	12 Months Ended					3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2013	Jun. 30, 2011	Jun. 28, 2011
				ATM Group and Cowen Equity Finance LP [Member]	ATM Group and Cowen Equity Finance LP [Member]	LaBranche and Co Inc. [Member]	LaBranche and Co Inc. [Member]
Business Acquisition [Line Items]	'	'	'	'	'	'	'
Cash and cash equivalents	'	'	'	$290,000	'	'	'
Securities owned, at fair value	'	'	'	17,000	'	'	'
Securities borrowed	'	'	'	527,854,000	'	'	'
Receivable from brokers	'	'	'	15,682,000	'	'	'
Fees receivable	'	'	'	751,000	'	'	'
Intangibles	'	'	'	9,782,000	'	'	'
Other assets	'	'	'	136,000	'	'	'
Securities loaned	'	'	'	-543,369,000	'	'	'
Compensation payable	'	'	'	-11,000	'	'	'
Fees payable	'	'	'	-56,000	'	'	'
Unfavorable lease liability	'	'	'	-91,000	'	'	'
Accounts payable, accrued expenses and other liabilities	'	'	'	-700,000	'	'	'
Total net assets acquired	'	'	'	10,285,000	'	'	176,000,000
Non compete agreements	'	'	'	167,000	'	'	2,300,000
Goodwill/(Bargain purchase gain) on transaction	0	0	-22,244,000	-8,517,000	'	-22,200,000	'
Total purchase price	'	'	'	18,969,000	'	'	'
Intangible assets	'	'	'	'	$9,900,000	'	$5,100,000

Significant_Accounting_Policie3

Significant Accounting Policies (Details) (USD $)

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

cowenfund

Investment Company

Maximum

Minimum

Telephone and computer equipment

Telephone and computer equipment

Computer software

Computer software

Furniture and fixtures

Furniture and fixtures

Leasehold improvements

Leasehold improvements

Capitalized lease assets

cowenfund

Maximum

Minimum

Maximum

Minimum

Maximum

Minimum

Maximum

Minimum

Organization [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Redeemable Noncontrolling Interest, Redemption Fee, Percent

'

'

'

5.00%

1.00%

'

'

'

'

'

'

'

'

'

Property, Plant and Equipment, Useful Life

'

'

'

'

'

'5 years

'3 years

'5 years

'3 years

'8 years

'3 years

'10 years

'1 year

'5 years

Number of funds, Consolidated

8

'

3

'

'

'

'

'

'

'

'

'

'

'

Deferred rent

$14,554,000

$13,822,000

'

'

'

'

'

'

'

'

'

'

'

'

Total net assets of consolidated VIEs

$8,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Significant_Accounting_Policie4

Significant Accounting Policies Revenue Recognition (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenue from External Customer [Line Items]	'	'	'
Commissions	$79.70	$63	$66
Principal transactions, net	28.1	22.5	27.1
Equity research fees	$6.80	$5.70	$6.50
Managed mutual funds [Member] | Maximum	'	'	'
Revenue from External Customer [Line Items]	'	'	'
Management Fees, Percent Fee	2.00%	'	'
Managed mutual funds [Member] | Minimum	'	'	'
Revenue from External Customer [Line Items]	'	'	'
Management Fees, Percent Fee	1.60%	'	'
Hedge Funds [Member] | Maximum	'	'	'
Revenue from External Customer [Line Items]	'	'	'
Management Fees, Percent Fee	2.00%	'	'
Alternative Solutions [Member] | Maximum	'	'	'
Revenue from External Customer [Line Items]	'	'	'
Management Fees, Percent Fee	2.00%	'	'
Real Estate Funds | Maximum	'	'	'
Revenue from External Customer [Line Items]	'	'	'
Management Fees, Percent Fee	1.50%	'	'
Real Estate Funds | Minimum	'	'	'
Revenue from External Customer [Line Items]	'	'	'
Management Fees, Percent Fee	0.75%	'	'
Cash management [Member] | Maximum	'	'	'
Revenue from External Customer [Line Items]	'	'	'
Management Fees, Percent Fee	0.20%	'	'
During investment period [Member] | Healthcare Royalty Partners	'	'	'
Revenue from External Customer [Line Items]	'	'	'
Management Fees, Percent Fee	2.00%	'	'
After investment period [Member] | Healthcare Royalty Partners	'	'	'
Revenue from External Customer [Line Items]	'	'	'
Management Fees, Percent Fee	2.00%	'	'
Commodity trading advisory [Member] | Ramius Trading Strategies Managed Futures Fund [Member] | Maximum	'	'	'
Revenue from External Customer [Line Items]	'	'	'
Management Fees, Percent Fee	1.00%	'	'
Hedge Funds [Member]	'	'	'
Revenue from External Customer [Line Items]	'	'	'
Incentive Fees, Percent Fee	20.00%	'	'
Alternative Solutions [Member]	'	'	'
Revenue from External Customer [Line Items]	'	'	'
Incentive Fees, Percent Fee	10.00%	'	'

Discontinued_Operations_Detail

Discontinued Operations (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Discontinued Operations and Disposal Groups [Abstract]	'	'	'
Total revenues, net of interest expense	'	'	$2,899
Loss from discontinued operations	'	'	-24,075
Income tax expense/(benefit)	'	'	-429
Net income (loss) from discontinued operations, net of tax	$0	$0	($23,646)

Cash_collateral_pledged_Detail

Cash collateral pledged (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Cash and Cash Equivalents [Abstract]	'	'
Cash collateral pledged	$10,907	$9,160

Investments_of_Operating_Entit2

Investments of Operating Entities and Consolidated Funds - Securities Owned at Fair Value (Details) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Derivative Liability, Number of Instruments Held	38,221		10,070,267		'
Securities owned, at fair value	$320,737,000		$624,127,000		'
Other investments	99,483,000		84,930,000		'
Derivative, Fair Value, Net	377,000		202,000		'
Derivative liabilities	1,101,000		973,000		'
Derivative, Number of Instruments Held	71,129		28,133,185		'
Consolidated Funds	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Securities owned, at fair value	'		3,525,000		'
Other investments	187,480,000		204,205,000		'
Consolidated Funds | US Treasury and Government [Member]	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Trading Securities, Debt	'		1,911,000	[1]	'
Consolidated Funds | US Treasury and Government [Member] | Minimum	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Debt securities, interest rate	'		0.28%		'
Consolidated Funds | US Treasury and Government [Member] | Maximum	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Debt securities, interest rate	'		4.00%		'
Consolidated Funds | Commercial Paper	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Trading Securities, Debt	'		1,614,000	[2]	'
Enterprise Master	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Securities owned, at fair value	6,841,000		5,923,000		'
Derivative, Fair Value, Net	-21,000		6,000		'
Enterprise Master | Currency Forwards	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Derivative, Fair Value, Net	-21,000		6,000		'
Enterprise Master | Debt	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Trading Securities, Equity	5,000		79,000		'
Enterprise Master | Common Stock	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Trading Securities, Equity	2,677,000		2,680,000		'
Enterprise Master | Preferred Stock	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Trading Securities, Equity	973,000		997,000		'
Enterprise Master | Private Equity	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Trading Securities, Equity	406,000		297,000		'
Enterprise Master | Restricted Stock	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Trading Securities, Equity	124,000		26,000		'
Enterprise Master | Rights	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Trading Securities, Equity	2,528,000		1,714,000		'
Enterprise Master | Warrants and Rights	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Trading Securities, Equity	0		2,000		'
Enterprise Master | Trade Claims	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Trading Securities, Equity	128,000		128,000		'
Operating Entities	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Securities owned, at fair value	320,737,000		624,127,000		'
Other investments	99,483,000		84,930,000		'
Securities sold, not yet purchased, at fair value	137,527,000		177,937,000		'
Operating Entities | Other Income	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Realized and unrealized gains/(losses) related to derivatives trading activities	4,400,000		7,800,000		7,000,000
Operating Entities | Derivative contracts, at fair value | Receivables from Brokers-Dealers and Clearing Organizations	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Collateral posted	10,000,000		6,700,000		'
Operating Entities | US Government Securities	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Trading Securities, Debt	9,000	[3]	137,478,000	[3]	'
Debt securities, interest rate	5.95%		'		'
Operating Entities | US Government Securities | Minimum	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Debt securities, interest rate	'		0.25%		'
Operating Entities | US Government Securities | Maximum	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Debt securities, interest rate	'		5.95%		'
Operating Entities | Convertible Bonds	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Trading Securities, Debt	5,958,000	[4]	6,202,000	[4]	'
Debt securities, interest rate	'		5.00%		'
Operating Entities | Convertible Bonds | Minimum	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Debt securities, interest rate	5.00%		'		'
Operating Entities | Convertible Bonds | Maximum	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Debt securities, interest rate	10.00%		'		'
Operating Entities | Common Stock	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Trading Securities, Equity	176,939,000		259,292,000		'
Operating Entities | Preferred Stock	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Trading Securities, Equity	324,000		2,332,000		'
Operating Entities | Corporate Debt Securities [Member] | Minimum	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Debt securities, interest rate	3.38%		'		'
Operating Entities | Options	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Trading Securities, Equity	9,698,000		20,546,000		'
Operating Entities | Warrants and Rights	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Trading Securities, Equity	5,912,000		2,354,000		'
Operating Entities | Mutual Funds	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Trading Securities, Equity	525,000		2,845,000		'
Operating Entities | Futures, Forwards and Equity Swap Contracts [Member] | Other	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Derivative assets	400,000		200,000		'
Operating Entities | Corporate Bonds	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Trading Securities, Debt	121,372,000	[5]	193,078,000	[5]	'
Operating Entities | Corporate Bonds | Minimum	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Debt securities, interest rate	'		3.09%		'
Operating Entities | Corporate Bonds | Maximum	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Debt securities, interest rate	11.75%		12.50%		'
Merger Master	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Securities owned, at fair value	48,545,000		'		'
Derivative, Fair Value, Net	-102,000		'		'
Merger Master | Common Stock	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Securities owned, at fair value	33,901,000		'		'
Merger Master | Options	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Securities owned, at fair value	200,000		'		'
Merger Master | Equity swap	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Derivative, Fair Value, Net	-10,000		'		'
Merger Master | Cross rate	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Derivative, Fair Value, Net	-92,000		'		'
Merger Master | Corporate Bonds	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Securities owned, at fair value	14,444,000	[6]	'		'
Merger Master | Corporate Bonds | Minimum	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Debt securities, interest rate	'		7.00%		'
Merger Master | Corporate Bonds | Maximum	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Debt securities, interest rate	'		10.88%		'
Futures, Forwards and Equity Swap Contracts [Member] | Operating Entities | Accounts Payable, Accrued Expenses and Other Liabilities	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Derivative liabilities	1,100,000		1,000,000		'
Options | Operating Entities	'		'		'
Schedule of Trading Securities and Other Trading Assets [Line Items]	'		'		'
Securities sold, not yet purchased, at fair value	$6,573,000		$9,076,000		'
[1]	As of DecemberB 31, 2012, maturities ranged from August 2013 to December 2014 and interest rates ranged between 0.28% and 4.00%.
[2]	As of DecemberB 31, 2012, commercial paper was purchased at a discount and matures on January 2, 2013.
[3]	As of DecemberB 31, 2013, the maturity was April 2016 with an interest rate of 5.95%. As of DecemberB 31, 2012, maturities ranged from November 2013 to November 2022 and interest rates ranged between 0.25% and 5.95%.
[4]	As of DecemberB 31, 2013, maturities ranged from May 2014 to October 2014 and interest rates ranged between 5.00% to 10.00%. As of DecemberB 31, 2012, maturities ranged from May 2014 to July 2014 with an interest rate of 5.00%.
[5]	As of DecemberB 31, 2013, maturities ranged from January 2014 to February 2046 and interest rates ranged between 3.38% and 11.75%. As of DecemberB 31, 2012, maturities ranged from January 2013 to February 2041 and interest rates ranged between 3.09% and 12.50%.
[6]	As of DecemberB 31, 2013, maturities ranged from April 2016 to October 2020 and interest rates ranged between 7.00% and 10.88%.

Investments_of_Operating_Entit3

Investments of Operating Entities and Consolidated Funds - Other Investments (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Investment Holdings [Line Items]	'	'	'
Net realized gains (losses) on investments and other transactions	$6,050	($8,121)	$4,959
Net unrealized gains (losses) on investments, Consolidated Funds	4,628	14,497	-34
Net realized gains (losses) on derivatives, Consolidated Funds	521	915	-651
Net unrealized gains (losses) on derivatives, Consolidated Funds	($156)	($38)	$68

Investments_of_Operating_Entit4

Investments of Operating Entities and Consolidated Funds - Portfolio Funds (Details) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Investment Holdings [Line Items]	'		'
Number of funds	8		'
Other investments	$99,483,000		$84,930,000
Operating Entities	'		'
Investment Holdings [Line Items]	'		'
Other investments	99,483,000		84,930,000
Consolidated Funds	'		'
Investment Holdings [Line Items]	'		'
Other investments	187,480,000		204,205,000
Consolidated Fund of Funds	'		'
Investment Holdings [Line Items]	'		'
Number of funds	3		'
RTS Global 3X Fund LP	'		'
Investment Holdings [Line Items]	'		'
Number of funds	6		'
Portfolio Funds | Operating Entities	'		'
Investment Holdings [Line Items]	'		'
Other investments	71,051,000		55,898,000
Portfolio Funds | Operating Entities | Healthcare Royalty Partners | Affiliated Entity	'		'
Investment Holdings [Line Items]	'		'
Other investments	9,741,000	[1],[2]	7,866,000	[1],[2]
Portfolio Funds | Operating Entities | Healthcare Royalty Partners II | Affiliated Entity	'		'
Investment Holdings [Line Items]	'		'
Other investments	4,961,000	[1],[2]	6,415,000	[1],[2]
Portfolio Funds | Operating Entities | Orchard Square Partners Credit Fund LP | Affiliated Entity	'		'
Investment Holdings [Line Items]	'		'
Other investments	12,674,000	[2],[3]	14,196,000	[2],[3]
Required notice period, redemption	'60 days		'60 days
Penalty on redemptions of less than one year	4.00%		4.00%
Portfolio Funds | Operating Entities | Tapestry Investment Co PCC Ltd	'		'
Investment Holdings [Line Items]	'		'
Other investments	0	[4]	194,000	[4]
Portfolio Funds | Operating Entities | Starboard Value and Opportunity Fund LP | Affiliated Entity	'		'
Investment Holdings [Line Items]	'		'
Other investments	17,495,000	[2],[5]	15,706,000	[2],[5]
Required notice period, withdrawal	'90 days		'90 days
Portfolio Funds | Operating Entities | Formation 8 Partners Fund I LP	'		'
Investment Holdings [Line Items]	'		'
Other investments	2,788,000	[6]	1,500,000	[6]
Portfolio Funds | Operating Entities | RCG LV Park Lane LLC	'		'
Investment Holdings [Line Items]	'		'
Other investments	678,000	[7]	708,000	[7]
Portfolio Funds | Operating Entities | RCGL 12E13th LLC	'		'
Investment Holdings [Line Items]	'		'
Other investments	558,000	[8]	0	[8]
Portfolio Funds | Operating Entities | RCGLongview Debt Fund V, L.P.	'		'
Investment Holdings [Line Items]	'		'
Other investments	11,979,000	[8]	0	[8]
Portfolio Funds | Operating Entities | Other Funds	'		'
Investment Holdings [Line Items]	'		'
Other investments	7,772,000	[9]	7,826,000	[9]
Portfolio Funds | Operating Entities | Other Funds | Affiliated Entity	'		'
Investment Holdings [Line Items]	'		'
Other investments	2,405,000	[10],[2]	1,487,000	[10],[2]
Portfolio Funds | Consolidated Funds	'		'
Investment Holdings [Line Items]	'		'
Other investments	182,638,000		190,081,000
Portfolio Funds | Enterprise Master	'		'
Investment Holdings [Line Items]	'		'
Other investments	144,223,000		167,147,000
Portfolio Funds | Enterprise Master | RCG Longview Equity Fund, LP | Affiliated Entity | Real Estate Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	8,470,000	[11]	11,027,000	[11]
Portfolio Funds | Enterprise Master | RCG Longview II, LP | Affiliated Entity | Real Estate Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	800,000	[11]	970,000	[11]
Portfolio Funds | Enterprise Master | RCG Longview Debt Fund IV, LP | Affiliated Entity | Real Estate Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	17,641,000	[11]	30,572,000	[11]
Portfolio Funds | Enterprise Master | RCG Longview, LP | Affiliated Entity | Real Estate Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	319,000	[11]	265,000	[11]
Portfolio Funds | Enterprise Master | RCG Soundview, LLC | Affiliated Entity | Real Estate Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	442,000	[11]	2,374,000	[11]
Portfolio Funds | Enterprise Master | RCG Urban American Real Estate Fund, L.P. | Affiliated Entity | Real Estate Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	1,812,000	[11]	1,987,000	[11]
Portfolio Funds | Enterprise Master | RCG International Sarl | Affiliated Entity | Multi-strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	1,795,000	[11]	752,000	[11]
Portfolio Funds | Enterprise Master | RCG Special Opportunities Fund, Ltd | Affiliated Entity | Multi-strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	82,119,000	[11]	80,166,000	[11]
Portfolio Funds | Enterprise Master | RCG Endeavour, LLC | Affiliated Entity | Multi-strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	6,000	[11]	43,000	[11]
Portfolio Funds | Enterprise Master | RCG Energy, LLC | Affiliated Entity | Energy Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	2,842,000	[11]	14,239,000	[11]
Portfolio Funds | Enterprise Master | RCG Renergys, LLC | Affiliated Entity | Energy Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	1,000	[11]	1,000	[11]
Portfolio Funds | Enterprise Master | Other Private Investment | Various Strategies	'		'
Investment Holdings [Line Items]	'		'
Other investments	12,952,000		12,430,000
Portfolio Funds | Enterprise Master | Real Estate Funds | Real Estate Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	15,024,000		12,321,000
Portfolio Funds | Enterprise LP	'		'
Investment Holdings [Line Items]	'		'
Other investments	155,530,000		173,348,000
Portfolio Funds | Merger Fund	'		'
Investment Holdings [Line Items]	'		'
Other investments	26,963,000		0
Portfolio Funds | Consolidated Fund of Funds	'		'
Investment Holdings [Line Items]	'		'
Other investments	145,000		16,733,000
Portfolio Funds | Consolidated Fund of Funds | Tapestry Pooled Account V LLC | Affiliated Entity | Credit-Based Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	0	[11],[12]	1,657,000	[11],[12]
Portfolio Funds | Consolidated Fund of Funds | Independently Advised Portfolio Funds | Affiliated Entity | Futures and Global Macro Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		7,161,000	[13]
Required notice period, redemption	'		'5 days
Required notice period, redemption, intra-month	'		'3 days
Intra-month redemption fee	'		10,000
Portfolio Funds | Consolidated Fund of Funds | Externally Managed Portfolio Funds | Event Driven Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	0	[14]	7,125,000	[14]
Portfolio Funds | Consolidated Fund of Funds | Externally Managed Portfolio Funds | Hedged Equity Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	145,000	[15]	790,000	[15]
Portfolio Funds | Ramius Levered Multi-Strategy FOF LP	'		'
Investment Holdings [Line Items]	'		'
Other investments	0		1,860,000
Portfolio Funds | Ramius Levered Multi-Strategy FOF LP | Tapestry Pooled Account V LLC | Affiliated Entity | Credit-Based Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	0	[11],[12]	315,000	[11],[12]
Portfolio Funds | Ramius Levered Multi-Strategy FOF LP | Independently Advised Portfolio Funds | Affiliated Entity | Futures and Global Macro Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		0	[13]
Portfolio Funds | Ramius Levered Multi-Strategy FOF LP | Externally Managed Portfolio Funds | Event Driven Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	0	[14]	1,545,000	[14]
Portfolio Funds | Ramius Levered Multi-Strategy FOF LP | Externally Managed Portfolio Funds | Hedged Equity Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	0	[15]	0	[15]
Portfolio Funds | Ramius Multi-Strategy Master FOF LP	'		'
Investment Holdings [Line Items]	'		'
Other investments	0		'
Portfolio Funds | Ramius Multi-Strategy Master FOF LP | Tapestry Pooled Account V LLC | Affiliated Entity | Credit-Based Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	0	[11],[12]	'
Portfolio Funds | Ramius Multi-Strategy Master FOF LP | Externally Managed Portfolio Funds | Event Driven Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	0	[14]	'
Portfolio Funds | Ramius Multi-Strategy Master FOF LP | Externally Managed Portfolio Funds | Hedged Equity Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	0	[15]	'
Portfolio Funds | Ramius Vintage Multi-Strategy Master FOF LP	'		'
Investment Holdings [Line Items]	'		'
Other investments	145,000		'
Portfolio Funds | Ramius Vintage Multi-Strategy Master FOF LP | Tapestry Pooled Account V LLC | Affiliated Entity | Credit-Based Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	0	[11],[12]	'
Portfolio Funds | Ramius Vintage Multi-Strategy Master FOF LP | Externally Managed Portfolio Funds | Event Driven Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	0	[14]	'
Portfolio Funds | Ramius Vintage Multi-Strategy Master FOF LP | Externally Managed Portfolio Funds | Hedged Equity Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	145,000	[15]	'
Portfolio Funds | Ramius Multi-Strategy FOF LP	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		2,965,000
Portfolio Funds | Ramius Multi-Strategy FOF LP | Tapestry Pooled Account V LLC | Affiliated Entity | Credit-Based Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		649,000	[11],[12]
Portfolio Funds | Ramius Multi-Strategy FOF LP | Independently Advised Portfolio Funds | Affiliated Entity | Futures and Global Macro Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		0	[13]
Portfolio Funds | Ramius Multi-Strategy FOF LP | Externally Managed Portfolio Funds | Event Driven Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		2,316,000	[14]
Portfolio Funds | Ramius Multi-Strategy FOF LP | Externally Managed Portfolio Funds | Hedged Equity Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		0	[15]
Portfolio Funds | Ramius Vintage Multi-Strategy FOF LP	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		4,747,000
Portfolio Funds | Ramius Vintage Multi-Strategy FOF LP | Tapestry Pooled Account V LLC | Affiliated Entity | Credit-Based Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		693,000	[11],[12]
Portfolio Funds | Ramius Vintage Multi-Strategy FOF LP | Independently Advised Portfolio Funds | Affiliated Entity | Futures and Global Macro Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		0	[13]
Portfolio Funds | Ramius Vintage Multi-Strategy FOF LP | Externally Managed Portfolio Funds | Event Driven Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		3,264,000	[14]
Portfolio Funds | Ramius Vintage Multi-Strategy FOF LP | Externally Managed Portfolio Funds | Hedged Equity Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		790,000	[15]
Portfolio Funds | RTS Global 3X Fund LP	'		'
Investment Holdings [Line Items]	'		'
Other investments	0		7,161,000
Derivative asset (liability)	'		338,000
Portfolio Funds | RTS Global 3X Fund LP | Futures	'		'
Investment Holdings [Line Items]	'		'
Derivative asset (liability)	'		239,000
Portfolio Funds | RTS Global 3X Fund LP | Bond Futures	'		'
Investment Holdings [Line Items]	'		'
Derivative asset (liability)	'		489,000
Portfolio Funds | RTS Global 3X Fund LP | Commodity Futures	'		'
Investment Holdings [Line Items]	'		'
Derivative asset (liability)	'		47,000
Portfolio Funds | RTS Global 3X Fund LP | Currency Futures	'		'
Investment Holdings [Line Items]	'		'
Derivative asset (liability)	'		264,000
Portfolio Funds | RTS Global 3X Fund LP | Equity Futures	'		'
Investment Holdings [Line Items]	'		'
Derivative asset (liability)	'		-27,000
Portfolio Funds | RTS Global 3X Fund LP | Index Future [Member]	'		'
Investment Holdings [Line Items]	'		'
Derivative asset (liability)	'		-257,000
Portfolio Funds | RTS Global 3X Fund LP | Interest Rate Futures	'		'
Investment Holdings [Line Items]	'		'
Derivative asset (liability)	'		40,000
Portfolio Funds | RTS Global 3X Fund LP | Commodity Forwards	'		'
Investment Holdings [Line Items]	'		'
Derivative asset (liability)	'		-659,000
Portfolio Funds | RTS Global 3X Fund LP | Currency Forwards	'		'
Investment Holdings [Line Items]	'		'
Derivative asset (liability)	'		202,000
Portfolio Funds | RTS Global 3X Fund LP | Tapestry Pooled Account V LLC | Affiliated Entity | Credit-Based Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	0	[11],[12]	0	[11],[12]
Portfolio Funds | RTS Global 3X Fund LP | Independently Advised Portfolio Funds | Affiliated Entity | Futures and Global Macro Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		7,161,000	[13]
Portfolio Funds | RTS Global 3X Fund LP | Externally Managed Portfolio Funds | Event Driven Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	0	[14]	0	[14]
Portfolio Funds | RTS Global 3X Fund LP | Externally Managed Portfolio Funds | Hedged Equity Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	$0	[15]	$0	[15]
[1]	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.
[2]	These portfolio funds are affiliates of the Company
[3]	Orchard Square Partners Credit Fund LP (formerly known as Ramius Global Credit FundB LP) has a quarterly redemption policy with a 60 day notice period and a 4% penalty on redemptions of investments of less than a year in duration.
[4]	Tapestry Investment Company PCCB Ltd had been fully liquidated at the manager's discretion.
[5]	Starboard Value and Opportunity FundB LP permits quarterly withdrawals upon 90 days notice.
[6]	Formation 8 Partners Fund I is a private equity fund which invests in equity of early stage and growth transformational information and energy technology companies. Distributions will be made when the underlying investments are liquidated.
[7]	RCG LV Park Lane LLC is a single purpose entity formed to participate in a joint venture which acquired, at a discount, the mortgage notes on a portfolio of multifamily real estate properties located in Birmingham, Alabama. RCG LV Park Lane LLC is a private equity structure and therefore distributions will be made when the underlying investments are liquidated.
[8]	RCGL 12E13th LLC and RCG Longview Debt Fund V, L.P. are real estate private equity structures and therefore distributions will be made when the underlying investments are liquidated.
[9]	Other private investment represents the Company's closed end investment in a wireless broadband communication provider in Italy.
[10]	The majority of these funds are affiliates of the Company or are managed by the Company and the investors can redeem from these funds as investments are liquidated.
[11]	These Portfolio Funds are affiliates of the Company.
[12]	The Credit-Based strategy aims to generate returns via positions in the credit sensitive sphere of the fixed income markets. The strategy generally involves the purchase of corporate bonds with hedging of the interest exposure. The investments held in Tapestry Pooled Account VB LLC, a related fund, are held solely in a credit based fund which the underlying fund's manager has placed in a side-pocket. The remaining amount of the investments within this category represents an investment in a fund that is in the process of liquidating. Distributions from this fund will be received as underlying investments are liquidated.
[13]	The Futures and Global Macro strategy was comprised of several portfolio accounts, each of which was advised independently by a commodity trading advisor implementing primarily managed futures or global macro-based investment strategies. The trading advisors (through their respective portfolio accounts) traded independently of each other and, as a group, employed a wide variety of systematic, relative value and discretionary trading programs in the global currency, fixed income, commodities and equity futures markets. In implementing their trading programs, the trading advisors traded primarily in the futures and forward markets (as well as in related options). Although certain trading advisors were permitted to use total return swaps and trade other financial instruments from time to time on an interim basis, the primary focus was on the futures and forward markets. Redemption frequency of these portfolio accounts were monthly (and intra month for a $10,000 fee) and the notification period for redemptions was 5 business days (or 3 business days for intra month redemptions).
[14]	The Event Driven strategy is generally implemented through various combinations and permutations of merger arbitrage, restructuring and distressed instruments. The investments in this category are primarily in a side pocket or suspended with undetermined payout dates.
[15]	The Hedged Equity strategy focuses on equity strategies with some directional market exposure. The strategy attempts to profit from market efficiencies and direction. The investee fund manager has side-pocketed investments.

Investments_of_Operating_Entit5

Investments of Operating Entities and Consolidated Funds - Real Estate Investments (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Investment Holdings [Line Items]	'	'
Other investments	$99,483,000	$84,930,000
Operating Entities	'	'
Investment Holdings [Line Items]	'	'
Other investments	99,483,000	84,930,000
RCG RE Manager, LLC | Operating Entities | Real Estate Equity Investment	'	'
Investment Holdings [Line Items]	'	'
Other investments	$2,088,000	$1,864,000

Investments_of_Operating_Entit6

Investments of Operating Entities and Consolidated Funds - Equity Method Investments (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Equity Method Investments [Line Items]	'	'	'
Other investments	$99,483,000	$84,930,000	'
Operating Entities	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Number of entities in which Company holds a majority	3	'	'
Other investments	99,483,000	84,930,000	'
Operating Entities | Net Gains (Losses) on Securities, Derivatives and Other Investments	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Income (loss) from equity method investments	16,100,000	15,600,000	5,400,000
Operating Entities | CBOE Stock Exchange, LLC	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Equity method investment, ownership percentage	9.70%	'	'
Operating Entities | Equity Method Investee, Exceeded Threshold for Income Test	'	'	'
Equity Method Investment, Summarized Financial Information [Abstract]	'	'	'
Assets	626,866,000	498,557,000	'
Liabilities	226,138,000	20,170,000	'
Equity	400,728,000	478,387,000	'
Revenues	75,429,000	77,502,000	33,061,000
Expenses	-69,893,000	-60,093,000	-45,335,000
Net realized and unrealized gains (losses)	77,042,000	5,575,000	9,365,000
Net Income	82,578,000	22,984,000	-2,909,000
Operating Entities | RCG Longview Partners II, LLC [Member] | Clawback Obligation | Accounts Payable, Accrued Expenses and Other Liabilities	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Contractual obligation	6,200,000	'	'
Operating Entities | Equity Method Investments	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Other investments	25,966,000	26,462,000	'
Operating Entities | Equity Method Investments | RCG Longview Debt Fund IV Management, LLC	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Other investments	1,533,000	1,954,000	'
Operating Entities | Equity Method Investments | RCG Longview Debt Fund V Partners, LLC	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Other investments	1,497,000	0	'
Operating Entities | Equity Method Investments | Healthcare Royalty GP, LLC	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Other investments	794,000	642,000	'
Operating Entities | Equity Method Investments | Healthcare Royalty GP II, LLC	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Other investments	840,000	1,086,000	'
Operating Entities | Equity Method Investments | Healthcare Royalty GP III, LLC	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Other investments	47,000	0	'
Operating Entities | Equity Method Investments | CBOE Stock Exchange, LLC	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Other investments	1,351,000	2,058,000	'
Operating Entities | Equity Method Investments | Starboard Value LP	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Other investments	14,263,000	12,757,000	'
Operating Entities | Equity Method Investments | RCG Longview Partners, LLC	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Other investments	1,839,000	1,535,000	'
Operating Entities | Equity Method Investments | RCG Longview Louisiana Manager, LLC	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Other investments	0	1,866,000	'
Operating Entities | Equity Method Investments | RCG Urban American, LLC	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Other investments	316,000	1,380,000	'
Operating Entities | Equity Method Investments | RCG Urban American Management, LLC	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Other investments	238,000	545,000	'
Operating Entities | Equity Method Investments | RCG Longview Equity Management, LLC	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Other investments	292,000	285,000	'
Operating Entities | Equity Method Investments | Urban American Real Estate Fund II, LLC	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Other investments	1,785,000	1,636,000	'
Operating Entities | Equity Method Investments | RCG Kennedy House, LLC	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Other investments	502,000	377,000	'
Operating Entities | Equity Method Investments | Equity Method Investee, Other	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Other investments	669,000	341,000	'
Operating Entities | Minimum	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Equity method investment, ownership percentage	30.00%	'	'
Operating Entities | Maximum	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Equity method investment, ownership percentage	55.00%	'	'
Starboard Value A LP [Member] | Operating Entities | Equity Method Investee, Exceeded Threshold for Income Test	'	'	'
Equity Method Investment, Summarized Financial Information [Abstract]	'	'	'
Cash	14,000	'	'
Performance Fee Receivable	25,214,000	20,448,000	'
Investments in Portfolio Funds	2,201,000	1,380,000	'
Liabilities	0	0	'
Equity	27,429,000	21,828,000	'
Performance Fee Revenues	23,098,000	20,448,000	4,750,000
Net realized and unrealized gains (losses)	283,000	254,000	18,000
Net Income	$23,381,000	$20,702,000	$4,768,000

Investments_of_Operating_Entit7

Investments of Operating Entities and Consolidated Funds - Lehman Claims (Details) (USD $)

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Nov. 30, 2013

Jun. 30, 2013

Dec. 31, 2012

Nov. 30, 2012

Nov. 02, 2012

Sep. 15, 2008

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Sep. 26, 2013

Feb. 29, 2012

Dec. 31, 2011

Jul. 31, 2010

Jun. 30, 2010

Dec. 31, 2013

Feb. 28, 2013

Nov. 30, 2012

Nov. 02, 2012

Sep. 15, 2008

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Jul. 31, 2013

Dec. 31, 2013

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Consolidated Funds

Consolidated Funds

Consolidated Funds

Consolidated Funds

Enterprise Master

Enterprise Master

Enterprise Master

Enterprise Master

Enterprise Master

Enterprise Master

Enterprise Master

Enterprise Master

Enterprise Master

Enterprise Master

Enterprise Master

Enterprise Master

Enterprise Master

Enterprise Master

Enterprise LP

Lehman claims, at fair value

Lehman claims, at fair value

Lehman claims, at fair value

Lehman claims, at fair value

Lehman claims, at fair value

Lehman claims, at fair value

Lehman claims, at fair value

Lehman claims, at fair value

Lehman claims, at fair value

Lehman claims, at fair value

Lehman claims, at fair value

Lehman claims, at fair value

Lehman claims, at fair value

Lehman claims, at fair value

Lehman claims, at fair value

Lehman claims, at fair value

Lehman claims, at fair value

Lehman claims, at fair value

Lehman claims, at fair value

Trust Assets

Foreign Denominated Assets

Cash

Cash

Lehman claims, at fair value

Investment Holdings [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Initial value

'

'

'

'

'

'

'

'

'

'

$1,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

$24,300,000

'

'

$4,900,000

$4,900,000

'

Unsecured claim

'

'

'

'

'

'

'

'

'

900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

1,300,000

'

'

'

'

'

'

Percent of client's Best Claim

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

105.00%

'

'

'

'

'

'

'

'

'

Distribution percent withheld for tax

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

30.00%

'

'

'

'

'

'

'

'

'

Value of Best Claim

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

800,000

'

'

'

'

'

'

'

'

'

Dividend percent received

'

'

'

'

'

23.70%

43.30%

'

25.20%

'

'

'

'

'

'

'

'

'

'

'

'

'

25.20%

'

'

'

'

'

'

'

Dividend amount received

'

'

'

'

'

200,000

400,000

'

200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

300,000

'

'

'

'

'

'

'

Total Dividend Amount Received

'

'

'

'

900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total Dividend percent received

'

'

'

'

92.20%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Other Investments, Claim Settlement Sold

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,300,000

'

'

'

'

'

'

'

'

Assets returned

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2,400,000

'

9,500,000

'

'

'

'

'

'

'

'

'

'

Proceeds from sale of returned assets

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10,700,000

'

'

'

'

'

'

'

'

'

'

'

Distributions of proceeds from returned assets

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

14,900,000

2,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Tax Withholding on Distribution of Proceeds from Sale of Returned Assets

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Other investments

99,483,000

84,930,000

99,483,000

84,930,000

378,000

'

'

706,000

'

'

'

187,480,000

204,205,000

4,842,000

14,124,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Other Investments, claim to trust assets held by LBIE through Lehman Brothers

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10,600,000

'

'

'

'

'

'

'

'

'

Percentage of securities liquidated at LBI

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

90.00%

'

'

'

'

'

'

'

'

'

Distributions of client's Best Claim

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Other Investments, initial claim current value

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

7,000,000

'

'

'

'

'

'

'

'

4,800,000

Claim Resolution Agreement fee

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1.00%

1.00%

'

'

'

Other Investments, not within control of LBIE

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$5,000,000

'

'

'

Recoverable claims assigned to variable interest entities

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100.00%

'

'

'

'

'

'

'

'

'

Percentage of Net Equity Claim

'

'

'

'

131.50%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Investments_of_Operating_Entit8

Investments of Operating Entities and Consolidated Funds - Securities Sold, Not Yet Purchased (Details) (Operating Entities, USD $)	Dec. 31, 2013		Dec. 31, 2012
Investments Sold, Not yet Purchased [Line Items]	'		'
Securities sold, not yet purchased, at fair value	$137,527,000		$177,937,000
Warrants and Rights	'		'
Investments Sold, Not yet Purchased [Line Items]	'		'
Securities sold, not yet purchased, at fair value	0		3,000
Corporate Bonds	'		'
Investments Sold, Not yet Purchased [Line Items]	'		'
Securities sold, not yet purchased, at fair value	55,000	[1]	61,000	[1]
Securities sold, not yet purchased, interest rate	5.55%		5.55%
Common Stock	'		'
Investments Sold, Not yet Purchased [Line Items]	'		'
Securities sold, not yet purchased, at fair value	130,899,000		168,797,000
Options	'		'
Investments Sold, Not yet Purchased [Line Items]	'		'
Securities sold, not yet purchased, at fair value	$6,573,000		$9,076,000
[1]	As of DecemberB 31, 2013 and 2012, the maturity was January 2026 with an interest rate of 5.55%

Investments_of_Operating_Entit9

Investments of Operating Entities and Consolidated Funds - Securities Purchased Under Agreements to Resell or Sold Under Agreements to Repurchase (Details) (USD $)	Dec. 31, 2013		Dec. 31, 2012
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]	'		'
Securities Sold under Agreements to Repurchase, Gross	$3,657,000		$165,945,000
Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral	0	[1]	0	[1]
Securities sold under agreements to repurchase	3,657,000		165,945,000
Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral	3,657,000	[2]	165,945,000	[2]
Securities sold under agreements to repurchase, net	0		0
Operating Entities | Securities Owned at Fair Value	'		'
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]	'		'
Securities pledged by the Company as collateral	4,600,000		173,700,000
Operating Entities | Maturity on Demand	'		'
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]	'		'
Securities sold under agreements to repurchase	3,657,000		165,945,000
Operating Entities | Royal Bank of Canada | Maturity on Demand	'		'
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]	'		'
Interest rates on repurchase agreements	1.75%		'
Securities sold under agreements to repurchase	3,657,000		29,039,000
Operating Entities | Royal Bank of Canada | Minimum | Maturity on Demand	'		'
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]	'		'
Interest rates on repurchase agreements	'		2.12%
Operating Entities | Royal Bank of Canada | Maximum | Maturity on Demand	'		'
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]	'		'
Interest rates on repurchase agreements	'		2.20%
Operating Entities | Barclays Capital Inc | Maturity on Demand	'		'
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]	'		'
Securities sold under agreements to repurchase	'		136,906,000
Operating Entities | Barclays Capital Inc | Minimum | Maturity on Demand	'		'
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]	'		'
Interest rates on repurchase agreements	'		-0.05%
Operating Entities | Barclays Capital Inc | Maximum | Maturity on Demand	'		'
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]	'		'
Interest rates on repurchase agreements	'		0.23%
US Treasury and Government [Member] | Operating Entities | Securities Owned at Fair Value	'		'
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]	'		'
Securities pledged by the Company as collateral	'		137,500,000
Corporate Bonds | Operating Entities | Securities Owned at Fair Value	'		'
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]	'		'
Securities pledged by the Company as collateral	'		$36,200,000
[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 collateral held/posted.

Recovered_Sheet1

Investments of Operating Entities and Consolidated Funds - Securities Lending and Borrowing Transactions (Details) (USD $)	Dec. 31, 2013		Dec. 31, 2012
Investments, Debt and Equity Securities [Abstract]	'		'
Securities Loaned, Fair Value	$881,700,000		$388,400,000
Securities Borrowed, Fair Value	892,800,000		391,600,000
Securities borrowed	927,773,000		406,326,000
Securities Borrowed, Amount Offset Against Collateral	0	[1]	0	[1]
Securities Borrowed	927,773,000		406,326,000
Securities Borrowed, Not Offset against Collateral	927,773,000	[2]	406,326,000	[2]
Securities Borrowed, net	0		0
Securities loaned	918,577,000		408,972,000
Securities Loaned, Amount Offset Against Collateral	0	[1]	0	[1]
Securities Loaned	918,577,000		408,972,000
Securities Loaned, Not Offset Against Collateral	918,577,000	[2]	408,972,000	[2]
Securities Loaned, net	$0		$0
[1]	Includes financial instruments subject to enforceable master netting provisions that are permitted to be offset to the extent an event of default has occurred.
[2]	Includes the amount of cash collateral held/posted.

Recovered_Sheet2

Investments of Operating Entities and Consolidated Funds - Variable Interest Entities (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Variable Interest Entity [Line Items]	'	'
Total assets of nonconsolidated variable interest entities	$1,700,000,000	$1,400,000,000
Total liabilities of nonconsolidated variable interest entities	242,500,000	22,800,000
Variable Interest Entity, Not Primary Beneficiary	'	'
Variable Interest Entity [Line Items]	'	'
Maximum exposure regarding nonconsolidated variable interest entities	$193,900,000	$208,400,000

Fair_Value_Measurements_for_Op2

Fair Value Measurements for Operating Entities and Consolidated Funds Assets and Liabilities at Fair Value on a Recurring Basis (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities sold, not yet purchased, at fair value	$137,527	$177,937
Operating Entities | Fair Value, Measurements, Recurring | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	394,631	682,797
Financial Liabilities Fair Value Disclosure	145,565	187,026
Operating Entities | Fair Value, Measurements, Recurring | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	181,901	413,843
Financial Liabilities Fair Value Disclosure	137,747	178,157
Operating Entities | Fair Value, Measurements, Recurring | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	146,977	233,605
Financial Liabilities Fair Value Disclosure	881	750
Operating Entities | Fair Value, Measurements, Recurring | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	65,753	35,349
Financial Liabilities Fair Value Disclosure	6,937	8,119
Operating Entities | Fair Value, Measurements, Recurring | Common Stock | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	130,899	168,797
Operating Entities | Fair Value, Measurements, Recurring | Common Stock | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	130,899	168,797
Operating Entities | Fair Value, Measurements, Recurring | Common Stock | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	0	0
Operating Entities | Fair Value, Measurements, Recurring | Common Stock | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	0	0
Operating Entities | Fair Value, Measurements, Recurring | Corporate Bonds | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	55	61
Operating Entities | Fair Value, Measurements, Recurring | Corporate Bonds | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	0	0
Operating Entities | Fair Value, Measurements, Recurring | Corporate Bonds | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	55	61
Operating Entities | Fair Value, Measurements, Recurring | Corporate Bonds | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	0	0
Operating Entities | Fair Value, Measurements, Recurring | Warrants and Rights | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	'	3
Operating Entities | Fair Value, Measurements, Recurring | Warrants and Rights | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	'	0
Operating Entities | Fair Value, Measurements, Recurring | Warrants and Rights | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	'	0
Operating Entities | Fair Value, Measurements, Recurring | Warrants and Rights | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	'	3
Operating Entities | Fair Value, Measurements, Recurring | Contingent liability payable [Member] | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	6,937	8,116
Operating Entities | Fair Value, Measurements, Recurring | Contingent liability payable [Member] | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	'	0
Operating Entities | Fair Value, Measurements, Recurring | Contingent liability payable [Member] | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	'	0
Operating Entities | Fair Value, Measurements, Recurring | Contingent liability payable [Member] | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	6,937	8,116
Operating Entities | Fair Value, Measurements, Recurring | Futures | Derivative Liabilities | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	275	370
Operating Entities | Fair Value, Measurements, Recurring | Futures | Derivative Liabilities | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	275	370
Operating Entities | Fair Value, Measurements, Recurring | Futures | Derivative Liabilities | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	0	0
Operating Entities | Fair Value, Measurements, Recurring | Futures | Derivative Liabilities | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	0	0
Operating Entities | Fair Value, Measurements, Recurring | Forward Contracts | Derivative Liabilities | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	301	603
Operating Entities | Fair Value, Measurements, Recurring | Forward Contracts | Derivative Liabilities | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	0	0
Operating Entities | Fair Value, Measurements, Recurring | Forward Contracts | Derivative Liabilities | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	301	603
Operating Entities | Fair Value, Measurements, Recurring | Forward Contracts | Derivative Liabilities | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	0	0
Operating Entities | Fair Value, Measurements, Recurring | Equity Swaps | Derivative Liabilities | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	525	'
Operating Entities | Fair Value, Measurements, Recurring | Equity Swaps | Derivative Liabilities | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	0	'
Operating Entities | Fair Value, Measurements, Recurring | Equity Swaps | Derivative Liabilities | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	525	'
Operating Entities | Fair Value, Measurements, Recurring | Equity Swaps | Derivative Liabilities | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	0	'
Operating Entities | Fair Value, Measurements, Recurring | Options | Derivative Liabilities | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	6,573	9,076
Operating Entities | Fair Value, Measurements, Recurring | Options | Derivative Liabilities | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	6,573	8,990
Operating Entities | Fair Value, Measurements, Recurring | Options | Derivative Liabilities | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	0	86
Operating Entities | Fair Value, Measurements, Recurring | Options | Derivative Liabilities | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Financial Liabilities Fair Value Disclosure	0	0
Operating Entities | Fair Value, Measurements, Recurring | Preferred Stock | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	324	2,332
Operating Entities | Fair Value, Measurements, Recurring | Preferred Stock | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Operating Entities | Fair Value, Measurements, Recurring | Preferred Stock | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Operating Entities | Fair Value, Measurements, Recurring | Preferred Stock | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	324	2,332
Operating Entities | Fair Value, Measurements, Recurring | US Government Securities | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	9	137,478
Operating Entities | Fair Value, Measurements, Recurring | US Government Securities | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	9	137,478
Operating Entities | Fair Value, Measurements, Recurring | US Government Securities | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Operating Entities | Fair Value, Measurements, Recurring | US Government Securities | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Operating Entities | Fair Value, Measurements, Recurring | Convertible Bonds | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	5,958	6,202
Operating Entities | Fair Value, Measurements, Recurring | Convertible Bonds | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Operating Entities | Fair Value, Measurements, Recurring | Convertible Bonds | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	4,008	6,202
Operating Entities | Fair Value, Measurements, Recurring | Convertible Bonds | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	1,950	0
Operating Entities | Fair Value, Measurements, Recurring | Corporate Bonds | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	121,372	193,078
Operating Entities | Fair Value, Measurements, Recurring | Corporate Bonds | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Operating Entities | Fair Value, Measurements, Recurring | Corporate Bonds | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	121,372	192,563
Operating Entities | Fair Value, Measurements, Recurring | Corporate Bonds | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	515
Operating Entities | Fair Value, Measurements, Recurring | Common Stock | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	176,939	259,292
Operating Entities | Fair Value, Measurements, Recurring | Common Stock | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	171,277	254,606
Operating Entities | Fair Value, Measurements, Recurring | Common Stock | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	2,103	2,137
Operating Entities | Fair Value, Measurements, Recurring | Common Stock | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	3,559	2,549
Operating Entities | Fair Value, Measurements, Recurring | Mutual Funds | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	525	2,845
Operating Entities | Fair Value, Measurements, Recurring | Mutual Funds | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	525	2,845
Operating Entities | Fair Value, Measurements, Recurring | Mutual Funds | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Operating Entities | Fair Value, Measurements, Recurring | Mutual Funds | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Futures | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	285	'
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Futures | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	285	'
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Futures | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	'
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Futures | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	'
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Forward Contracts | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	22	202
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Forward Contracts | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Forward Contracts | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	22	202
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Forward Contracts | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Equity Swaps | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	70	'
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Equity Swaps | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	'
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Equity Swaps | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	70	'
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Equity Swaps | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	'
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Options | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	9,698	20,546
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Options | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	9,698	18,273
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Options | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	2,273
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Options | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Operating Entities | Fair Value, Measurements, Recurring | Warrants and Rights | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	5,912	2,354
Operating Entities | Fair Value, Measurements, Recurring | Warrants and Rights | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	107	641
Operating Entities | Fair Value, Measurements, Recurring | Warrants and Rights | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Operating Entities | Fair Value, Measurements, Recurring | Warrants and Rights | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	5,805	1,713
Operating Entities | Fair Value, Measurements, Recurring | Portfolio Funds, at fair value | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	71,051	55,898
Operating Entities | Fair Value, Measurements, Recurring | Portfolio Funds, at fair value | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Operating Entities | Fair Value, Measurements, Recurring | Portfolio Funds, at fair value | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	19,402	30,228
Operating Entities | Fair Value, Measurements, Recurring | Portfolio Funds, at fair value | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	51,649	25,670
Operating Entities | Fair Value, Measurements, Recurring | Real Estate Investments, at fair value | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	2,088	1,864
Operating Entities | Fair Value, Measurements, Recurring | Real Estate Investments, at fair value | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Operating Entities | Fair Value, Measurements, Recurring | Real Estate Investments, at fair value | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Operating Entities | Fair Value, Measurements, Recurring | Real Estate Investments, at fair value | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	2,088	1,864
Operating Entities | Fair Value, Measurements, Recurring | Lehman claims, at fair value | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	378	706
Operating Entities | Fair Value, Measurements, Recurring | Lehman claims, at fair value | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Operating Entities | Fair Value, Measurements, Recurring | Lehman claims, at fair value | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Operating Entities | Fair Value, Measurements, Recurring | Lehman claims, at fair value | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	378	706
Consolidated Funds | Fair Value, Measurements, Recurring | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	187,480	207,730
Consolidated Funds | Fair Value, Measurements, Recurring | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	1,911
Consolidated Funds | Fair Value, Measurements, Recurring | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	26,964	8,775
Consolidated Funds | Fair Value, Measurements, Recurring | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	160,516	197,044
Consolidated Funds | Fair Value, Measurements, Recurring | US Government Securities | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	'	1,911
Consolidated Funds | Fair Value, Measurements, Recurring | US Government Securities | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	'	1,911
Consolidated Funds | Fair Value, Measurements, Recurring | US Government Securities | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	'	0
Consolidated Funds | Fair Value, Measurements, Recurring | US Government Securities | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	'	0
Consolidated Funds | Fair Value, Measurements, Recurring | Commercial Paper | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	'	1,614
Consolidated Funds | Fair Value, Measurements, Recurring | Commercial Paper | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	'	0
Consolidated Funds | Fair Value, Measurements, Recurring | Commercial Paper | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	'	1,614
Consolidated Funds | Fair Value, Measurements, Recurring | Commercial Paper | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	'	0
Consolidated Funds | Fair Value, Measurements, Recurring | Portfolio Funds, at fair value | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	182,638	190,081
Consolidated Funds | Fair Value, Measurements, Recurring | Portfolio Funds, at fair value | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Portfolio Funds, at fair value | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	26,964	7,161
Consolidated Funds | Fair Value, Measurements, Recurring | Portfolio Funds, at fair value | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	155,674	182,920
Consolidated Funds | Fair Value, Measurements, Recurring | Lehman claims, at fair value | Total Estimated Fair Value	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	4,842	14,124
Consolidated Funds | Fair Value, Measurements, Recurring | Lehman claims, at fair value | Level 1	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Lehman claims, at fair value | Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	0	0
Consolidated Funds | Fair Value, Measurements, Recurring | Lehman claims, at fair value | Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Assets, Fair Value Disclosure, Recurring	$4,842	$14,124

Fair_Value_Measurements_for_Op3

Fair Value Measurements for Operating Entities and Consolidated Funds Unobservable Input Roll Forward (Details) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Operating Entities | Preferred Stock	'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'
Transfers In	$0		$0		'
Transfers Out	-2,000,000	[1]	0		'
Purchases/(covers)	0		2,000,000		'
(Sales)/short buys	0		0		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Realized Gain (Loss) Included in Earnings	0		0		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Unrealized Gain (Loss) Included in Earnings	-8,000		82,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	324,000		2,332,000		250,000
Operating Entities | Common Stock	'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'
Transfers In	0		0		'
Transfers Out	0		0		'
Purchases/(covers)	4,000		1,789,000		'
(Sales)/short buys	-275,000		-6,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Realized Gain (Loss) Included in Earnings	260,000		6,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Unrealized Gain (Loss) Included in Earnings	1,021,000		-59,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	3,559,000		2,549,000		819,000
Operating Entities | Corporate Bonds	'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'
Transfers In	0		0		'
Transfers Out	0		0		'
Purchases/(covers)	2,735,000		4,600,000		'
(Sales)/short buys	-3,346,000		-3,050,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Realized Gain (Loss) Included in Earnings	-914,000		0		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Unrealized Gain (Loss) Included in Earnings	1,010,000		-1,035,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	0		515,000		0
Operating Entities | Convertible Bonds	'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'
Transfers In	0		'		'
Transfers Out	0		'		'
Purchases/(covers)	3,938,000		'		'
(Sales)/short buys	-1,988,000		'		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Realized Gain (Loss) Included in Earnings	0		'		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Unrealized Gain (Loss) Included in Earnings	0		'		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	1,950,000		0		'
Operating Entities | Warrants and Rights	'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'
Transfers In	291,000	[2]	0		'
Transfers Out	0		-89,000	[3]	'
Purchases/(covers)	166,000		632,000		'
(Sales)/short buys	-110,000		-212,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Realized Gain (Loss) Included in Earnings	-1,000		56,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Unrealized Gain (Loss) Included in Earnings	3,746,000		-208,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	5,805,000		1,713,000		1,534,000
Operating Entities | Warrants and Rights, sold not yet purchased	'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3	0		1,004,000	[4]	'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases	0		-297,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales	0		977,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Realized Gain (Loss), Included in Earnings	-4,000		-37,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Unrealized Gain (Loss) Included in Earnings	-1,000		-364,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	0		3,000		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3	0		0		'
Operating Entities | Portfolio Funds, at fair value	'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'
Transfers In	13,128,000	[5]	0		'
Transfers Out	0		0		'
Purchases/(covers)	16,932,000		10,116,000		'
(Sales)/short buys	-9,012,000		-3,482,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Realized Gain (Loss) Included in Earnings	-366,000		-41,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Unrealized Gain (Loss) Included in Earnings	5,297,000		2,158,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	51,649,000		25,670,000		16,919,000
Operating Entities | Real Estate Investments, at fair value	'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'
Transfers In	0		0		'
Transfers Out	0		0		'
Purchases/(covers)	0		153,000		'
(Sales)/short buys	-124,000		-781,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Realized Gain (Loss) Included in Earnings	0		0		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Unrealized Gain (Loss) Included in Earnings	348,000		139,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	2,088,000		1,864,000		2,353,000
Operating Entities | Lehman claims, at fair value	'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'
Transfers In	0		0		'
Transfers Out	0		0		'
Purchases/(covers)	0		0		'
(Sales)/short buys	-607,000		-234,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Realized Gain (Loss) Included in Earnings	0		0		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Unrealized Gain (Loss) Included in Earnings	279,000		387,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	378,000		706,000		553,000
Consolidated Funds | Portfolio Funds, at fair value	'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'
Transfers In	0		16,227,000	[6]	'
Transfers Out	0		-17,151,000	[6]	'
Purchases/(covers)	0		434,000		'
(Sales)/short buys	-33,504,000		-28,892,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Realized Gain (Loss) Included in Earnings	211,000		-3,823,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Unrealized Gain (Loss) Included in Earnings	6,047,000		2,723,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	155,674,000		182,920,000		213,402,000
Consolidated Funds | Lehman claims, at fair value	'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'
Transfers In	0		0		'
Transfers Out	0		0		'
Purchases/(covers)	0		0		'
(Sales)/short buys	-13,377,000		-2,292,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Realized Gain (Loss) Included in Earnings	8,597,000		1,914,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Unrealized Gain (Loss) Included in Earnings	-4,502,000		7,162,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	4,842,000		14,124,000		7,340,000
Level 3 | Operating Entities	'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'
Investments at fair value, end of period	16,216,000		'		'
Contingent liability payable [Member] | Operating Entities	'		'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'		'		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3	0		0		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases	-779,000		-64,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales	0		8,180,000		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Realized Gain (Loss), Included in Earnings	0		0		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Unrealized Gain (Loss) Included in Earnings	400,000		0		'
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	'		8,116,000		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3	$0		$0		'
[1]	The company completed an initial public offering.
[2]	The security was acquired through an acquisition (See Note 2).
[3]	The security was listed on an exchange subsequent to a private funding.
[4]	The security began trading on an exchange due to a business combination.
[5]	The investment was transferred into level 3 due to Companybs commitment as part of its long term extension of its partnership with credit funds.
[6]	Change in consolidated funds (from master-feeder to stand alone funds).

Fair_Value_Measurements_for_Op4

Fair Value Measurements for Operating Entities and Consolidated Funds Fair Value Inputs, Unobservable Inputs, Quantitative Information (Details) (Operating Entities, USD $)

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

In Thousands, unless otherwise specified

Income Approach and Market Approach Valuation Techniques

Market Approach Valuation Technique

Level 3

Level 3

Level 3

Level 3

Level 3

Level 3

Level 3

Contingent liability payable [Member]

Contingent liability payable [Member]

Contingent liability payable [Member]

Contingent liability payable [Member]

Contingent liability payable [Member]

Common and Preferred Stock

Warrants and Rights

Other Assets and Liabilities

Income Approach and Market Approach Valuation Techniques

Income Approach and Market Approach Valuation Techniques

Market Approach Valuation Technique

Market Approach Valuation Technique

Market Approach Valuation Technique

Income Approach Valuation Technique [Member]

Level 3

Level 3

Common and Preferred Stock

Common and Preferred Stock

Warrants and Rights

Warrants and Rights

Warrants and Rights

Income Approach and Market Approach Valuation Techniques

Income Approach and Market Approach Valuation Techniques

Minimum

Maximum

Minimum

Maximum

Minimum

Maximum

Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

DCF discount rate

'

'

'

'

'

'

'

'

'

'

'

'

0.00%

15.00%

Market multiple

'

'

'

'

2

3

'

'

'

'

'

'

'

'

Volatility

'

'

'

'

'

'

'

20.00%

100.00%

'

'

'

'

'

Investments at fair value

$3,474

$5,805

$16,216

'

'

'

'

'

'

'

'

'

'

'

Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value

'

'

'

'

'

'

'

'

'

8,116

0

6,937

'

'

Assets and liabilities at fair value

'

'

$233,206

$216,990

[1]

'

'

'

'

'

'

'

'

'

'

Fair Value Assumptions, Weighted Average Volatility Rate

'

'

'

'

'

'

37.00%

'

'

'

'

'

'

'

[1]

Quantitative disclosures of unobservable inputs and assumptions are not required for investments for which NAV per share is used as a practical expedient to determine fair value, as their redemption features rather than observability of inputs cause them to be classified as a level 3 type asset within the fair value hierarchy. In addition, the fair value of the Consolidated Funds' investments are determined based on net asset value and therefore quantitative disclosures are not included in the table above. The quantitative disclosures also exclude financial instruments for which the determination of fair value is based on prices from prior transactions.

Receivables_from_and_Payable_t1

Receivables from and Payable to Brokers (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Brokers and Dealers [Abstract]	'	'
Receivable from brokers	$66,980	$71,306
Payable to brokers	$75,420	$188,788

Fixed_Assets_Details

Fixed Assets (Details) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]	'	'	'	'
Depreciation and amortization	'	$6,500,000	$6,700,000	$7,400,000
Fixed assets	'	48,852,000	62,205,000	'
Less: Accumulated depreciation and amortization	'	-21,853,000	-30,003,000	'
Fixed assets, net	'	26,999,000	32,202,000	'
Depreciation and Amortization, Discontinued Operations	8,800,000	'	'	'
Property, Plant and Equipment, Transfers and Changes	'	13,700,000	'	'
Net Income (Loss) from Discontinued Operations, Net of Taxes [Member]	'	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'	'
Depreciation and Amortization, Discontinued Operations	'	'	'	7,500,000
Depreciation and Amortization Expense [Member]	'	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'	'
Depreciation and Amortization, Discontinued Operations	'	'	'	1,300,000
Telephone and computer equipment	'	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'	'
Fixed assets	'	5,923,000	13,215,000	'
Computer software	'	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'	'
Fixed assets	'	2,079,000	5,928,000	'
Furniture and fixtures	'	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'	'
Fixed assets	'	5,418,000	6,265,000	'
Leasehold improvements	'	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'	'
Fixed assets	'	29,047,000	30,412,000	'
Assets acquired under capital leases-equipment	'	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'	'
Fixed assets	'	6,337,000	6,337,000	'
Other	'	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'	'
Fixed assets	'	48,000	48,000	'
Capitalized lease assets	'	'	'	'
Property, Plant and Equipment [Line Items]	'	'	'	'
Depreciation	'	$1,300,000	$1,300,000	$500,000

Goodwill_and_Intangible_Assets2

Goodwill and Intangible Assets Schedule of Goodwill by Segment (Details) (USD $)

12 Months Ended

3 Months Ended

12 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Mar. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2009

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2009

Dec. 31, 2013

Dahlman Rose & Company, LLC

Alternative Investment

Alternative Investment

Alternative Investment

Alternative Investment

Broker-Dealer

Broker-Dealer

Broker-Dealer

Broker-Dealer

Broker-Dealer

Prior transactions [Member]

Prior transactions [Member]

ATM Group and Cowen Equity Finance LP [Member]

Goodwill [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

Goodwill, Gross

$54,591,000

$45,896,000

$37,379,000

'

$30,228,000

$30,228,000

$30,228,000

'

$24,363,000

$15,668,000

$7,151,000

'

'

Goodwill other changes

'

'

'

8,700,000

'

'

'

30,200,000

'

'

'

7,200,000

8,500,000

Goodwill, Acquired During Period

8,695,000

8,517,000

'

'

0

0

'

'

8,695,000

8,517,000

'

'

'

Goodwill impairment

0

0

-7,151,000

'

0

0

'

'

0

0

-7,200,000

'

'

Goodwill, Impaired, Accumulated Impairment Loss

-17,351,000

-17,351,000

-17,351,000

'

-10,200,000

-10,200,000

-10,200,000

'

-7,151,000

-7,151,000

-7,151,000

'

'

Goodwill

$37,240,000

$28,545,000

$20,028,000

'

$20,028,000

$20,028,000

$20,028,000

'

$17,212,000

$8,517,000

$0

'

'

Goodwill_and_Intangible_Assets3

Goodwill and Intangible Assets Schedule of Intangible Assets (Details) (USD $)

12 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2011

Jun. 28, 2011

Dec. 31, 2011

Investment Contracts

Investment Contracts

Trade Names

Trade Names

Trade Names

Trade Names

Customer Relationships

Customer Relationships

Customer Relationships

Customer Relationships

Customer Contracts

Customer Contracts

Noncompete agreements and covenants with limiting conditions acquired

Noncompete agreements and covenants with limiting conditions acquired

Noncompete agreements and covenants with limiting conditions acquired

Noncompete agreements and covenants with limiting conditions acquired

Intellectual property

Intellectual property

Intellectual property

Intellectual property

ATM Group and Cowen Equity Finance LP [Member]

Dahlman Rose & Company, LLC

LaBranche and Co Inc. [Member]

LaBranche and Co Inc. [Member]

Prior transactions [Member]

Minimum

Maximum

Minimum

Maximum

Minimum

Maximum

Minimum

Maximum

Acquired Finite-Lived Intangible Assets [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Finite-Lived Intangible Asset, Useful Life

'

'

'

'5 years

'

'

'

'5 years

'7 years 6 months

'

'

'4 years

'10 years

'1 year 2 months 12 days

'

'

'

'1 year

'10 years

'

'

'3 years

'10 years

'

'

'

'

'

Intangible assets

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$9,900,000

$2,800,000

'

$5,100,000

'

Impairment of Intangible Assets, Finite-lived

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2,900,000

'

5,200,000

Amortization of Intangible Assets

3,700,000

2,700,000

8,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,000,000

'

'

Finite-Lived Intangible Assets, Gross

38,704,000

35,929,000

'

3,900,000

3,900,000

9,612,000

9,572,000

'

'

14,744,000

11,974,000

'

'

800,000

800,000

2,697,000

2,732,000

'

'

6,951,000

6,951,000

'

'

'

'

'

'

'

Intangible assets, accumulated amortization (in dollars)

-26,610,000

-22,945,000

'

-3,900,000

-3,900,000

-7,747,000

-7,190,000

'

'

-8,375,000

-6,284,000

'

'

-800,000

-800,000

-2,583,000

-2,576,000

'

'

-3,205,000

-2,195,000

'

'

'

'

'

'

'

Intangible Assets, Net

$12,094,000

$12,984,000

'

$0

$0

$1,865,000

$2,382,000

'

'

$6,369,000

$5,690,000

'

'

$0

$0

$114,000

$156,000

'

'

$3,746,000

$4,756,000

'

'

'

'

'

'

'

Intangible Assets Amortization, Period for Recognition

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'8 years 6 months 18 days

'4 years 8 months 1 day

'

'

'

Goodwill_and_Intangible_Assets4

Goodwill and Intangible Assets Amortization of Intangible Assets (Details) (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Goodwill and Intangible Assets Disclosure [Abstract]	'
2014	$2,737
2015	2,483
2016	2,144
2017	1,411
2018	849
Thereafter	2,470
Finite-Lived Intangible Assets, Net	$12,094

Other_Assets_Details

Other Assets (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Other Assets [Line Items]	'	'
Deposits	$683	$769
Prepaid Expense	5,097	5,100
Taxes Receivable	1,911	2,105
Derivative contracts, at fair value	377	202
Deferred Rent Asset	897	433
Interest and dividends receivable	4,716	6,031
Other	4,257	3,408
Other Assets	$17,938	$18,048

Accounts_Payable_Accrued_Expen2

Accounts Payable Accrued Expenses and Other Liabilities (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Accounts Payable, Accrued Expenses and Other Liabilities [Abstract]	'	'
Deferred rent obligations	$14,554	$13,822
Deferred income	1,147	540
Equity in RCG Longview Partners II, LLC	5,938	5,970
Legal and regulatory reserve	0	3,337
Contingent consideration payable	6,937	8,116
Liability for future rent payments	0	2,775
Termination of service contracts	259	465
Derivative contracts, at fair value	1,101	973
Interest and dividends payable	2,073	2,324
Accrued expenses and accounts payable	11,879	16,142
Taxes Payable, Current	2,503	2,430
Accrued tax liabilities	400	'
Accounts Payable, Accrued Expenses and Other Liabilities	$46,391	$56,894

Redeemable_NonControlling_Inte2

Redeemable Non-Controlling Interests in Consolidated Subsidiaries (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Noncontrolling Interest [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Redeemable non-controlling interests in consolidated subsidiaries	$85,814	'	'	'	$85,703	'	'	'	$85,814	$85,703	'
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	2,684	4,759	2,255	3,495	1,154	-1,033	-2,434	2,241	13,193	-72	5,827
Operating Entities	'	'	'	'	'	'	'	'	'	'	'
Noncontrolling Interest [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Redeemable non-controlling interests in consolidated subsidiaries	12,009	'	'	'	4,106	'	'	'	12,009	4,106	'
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	'	'	'	'	'	'	'	'	10,461	301	7,002
Consolidated Funds	'	'	'	'	'	'	'	'	'	'	'
Noncontrolling Interest [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Redeemable non-controlling interests in consolidated subsidiaries	73,805	'	'	'	81,597	'	'	'	73,805	81,597	'
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	'	'	'	'	'	'	'	'	$2,732	($373)	($1,175)

Other_Revenues_and_Expenses_De

Other Revenues and Expenses (Details) (USD $)	1 Months Ended	12 Months Ended
	Jun. 30, 2008	Dec. 31, 2013	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2008
			Luxembourg Reinsurance Companies [Member]	October LLC [Member]	October LLC [Member]	October LLC [Member]	October LLC [Member]
Other revenues and expenses	'	'	'	'	'	'	'
Gross insurance premium income	'	'	$35,000,000	'	'	'	'
Gross reinsurance premium expense	'	'	35,000,000	'	'	'	'
Sale Leaseback Transaction, Current Period Gain Recognized	500,000	'	'	500,000	500,000	500,000	'
Sale Leaseback Transaction, Net gain	'	'	'	'	'	'	2,800,000
Lessee Leasing Arrangements, Operating Leases, Term of Contract	'	'0 years 67 months 0 days	'	'	'	'	'
Sale Leaseback Transaction, Minimum Assets Balance	'	'	'	6,500,000,000	'	'	'
Sale Leaseback Transaction, Annual Rental Payments	'	'	'	$100,000	'	'	'

ShareBased_Compensation_and_Em2

Share-Based Compensation and Employee Ownership Plans Narrative (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Equity Plans	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Shares authorized under compensation plan, in shares	17,725,000	'	'
Shares available for issuance under compensation plan, in shares	700,000	'	'
Stock-compensation expense recognized in connection with compensation plan	$17.90	$19.90	$22.90
Tax benefit of stock-compensation expense recognized in connection with compensation plan	9.7	11.3	11.5
Equity Plans | Employee Stock Option	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Stock options, initial term	'7 years	'	'
Equity Plans | Employee Stock Option | Minimum	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Stock compensation award, vesting period	'2 years	'	'
Equity Plans | Employee Stock Option | Maximum	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Stock compensation award, vesting period	'5 years	'	'
Equity Plans | Restricted Shares and Restricted Stock Units (RSUs)	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Vested, shares	4,463,990	4,855,489	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	13,551,544	10,252,023	7,517,682
Equity Plans | Stock Appreciation Rights (SARs)	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
SAR's, initial term	'5 years	'	'
Vested, shares	0	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	400,000	0	'
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]	'	'	'
Vested, shares	112,320	'	'
Granted, shares	257,947	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	482,522	'	'
RCG Grants	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Stock-compensation expense recognized in connection with compensation plan	'	4.9	5.4
Tax benefit of stock-compensation expense recognized in connection with compensation plan	'	$1.90	$2.10
RCG Grants | Restricted Stock	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Stock compensation award, vesting period	'3 years	'	'

ShareBased_Compensation_and_Em3

Share-Based Compensation and Employee Ownership Plans Deferred Compensation (Details) (Cowen Group, Inc. 2010 Equity and Incentive Plan, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013
Deferred Cash Award	'
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]	'
Deferred cash awards granted	29
Deferred cash awards, unrecognized compensation expense	24.7
Maximum | Deferred Cash Award	'
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]	'
Deferred cash award, interest rate	0.75%
Minimum | Deferred Cash Award	'
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]	'
Deferred cash award, interest rate	0.70%
Deferred Cash Award	'
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]	'
Deferred cash awards, vesting period	'5 years

ShareBased_Compensation_and_Em4

Share-Based Compensation and Employee Ownership Plans Stock Options (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'		'		'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	0.00%		'		'
Weighted Average Exercise Price/Share	'		'		'
Weighted average remaining term, options outstanding	'2 years 4 months 26 days		'1 year 7 months 6 days		'2 years 6 months
Weighted average remaining term, options exercisable	'2 years 4 months 26 days		'0 years 10 months 24 days		'
Aggregate Intrinsic Value	'		'		'
Closing stock price, in dollars per share	$3.91		$2.45		'
Equity Plans	'		'		'
Shares Subject to Option	'		'		'
Balance outstanding, beginning of period, shares	773,763		866,428		'
Options granted, shares	0		'		'
Options acquired, shares	0		'		'
Options expired, shares	-473,757		-92,665		'
Balance outstanding, end of period, shares	300,006		773,763		'
Options exercisable, shares	300,006		623,760		'
Weighted Average Exercise Price/Share	'		'		'
Balance outstanding, beginning of period, in dollars per share	$12.58		$12.95		'
Options granted, in dollars per share	$0		'		'
Options acquired, in dollars per share	$0		'		'
Options expired, in dollars per share	$16		$16		'
Balance outstanding, end of period, in dollars per share	$7.19		$12.58		'
Options exercisable, in dollars per share	$7.19		$14.66		'
Aggregate Intrinsic Value	'		'		'
Balance outstanding, beginning of period	$0	[1]	$0	[1]	'
Balance outstanding, end of period	0	[1]	0	[1]	'
Options exercisable	$0	[1]	'		'
[1]	Based on the Company's closing stock price of $3.91 on DecemberB 31, 2013 and $2.45 on DecemberB 31, 2012.

ShareBased_Compensation_and_Em5

Share-Based Compensation and Employee Ownership Plans SARs (Details) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Weighted Average Exercise Price/Share	'		'
Closing stock price, in dollars per share	$3.91		$2.45
Equity Plans	'		'
Weighted Average Exercise Price/Share	'		'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	$0	[1]	'
Equity Plans | Stock Appreciation Rights (SARs)	'		'
Shares Subject to Option	'		'
Balance outstanding, beginning of period, shares	0		'
Granted, shares	400,000		'
Acquired, shares	0		'
Expired, shares	0		'
Balance outstanding, end of period, shares	400,000		'
Balance exercisable, shares	0		'
Weighted Average Exercise Price/Share	'		'
Balance outstanding, beginning of period, in dollars per share	$0		'
Granted, in dollars per share	$2.90		'
Acquired, in dollars per share	$0		'
Expired, in dollars per share	$0		'
Balance outstanding, end of period, in dollars per share	$2.90		'
Balance exercisable, in dollars per share	$0		'
Weighted Average Remaining Term Outstanding	'4 years 2 months 16 days		'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	608,000	[2]	0	[2]
Unrecognized compensation expense	$300,000		'
[1]	Based on the Company's closing stock price of $3.91 on DecemberB 31, 2013 and $2.45 on DecemberB 31, 2012.
[2]	Based on the Company's closing stock price of $3.91 on DecemberB 31, 2013.

ShareBased_Compensation_and_Em6

Share-Based Compensation and Employee Ownership Plans Restricted Shares and Restricted Stock Units (Details) (Equity Plans, USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Restricted Shares and Restricted Stock Units (RSUs)	'		'
Nonvested Restricted Shares and Restricted Stock Units	'		'
Balance outstanding, beginning of period, shares	10,252,023		7,517,682
Granted, shares	7,939,924	[1]	8,381,939
Vested, shares	-4,463,990		-4,855,489
Cancelled, shares	0		0
Forfeited, shares	-176,413		-792,109
Balance outstanding, end of period, shares	13,551,544		10,252,023
Weighted-Average Grant Date Fair Value	'		'
Balance outstanding, beginning of period, in dollars per share	$4.15		$5.57
Granted, in dollars per share	$2.63	[1]	$2.82
Vested, in dollars per share	$3.86		$4.16
Cancelled, in dollars per share	$0		$0
Forfeited, in dollars per share	$3.15		$3.51
Balance outstanding, end of period, in dollars per share	$3.37		$4.15
Unrecognized compensation expense	$27.70		'
Weighted-average recognition period for unrecognized compensation expense	'1 year 7 months 3 days		'
Performance Shares [Member]	'		'
Nonvested Restricted Shares and Restricted Stock Units	'		'
Granted, shares	'		705,000
[1]	(1) On December 30, 2013, the Company awarded 705,000 performance linked restricted stock units to employees of the Company. The awards will vest on June 10, 2019 and will be earned only to the extent that the Company attains specified performance goals relating its volume-weighted average share price and the aggregate net income for the years from 2014 to 2018. The actual number of RSUs ultimately earned could vary from zero, if performance goals are not met, to as much as 100% of award. Each RSU is equal to the one share of the Companybs common stock. The value of the award will fluctuate with changes in Companybs share price and the attainment of the specified performance goals, until the RSUs are settled solely in shares after the end of the performance period.

ShareBased_Compensation_and_Em7

Share-Based Compensation and Employee Ownership Plans RCG Grants (Details) (RCG Grants, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
RCG Grants	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Allocated Share-based Compensation Expense	$4.90	$5.40
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	$1.90	$2.10

Defined_Benefit_Plans_Details

Defined Benefit Plans (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair Value of Plan Assets	$4,389		$5,230		$5,639
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]	'		'		'
Benefit Obligation	4,436		5,591		'
Service cost	0		53		50
Interest cost	207		216		264
Actuarial loss (gain)	-93		-50		'
Benefits Paid	-48		0		'
Curtailments	0		-98		'
Lump sum settlements	-910		-1,269		'
Effect of change in currency conversion	0		-7		'
Benefit Obligation	3,592		4,436		5,591
Defined Benefit Plan, Change in Plan Assets [Roll Forward]	'		'		'
Fair Value of Plan Assets	5,230		5,639		'
Actual Return on Plan Assets	153		676		'
Defined Benefit Plan, Contributions by Employer	1		0		'
Benefits Paid	956		1,085		'
Expenses paid from the plan	-39		0		'
Fair Value of Plan Assets	4,389		5,230		5,639
Funded balance at end of year	797		794		'
Pension and Other Postretirement Defined Benefit Plans, Liabilities [Abstract]	'		'		'
Pension and Other Postretirement Defined Benefit Plans, Liabilities	797		794		'
Accumulated Benefit Obligation	3,592		4,436		'
Components of net periodic benefit cost included in employee compensation and benefits	'		'		'
Service cost	0		53		50
Interest cost	207		216		264
Expected return on plan assets	-251		-235		-276
Amortization of (loss) / gain	0		0		0
Amortization of prior service cost	21		20		21
Effect of Curtailments	360		-59		0
Effect of special termination benefits	0		6		0
Effect of settlement	-95		-95		-29
Net periodic benefit cost	242		-94		30
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]	'		'		'
Net Gain (Loss)	137		-557		-33
Effect of Curtailment	-360		59		0
Effect of Settlement	0		98		31
Amortization of Loss (Gain)	0		0		0
Amortization of prior service cost	23		23		23
Total recognized in other comprehensive income (loss)	-246		-423		-25
Defined Benefit Plan, Amounts Recognized in Net Periodic Benefit Cost and Other Comprehensive Loss (Income)	-4		-517		5
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]	'		'		'
Net Gains (Losses)	344		479		116
Prior Service Cost	0		-381		-441
Effect of change in currency conversion	0		0		0
Total recognized in accumulated other comprehensive income (loss)	-344		-98		325
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]	'		'		'
Prior Service Cost	0		19		19
Net Gains (Losses)	0		0		0
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]	'		'		'
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	0		'		'
Cash Balance Plan [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair Value of Plan Assets	4,389		5,230		'
Defined Benefit Plan, Change in Plan Assets [Roll Forward]	'		'		'
Fair Value of Plan Assets	5,230		'		'
Fair Value of Plan Assets	4,389		5,230		'
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year [Abstract]	'		'		'
Expected Long-term Return on Assets	6.00%		6.00%		6.00%
Cash Balance Plan [Member] | Ramius Multi-Strategy Fund Ltd [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair Value of Plan Assets	390	[1]	513	[1]	'
Defined Benefit Plan, Change in Plan Assets [Roll Forward]	'		'		'
Fair Value of Plan Assets	390	[1]	513	[1]	'
Cash Balance Plan [Member] | Merger Fund	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair Value of Plan Assets	2,279		0		'
Defined Benefit Plan, Change in Plan Assets [Roll Forward]	'		'		'
Fair Value of Plan Assets	2,279		0		'
Cash Balance Plan [Member] | Orchard Square Partners Credit Fund Ltd [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair Value of Plan Assets	1,640	[2]	1,304	[2]	'
Defined Benefit Plan, Change in Plan Assets [Roll Forward]	'		'		'
Fair Value of Plan Assets	1,640	[2]	1,304	[2]	'
Cash Balance Plan [Member] | External Mutual Funds Total Return [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair Value of Plan Assets	7	[3]	1,358	[3]	'
Defined Benefit Plan, Change in Plan Assets [Roll Forward]	'		'		'
Fair Value of Plan Assets	7	[3]	1,358	[3]	'
Cash Balance Plan [Member] | External Mutual Funds Real Return [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair Value of Plan Assets	34	[4]	1,019	[4]	'
Defined Benefit Plan, Change in Plan Assets [Roll Forward]	'		'		'
Fair Value of Plan Assets	34	[4]	1,019	[4]	'
Cash Balance Plan [Member] | External Mutual Funds Conservative [Member]	'		'		'
Defined Benefit Plan Disclosure [Line Items]	'		'		'
Fair Value of Plan Assets	39	[5]	1,036	[5]	'
Defined Benefit Plan, Change in Plan Assets [Roll Forward]	'		'		'
Fair Value of Plan Assets	$39	[5]	$1,036	[5]	'
[1]	Ramius Multi-Strategy FundB Ltd invests substantially all of its capital through a "master feeder" structure in Ramius Intermediate Fund,B L.P. which invests in funds that employ a variety of diversified, non-directional investment strategies that seek to achieve, over the long term, a target return with low volatility.
[2]	Orchard Square Partners Credit Fund Ltd invests substantially all of its capital through a "master-feeder" structure in Orchard Square Partners Credit Intermediate Fund, LP which invests in a fund whose objective is to seek to achieve superior returns.
[3]	External Mutual FundsbTotal Return's main objective is to achieve maximum total return by investing assets in a diversified portfolio of fixed income instruments of varying maturities which may be represented by derivatives.
[4]	External Mutual FundsbReal Return's main objective is to seek to achieve maximum total return after inflation consistent with preservation of real capital and prudent investment management.
[5]	External Mutual FundsbConservative's main objective is to seek to achieve a high level of current income with some consideration given to the growth of capital by investing in fixed-income securities.

Defined_Contribution_Plans_Det

Defined Contribution Plans (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Contribution Plans [Abstract]	'	'	'
Defined Benefit Plan, Contributions by Employer	$0.40	$1.40	$1.50

Income_Taxes_Income_Tax_Expens

Income Taxes Income Tax Expense (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Current Federal Tax Expense (Benefit)	'	'	'	'	'	'	'	'	$0	$0	$0
Current State and Local Tax Expense (Benefit)	'	'	'	'	'	'	'	'	241	-133	560
Current Foreign Tax Expense (Benefit)	'	'	'	'	'	'	'	'	188	569	897
Current Income Tax Expense (Benefit)	'	'	'	'	'	'	'	'	429	436	1,457
Deferred Federal Income Tax Expense (Benefit)	'	'	'	'	'	'	'	'	0	8	2
Deferred State and Local Income Tax Expense (Benefit)	'	'	'	'	'	'	'	'	0	2	-6
Deferred Foreign Income Tax Expense (Benefit)	'	'	'	'	'	'	'	'	28	2	-21,526
Deferred Income Tax Expense (Benefit)	'	'	'	'	'	'	'	'	28	12	-21,530
Income Tax Expense (Benefit), Continuing Operations	169	-46	158	176	-48	163	191	142	457	448	-20,073
Current Federal Tax Expense (Benefit), Discontinued Operations	'	'	'	'	'	'	'	'	0	0	0
Current State and Local Tax Expense (Benefit), Discontinued Operations	'	'	'	'	'	'	'	'	0	0	-5
Current Foreign Tax Expense (Benefit), Discontinued Operations	'	'	'	'	'	'	'	'	0	0	-424
Current Income Tax Expense (Benefit), Discontinued Operations	'	'	'	'	'	'	'	'	0	0	-429
Deferred Federal Income Tax Expense (Benefit), Discontinued Operations	'	'	'	'	'	'	'	'	0	0	0
Deferred State and Local Income Tax Expense (Benefit), Discontinued Operations	'	'	'	'	'	'	'	'	0	0	0
Deferred Foreign Income Tax Expense (Benefit), Discontinued Operations	'	'	'	'	'	'	'	'	0	0	0
Deferred Income Tax Expense (Benefit), Discontinued Operations	'	'	'	'	'	'	'	'	0	0	0
Income Tax Expense (Benefit), Discontinued Operations	'	'	'	'	'	'	'	'	0	0	-429
Current Federal Tax Expense (Benefit), Continuing and Discontinued Operations	'	'	'	'	'	'	'	'	0	0	0
Current State and Local Tax Expense (Benefit), Continuing and Discontinued Operations	'	'	'	'	'	'	'	'	241	-133	555
Current Foreign Tax Expense (Benefit), Continuing and Discontinued Operations	'	'	'	'	'	'	'	'	188	569	473
Current Income Tax Expense (Benefit), Continuing and Discontinued Operations	'	'	'	'	'	'	'	'	429	436	1,028
Deferred Federal Income Tax Expense (Benefit), Continuing and Discontinued Operations	'	'	'	'	'	'	'	'	0	8	2
Deferred State and Local Income Tax Expense (Benefit), Continuing and Discontinued Operations	'	'	'	'	'	'	'	'	0	2	-6
Deferred Foreign Income Tax Expense (Benefit), Continuing and Discontinued Operations	'	'	'	'	'	'	'	'	28	2	-21,526
Deferred Income Tax Expense (Benefit), Continuing and Discontinued Operations	'	'	'	'	'	'	'	'	28	12	-21,530
Income Tax Expense (Benefit), Continuing and Discontinued Operations	'	'	'	'	'	'	'	'	$457	$448	($20,502)

Income_Taxes_Income_Tax_Rate_R

Income Taxes Income Tax Rate Reconciliation (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]	'	'	'
Income (Loss) before income taxes, Domestic	$11,900,000	($25,900,000)	($122,200,000)
Income (Loss) before Income Taxes, Foreign	6,400,000	2,400,000	-500,000
Pre-tax loss at U.S. statutory rate	35.00%	35.00%	35.00%
Stock Compensation	12.60%	-28.10%	0.00%
Change in valuation allowance	-27.20%	-7.60%	-33.30%
Deferred asset recognition	0.00%	0.00%	11.50%
Bargain purchase price	0.00%	0.00%	6.30%
Minority interest reversal	-25.20%	-0.10%	1.70%
Other, net	7.30%	-1.10%	-4.50%
Income Taxes Receivable	1,911,000	2,105,000	'
Accrued tax liabilities	$400,000	'	'
Total	2.50%	-1.90%	16.70%

Income_Taxes_Deferred_Tax_Asse

Income Taxes Deferred Tax Assets and Liabilities (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Deferred Tax Assets and Liabilities [Line Items]	'	'	'
Income Taxes Receivable	$1,911,000	$2,105,000	'
Deferred tax assets, net of valuation allowance	'	'	'
Net operating loss	130,562,000	135,108,000	'
Deferred compensation	22,538,000	23,373,000	'
Unrealized losses on investments	0	4,450,000	'
Goodwill	9,937,000	10,885,000	'
Legal reserves	0	803,000	'
Foreign tax credits	1,820,000	1,756,000	'
Acquired lease liability	3,336,000	1,036,000	'
Deferred Tax Assets, Other	4,842,000	3,532,000	'
Total deferred tax assets	173,035,000	180,943,000	'
Valuation allowance	-148,816,000	-161,181,000	'
Deferred tax assets, net of valuation allowance	24,219,000	19,762,000	'
Deferred tax liabilities	'	'	'
Basis difference on investments	-15,352,000	-15,351,000	'
Unrealized gains on investments	-6,354,000	0	'
Fixed assets	-761,000	-1,405,000	'
Intangible assets	-1,177,000	-1,230,000	'
Deferred Tax Liabilities, Other	-602,000	-1,766,000	'
Total deferred tax liabilities	-24,246,000	-19,752,000	'
Deferred Tax Liabilities, Net	-27,000	'	'
Deferred tax assets, net	'	10,000	'
Deferred Income Tax Expense (Benefit)	-28,000	-12,000	21,530,000
Valuation Allowance, Amount	148,816,000	161,181,000	'
Luxembourg Reinsurance Companies [Member]	'	'	'
Deferred tax assets, net of valuation allowance	'	'	'
Deferred Tax Assets, Other	160,100,000	'	'
Valuation allowance	-160,100,000	'	'
Deferred tax liabilities	'	'	'
Deferred Income Tax Expense (Benefit)	'	'	21,700,000
Deferred Tax Liabilities, Gross, Current	193,400,000	'	'
Valuation Allowance, Amount	$160,100,000	'	'

Income_Taxes_Summary_of_Operat

Income Taxes Summary of Operating Loss Carryforwards (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013
			Internal Revenue Service (IRS) [Member]	The New York State [Member]	Hong Kong Inland Revenue Department [Member]	Luxembourg Reinsurance Companies [Member]	LaBranche and Co Inc. [Member]
Operating Loss Carryforwards [Line Items]	'	'	'	'	'	'	'
Operating Loss Carryforwards	'	'	$323,000,000	$390,000,000	$14,000,000	'	'
Operating Loss Carryforwards, Expiration Dates	'	'	31-Dec-33	31-Dec-33	'	'	'
Deferred Tax Assets, Other	4,842,000	3,532,000	'	'	'	160,100,000	'
Deferred Tax Liabilities, Gross, Current	'	'	'	'	'	193,400,000	'
Valuation Allowance, Amount	148,816,000	161,181,000	'	'	'	160,100,000	'
Deferred Tax Assets, Operating Loss Carryforwards, Foreign	1,800,000	'	'	'	'	'	'
Deferred tax asset, deduction limitation	2,400,000	'	'	'	'	'	6,700,000
Pre transaction losses	$13,700,000	'	'	'	'	'	$87,400,000

Income_Taxes_Unrecognized_Tax_

Income Taxes Unrecognized Tax Benefits (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Income Tax Disclosure [Abstract]	'	'
Undistributed Earnings of Foreign Subsidiaries	$1.10	$3.50
Tax Liabilities, Undistributed Foreign Earnings	$0.20	$0.30

Commitments_and_Contingencies_1

Commitments and Contingencies (Details) (USD $)

12 Months Ended

12 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Apr. 30, 2011

Dec. 31, 2013

Apr. 30, 2013

Jan. 31, 2013

Sep. 30, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Equipment Leases

Service Payments

Facility Leases

Buildings, Avenue of Americas

Buildings, Avenue of Americas

Clawback Obligation [Member]

Clawback Obligation [Member]

Commitment to Invest

Commitment to Invest

Commitment to Invest

Commitment to Invest

Commitment to Invest

Commitment to Invest

Commitment to Invest

Commitment to Invest

Commitment to Invest

Unfunded Commitments

Unfunded Commitments

Healthcare Royalty Partners

Healthcare Royalty Partners

Healthcare Royalty Partners

Starboard Value and Opportunity Fund LP

Starboard Leaders Fund LP

Starboard Leaders Fund LP

Orchard Square Partners Credit Fund LP

Formation 8 Partners Fund I LP

Formation 8 Partners Fund I LP

cowenfund

Affiliated Entity

Affiliated Entity

Affiliated Entity

Affiliated Entity

Affiliated Entity

Affiliated Entity

Affiliated Entity

Affiliated Entity

Affiliated Entity

Affiliated Entity

Minimum

Maximum

Lease Obligations

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net rent expense

$15,600,000

$14,300,000

$16,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Future Rent Payments Liability

'

'

'

'

'

'

'

5,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Liability relating to vacating premises

'

'

'

'

'

'

2,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Future minimum annual lease and service payments

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contractual Obligation, Due in Next Twelve Months

'

'

'

810,000

[1]

11,970,000

17,862,000

[2]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contractual Obligation, Due in Second Year

'

'

'

405,000

[1]

5,499,000

17,375,000

[2]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contractual Obligation, Due in Third Year

'

'

'

86,000

[1]

1,634,000

14,283,000

[2]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contractual Obligation, Due in Fourth Year

'

'

'

0

[1]

1,133,000

11,174,000

[2]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contractual Obligation, Due in Fifth Year

'

'

'

0

[1]

1,049,000

10,885,000

[2]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contractual Obligation, Due after Fifth Year

'

'

'

0

[1]

22,000

39,594,000

[2]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Future minimum annual lease and service payments

'

'

'

1,301,000

[1]

21,307,000

111,173,000

[2]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Sublease income related to operating leases

1,500,000

1,200,000

300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contractual obligation

'

'

'

'

'

'

'

'

6,200,000

6,200,000

42,400,000

'

'

15,000,000

'

1,000,000

10,000,000

'

'

'

13,200,000

Number of real estate investments, in investments

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

4

'

Expected call period

'

'

'

'

'

'

'

'

'

'

'

'2 years

'5 years

'

'

'

'

'

'

'

'

Funding toward commitments

'

'

'

'

'

'

'

'

'

'

29,900,000

'

'

'

500,000

'

'

'

3,000,000

'

'

Commitments made

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$10,000,000

'

'

'

Term of capital commitment

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'5 years

'

'

[1]

Equipment Leases include the Company's commitments relating to operating and capital leases. See NoteB 20 for further information on the capital lease minimum payments which are included in the table

[2]

The Company has entered into various agreements to sublease certain of its premises. The Company recorded sublease income related to these leases of $1.5 million, $1.2 million, and $0.3 million for the years ended DecemberB 31, 2013, 2012, and 2011, respectively.

ShortTerm_Borrowings_and_Other2

Short-Term Borrowings and Other Debt (Details) (USD $)

3 Months Ended

12 Months Ended

Dec. 31, 2010

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Jan. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

letters_of_credit

Minimum

Maximum

Insurance Note

Insurance Note

Letter of Credit, San Francisco Office, Expires May 2014

Letter of Credit, NY Office, Expires September 2014

Letter of Credit, NY Office, Expires December 2014

Letter of Credit, NY Office, Expires February 2014

Letter of Credit, NY Office, Expires March 2014

Letter of Credit

Letter of Credit

Letter of Credit

Letter of Credit

Letter of Credit

Debt and Capital Lease Obligations [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

Capital Lease Obligations removed

'

$900,000

'

'

'

'

'

'

'

'

'

'

'

Number of Letters of Credit

'

5

'

'

'

'

'

'

'

'

'

'

'

Components of short-term borrowings and other debt

'

'

'

'

'

'

'

'

'

'

'

'

'

Notes payable

'

41,000

206,000

'

'

'

'

2,000,000

'

'

'

'

'

Capital lease obligations

'

2,523,000

3,926,000

'

'

'

'

'

'

'

'

'

'

Short-term borrowings and other debt

'

2,564,000

4,132,000

'

'

'

'

'

'

'

'

'

'

Interest rate

'

'

'

'

'

'

2.22%

'

'

'

'

'

'

Monthly payment

'

'

'

'

'

'

200,000

'

'

'

'

'

'

Capital Lease Obligations Incurred

6,300,000

'

'

'

'

'

'

'

'

'

'

'

'

Capital Lease Obligation, Initial Term

'

'

'

'

'48 months

'60 months

'

'

'

'

'

'

'

Capital leases, interest rate

'

'

'

'

0.60%

6.14%

'

'

'

'

'

'

'

Capital lease interest expense

'

100,000

200,000

200,000

'

'

'

'

'

'

'

'

'

Letter of credit, borrowing capacity

'

'

'

'

'

'

'

'

82,000

1,191,000

6,746,000

1,000,000

1,861,000

Future minimum lease payments for capital lease obligations

'

'

'

'

'

'

'

'

'

'

'

'

'

Capital leases, Future Minimum Payments Due, Next Twelve Months

'

1,402,000

'

'

'

'

'

'

'

'

'

'

'

Capital Leases, Future Minimum Payments Due in Two Years

'

1,051,000

'

'

'

'

'

'

'

'

'

'

'

Capital Leases, Future Minimum Payments Due in Three Years

'

194,000

'

'

'

'

'

'

'

'

'

'

'

Capital Leases, Future Minimum Payments Due in Four Years

'

0

'

'

'

'

'

'

'

'

'

'

'

Capital Leases, Future Minimum Payments Due in Five Years

'

0

'

'

'

'

'

'

'

'

'

'

'

Capital Leases, Future Minimum Payment Due Thereafter

'

0

'

'

'

'

'

'

'

'

'

'

'

Subtotal

'

2,647,000

'

'

'

'

'

'

'

'

'

'

'

Less: Amount representing interest

'

-124,000

[1]

'

'

'

'

'

'

'

'

'

'

'

Capital lease obligations

'

2,523,000

3,926,000

'

'

'

'

'

'

'

'

'

'

Repayments on long-term and short-term borrowings

'

'

'

'

'

'

'

'

'

'

'

'

'

Notes Payable, Repayments in Next Twelve Months

'

46,000

'

'

'

'

'

'

'

'

'

'

'

Notes Payable, Repayments in Year Two

'

0

'

'

'

'

'

'

'

'

'

'

'

Notes Payable, Repayments in Year Three

'

0

'

'

'

'

'

'

'

'

'

'

'

Notes Payable, Repayments in Year Four

'

0

'

'

'

'

'

'

'

'

'

'

'

Notes Payable, Repayments in Year Five

'

0

'

'

'

'

'

'

'

'

'

'

'

Notes Payable, Repayments Due after Year Five

'

0

'

'

'

'

'

'

'

'

'

'

'

Subtotal

'

46,000

'

'

'

'

'

'

'

'

'

'

'

Less: Amount representing interest

'

-5,000

[1]

'

'

'

'

'

'

'

'

'

'

'

Notes payable

'

$41,000

$206,000

'

'

'

'

$2,000,000

'

'

'

'

'

[1]

Amount necessary to reduce net minimum lease payments to present value calculated at the Company's implicit rate at lease inception.

Stockholders_Equity_Details

Stockholders' Equity (Details) (USD $)

12 Months Ended

1 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

1 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2009

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2009

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2010

Jun. 28, 2011

Dec. 31, 2011

Dec. 31, 2009

class

Common Stock

Treasury Stock

Common Stock Class A

Common Stock Class A

Common Stock Class A

Common Stock Class B

Common Stock Class B

RCG Holdings, LLC [Member]

HVB [Member]

RCG Holdings, LLC [Member]

RCG Holdings, LLC [Member]

LaBranche and Co Inc. [Member]

LaBranche and Co Inc. [Member]

RCG Holdings, LLC [Member]

Common Stock Class A

Common Stock Class A

Common Stock Class A

Common Stock Class A

Common Stock

Equity, Class of Stock [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Common stock, shares authorized

500,000,000

'

'

'

'

'

250,000,000

250,000,000

250,000,000

250,000,000

'

'

'

'

'

'

'

Common stock, par value (in dollars per share)

'

'

'

'

'

'

$0.01

$0.01

$0.01

$0.01

'

'

'

'

'

'

'

Treasury Stock, Shares [Roll Forward]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Treasury stock, shares, beginning of period

'

'

'

'

11,292,220

'

11,292,220

'

'

'

'

'

'

'

'

'

'

Shares purchased for minimum tax withholding under the Equity Plan or other similar transactions

'

'

'

'

1,203,454

'

'

'

'

'

'

'

'

'

'

'

'

Treasury stock reissued, shares

'

'

'

'

-24,744

'

'

'

'

'

'

'

'

'

'

'

'

Purchase of treasury stock, shares

'

'

'

'

3,402,619

'

'

'

'

'

'

'

'

'

'

'

'

Treasury stock, shares, end of period

'

'

'

'

15,873,549

'

15,873,549

11,292,220

'

'

'

'

'

'

'

'

'

Treasury Stock, Cost [Roll Forward]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Treasury stock, cost, beginning of period

$31,728,000

'

'

'

'

'

$31,728,000

'

'

'

'

'

'

'

'

'

'

Shares purchased for minimum tax withholding, cost

3,649,000

3,988,000

3,631,000

'

3,649,000

'

'

'

'

'

'

'

'

'

'

'

'

Treasury stock reissued, cost

-90,000

'

0

'

-90,000

'

'

'

'

'

'

'

'

'

'

'

'

Purchase of treasury stock, cost

'

'

'

'

12,797,000

'

'

'

'

'

'

'

'

'

'

'

'

Treasury stock, cost, end of period

48,100,000

31,728,000

'

'

48,084,000

'

48,084,000

31,728,000

'

'

'

'

'

'

'

'

'

Treasury Stock, Average Cost Per Share [Roll Forward]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Treasury stock, average cost per share, beginning of period, in dollars per share

'

'

'

'

$2.81

'

'

'

'

'

'

'

'

'

'

'

'

Shares purchased for minimum tax withholding, average cost per share, in dollars per share

'

'

'

'

$3.03

'

'

'

'

'

'

'

'

'

'

'

'

Treasury stock reissued, average cost per share, in dollars per share

'

'

'

'

$3.64

'

'

'

'

'

'

'

'

'

'

'

'

Purchase of treasury stock, average cost per share, in dollars per share

'

'

'

'

$3.76

'

'

'

'

'

'

'

'

'

'

'

'

Treasury stock, average cost per share, end of period, in dollars per share

'

'

'

'

$3.03

'

'

'

'

'

'

'

'

'

'

'

'

Shares issued at the consummation of transaction

'

'

'

'

'

'

'

'

'

'

'

2,713,882

'

'

'

'

'

Number of classes

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Shares converted at the time of the transaction

'

'

'

'

'

'

15,042,290

'

'

'

'

'

'

'

'

'

'

Stock Issued During Period, Shares, New Issues

'

'

'

'

'

17,292,698

'

'

'

'

'

'

'

'

'

'

284,655

Stock Issued During Period, Value, New Issues

'

'

'

'

'

$82,000,000

'

'

'

'

'

'

'

'

'

'

'

Common stock, shares outstanding

'

'

'

'

'

'

115,026,633

112,447,892

0

0

'

'

16,135,162

33,576,099

'

'

'

Stockholders' Equity, Shares Transferred to Member's Ownership

'

'

'

'

'

'

16,045,865

9,054,175

'

'

'

'

'

'

'

'

'

Business Acquisition, Equity Interest Issued or Issuable, Exchange Ratio

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.998

'

'

Stock Issued During Period, Shares, Acquisitions

'

'

'

2,491,647

'

'

'

'

'

'

37,536,826

'

'

'

'

40,850,133

'

Preferred stock, shares authorized

10,000,000

10,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Preferred stock, par value (in dollars per share)

$0.01

$0.01

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Loss) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Accumulated Other Comprehensive Income [Abstract]	'		'		'		'
Foreign Currency Translations	$248	[1]	$258	[1]	$110	[1]	$370	[1]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	-10	[1]	148	[1]	-260	[1]	'
Defined Benefit Plans	344	[1]	98	[1]	-325	[1]	-350	[1]
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent	-246	[1]	-423	[1]	-25	[1]	'
Other Comprehensive Income (Loss), Net of Tax	236		571		-235		'
Accumulated other comprehensive income (loss)	$592		$356		($215)		$20
[1]	(a) During the periods presented, the Company did not have material reclassifications out of other comprehensive income.

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Computation of earnings per share:	'	'	'	'	'	'	'	'	'	'	'
Net income (loss) from continuing operations	$5,203	$8,370	$3,348	$919	($8,195)	($11,618)	($10,380)	$6,236	$17,840	($23,957)	($78,537)
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	2,684	4,759	2,255	3,495	1,154	-1,033	-2,434	2,241	13,193	-72	5,827
Net income (loss) attributable to Cowen Group, Inc. stockholders	'	'	'	'	'	'	'	'	4,647	-23,885	-84,364
Net income (loss) from discontinued operations, net of tax	'	'	'	'	'	'	'	'	$0	$0	($23,646)
Shares for basic and diluted calculations:	'	'	'	'	'	'	'	'	'	'	'
Weighted average shares used in basic computation, shares	117,514,000	118,359,000	117,235,000	113,798,000	113,939,000	114,989,000	114,561,000	114,281,000	116,703,000	114,400,000	95,532,000
Weighted average shares used in diluted computation, shares	123,573,000	122,708,000	120,901,000	113,798,000	113,939,000	114,989,000	114,561,000	115,663,000	121,117,000	114,400,000	95,532,000
Earnings (loss) per share:	'	'	'	'	'	'	'	'	'	'	'
Income (loss) from continuing operations, basic (in dollars per share)	$0.02	$0.03	$0.01	($0.02)	($0.08)	($0.09)	($0.07)	$0.03	$0.04	($0.21)	($0.88)
Income (loss) from discontinued operations, basic (in dollars per share)	'	'	'	'	'	'	'	'	$0	$0	($0.25)
Income (loss) from continuing operations, diluted (in dollars per share)	$0.02	$0.03	$0.01	($0.02)	($0.08)	($0.09)	($0.07)	$0.03	$0.04	($0.21)	($0.88)
Income (loss) from discontinued operations, diluted (in dollars per share)	'	'	'	'	'	'	'	'	$0	$0	($0.25)
Stock Options	'	'	'	'	'	'	'	'	'	'	'
Shares for basic and diluted calculations:	'	'	'	'	'	'	'	'	'	'	'
Shares attributable to share-based payment awards, shares	'	'	'	'	'	'	'	'	0	0	0
Stock Appreciation Rights (SARs)	'	'	'	'	'	'	'	'	'	'	'
Shares for basic and diluted calculations:	'	'	'	'	'	'	'	'	'	'	'
Shares attributable to share-based payment awards, shares	'	'	'	'	'	'	'	'	306,000	0	0
Restricted Stock	'	'	'	'	'	'	'	'	'	'	'
Shares for basic and diluted calculations:	'	'	'	'	'	'	'	'	'	'	'
Shares attributable to share-based payment awards, shares	'	'	'	'	'	'	'	'	4,108,000	0	0
Non-employee Director | Equity Plans | Restricted Stock Units (RSUs)	'	'	'	'	'	'	'	'	'	'	'
Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Common stock, restricted shares, shares	482,522	'	'	'	'	'	'	'	482,522	'	'
Common Stock Class A	'	'	'	'	'	'	'	'	'	'	'
Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Common stock, shares outstanding, shares	115,026,633	'	'	'	112,447,892	'	'	'	115,026,633	112,447,892	'
Common stock, restricted shares, shares	482,522	'	'	'	336,895	'	'	'	482,522	336,895	'

Segment_Reporting_Details

Segment Reporting (Details) (USD $)

3 Months Ended

12 Months Ended

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

customer

customer

customer

customer

segment

Segment Reporting Information [Line Items]

'

'

'

'

'

'

'

'

'

'

'

Number of Operating Segments

'

'

'

'

'

'

'

'

2

'

'

Revenues

'

'

'

'

'

'

'

'

'

'

'

Investment banking

'

'

'

'

'

'

'

'

$105,333,000

$71,762,000

$50,976,000

Brokerage

'

'

'

'

'

'

'

'

114,593,000

91,167,000

99,611,000

Management fees

'

'

'

'

'

'

'

'

37,303,000

38,116,000

52,466,000

Incentive income

'

'

'

'

'

'

'

'

12,586,000

5,411,000

3,265,000

Interest and dividends

'

'

'

'

'

'

'

'

39,454,000

24,608,000

22,306,000

Reimbursement from affiliates

'

'

'

'

'

'

'

'

9,161,000

5,239,000

4,322,000

Total revenues

97,438,000

81,360,000

81,207,000

67,241,000

65,932,000

57,598,000

59,470,000

57,480,000

327,246,000

240,480,000

235,278,000

Expenses

'

'

'

'

'

'

'

'

'

'

'

Employee compensation and benefits

'

'

'

'

'

'

'

'

207,248,000

194,034,000

203,767,000

Interest and dividends

'

'

'

'

'

'

'

'

27,299,000

12,137,000

9,233,000

Goodwill impairment

'

'

'

'

'

'

'

'

0

0

7,151,000

Total expenses

'

'

'

'

'

'

'

'

360,917,000

326,900,000

375,655,000

Other income (loss)

'

'

'

'

'

'

'

'

'

'

'

Net gain (losses) on securities, derivatives and other investments

'

'

'

'

'

'

'

'

40,924,000

55,665,000

15,128,000

Bargain purchase gain

'

'

'

'

'

'

'

'

0

0

22,244,000

Total other income (loss)

'

'

'

'

'

'

'

'

51,968,000

62,911,000

41,767,000

Income (loss) before income taxes and non-controlling interests

5,372,000

8,324,000

3,506,000

1,095,000

-8,243,000

-11,455,000

-10,189,000

6,378,000

18,297,000

-23,509,000

-98,610,000

Income tax expense (benefit)

169,000

-46,000

158,000

176,000

-48,000

163,000

191,000

142,000

457,000

448,000

-20,073,000

Economic income (loss)/ net income (loss) before non-controlling interests

'

'

'

'

'

'

'

'

17,840,000

-23,957,000

-102,183,000

Net income (loss) from discontinued operations, net of tax

'

'

'

'

'

'

'

'

0

0

-23,646,000

Net income (loss) attributable to Cowen Group, Inc. stockholders

2,519,000

3,611,000

1,093,000

-2,576,000

-9,349,000

-10,585,000

-7,946,000

3,995,000

4,647,000

-23,885,000

-108,010,000

Number of major customers

0

'

'

'

0

'

'

'

0

0

'

Reported Under U.S. GAAP

'

'

'

'

'

'

'

'

'

'

'

Revenues

'

'

'

'

'

'

'

'

'

'

'

Investment banking

'

'

'

'

'

'

'

'

105,333,000

71,762,000

50,976,000

Brokerage

'

'

'

'

'

'

'

'

114,593,000

91,167,000

99,611,000

Management fees

'

'

'

'

'

'

'

'

37,303,000

38,116,000

52,466,000

Incentive income

'

'

'

'

'

'

'

'

12,586,000

5,411,000

3,265,000

Investment Income

'

'

'

'

'

'

'

'

0

0

0

Interest and dividends

'

'

'

'

'

'

'

'

39,454,000

24,608,000

22,306,000

Reimbursement from affiliates

'

'

'

'

'

'

'

'

9,161,000

5,239,000

4,322,000

Other revenue

'

'

'

'

'

'

'

'

5,418,000

3,668,000

1,583,000

Total revenues

'

'

'

'

'

'

'

'

327,246,000

240,480,000

235,278,000

Expenses

'

'

'

'

'

'

'

'

'

'

'

Employee compensation and benefits

'

'

'

'

'

'

'

'

207,248,000

194,034,000

203,767,000

Interest and dividends

'

'

'

'

'

'

'

'

27,299,000

12,137,000

9,233,000

Non-compensation expenses - Fixed

'

'

'

'

'

'

'

'

0

0

0

Non-compensation expenses - Variable

'

'

'

'

'

'

'

'

0

0

0

Non-compensation expenses

'

'

'

'

'

'

'

'

124,331,000

119,053,000

152,722,000

Goodwill impairment

'

'

'

'

'

'

'

'

'

'

7,151,000

Reimbursement from affiliates

'

'

'

'

'

'

'

'

0

0

0

Total expenses

'

'

'

'

'

'

'

'

360,917,000

326,900,000

375,655,000

Other income (loss)

'

'

'

'

'

'

'

'

'

'

'

Net gain (losses) on securities, derivatives and other investments

'

'

'

'

'

'

'

'

40,924,000

55,665,000

15,128,000

Bargain purchase gain

'

'

'

'

'

'

'

'

'

'

22,244,000

Total other income (loss)

'

'

'

'

'

'

'

'

51,968,000

62,911,000

41,767,000

Income (loss) before income taxes and non-controlling interests

'

'

'

'

'

'

'

'

18,297,000

-23,509,000

-98,610,000

Income tax expense (benefit)

'

'

'

'

'

'

'

'

457,000

448,000

-20,073,000

Economic income (loss)/ net income (loss) before non-controlling interests

'

'

'

'

'

'

'

'

17,840,000

-23,957,000

-78,537,000

Net income (loss) from discontinued operations, net of tax

'

'

'

'

'

'

'

'

'

'

-23,646,000

(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries

'

'

'

'

'

'

'

'

-13,193,000

72,000

-5,827,000

Net income (loss) attributable to Cowen Group, Inc. stockholders

'

'

'

'

'

'

'

'

4,647,000

-23,885,000

-108,010,000

Operating Segments | Reported Under Economic Income/(Loss)

'

'

'

'

'

'

'

'

'

'

'

Revenues

'

'

'

'

'

'

'

'

'

'

'

Investment banking

'

'

'

'

'

'

'

'

105,333,000

71,762,000

50,976,000

Brokerage

'

'

'

'

'

'

'

'

121,065,000

93,903,000

99,611,000

Management fees

'

'

'

'

'

'

'

'

56,984,000

56,381,000

67,309,000

Incentive income

'

'

'

'

'

'

'

'

21,933,000

15,205,000

10,366,000

Investment Income

'

'

'

'

'

'

'

'

36,660,000

50,116,000

41,347,000

Interest and dividends

'

'

'

'

'

'

'

'

0

0

0

Reimbursement from affiliates

'

'

'

'

'

'

'

'

0

0

0

Other revenue

'

'

'

'

'

'

'

'

2,534,000

1,248,000

615,000

Total revenues

'

'

'

'

'

'

'

'

344,509,000

288,615,000

270,224,000

Expenses

'

'

'

'

'

'

'

'

'

'

'

Employee compensation and benefits

'

'

'

'

'

'

'

'

204,836,000

188,155,000

192,558,000

Interest and dividends

'

'

'

'

'

'

'

'

350,000

339,000

735,000

Non-compensation expenses - Fixed

'

'

'

'

'

'

'

'

95,524,000

95,462,000

103,181,000

Non-compensation expenses - Variable

'

'

'

'

'

'

'

'

30,643,000

25,275,000

41,497,000

Non-compensation expenses

'

'

'

'

'

'

'

'

0

0

0

Goodwill impairment

'

'

'

'

'

'

'

'

'

'

0

Reimbursement from affiliates

'

'

'

'

'

'

'

'

-6,380,000

-5,527,000

-4,602,000

Total expenses

'

'

'

'

'

'

'

'

324,973,000

303,704,000

333,369,000

Other income (loss)

'

'

'

'

'

'

'

'

'

'

'

Net gain (losses) on securities, derivatives and other investments

'

'

'

'

'

'

'

'

0

0

0

Bargain purchase gain

'

'

'

'

'

'

'

'

'

'

0

Total other income (loss)

'

'

'

'

'

'

'

'

0

0

0

Income (loss) before income taxes and non-controlling interests

'

'

'

'

'

'

'

'

19,536,000

-15,089,000

-63,145,000

Income tax expense (benefit)

'

'

'

'

'

'

'

'

0

0

0

Economic income (loss)/ net income (loss) before non-controlling interests

'

'

'

'

'

'

'

'

19,536,000

-15,089,000

-63,145,000

Net income (loss) from discontinued operations, net of tax

'

'

'

'

'

'

'

'

'

'

0

(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries

'

'

'

'

'

'

'

'

-12,995,000

-2,480,000

-8,292,000

Net income (loss) attributable to Cowen Group, Inc. stockholders

'

'

'

'

'

'

'

'

6,541,000

-17,569,000

-71,437,000

Alternative Investment

'

'

'

'

'

'

'

'

'

'

'

Expenses

'

'

'

'

'

'

'

'

'

'

'

Goodwill impairment

'

'

'

'

'

'

'

'

0

0

'

Alternative Investment | Reported Under Economic Income/(Loss)

'

'

'

'

'

'

'

'

'

'

'

Revenues

'

'

'

'

'

'

'

'

'

'

'

Investment banking

'

'

'

'

'

'

'

'

0

0

0

Brokerage

'

'

'

'

'

'

'

'

0

0

0

Management fees

'

'

'

'

'

'

'

'

56,984,000

56,381,000

67,309,000

Incentive income

'

'

'

'

'

'

'

'

21,933,000

15,205,000

10,366,000

Investment Income

'

'

'

'

'

'

'

'

30,713,000

40,374,000

33,599,000

Interest and dividends

'

'

'

'

'

'

'

'

0

0

0

Reimbursement from affiliates

'

'

'

'

'

'

'

'

0

0

0

Other revenue

'

'

'

'

'

'

'

'

524,000

844,000

622,000

Total revenues

'

'

'

'

'

'

'

'

110,154,000

112,804,000

111,896,000

Expenses

'

'

'

'

'

'

'

'

'

'

'

Employee compensation and benefits

'

'

'

'

'

'

'

'

54,656,000

59,647,000

46,757,000

Interest and dividends

'

'

'

'

'

'

'

'

231,000

151,000

184,000

Non-compensation expenses - Fixed

'

'

'

'

'

'

'

'

33,986,000

32,575,000

33,954,000

Non-compensation expenses - Variable

'

'

'

'

'

'

'

'

4,520,000

4,941,000

17,085,000

Non-compensation expenses

'

'

'

'

'

'

'

'

0

0

0

Goodwill impairment

'

'

'

'

'

'

'

'

'

'

0

Reimbursement from affiliates

'

'

'

'

'

'

'

'

-6,380,000

-5,527,000

-4,602,000

Total expenses

'

'

'

'

'

'

'

'

87,013,000

91,787,000

93,378,000

Other income (loss)

'

'

'

'

'

'

'

'

'

'

'

Net gain (losses) on securities, derivatives and other investments

'

'

'

'

'

'

'

'

0

0

0

Bargain purchase gain

'

'

'

'

'

'

'

'

'

'

0

Total other income (loss)

'

'

'

'

'

'

'

'

0

0

0

Income (loss) before income taxes and non-controlling interests

'

'

'

'

'

'

'

'

23,141,000

21,017,000

18,518,000

Income tax expense (benefit)

'

'

'

'

'

'

'

'

0

0

0

Economic income (loss)/ net income (loss) before non-controlling interests

'

'

'

'

'

'

'

'

23,141,000

21,017,000

18,518,000

Net income (loss) from discontinued operations, net of tax

'

'

'

'

'

'

'

'

'

'

0

(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries

'

'

'

'

'

'

'

'

-12,995,000

-2,480,000

-8,292,000

Net income (loss) attributable to Cowen Group, Inc. stockholders

'

'

'

'

'

'

'

'

10,146,000

18,537,000

10,226,000

Broker-Dealer

'

'

'

'

'

'

'

'

'

'

'

Expenses

'

'

'

'

'

'

'

'

'

'

'

Goodwill impairment

'

'

'

'

'

'

'

'

0

0

7,200,000

Broker-Dealer | Reported Under Economic Income/(Loss)

'

'

'

'

'

'

'

'

'

'

'

Revenues

'

'

'

'

'

'

'

'

'

'

'

Investment banking

'

'

'

'

'

'

'

'

105,333,000

[1]

71,762,000

[2]

50,976,000

[3]

Brokerage

'

'

'

'

'

'

'

'

121,065,000

[1]

93,903,000

[2]

99,611,000

[3]

Management fees

'

'

'

'

'

'

'

'

0

[1]

0

[2]

0

[3]

Incentive income

'

'

'

'

'

'

'

'

0

[1]

0

[2]

0

[3]

Investment Income

'

'

'

'

'

'

'

'

5,947,000

[1]

9,742,000

[2]

7,748,000

[3]

Interest and dividends

'

'

'

'

'

'

'

'

0

[1]

0

[2]

0

[3]

Reimbursement from affiliates

'

'

'

'

'

'

'

'

0

[1]

0

[2]

0

[3]

Other revenue

'

'

'

'

'

'

'

'

2,010,000

[1]

404,000

[2]

-7,000

[3]

Total revenues

'

'

'

'

'

'

'

'

234,355,000

[1]

175,811,000

[2]

158,328,000

[3]

Expenses

'

'

'

'

'

'

'

'

'

'

'

Employee compensation and benefits

'

'

'

'

'

'

'

'

150,180,000

[1]

128,508,000

[2]

145,801,000

[3]

Interest and dividends

'

'

'

'

'

'

'

'

119,000

[1]

188,000

[2]

551,000

[3]

Non-compensation expenses - Fixed

'

'

'

'

'

'

'

'

61,538,000

[1]

62,887,000

[2]

69,227,000

[3]

Non-compensation expenses - Variable

'

'

'

'

'

'

'

'

26,123,000

[1]

20,334,000

[2]

24,412,000

[3]

Non-compensation expenses

'

'

'

'

'

'

'

'

0

[1]

0

[2]

0

[3]

Goodwill impairment

'

'

'

'

'

'

'

'

'

'

0

Reimbursement from affiliates

'

'

'

'

'

'

'

'

0

[1]

0

[2]

0

[3]

Total expenses

'

'

'

'

'

'

'

'

237,960,000

[1]

211,917,000

[2]

239,991,000

[3]

Other income (loss)

'

'

'

'

'

'

'

'

'

'

'

Net gain (losses) on securities, derivatives and other investments

'

'

'

'

'

'

'

'

0

[1]

0

[2]

0

[3]

Bargain purchase gain

'

'

'

'

'

'

'

'

'

'

0

[3]

Total other income (loss)

'

'

'

'

'

'

'

'

0

[1]

0

[2]

0

[3]

Income (loss) before income taxes and non-controlling interests

'

'

'

'

'

'

'

'

-3,605,000

[1]

-36,106,000

[2]

-81,663,000

[3]

Income tax expense (benefit)

'

'

'

'

'

'

'

'

0

[1]

0

[2]

0

[3]

Economic income (loss)/ net income (loss) before non-controlling interests

'

'

'

'

'

'

'

'

-3,605,000

[1]

-36,106,000

[2]

-81,663,000

[3]

Net income (loss) from discontinued operations, net of tax

'

'

'

'

'

'

'

'

'

'

0

(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries

'

'

'

'

'

'

'

'

0

[1]

0

[2]

0

[3]

Net income (loss) attributable to Cowen Group, Inc. stockholders

'

'

'

'

'

'

'

'

-3,605,000

[1]

-36,106,000

[2]

-81,663,000

[3]

Investment Income from Entity's Capital

'

'

'

'

'

'

'

'

7,600,000

10,200,000

5,600,000

Compensation Expense Related to Investment of Entity's Capital

'

'

'

'

'

'

'

'

2,500,000

3,400,000

1,800,000

Significant Reconciling Items | Reconciliation from Economic Income/(Loss) to U.S. GAAP

'

'

'

'

'

'

'

'

'

'

'

Revenues

'

'

'

'

'

'

'

'

'

'

'

Investment banking

'

'

'

'

'

'

'

'

0

0

0

Brokerage

'

'

'

'

'

'

'

'

-6,472,000

[4]

-2,736,000

[4]

0

Management fees

'

'

'

'

'

'

'

'

-18,535,000

[5]

-16,791,000

[5]

-13,034,000

[5]

Incentive income

'

'

'

'

'

'

'

'

-9,347,000

[5]

-9,794,000

[5]

-7,101,000

[5]

Investment Income

'

'

'

'

'

'

'

'

-36,660,000

[6]

-50,116,000

[6]

-41,347,000

[6]

Interest and dividends

'

'

'

'

'

'

'

'

39,454,000

[6]

24,608,000

[6]

22,306,000

[6]

Reimbursement from affiliates

'

'

'

'

'

'

'

'

9,260,000

[7]

5,527,000

[7]

4,602,000

[7]

Other revenue

'

'

'

'

'

'

'

'

2,884,000

[6]

2,420,000

[6]

968,000

[6]

Total revenues

'

'

'

'

'

'

'

'

-19,416,000

-46,882,000

-33,606,000

Expenses

'

'

'

'

'

'

'

'

'

'

'

Employee compensation and benefits

'

'

'

'

'

'

'

'

2,412,000

5,879,000

11,209,000

Interest and dividends

'

'

'

'

'

'

'

'

26,949,000

[6]

11,798,000

[6]

8,498,000

[6]

Non-compensation expenses - Fixed

'

'

'

'

'

'

'

'

-95,524,000

[6],[8]

-95,462,000

[6],[8]

-103,181,000

[6],[8]

Non-compensation expenses - Variable

'

'

'

'

'

'

'

'

-30,643,000

[6],[8]

-25,275,000

[6],[8]

-41,497,000

[6],[8]

Non-compensation expenses

'

'

'

'

'

'

'

'

124,331,000

[6],[8]

119,053,000

[6],[8]

152,722,000

[6],[8]

Goodwill impairment

'

'

'

'

'

'

'

'

'

'

7,151,000

[9]

Reimbursement from affiliates

'

'

'

'

'

'

'

'

6,380,000

[7]

5,527,000

[7]

4,602,000

[7]

Total expenses

'

'

'

'

'

'

'

'

33,905,000

21,520,000

39,504,000

Other income (loss)

'

'

'

'

'

'

'

'

'

'

'

Net gain (losses) on securities, derivatives and other investments

'

'

'

'

'

'

'

'

40,924,000

[6]

55,665,000

[6]

15,128,000

[6]

Bargain purchase gain

'

'

'

'

'

'

'

'

'

'

22,244,000

[10]

Total other income (loss)

'

'

'

'

'

'

'

'

49,350,000

60,355,000

38,820,000

Income (loss) before income taxes and non-controlling interests

'

'

'

'

'

'

'

'

-3,971,000

-8,047,000

-34,290,000

Income tax expense (benefit)

'

'

'

'

'

'

'

'

457,000

[7]

448,000

[7]

-20,073,000

[7]

Economic income (loss)/ net income (loss) before non-controlling interests

'

'

'

'

'

'

'

'

-4,428,000

-8,495,000

-14,217,000

Net income (loss) from discontinued operations, net of tax

'

'

'

'

'

'

'

'

'

'

-23,646,000

[11]

(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries

'

'

'

'

'

'

'

'

2,534,000

2,179,000

1,290,000

Net income (loss) attributable to Cowen Group, Inc. stockholders

'

'

'

'

'

'

'

'

-1,894,000

-6,316,000

-36,573,000

Funds Consolidation | Reconciliation from Economic Income/(Loss) to U.S. GAAP

'

'

'

'

'

'

'

'

'

'

'

Revenues

'

'

'

'

'

'

'

'

'

'

'

Investment banking

'

'

'

'

'

'

'

'

0

0

0

Brokerage

'

'

'

'

'

'

'

'

0

0

0

Management fees

'

'

'

'

'

'

'

'

-1,146,000

-1,474,000

-1,809,000

Incentive income

'

'

'

'

'

'

'

'

0

0

0

Investment Income

'

'

'

'

'

'

'

'

0

0

0

Interest and dividends

'

'

'

'

'

'

'

'

0

0

0

Reimbursement from affiliates

'

'

'

'

'

'

'

'

-99,000

-288,000

-280,000

Other revenue

'

'

'

'

'

'

'

'

0

0

0

Total revenues

'

'

'

'

'

'

'

'

2,153,000

-1,253,000

-1,340,000

Expenses

'

'

'

'

'

'

'

'

'

'

'

Employee compensation and benefits

'

'

'

'

'

'

'

'

0

0

0

Interest and dividends

'

'

'

'

'

'

'

'

0

0

0

Non-compensation expenses - Fixed

'

'

'

'

'

'

'

'

0

0

0

Non-compensation expenses - Variable

'

'

'

'

'

'

'

'

0

0

0

Non-compensation expenses

'

'

'

'

'

'

'

'

0

0

0

Goodwill impairment

'

'

'

'

'

'

'

'

'

'

0

Reimbursement from affiliates

'

'

'

'

'

'

'

'

0

0

0

Total expenses

'

'

'

'

'

'

'

'

2,039,000

1,676,000

2,782,000

Other income (loss)

'

'

'

'

'

'

'

'

'

'

'

Net gain (losses) on securities, derivatives and other investments

'

'

'

'

'

'

'

'

0

0

0

Bargain purchase gain

'

'

'

'

'

'

'

'

'

'

0

Total other income (loss)

'

'

'

'

'

'

'

'

2,618,000

2,556,000

2,947,000

Income (loss) before income taxes and non-controlling interests

'

'

'

'

'

'

'

'

2,732,000

-373,000

-1,175,000

Income tax expense (benefit)

'

'

'

'

'

'

'

'

0

0

0

Economic income (loss)/ net income (loss) before non-controlling interests

'

'

'

'

'

'

'

'

2,732,000

-373,000

-1,175,000

Net income (loss) from discontinued operations, net of tax

'

'

'

'

'

'

'

'

'

'

0

(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries

'

'

'

'

'

'

'

'

-2,732,000

373,000

1,175,000

Net income (loss) attributable to Cowen Group, Inc. stockholders

'

'

'

'

'

'

'

'

0

0

0

Consolidated Funds | Reported Under U.S. GAAP

'

'

'

'

'

'

'

'

'

'

'

Revenues

'

'

'

'

'

'

'

'

'

'

'

Total revenues

'

'

'

'

'

'

'

'

3,398,000

509,000

749,000

Expenses

'

'

'

'

'

'

'

'

'

'

'

Total expenses

'

'

'

'

'

'

'

'

2,039,000

1,676,000

2,782,000

Other income (loss)

'

'

'

'

'

'

'

'

'

'

'

Net gain (losses) on securities, derivatives and other investments

'

'

'

'

'

'

'

'

11,044,000

7,246,000

4,395,000

Consolidated Funds | Operating Segments | Reported Under Economic Income/(Loss)

'

'

'

'

'

'

'

'

'

'

'

Revenues

'

'

'

'

'

'

'

'

'

'

'

Total revenues

'

'

'

'

'

'

'

'

0

0

0

Expenses

'

'

'

'

'

'

'

'

'

'

'

Total expenses

'

'

'

'

'

'

'

'

0

0

0

Other income (loss)

'

'

'

'

'

'

'

'

'

'

'

Net gain (losses) on securities, derivatives and other investments

'

'

'

'

'

'

'

'

0

0

0

Consolidated Funds | Alternative Investment | Reported Under Economic Income/(Loss)

'

'

'

'

'

'

'

'

'

'

'

Revenues

'

'

'

'

'

'

'

'

'

'

'

Total revenues

'

'

'

'

'

'

'

'

0

0

0

Expenses

'

'

'

'

'

'

'

'

'

'

'

Total expenses

'

'

'

'

'

'

'

'

0

0

0

Other income (loss)

'

'

'

'

'

'

'

'

'

'

'

Net gain (losses) on securities, derivatives and other investments

'

'

'

'

'

'

'

'

0

0

0

Consolidated Funds | Broker-Dealer | Reported Under Economic Income/(Loss)

'

'

'

'

'

'

'

'

'

'

'

Revenues

'

'

'

'

'

'

'

'

'

'

'

Total revenues

'

'

'

'

'

'

'

'

0

[1]

0

[2]

0

[3]

Expenses

'

'

'

'

'

'

'

'

'

'

'

Total expenses

'

'

'

'

'

'

'

'

0

[1]

0

[2]

0

[3]

Other income (loss)

'

'

'

'

'

'

'

'

'

'

'

Net gain (losses) on securities, derivatives and other investments

'

'

'

'

'

'

'

'

0

[1]

0

[2]

0

[3]

Consolidated Funds | Significant Reconciling Items | Reconciliation from Economic Income/(Loss) to U.S. GAAP

'

'

'

'

'

'

'

'

'

'

'

Revenues

'

'

'

'

'

'

'

'

'

'

'

Total revenues

'

'

'

'

'

'

'

'

0

'

0

Expenses

'

'

'

'

'

'

'

'

'

'

'

Total expenses

'

'

'

'

'

'

'

'

0

'

0

Other income (loss)

'

'

'

'

'

'

'

'

'

'

'

Net gain (losses) on securities, derivatives and other investments

'

'

'

'

'

'

'

'

8,426,000

'

1,448,000

Consolidated Funds | Funds Consolidation | Reconciliation from Economic Income/(Loss) to U.S. GAAP

'

'

'

'

'

'

'

'

'

'

'

Revenues

'

'

'

'

'

'

'

'

'

'

'

Total revenues

'

'

'

'

'

'

'

'

3,398,000

509,000

749,000

Expenses

'

'

'

'

'

'

'

'

'

'

'

Total expenses

'

'

'

'

'

'

'

'

2,039,000

1,676,000

2,782,000

Other income (loss)

'

'

'

'

'

'

'

'

'

'

'

Net gain (losses) on securities, derivatives and other investments

'

'

'

'

'

'

'

'

2,618,000

2,556,000

2,947,000

Consolidated Funds | Other Adjustments [Member] | Reconciliation from Economic Income/(Loss) to U.S. GAAP

'

'

'

'

'

'

'

'

'

'

'

Revenues

'

'

'

'

'

'

'

'

'

'

'

Total revenues

'

'

'

'

'

'

'

'

'

0

'

Expenses

'

'

'

'

'

'

'

'

'

'

'

Total expenses

'

'

'

'

'

'

'

'

'

0

'

Other income (loss)

'

'

'

'

'

'

'

'

'

'

'

Net gain (losses) on securities, derivatives and other investments

'

'

'

'

'

'

'

'

'

$4,690,000

'

[1]

For the year ended DecemberB 31, 2013, the Company has reflected $7.6 million of investment income and related compensation expense of $2.5 million within the broker-dealer segment in proportion to its capital.

[2]

For the year ended DecemberB 31, 2012, the Company has reflected $10.2 million of investment income and related compensation expense of $3.4 million within the broker-dealer segment in proportion to its capital.

[3]

For the year ended DecemberB 31, 2011, the Company has reflected $5.6 million of investment income and related compensation expense of $1.8 million within the broker-dealer segment in proportion to its capital.

[4]

Economic Income (Loss) recognizes stock borrow/loan activity and other brokerage dividends as brokerage revenue.

[5]

Economic Income (Loss) recognizes revenues (i) net of distribution fees paid to agents and (ii) our proportionate share of management and incentive fees of certain real estate operating entities and the activist business.

[6]

Economic Income (Loss) recognizes Company income from proprietary trading net of related expenses.

[7]

Economic Income (Loss) excludes income taxes as management does not consider this item when evaluating the performance of the segment. Also, reimbursement from affiliates is shown as a reduction of Economic Income expenses, but is included as a part of revenues under US GAAP.

[8]

Economic Income (Loss) recognizes the Company's proportionate share of expenses for certain real estate and other operating entities for which the investments are recorded under the equity method of accounting for investments.

[9]

Economic Income (Loss) excludes goodwill impairment.

[10]

Economic Income (Loss) excludes the bargain purchase gain which resulted from the LaBranche acquisition.

[11]

Economic Income (Loss) excludes discontinued operations.

Regulatory_Requirements_Detail

Regulatory Requirements (Details) (USD $)	Dec. 31, 2013
Cowen and Company	'
Regulatory Requirements for Broker-Dealers [Line Items]	'
Net capital requirement under alternative method	$1,000,000
Net capital	36,400,000
Excess capital	35,400,000
ATM Execution	'
Regulatory Requirements for Broker-Dealers [Line Items]	'
Minimum net capital required	250,000
Net capital	2,700,000
Excess capital	2,400,000
ATM USA	'
Regulatory Requirements for Broker-Dealers [Line Items]	'
Minimum net capital required	250,000
Net capital	1,200,000
Excess capital	900,000
Cowen Equity Finance	'
Regulatory Requirements for Broker-Dealers [Line Items]	'
Minimum net capital required	250,000
Net capital	12,000,000
Excess capital	11,700,000
U.K. Financial Services Authority | Raimus U.K., Ltd.	'
Regulatory Requirements for Broker-Dealers [Line Items]	'
Financial resources	350,000
Financial resources requirement	180,000
Excess financial resources	170,000
U.K. Financial Services Authority | Cowen International Limited	'
Regulatory Requirements for Broker-Dealers [Line Items]	'
Financial resources	4,400,000
Financial resources requirement	2,200,000
Excess financial resources	2,200,000
H.K. Securities and Futures Commission | Cowen and Company (Asia) Limited	'
Regulatory Requirements for Broker-Dealers [Line Items]	'
Financial resources	1,100,000
Financial resources requirement	400,000
Excess financial resources	$700,000

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)

12 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Apr. 30, 2011

Apr. 30, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Affiliated Entity

Affiliated Entity

Affiliated Entity

Affiliated Entity

Affiliated Entity

Affiliated Entity

Affiliated Entity

Employees

Employees

Equity Method Investee

Equity Method Investee

Equity Method Investee

Investor

Investor

Minimum

Maximum

Management Fee and Incentive Income

Management Fee and Incentive Income

Management Fee and Incentive Income

Fees Payable

Fees Payable

Starboard Value LP

Starboard Value LP

Due from Related Parties

LIBOR

Starboard Value LP

Related Party Transaction [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fees receivable, net of allowance

$45,067,000

$34,707,000

'

$18,900,000

$13,600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Reimbursement to affiliated funds

'

'

'

'

'

1,700,000

1,500,000

1,600,000

'

'

'

'

'

'

'

'

'

'

'

Fees payable to related parties

'

'

'

'

'

'

'

'

1,700,000

1,700,000

'

'

'

'

'

'

'

'

'

Due from employees

'

'

'

'

'

'

'

'

'

'

6,000,000

5,100,000

'

'

'

'

'

'

'

Forgivable Loan Balances

'

'

'

'

'

'

'

'

'

'

3,800,000

2,300,000

'

'

'

'

'

'

'

Forgivable Loans, Vesting Period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'1 year

'3 years

Amortization on Forgivable Loans

3,200,000

1,900,000

1,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Credit agreement with related party, maximum loan amount

'

'

'

'

'

'

'

'

'

'

'

'

3,000,000

'

'

'

'

'

'

Credit agreement with related party, interest rate

'

'

'

'

'

'

'

'

'

'

'

'

'

3.75%

'

'

'

'

'

Credit agreement with related party, loan receivable

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,500,000

'

'

'

'

Interest Income, Other

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100,000

'

'

'

'

Due to Affiliate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$400,000

$400,000

'

'

Guarantees_and_OffBalance_Shee1

Guarantees and Off-Balance Sheet Arrangements (Details) (USD $)	Dec. 31, 2013
Securities Lending	'
Guaranty loans	$150,000,000
Employee Loans	'
Guaranty loans	$2,500,000

Subsequent_Events_Details_Deta

Subsequent Events Details (Details) (USD $)	0 Months Ended	1 Months Ended	3 Months Ended	12 Months Ended
	Feb. 26, 2014	Jan. 31, 2014	Dec. 31, 2010	Dec. 31, 2013
Subsequent Event [Line Items]	'	'	'	'
Capital Lease Obligations Incurred	'	'	$6,300,000	'
Lessee Leasing Arrangements, Operating Leases, Term of Contract	'	'	'	'0 years 67 months 0 days
Reduction in monthly lease payments	'	40,000	'	'
Stock Repurchase Program, Authorized Amount	10,000,000	'	'	'
Subsequent Event [Member]	'	'	'	'
Subsequent Event [Line Items]	'	'	'	'
Capital Lease Obligation, Initial Term	'	'5 years	'	'
Capital Lease Obligations Incurred	'	5,000,000	'	'
Lessee Leasing Arrangements, Operating Leases, Term of Contract	'	'5 years 6 months	'	'
Operating lease obligations incurred	'	$6,900,000	'	'

Supplemental_Financial_Informa2

Supplemental Financial Information (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Statement [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Revenues	$97,438	$81,360	$81,207	$67,241	$65,932	$57,598	$59,470	$57,480	$327,246	$240,480	$235,278
Income (loss) before income taxes	5,372	8,324	3,506	1,095	-8,243	-11,455	-10,189	6,378	18,297	-23,509	-98,610
Income tax expense (benefit)	169	-46	158	176	-48	163	191	142	457	448	-20,073
Net income (loss) from continuing operations	5,203	8,370	3,348	919	-8,195	-11,618	-10,380	6,236	17,840	-23,957	-78,537
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries and funds	2,684	4,759	2,255	3,495	1,154	-1,033	-2,434	2,241	13,193	-72	5,827
Net income (loss) attributable to Cowen Group, Inc. stockholders	$2,519	$3,611	$1,093	($2,576)	($9,349)	($10,585)	($7,946)	$3,995	$4,647	($23,885)	($108,010)
Earnings (loss) per share:	'	'	'	'	'	'	'	'	'	'	'
Income (loss) from continuing operations, basic (in dollars per share)	$0.02	$0.03	$0.01	($0.02)	($0.08)	($0.09)	($0.07)	$0.03	$0.04	($0.21)	($0.88)
Income (loss) from continuing operations, diluted (in dollars per share)	$0.02	$0.03	$0.01	($0.02)	($0.08)	($0.09)	($0.07)	$0.03	$0.04	($0.21)	($0.88)
Weighted average common shares outstanding:	'	'	'	'	'	'	'	'	'	'	'
Basic (in shares)	117,514	118,359	117,235	113,798	113,939	114,989	114,561	114,281	116,703	114,400	95,532
Diluted (in shares)	123,573	122,708	120,901	113,798	113,939	114,989	114,561	115,663	121,117	114,400	95,532