Cowen (COWN) 10-Q 7 Nov 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Nov. 06, 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-Q	'
Document Period End Date	30-Sep-13	'
Document Fiscal Year Focus	'2013	'
Document Fiscal Period Focus	'Q3	'
Amendment Flag	'false	'
Entity Common Stock, Shares Outstanding	'	117,849,034

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Financial Condition (USD $)	Sep. 30, 2013	Dec. 31, 2012
Assets	'	'
Cash and cash equivalents	$39,217,000	$83,538,000
Cash collateral pledged	10,899,000	9,160,000
Securities owned, at fair value	380,599,000	624,127,000
Securities borrowed	902,572,000	408,096,000
Other investments	98,162,000	84,930,000
Receivable from brokers	67,966,000	71,306,000
Fees receivable, net of allowance	39,174,000	34,707,000
Due from related parties	26,658,000	21,022,000
Fixed assets, net of accumulated depreciation and amortization of $34,556 and $30,003, respectively	28,580,000	32,202,000
Goodwill	36,207,000	28,545,000
Intangible assets, net of accumulated amortization of $25,784 and $22,945, respectively	12,920,000	12,984,000
Other assets	29,158,000	16,278,000
Consolidated Funds	'	'
Cash and cash equivalents	1,488,000	3,559,000
Securities owned, at fair value	0	3,525,000
Other investments, at fair value	200,210,000	204,205,000
Other assets	458,000	292,000
Total Assets	1,874,268,000	1,638,476,000
Liabilities	'	'
Securities sold, not yet purchased, at fair value	131,129,000	177,937,000
Securities sold under agreement to repurchase	6,311,000	165,945,000
Securities loaned	894,790,000	410,441,000
Payable to brokers	149,276,000	188,788,000
Compensation payable	30,061,000	45,752,000
Short-term borrowings and other debt	3,369,000	4,132,000
Fees payable	8,210,000	5,277,000
Due to related parties	466,000	662,000
Accounts payable, accrued expenses and other liabilities	49,017,000	55,425,000
Consolidated Funds	'	'
Capital withdrawals payable	0	2,891,000
Accounts payable, accrued expenses and other liabilities	154,000	414,000
Total Liabilities	1,272,783,000	1,057,664,000
Commitments and Contingencies (Note 13)	'	'
Redeemable non-controlling interests	90,179,000	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	733,286,000	713,211,000
(Accumulated deficit) retained earnings	-185,762,000	-187,865,000
Accumulated other comprehensive income (loss)	139,000	356,000
Total Stockholders' Equity	511,306,000	495,109,000
Total Liabilities and Stockholders' Equity	1,874,268,000	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, 13,131,160 and 11,292,220 shares as of September 30, 2013 and December 31, 2012, respectively.	-37,517,000	-31,728,000
Common Stock Class B	'	'
Stockholders' equity	'	'
Common stock	$0	$0

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Financial Condition (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified
Assets	'	'
Fixed assets, accumulated depreciation and amortization (in dollars)	$34,556	$30,003
Intangible assets, accumulated amortization (in dollars)	$25,784	$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 Class A	'	'
Stockholders' equity	'	'
Treasury stock, shares	13,131,160	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	130,567,432	123,740,112
Common stock, shares outstanding	117,411,528	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 $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues	'	'	'	'
Investment banking	$27,694	$18,666	$70,431	$50,550
Brokerage	28,462	22,701	86,583	71,282
Management fees	9,327	8,866	28,518	28,515
Incentive income	2,521	1,416	7,086	2,687
Interest and dividends	10,969	3,605	30,905	14,845
Reimbursement from affiliates	1,386	1,370	4,085	3,796
Other revenues	556	701	1,519	2,398
Consolidated Funds	'	'	'	'
Interest and dividends	255	24	414	115
Other revenues	190	249	267	359
Total revenues	81,360	57,598	229,808	174,547
Expenses	'	'	'	'
Employee compensation and benefits	53,614	47,322	145,344	137,102
Floor brokerage and trade execution	4,033	3,058	13,479	10,992
Interest and dividends	6,133	2,056	20,287	7,107
Professional, advisory and other fees	4,022	3,534	10,878	11,158
Service fees	2,351	2,807	7,615	8,198
Communications	4,670	4,522	13,423	11,775
Occupancy and equipment	6,752	5,808	19,019	16,594
Depreciation and amortization	2,624	2,427	7,786	6,945
Client services and business development	3,493	3,510	12,251	11,089
Other expenses	3,595	3,680	10,142	10,919
Consolidated Funds	'	'	'	'
Interest and dividends	96	2	157	22
Professional, advisory and other fees	230	263	717	1,112
Floor brokerage and trade execution	91	0	196	0
Other expenses	33	65	167	205
Total expenses	91,737	79,054	261,461	233,218
Other income (loss)	'	'	'	'
Net gains (losses) on securities, derivatives and other investments	15,469	12,510	32,873	41,969
Consolidated Funds	'	'	'	'
Net realized and unrealized gains (losses) on investments and other transactions	3,096	-2,730	11,274	817
Net realized and unrealized gains (losses) on derivatives	-32	212	430	626
Net gains (losses) on foreign currency transactions	168	9	1	-6
Total other income (loss)	18,701	10,001	44,578	43,406
Income (loss) before income taxes	8,324	-11,455	12,925	-15,265
Income tax expense (benefit)	-46	163	288	496
Net income (loss)	8,370	-11,618	12,637	-15,761
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries	4,759	-1,033	10,509	-1,225
Net income (loss) attributable to Cowen Group, Inc. stockholders	$3,611	($10,585)	$2,128	($14,536)
Weighted average common shares outstanding:	'	'	'	'
Basic (in shares)	118,359	114,989	116,012	114,587
Diluted (in shares)	122,708	114,989	119,891	114,587
Earnings (loss) per share:	'	'	'	'
Basic (in dollars per share)	$0.03	($0.09)	$0.02	($0.13)
Diluted (in dollars per share)	$0.03	($0.09)	$0.02	($0.13)

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Comprehensive Income (Loss) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Statement of Other Comprehensive Income [Abstract]	'	'
Net income (loss)	$12,637	($15,761)
Other comprehensive income (loss), net of tax:	'	'
Foreign currency translation	-10	126
Defined benefit pension plans:	'	'
Net gain/(loss) arising during the period	-223	235
Add: amortization of prior service cost included in net periodic pension cost	16	15
Pension adjustment	-207	250
Total other comprehensive income, net of tax	-217	376
Comprehensive income (loss)	$12,420	($15,385)

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
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	-14,536,000	'	'	'	'	-14,536,000	'
Net income (loss) attributable to redeemable non-controlling interests	-1,225,000	'	'	'	'	'	-1,225,000
Defined benefit plans	250,000	'	'	'	250,000	'	'
Foreign currency translation	126,000	'	'	'	126,000	'	'
Deconsolidation of funds	'	'	'	'	'	'	-17,104,000
Consolidation of funds	'	'	'	'	'	'	18,521,000
Capital contributions	'	'	'	'	'	'	500,000
Capital withdrawals	'	'	'	'	'	'	-17,268,000
Restricted stock awards issued, shares	'	4,189,400	'	'	'	'	'
Common stock issued upon acquisition (See Note 2)	0	'	'	'	'	'	'
Purchase of treasury stock, at cost	-10,904,000	'	-10,904,000	'	'	'	'
Purchase of treasury stock, at cost, shares	'	-4,274,148	'	'	'	'	'
Amortization of share based compensation	20,578,000	'	'	20,578,000	'	'	'
Balance at Sep. 30, 2012	503,979,000	1,135,000	-27,806,000	709,005,000	161,000	-178,516,000	88,011,000
Balance, shares at Sep. 30, 2012	'	113,962,889	'	'	'	'	'
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	2,128,000	'	'	'	'	2,128,000	'
Net income (loss) attributable to redeemable non-controlling interests	10,509,000	'	'	'	'	'	10,509,000
Defined benefit plans	-207,000	'	'	'	-207,000	'	'
Foreign currency translation	-10,000	'	'	'	-10,000	'	'
Capital contributions	'	'	'	'	'	'	11,656,000
Capital withdrawals	'	'	'	'	'	'	-17,689,000
Restricted stock awards issued, shares	'	4,288,108	'	'	'	'	'
Common stock issued upon acquisition (See Note 2)	6,297,000	25,000	'	6,272,000	'	'	'
Common stock issued upon acquisition (See Note 2), shares	'	2,514,468	'	'	'	'	'
Treasury stock re-issuance	65,000	'	90,000	'	'	-25,000	'
Treasury stock re-issuance, shares	'	24,744	24,744	'	'	'	'
Purchase of treasury stock, at cost	-5,879,000	'	-5,879,000	'	'	'	'
Purchase of treasury stock, at cost, shares	'	-1,863,684	'	'	'	'	'
Amortization of share based compensation	13,803,000	'	'	13,803,000	'	'	'
Balance at Sep. 30, 2013	$511,306,000	$1,160,000	($37,517,000)	$733,286,000	$139,000	($185,762,000)	$90,179,000
Balance, shares at Sep. 30, 2013	'	117,411,528	'	'	'	'	'

Condensed_Consolidated_Stateme5

Condensed Consolidated Statements of Cash Flows (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:	'	'
Net income (loss)	$12,637,000	($15,761,000)
Adjustments to reconcile net income (loss) to net cash provided by / (used in) operating activities:	'	'
Depreciation and amortization	7,786,000	6,945,000
Share-based compensation	13,803,000	20,578,000
Deferred rent obligations	-2,195,000	-1,316,000
Net loss on disposal of fixed assets	350,000	0
Purchases of securities owned, at fair value	-6,000,365,000	-4,776,378,000
Proceeds from sales of securities owend, at fair value	6,224,311,000	4,818,865,000
Proceeds from sales of securities sold, not yet purchased, at fair value	2,442,760,000	3,487,601,000
Payments to cover securities sold, not yet purchased, at fair value	-2,472,108,000	-3,582,578,000
Net (gains) losses on securities, derivatives and other investments	-30,003,000	-33,576,000
Consolidated Funds	'	'
Purchases of securities owned, at fair value	-298,220,000	-249,731,000
Proceeds from sales of securities owned, at fair value	287,412,000	252,966,000
Proceeds from sales of securities sold, not yet purchased, at fair value	42,701,000	0
Payments to cover securities sold, not yet purchased, at fair value	-42,387,000	0
Purchases of other investments	-973,000	-8,273,000
Proceeds from sales of other investments	39,195,000	33,795,000
Net realized and unrealized (gains) losses on investments and other transactions	-12,729,000	-2,718,000
(Increase) decrease in operating assets:	'	'
Cash acquired upon transaction	10,747,000	0
Cash collateral pledged	143,000	516,000
Securities owned, at fair value, held at broker dealer	13,144,000	56,796,000
Securities borrowed	-494,476,000	0
Receivable from brokers	4,628,000	-41,779,000
Fees receivable, net of allowance	-4,237,000	934,000
Due from related parties	-5,636,000	188,000
Other assets	-11,207,000	4,158,000
Consolidated Funds	'	'
Cash and cash equivalents	2,071,000	-659,000
Other assets	-362,000	1,290,000
Increase (decrease) in operating liabilities:	'	'
Securities sold, not yet purchased, at fair value, held at broker dealer	-8,480,000	-13,086,000
Securities loaned	484,349,000	0
Payable to brokers	-39,512,000	-10,110,000
Compensation payable	-34,020,000	-46,323,000
Fees payable	2,933,000	-587,000
Due to related parties	-196,000	-1,268,000
Accounts payable, accrued expenses and other liabilities	-10,392,000	-4,487,000
Consolidated Funds	'	'
Payable to brokers	1,030,000	0
Due to related parties	0	25,000
Accounts payable, accrued expenses and other liabilities	-249,000	777,000
Net cash provided by / (used in) operating activities	122,253,000	-103,196,000
Cash flows from investing activities:	'	'
Securities purchased under agreement to resell	0	166,260,000
Purchases of other investments	-19,406,000	-4,291,000
Proceeds from sales of other investments	25,668,000	9,036,000
Purchase of business, net of cash acquired (Note 2)	0	-10,063,000
Cash paid to acquire net assets (contingent payable)	-73,000	0
Purchase of fixed assets	-784,000	-1,695,000
Net cash provided by / (used in) investing activities	5,405,000	159,247,000
Cash flows from financing activities:	'	'
Securities sold under agreement to repurchase	-159,634,000	-104,944,000
Borrowings on short-term borrowings and other debt	2,044,000	0
Repayments on short-term borrowings and other debt	-2,807,000	-1,134,000
Purchase of treasury stock	-2,658,000	-8,252,000
Capital contributions by non-controlling interests in operating entities	501,000	0
Capital withdrawals to non-controlling interests in operating entities	-2,282,000	-2,717,000
Consolidated Funds	'	'
Capital contributions by non-controlling interests in Consolidated Funds	11,155,000	0
Capital withdrawals to non-controlling interests in Consolidated Funds	-18,298,000	-12,103,000
Net cash provided by / (used in) financing activities	-171,979,000	-129,150,000
Change in cash and cash equivalents	-44,321,000	-73,099,000
Cash and cash equivalents at beginning of period	83,538,000	128,875,000
Cash and cash equivalents at end of period	39,217,000	55,776,000
Supplemental non-cash information	'	'
Non compete agreements and covenants with limiting conditions acquired (see Note 2)	460,000	0
Common stock issuance upon close of acquisition (see Note 2)	6,297,000	0
Purchase of treasury stock, at cost, through net settlement (see Note 15)	3,156,000	2,652,000
Re-issuance of treasury stock for services provided	65,000	'
Net assets transferred to Merger Master (see Note 5)	22,152,000	'
Net assets of consolidated entities	0	18,521,000
Net assets of deconsolidated entities	$0	$17,104,000

Organization_and_Business

Organization and Business	9 Months Ended
	Sep. 30, 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 services through its two business segments: alternative investment and broker-dealer. The Company's alternative investment segment includes hedge funds, replication products, 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	9 Months Ended
	Sep. 30, 2013
Business Combinations [Abstract]	'
Acquisitions	'
	Acquisitions
	On March 11, 2013, the Company completed its acquisition of Dahlman Rose & Company, LLC, 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 Rose & Company, LLC was subsequently renamed to Cowen Securities LLC ("Cowen Securities"). Post acquisition, Cowen Securities is included in the broker-dealer segment (See Note 17).
	The Company is in discussions with the sellers regarding certain closing date balance sheet adjustments, resolution of which will potentially impact the purchase price, assets and liabilities recognized and the resulting goodwill. The Company does not believe the impact of these adjustments will be material. The preliminary purchase price allocation of Cowen Securities is based upon all information available to us at the present time, and is based upon management's preliminary estimates of the fair values using valuation techniques including income, cost and market approaches. As of September 30, 2013, the purchase price allocation is preliminary pending the final resolution of the closing date balance sheet adjustments, which the Company expects will occur within twelve months following the acquisition. Upon the completion of the final purchase price allocation, any reallocation of fair values to the assets acquired and liabilities assumed in the acquisitions could have an impact on the amounts recognized on the condensed consolidated statements of financial condition.
	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 condensed 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 condensed consolidated statement of financial condition.

Significant_Accounting_Policie

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Significant Accounting Policies	'
	Significant Accounting Policies
	a.	Basis of presentation
	These unaudited condensed consolidated financial statements and related notes have been prepared in accordance with US GAAP and the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) related to interim financial statements. Results for interim periods should not be considered indicative of results for any other interim period or for the full year. These financial statements should be read in conjunction with the audited consolidated financial statements as of December 31, 2012 and 2011 and for the years ended December 31, 2012, 2011, and 2010, included in the Form 10-K of Cowen Group as filed with the SEC on March 7, 2013. The financial information contained herein is unaudited; however, management believes all adjustments have been made that are necessary for a fair presentation of the results for the interim periods. The year-end condensed balance sheet data was derived from audited financial statements, but does not include all disclosures required by US GAAP. All material intercompany transactions and balances have been eliminated in consolidation. Certain fund entities that are consolidated in these condensed consolidated financial statements, as further discussed below, are not subject to these consolidation provisions with respect to their own investments pursuant to their specialized accounting.
	The Company serves as the managing member/general partner and/or investment manager to affiliated fund entities which it sponsors and manages. Funds in which the Company has a controlling financial interest are consolidated with the Company pursuant to US GAAP as described below. Consequently, the Company's condensed consolidated financial statements reflect the assets, liabilities, income and expenses of these funds on a gross basis. The ownership interests in these funds that are not owned by the Company are reflected as redeemable non-controlling interests in consolidated subsidiaries in the accompanying condensed consolidated financial statements. The management fees and incentive income earned by the Company from these funds are eliminated in consolidation.
	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 September 30, 2013 and December 31, 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 (formerly known as Cowen Bluebird LLC) and Ramius Co-Investment II LLC (formerly known as RCG Ultragenex Holdings 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 September 30, 2013 the Company consolidates three VIEs and as of December 31, 2012 the Company does not consolidate any VIEs. As of September 30, 2013, the total net assets of the consolidated VIEs are $7.1 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 September 30, 2013 and December 31, 2012, the Company holds a variable interest in Ramius Enterprise Master Fund Ltd (“Enterprise Master”) (the “Unconsolidated Master Fund”) through one of its Consolidated Funds, Enterprise LP. 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 Fund.
	In the ordinary course of business, the Company also sponsors various other entities that it has determined to be VIEs. These VIEs are primarily 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 5 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 condensed consolidated statements of financial condition. The Company's share of earnings or losses from equity method investees is included in net gains (losses) on securities, derivatives and other investments in the condensed 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 condensed 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 condensed consolidated statements of financial condition at their estimated fair value, with unrealized gains (losses) resulting from changes in fair value reflected within net realized and unrealized gains (losses) on investments and other transactions. Accordingly, the accompanying condensed consolidated financial statements reflect different accounting policies for investments depending on whether or not they are held through a consolidated investment company. In addition, the Company's broker‑dealer subsidiaries, Cowen and Company, LLC (“Cowen and Company”), 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 condensed consolidated financial statements in conformity with US GAAP requires the management of the Company to make estimates and assumptions that affect the fair value of securities and other investments, the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the accompanying condensed consolidated financial statements, the accounting for goodwill and identifiable intangible assets and the reported amounts of revenues and expenses during the reporting period. Actual results could materially differ from those estimates. Certain reclassifications have been made to prior period amounts in order to conform with current period presentation.
	d.	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 condensed consolidated financial statements. Certain of the Company's investments are relatively illiquid or thinly traded and may not be immediately liquidated on demand if needed. Fair values assigned to these investments may differ significantly from the fair values that would have been used had a ready market for the investments existed and such differences could be material.
	The Company primarily uses the “market approach” to value its financial instruments measured at fair value. In determining an instrument's level within the hierarchy, the Company categorizes the Company's financial instruments into three categories: securities, derivative contracts and other investments. To the extent applicable, each of these categories can further be divided between those held long or sold short.
	The Company has the option to measure certain financial assets and financial liabilities at fair value with changes in fair value recognized in earnings each period. The election is made on an instrument by instrument basis at initial recognition of an asset or liability or upon an event that gives rise to a new basis of accounting for that instrument.  The Company has elected the fair value option for 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 condensed consolidated statements of financial condition and all other derivatives are included within securities owned, at fair value on the accompanying condensed 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 5 and 6 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 5 and 6 for further information regarding the Company's investments, including equity method investments, and fair value measurements.
	e.	Securities borrowed and securities loaned
	Securities borrowed and securities loaned are carried at the amounts of cash collateral advanced or received. 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.
	f.	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 September 30, 2013 and December 31, 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 September 30, 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 counter party. 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.
	g.    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 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 condensed consolidated statements of financial condition, as of September 30, 2013 and December 31, 2012 is $16.2 million and $13.8 million, respectively.
	h.    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.

Cash_collateral_pledged

Cash collateral pledged	9 Months Ended
	Sep. 30, 2013
Cash and Cash Equivalents [Abstract]	'
Cash collateral pledged	'
	Cash collateral pledged
	As of September 30, 2013 and December 31, 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 14).

Investments_of_Operating_Entit

Investments of Operating Entities and Consolidated Funds	9 Months Ended
	Sep. 30, 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 September 30, 2013 and December 31, 2012, securities owned, at fair value consisted of the following:
		As of September 30, 2013				As of December 31, 2012
		(dollars in thousands)
	U.S. Government securities (a)	$	3,506			$	137,478
	Preferred stock	333				2,332
	Common stocks	223,527				259,292
	Convertible bonds (b)	4,129				6,202
	Corporate bonds (c)	134,827				193,078
	Options	10,974				20,546
	Warrants and rights	2,778				2,354
	Mutual funds	525				2,845
		$	380,599			$	624,127
	(a)	As of September 30, 2013, maturities ranged from October 2013 to April 2016 and interest rates ranged between 0.02% and 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 September 30, 2013, the maturity was July 2014 with an interest rate of 5.00%. As of December 31, 2012, maturities ranged from May 2014 to July 2014 with an interest rate of 5.00%.
	(c)	As of September 30, 2013, maturities ranged from December 2013 to February 2046 and interest rates ranged between 2.58% 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 September 30, 2013 and December 31, 2012 of $0.6 million and $0.2 million, respectively, is included in other assets in the accompanying condensed consolidated statements of financial condition. The Company's short exposure to futures, currency forwards and equity swaps, at fair value, as of September 30, 2013 and December 31, 2012 of $0.3 million and $1.0 million, respectively, is included in accounts payable, accrued expenses and other liabilities in the accompanying condensed consolidated statements of financial condition. The realized and unrealized gains/(losses) related to derivatives trading activities for the three months ended September 30, 2013, and 2012, were $0.8 million, and $3.0 million, respectively, and was $3.1 million and $5.0 million for the nine months ended September 30, 2013 and 2012, respectively, and are included in other income in the accompanying condensed consolidated statements of operations.
	Pursuant to the various derivatives transactions discussed above, the Company is required to post collateral for its obligations or potential obligations. As of September 30, 2013 and December 31, 2012, collateral consisting of $8.9 million and $6.7 million of cash, respectively, is included in receivable from brokers on the accompanying condensed consolidated statements of financial condition. As of September 30, 2013 and December 31, 2012 all derivative contracts were with multiple major financial institutions.
	Other investments
	As of September 30, 2013 and December 31, 2012, other investments consisted of the following:
		As of September 30, 2013				As of December 31, 2012
		(dollars in thousands)
	(1) Portfolio Funds, at fair value	$	70,813			$	55,898
	(2) Real estate investments, at fair value	2,127				1,864
	(3) Equity method investments	24,664				26,462
	(4) Lehman claims, at fair value	558				706
		$	98,162			$	84,930
	-1	Portfolio Funds, at fair value
	The Portfolio Funds, at fair value as of September 30, 2013 and December 31, 2012, included the following:
		As of September 30, 2013				As of December 31, 2012
		(dollars in thousands)
	HealthCare Royalty Partners (a)(*)	$	10,204			$	7,866
	HealthCare Royalty Partners II (a)(*)	4,510				6,415
	Orchard Square Partners Credit Fund LP (formerly known as Ramius Global Credit Fund LP) (b)(*)	12,417				14,196
	Tapestry Investment Co PCC Ltd (c)	86				194
	Starboard Value and Opportunity Fund LP (d)(*)	17,242				15,706
	Formation 8 Partners Fund I (e)	2,802				1,500
	RCG LV Park Lane LLC (f)	685				708
	RCGL 12E13th LLC (g)	400				—
	RCG Longview Debt Fund V, L.P. (g)	11,679				—
	Other private investment (h)	8,004				7,826
	Other affiliated funds (i)(*)	2,784				1,487
		$	70,813			$	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 13.
	(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 is in the process of liquidation and redemptions will be made periodically at the investment managers' decision as the underlying investments are liquidated.
	(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 September 30, 2013 and December 31, 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 20% 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 are the investments in (a) the three HealthCare Royalty Partners General Partners, which serve as the general partners for the Healthcare Royalty Funds, (b) an investment in the CBOE (Chicago Board Options Exchange) Stock Exchange LLC representing a 9.6% 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 LP (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 following table summarizes equity method investments held by the Company:
		As of September 30, 2013				As of December 31, 2012
		(dollars in thousands)
RCG Longview Debt Fund IV Management, LLC	$	1,594			$	1,954
RCG Longview Debt Fund V Partners, LLC	1,010				—
HealthCare Royalty GP, LLC	832				642
HealthCare Royalty GP II, LLC	764				1,086
HealthCare Royalty GP III, LLC	47				—
CBOE Stock Exchange, LLC	1,810				2,058
Starboard Value LP	11,692				12,757
RCG Longview Partners, LLC	2,016				1,535
RCG Longview Louisiana Manager, LLC	1,327				1,866
RCG Urban American, LLC	281				1,380
RCG Urban American Management, LLC	141				545
RCG Longview Equity Management, LLC	230				285
Urban American Real Estate Fund II, LLC	1,612				1,636
RCG Kennedy House, LLC	428				377
Other	880				341
	$	24,664			$	26,462
As of September 30, 2013 and December 31, 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 condensed consolidated statements of financial condition. RCG Longview Partners II, LLC, as general partner to a real estate fund, has reversed previously recorded incentive income allocations and has recorded a current clawback obligation to the limited partners in 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 $5.2 million and $1.5 million, for the three months ended September 30, 2013 and 2012, respectively, and was $12.6 million and $9.4 million for the nine months ended September 30, 2013 and 2012, respectively, and is included in net gains (losses) on securities, derivatives and other investments on the accompanying condensed consolidated statements of operations. In addition, the Company recorded no impairment charges in relation to its equity method investments for the three and nine months ended September 30, 2013 and 2012, respectively.
For the period ended September 30, 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 income statement information for the significant investees for the three and nine months ended September 30, 2013 and 2012. The summarized income statement information for the Company's investments in the individually significant investees is as follows:
	Three Months Ended September 30,								Nine Months Ended September 30,
	2013				2012				2013				2012
	(dollars in thousands)
Revenues	$	6,821			$	3,909			$	17,746			$	16,190
Expenses	(2,266		)		(2,785		)		(6,945		)		(7,850		)
Net realized and unrealized gains (losses)	(16		)		26				(116		)		135
Net Income	$	4,539			$	1,150			$	10,685			$	8,475
-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 status and ultimate resolution of the assets under LBIE's Administration proceedings is uncertain. 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 and 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 and 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. 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, although in October 2013 LBIE announced its intention to pay a third interim dividend before the end of 2013. The amount of the dividend has not yet been determined.
Given the fact that LBIE has begun to make 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 127.5% as of September 30, 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 5b(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 condensed consolidated financial statements. However, these transactions result in off-balance sheet risk, as the Company's ultimate cost to satisfy the delivery of securities sold, not yet purchased, at fair value may exceed the amount reflected in the accompanying condensed consolidated statements of financial condition. Substantially all equity securities and options are pledged to the clearing broker under terms which permit the clearing broker to sell or re-pledge the securities to others subject to certain limitations. As of September 30, 2013 and December 31, 2012 securities sold, not yet purchased, at fair value consisted of the following:
	As of September 30, 2013				As of December 31, 2012
	(dollars in thousands)
Common stocks	$	122,211			$	168,797
Corporate bonds (a)	56				61
Options	8,862				9,076
Warrants and rights	—				3
	$	131,129			$	177,937
(a)	As of September 30, 2013 and December 31, 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 September 30, 2013 and December 31, 2012:
	As of September 30, 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 January 2016	$	6,311
	$	6,311
	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
For all of the Company's holdings of repurchase agreements as of September 30, 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 September 30, 2013 and December 31, 2012, the Company had pledged collateral, consisting of government and corporate bonds, in the amount of $7.7 million and $173.7 million, respectively, which is included in securities owned, at fair value in the accompanying condensed consolidated statements of financial condition.
Securities lending and borrowing transactions
Securities borrowed and securities loaned are carried at the amounts of cash collateral advanced or received. 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.
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 September 30, 2013 and December 31, 2012, the Company does not have any securities lending transactions for which fair value basis of accounting was elected.
As of September 30, 2013, the Company has loaned to brokers and dealers, securities having a market value of $856.3 million.  In addition, as of September 30, 2013, the Company has borrowed from brokers and dealers, securities having a market value of $866.7 million.
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 $1.6 billion and $228.3 million as of September 30, 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 September 30, 2013 was $205.8 million, and as of December 31, 2012 was $220.9 million, all of which is included in other investments, at fair value in the Company's condensed consolidated statements of financial condition. The exposure to loss primarily relates to the Consolidated Feeder Funds' investment in their Unconsolidated Master Funds as of September 30, 2013 and December 31, 2012.
b.	Consolidated Funds
Securities owned, at fair value
As of September 30, 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 September 30, 2013 and December 31, 2012 other investments, at fair value, held by the Consolidated Funds are comprised of:
	As of September 30, 2013				As of December 31, 2012
	(dollars in thousands)
(1) Portfolio Funds	$	183,727			$	190,081
(2) Lehman claims	16,483				14,124
	$	200,210			$	204,205
-1	Investments in Portfolio Funds, at fair value
As of September 30, 2013 and December 31, 2012, investments in Portfolio Funds, at fair value, included the following:
	As of September 30, 2013				As of December 31, 2012
	(dollars in thousands)
Investments of Enterprise LP	$	154,363			$	173,348
Investments of Merger Fund	22,641				—
Investments of consolidated fund of funds	6,723				16,733
	$	183,727			$	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 $154.4 million and $173.3 million in Enterprise Master as of September 30, 2013 and December 31, 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 $22.6 million in Merger Master as of September 30, 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 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 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 $6.7 million and $16.7 million as of September 30, 2013 and December 31, 2012, respectively. These investments include the investments of Levered FOF, Multi-Strat Master FOF and Vintage Master FOF, all of which are investment companies managed by Ramius Alternative Solutions LLC and RTS Global 3X, which was managed by Ramius Trading Strategies LLC. Multi-Strat Master FOF's investment objective is 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 is no longer levered. Vintage Master FOF's investment objective is 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. Levered FOF, Multi-Strat Master FOF and Vintage Master FOF are all in liquidation. 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 September 30, 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 September 30, 2013 and December 31, 2012:
			Fair Value as of September 30, 2013
	Strategy		Ramius Levered Multi-Strategy FOF LP				Ramius Multi-Strategy Master FOF LP				Ramius Vintage Multi-Strategy Master FOF LP				Total
			(dollars in thousands)
Tapestry Pooled Account V LLC*	Credit-Based		$	254			$	524			$	559			$	1,337	(a)
Externally Managed Portfolio Funds	Event Driven		1,015				1,522				2,145				4,682		(c)
Externally Managed Portfolio Funds	Hedged Equity		—				—				704				704		(d)
			$	1,269			$	2,046			$	3,408			$	6,723
			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 September 30, 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 Master and its affiliated funds. A distribution of $2.9 million occurred in February of 2012. After giving effect of these distributions, the remaining Net Equity Claim for Enterprise Master held directly and through its ownership interest in affiliated funds is $12.4 million. 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 is 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. Enterprise Master is valuing the $11.7 million claim at $20.7 million as of September 30, 2013. Of the $20.7 million current valuation of Enterprise Master's claim, $16.5 million was attributable to Enterprise LP based on its ownership percentage in Enterprise Master at the time of the Administration. Of the $11.7 million net equity claim, $10.6 million represents claims to trust assets that the Company believes were held by LBIE through Lehman Brothers, Inc. (“LBI”). LBIE has 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 has liquidated approximately 90% of the aggregate value of securities received or to be received from LBI and that it intends 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 September 30, 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.
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 $20.7 million value as of September 30, 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 $4.7 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 September 30, 2013 and December 31, 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 September 30, 2013 or December 31, 2012.
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 September 30, 2013 and December 31, 2012:
Securities owned and securities sold, but not yet purchased by Enterprise Master, at fair value
	As of September 30, 2013				As of December 31, 2012
	(dollars in thousands)
Bank debt	$	5			$	79
Common stock	2,703				2,680
Preferred stock	997				997
Private equity	309				297
Restricted stock	137				26
Rights	2,455				1,714
Trade claims	128				128
Warrants	—				2
	$	6,734			$	5,923
Derivative contracts, at fair value, owned by Enterprise Master, net
	As of September 30, 2013				As of December 31, 2012
Description	(dollars in thousands)
Currency forwards	$	(7	)		$	6
	$	(7	)		$	6
Portfolio Funds, owned by Enterprise Master, at fair value
			As of September 30, 2013				As of December 31, 2012
	Strategy		(dollars in thousands)
RCG Longview Equity Fund, LP*	Real Estate		$	10,599			$	11,027
RCG Longview II, LP*	Real Estate		819				970
RCG Longview Debt Fund IV, LP*	Real Estate		18,362				30,572
RCG Longview, LP*	Real Estate		332				265
RCG Soundview, LLC*	Real Estate		446				2,374
RCG Urban American Real Estate Fund, L.P.*	Real Estate		1,936				1,987
RCG International Sarl*	Multi-Strategy		1,700				752
RCG Special Opportunities Fund, Ltd*	Multi-Strategy		83,418				80,166
RCG Endeavour, LLC*	Multi-Strategy		32				43
RCG Energy, LLC *	Energy		3,363				14,239
RCG Renergys, LLC*	Energy		1				1
Other Private Investments	Various		12,396				12,430
Real Estate Investments	Real Estate		14,970				12,321
			$	148,374			$	167,147
*	These Portfolio Funds are affiliates of the Company.
Merger Master
Securities owned and securities sold, but not yet purchased by Merger Master, at fair value
	As of September 30, 2013
	(dollars in thousands)
Common stocks	$	29,408
Corporate bond (a)	9,580
Options	376
	$	39,364
(a)	As of September 30, 2013, maturities ranged from October 2018 to October 2020 and interest rates ranged between 7.75% and 8.13% .
Derivative contracts, at fair value, owned by Merger Master, net
	As of September 30, 2013
Description	(dollars in thousands)
Equity swap	$	43
Cross rate	(3		)
	$	40
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 September 30, 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	9 Months Ended
	Sep. 30, 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 condensed consolidated statements of financial condition by caption and by level within the valuation hierarchy as of September 30, 2013 and 2012:
	Operating Entities
		Assets at Fair Value as of September 30, 2013
		Level 1		Level 2				Level 3				Total
				(dollars in thousands)
	Securities owned and derivatives
	US Government securities	$	3,506	$	—			$	—			$	3,506
	Preferred stock	—		—				333				333
	Common stocks	219,315		2,103				2,109				223,527
	Convertible bonds	—		4,129				—				4,129
	Corporate bonds	—		134,827				—				134,827
	Futures	263		—				—				263
	Currency forwards	—		49				—				49
	Equity swaps	—		276				—				276
	Options	10,965		9				—				10,974
	Warrants and rights	111		—				2,667				2,778
	Mutual funds	525		—				—				525
	Other investments
	Portfolio Funds	—		19,110				51,703				70,813
	Real estate investments	—		—				2,127				2,127
	Lehman claim	—		—				558				558
		$	234,685	$	160,503			$	59,497			$	454,685
		Liabilities at Fair Value as of September 30, 2013
		Level 1		Level 2				Level 3				Total
		(dollars in thousands)
	Securities sold, not yet purchased and derivatives
	Common stocks	$	122,211	$	—			$	—			$	122,211
	Corporate bonds	—		56				—				56
	Futures	160		—				—				160
	Currency forwards	—		105				—				105
	Equity swaps	—		4				—				4
	Options	8,603		259				—				8,862
		$	130,974	$	424			$	—			$	131,398
		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
		$	178,157	$	750			$	3			$	178,910
Consolidated Funds' investments
	Assets at Fair Value as of September 30, 2013
	Level 1		Level 2				Level 3				Total
			(dollars in thousands)
Other investments
Portfolio Funds	$	—	$	22,641			$	161,086			$	183,727
Lehman claims	—		—				16,483				16,483
	$	—	$	22,641			$	177,569			$	200,210
	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 three and nine months ended September 30, 2013 and 2012 for financial instruments classified within level 3. The classification of a financial instrument within level 3 is based upon the significance of the unobservable inputs to the overall fair value measurement.
	Three Months Ended September 30, 2013
	Balance at June 30, 2013		Transfers in				Transfers out				Purchases/(covers)				(Sales)/shorts				Realized gains (losses)				Unrealized gains (losses)				Balance at September 30, 2013
	(dollars in thousands)
Operating Entities
Preferred stock	$	333	$	—			$	—			$	—			$	—			$	—			$	—			$	333
Common stocks	2,273		—				—				—				(2		)		—				(162		)		2,109
Warrants and Rights	2,136		—				—				—				—				—				531				2,667
Portfolio Funds	43,343		—				—				6,491				(289		)		712				1,446				51,703
Real estate	2,158		—				—				—				—				—				(31		)		2,127
Lehman claim	278		—				—				—				—				—				280				558
Consolidated Funds
Portfolio Funds	177,848		—				—				—				(17,886		)		185				939				161,086
Lehman claim	15,434		—				—				—				—				—				1,049				16,483
	Three Months Ended September 30, 2012
	Balance at June 30, 2012		Transfers in				Transfers out				Purchases/(covers)				(Sales)/shorts				Realized gains (losses)				Unrealized gains (losses)				Balance at September 30, 2012
	(dollars in thousands)
Operating Entities
Preferred stock	$	240	$	—			$	—			$	2,000			$	—			$	—			$	34			$	2,274
Common stocks	719		—				—				—				—				—				(33		)		686
Warrants and Rights	2,844		—				—				341				—				—				877				4,062
Warrants and Rights, sold not yet purchased	3		—				—				—				—				(3		)		—				—
Portfolio Funds	19,876		—				—				320				(361		)		(48		)		706				20,493
Real estate	2,079		—				—				—				—				—				23				2,102
Lehman claim	731		—				—				—				—				—				30				761
Consolidated Funds
Portfolio Funds	209,507		—				—				—				(19,233		)		182				(2,659		)		187,797
Lehman claim	6,538		—				—				—				—				—				322				6,860
	Nine Months Ended September 30, 2013
	Balance at December 31, 2012		Transfers in				Transfers out				Purchases/(covers)				(Sales)/shorts				Realized gains (losses)				Unrealized gains (losses)				Balance at September 30, 2013
	(dollars in thousands)
Operating Entities
Preferred stock	$	2,332	$	—			$	(2,000	)	(e)	$	—			$	—			$	—			$	1			$	333
Common stocks	2,549		—				—				—				(275		)		260				(425		)		2,109
Corporate Bond	515		—				—				2,735				(3,346		)		(914		)		1,010				—
Warrants and Rights	1,713		290			(c)	—				166				(110		)		—				608				2,667
Warrants and Rights, sold not yet purchased	3		—				—				—				—				(4		)		1				—
Portfolio Funds	25,670		13,128			(f)	—				16,560				(7,821		)		(375		)		4,541				51,703
Real estate	1,864		—				—				—				—				—				263				2,127
Lehman claim	706		—				—				—				(382		)		—				234				558
Consolidated Funds
Portfolio Funds	182,920		—				—				—				(27,835		)		505				5,496				161,086
Lehman claim	14,124		—				—				—				(1,449		)		1,360				2,448				16,483
	Nine Months Ended September 30, 2012
	Balance at December 31, 2011		Transfers in					Transfers out					Purchases/(covers)				(Sales)/shorts				Realized gains (losses)				Unrealized gains (losses)				Balance at September 30, 2012
	(dollars in thousands)
Operating Entities
Preferred stock	$	250	$	—				$	—				$	2,000			$	—			$	—			$	24			$	2,274
Common stocks	819		—					—					—				(6		)		6				(133		)		686
Warrants and Rights	1,534		—					(88		)	(b)		623				(65		)		56				2,002				4,062
Warrants and Rights, sold not yet purchased	—		—					(1,004		)	(d)		(306		)		982				(38		)		366				—
Portfolio Funds	16,919		—					—					3,171				(1,175		)		(41		)		1,619				20,493
Real estate	2,353		—					—					152				(501		)		—				98				2,102
Lehman claim	553		—					—					—				—				—				208				761
Consolidated Funds
Portfolio Funds	213,402		16,227			(a)		(17,151		)	(a)		434				(24,259		)		(1,510		)		654				187,797
Lehman claim	7,340		—					—					—				(2,291		)		1,914				(103		)		6,860
(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 condensed consolidated statements of operations.
Certain assets and liabilities are measured at fair value on a nonrecurring basis and therefore are not included in the tables above.
The Company recognizes all transfers and the related unrealized gain (loss) at the beginning of the reporting period.
Transfers between level 1 and 2 generally relate to whether the principal market for the security becomes active or inactive. Transfers between level 2 and 3 generally relate to whether significant relevant observable inputs are available for the fair value measurements or due to change in liquidity restrictions for the investments.
During the three and nine months ended September 30, 2013 and 2012, there were no transfers between level 1 and level 2 assets and liabilities.
The following table includes quantitative information as of September 30, 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 September 30, 2013		Valuation techniques		Unobservable Inputs		Range
Common and preferred stocks	$	2,351	Discounted cash flows, market multiples, recent transactions, bid levels, and comparable transactions		Market multiples and DCF discount rate		DCF discount rates: 15%-25%, Market multiples: 9x-10x
Warrants and rights, net	2,667		Model based		Volatility		Volatility: 10% to 130%
	$	5,018
Other level 3 assets and liabilities (a)	232,048
Total level 3 assets and liabilities	$	237,066
(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	9 Months Ended
	Sep. 30, 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 September 30, 2013 and December 31, 2012, receivable from brokers was $68.0 million and $71.3 million, respectively. Payable to brokers was $149.3 million and $188.8 million as of September 30, 2013 and December 31, 2012, respectively. The Company's receivables from and payable to brokers balances are held at multiple reputable financial institutions.

Goodwill

Goodwill	9 Months Ended
	Sep. 30, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Goodwill	'
	Goodwill
	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 acquisition of Dahlman Rose & Company, LLC, during the first quarter of 2013, the Company recognized provisional goodwill in the amount of $7.7 million within the broker dealer segment (See Note 2).
	No impairment charges for goodwill were recognized during the three and nine months ended September 30, 2013 and 2012.

Redeemable_NonControlling_Inte

Redeemable Non-Controlling Interests in Consolidated Subsidiaries	9 Months Ended
	Sep. 30, 2013
Noncontrolling Interest [Abstract]	'
Redeemable Non-Controlling Interests in Consolidated Subsidiaries	'
	Redeemable Non-Controlling Interests in Consolidated Subsidiaries
	Redeemable non-controlling interests in consolidated subsidiaries and the related net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries are comprised as follows:
		As of September 30, 2013		As of December 31, 2012
		(dollars in thousands)
	Redeemable non-controlling interests in consolidated subsidiaries
	Operating companies	$	9,606	$	4,106
	Consolidated funds	80,573		81,597
		$	90,179	$	85,703
		Three Months Ended September 30,					Nine Months Ended September 30,
		2013		2012			2013		2012
		(dollars in thousands)
	Income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries
	Operating companies	$	3,884	$	298		$	7,280	$	893
	Consolidated funds	875		(1,331		)	3,229		(2,118		)
		$	4,759	$	(1,033	)	$	10,509	$	(1,225	)

ShareBased_Compensation_and_Em

Share-Based Compensation and Employee Ownership Plans	9 Months Ended
	Sep. 30, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Share-Based Compensation and Employee Ownership Plans	'
	Share-Based 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 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. Stock appreciation rights awards ("SAR's") vest and expire after 5 years from grant date. As of September 30, 2013, there were approximately 1.4 million shares available for future issuance under the Equity Plans.
	Under the 2010 Equity Plan, the Company awarded $27.7 million of deferred cash awards to its employees in February 2013 in addition to awards granted during 2012. These awards vest over a period of five years and accrue interest at 0.75% per year. As of September 30, 2013, the Company had unrecognized compensation expense related to these awards of $29.8 million.
	In addition to the Equity Plans, certain employees of the Company, in November 2009, were issued membership interests in RCG Holdings LLC (formerly Ramius 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 $4.3 million and $5.7 million for the three months ended September 30, 2013 and 2012, respectively, and $13.8 million and $16.2 million for the nine months ended September 30, 2013 and 2012, respectively. The income tax effect recognized for the Equity Plans was a benefit of $2.9 million and $4.4 million for the three months ended September 30, 2013 and 2012, respectively, and $8.5 million and $9.0 million for the nine months ended September 30, 2013 and 2012, respectively; however, these benefits were offset by a valuation allowance.
	In relation to awards under the RCG Grants, the Company recognized expense of $1.3 million and $4.4 million for the three and nine months ended September 30, 2012, respectively. The income tax effect recognized for the RCG Grants was a benefit of $0.5 million and $1.7 million for the three and nine months ended September 30, 2012, respectively; however, these benefits were offset by valuation allowances.
	Stock Options and Stock Appreciation Rights
	The Company values options and SAR's 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.
	The fair value of each award is estimated on the date of grant utilizing a Black-Scholes option valuation model that uses the following assumptions:
	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 nine months ended September 30, 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	773,763		$	12.58	1.6	$	—
	Options granted	—		—		—	—
	Options acquired	—		—		—	—
	Options expired	(473.757	)	16		—	—
	Balance outstanding at September 30, 2013	300.006		$	7.18	2.66	$	—
	Options exercisable at September 30, 2013	200.004		$	9.04	1.94	$	—
	-1	Based on the Company's closing stock price of $3.44 on September 30, 2013 and $2.45 on December 31, 2012.
	As of September 30, 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 nine months ended September 30, 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 September 30, 2013	400,000		$	2.9	4.46	$	467,640
	SAR's exercisable at September 30, 2013	—		$	—	—	$	—
	-1	Based on the Company's closing stock price of $3.44 on September 30, 2013.
	As of September 30, 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 nine months ended September 30, 2013:
		Nonvested Restricted Shares and Restricted Stock Units		Weighted-Average
				Grant Date
				Fair Value
	Balance outstanding at December 31, 2012	10,252,023		$	4.15
	Granted	7,234,924		2.66
	Vested	(4,178,314	)	3.94
	Cancelled	—		—
	Forfeited	(176,413	)	3.15
	Balance outstanding at September 30, 2013	13,132,220		$	3.41
	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 September 30, 2013, there was $30.0 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 1.83 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 three and nine months ended September 30, 2013. Vested awards of 112,320 were delivered during the three and nine months ended September 30, 2013. As of September 30, 2013 there were 482,522 restricted stock units outstanding.

Defined_Benefit_Plans

Defined Benefit Plans	9 Months Ended
	Sep. 30, 2013
Compensation and Retirement Disclosure [Abstract]	'
Defined Benefit Plans	'
	Defined Benefit Plan
	The amounts contained in the following table relate to the Company's defined benefit plan for the three and nine months ended September 30, 2013 and 2012:
		Three Months Ended September 30,						Nine Months Ended September 30,
		2013			2012			2013			2012
		(dollars in thousands)
	Components of net periodic benefit cost included in employee compensation and benefits
	Service cost	$	—		$	—		$	—		$	—
	Interest cost	54			53			152			159
	Expected return on plan assets	(64		)	(60		)	(186		)	(176		)
	Amortization of (loss) / gain	—			—			—			—
	Amortization of prior service cost	5			5			16			15
	Effect of settlement	—			(17		)	(95		)	(20		)
	Net periodic benefit cost	$	(5	)	$	(19	)	$	(113	)	$	(22	)

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 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 Company calculates its U.S. tax provision using the estimated annual effective tax rate methodology. The tax expense or benefit caused by an unusual or infrequent item is recorded in the quarter in which it occurs. The Company uses the discrete methodology to calculate its income tax provision for its foreign subsidiaries. Based on these methodologies, the Company’s effective income tax rate was 2.22% and (3.26)% for the nine months ended September 30, 2013 and 2012, respectively. During the nine months ended September 30, 2013, the unusual or infrequent item whose tax impact was recorded discretely was primarily related to the tax provisions of the Company’s foreign subsidiaries.
	For the nine months ended September 30, 2013 and 2012, the effective tax rate differs from the statutory rate of 35% primarily due to a change in the Company's valuation allowance, stock compensation and other nondeductible expenses.
	The Company records deferred tax assets and liabilities for the future tax benefit or expense that will result from differences between the carrying value of its assets for income tax purposes and for financial reporting purposes, as well as for operating or capital loss and tax credit carryovers. A valuation allowance is recorded to bring the net deferred tax assets to a level that, in management’s view, is more likely than not to be realized in the foreseeable future. This level will be estimated based on a number of factors, especially the amount of net deferred tax assets of the Company that are actually expected to be realized, for tax purposes, in the foreseeable future. As of September 30, 2013, the Company recorded a valuation allowance against substantially all of its net deferred tax assets.
	The Company may be examined by the United States Internal Revenue Service (IRS), the United Kingdom Inland Revenue Service and state and 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 its 2009 tax year. No significant adjustments are expected as a result of this audit. During the third quarter of 2013, the Company concluded an IRS examination of one of the Company’s former consolidated tax groups for its 2010 tax year with no adjustments.
	The Company intends to permanently reinvest the capital and accumulated earnings of its foreign subsidiaries in the respective subsidiary, but repatriates the current earnings of its foreign subsidiaries to the United States to the extent such repatriation is permissible under local regulatory rules. The undistributed earnings of the Company’s foreign subsidiaries totaled $1.2 million as of September 30, 2013. The tax liability that would arise if these earnings were remitted to the United States is approximately $0.1 million.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 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 $4.3 million and $3.6 million for the three months ended September 30, 2013 and 2012, respectively, and $12.3 million and $11.0 million for the nine months ended September 30, 2013 and 2012, 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 $0.3 million and $2.8 million as of September 30, 2013 and December 31, 2012, respectively.
	As of September 30, 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)
	2013	$	825	$	3,520	$	4,899
	2014	1,548		11,577		19,223
	2015	1,051		3,876		16,181
	2016	194		247		13,069
	2017	—		—		9,946
	Thereafter	—		—		43,733
		$	3,618	$	19,220	$	107,051
	(a)	Equipment Leases include the Company's commitments relating to operating and capital leases. See Note 14 for further information on the capital lease minimum payments which are included in the table.
	(b)	The Company has entered into various agreements to sublease certain of its premises. The Company recorded sublease income related to these leases of $0.4 million and $0.3 million for the three months ended September 30, 2013 and 2012, respectively, and $1.0 million and $1.0 million for the nine months ended September 30, 2013 and 2012, 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.
	The actual clawback liability, however, does not become realized until the end of a fund's life. The life of the real estate funds with a potential clawback obligation, including available contemplated extensions, are currently anticipated to expire at the end of 2013. Further extensions of such terms may be implemented under certain circumstances. As of September 30, 2013, the clawback obligations were $6.2 million.
	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 September 30, 2013, the Company had unfunded commitments of $19.4 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 September 30, 2013, the Company has funded $29.3 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 September 30, 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 September 30, 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 September 30, 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 condensed consolidated statements of financial condition. Estimates, by their nature, are based on judgment and currently available information and involve a variety of factors, including, but not limited to, the type and nature of the litigation, claim or proceeding, the progress of the matter, the advice of legal counsel, the Company's defenses and its experience in similar cases or proceedings as well as its assessment of matters, including settlements, involving other defendants in similar or related cases or proceedings. The Company may increase or decrease its legal reserves in the future, on a matter-by-matter basis, to account for developments in such matters.
	There have been no developments with respect to the Company’s legal proceedings that occurred during the three months ended September 30, 2013.

ShortTerm_Borrowings_and_Other

Short-Term Borrowings and Other Debt	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Short-Term Borrowings and Other Debt	'
	Short-Term Borrowings and Other Debt
	As of September 30, 2013 and December 31, 2012, short term borrowings and other debt of the Company were as follows:
		As of September 30, 2013			As of December 31, 2012
		(dollars in thousands)
	Notes payable	$	491		$	206
	Capital lease obligations	2,878			3,926
		$	3,369		$	4,132
	In January 2013, the Company borrowed $2 million to fund insurance premium payments. This notes bears interest at 2.22% and is due on December 1, 2013, with monthly payment requirements of $0.2 million. As of September 30, 2013, the outstanding balance on this note payable was $0.5 million. Interest expense for the three and nine months ended September 30, 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 condensed 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 September 30, 2013, the remaining balance on these capital leases was $2.9 million. Interest expense was $0.1 million and $0.1 million for the three months ended September 30, 2013 and 2012, respectively, and $0.1 million and $0.1 million for the nine months ended September 30, 2013 and 2012, respectively.
	As of September 30, 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		12-May-14
	New York		$	1,191		3-Sep-14
	New York		$	6,746		12-Dec-13
	New York		$	1,000		22-Feb-14
	New York		$	1,861		19-Mar-14
	To the extent any letter of credit is drawn upon, interest will be assessed at the prime commercial lending rate. As of September 30, 2013 and December 31, 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 September 30, 2013, are as follows:
		Capital Lease			Short Term
		Obligation			Borrowings
		(dollars in thousands)
	2013	$	385		$	464
	2014	1,402			46
	2015	1,051			—
	2016	194			—
	2017	—			—
	Thereafter	—			—
	Subtotal	3,032			510
	Less: Amount representing interest (a)	(154		)	(19		)
	Total	$	2,878		$	491
	(a)	Amount necessary to reduce net minimum lease payments to present value calculated at the Company's implicit rate at lease inception.

Treasury_stock

Treasury stock	9 Months Ended
	Sep. 30, 2013
Equity [Abstract]	'
Treasury stock	'
	Treasury stock
	Treasury stock of $37.5 million as of September 30, 2013, compared to $31.7 million as of December 31, 2012, resulted from $3.2 million acquired through repurchases of shares to cover employee minimum tax withholding obligations related to stock compensation vesting events under the Company's Equity Plan, $2.7 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 nine months ended September 30, 2013:
		Treasury stock shares		Cost			Average cost
				(dollars in thousands)			per share
	Balance outstanding at December 31, 2012	11,292,220		$	31,728		$	2.81
	Shares purchased for minimum tax withholding under the Equity Plan	1,049,740		3,156			3.01
	Treasury stock reissued	(24,744	)	(90		)	3.64
	Purchase of treasury stock	813,944		2,723			3.35
	Balance outstanding at September 30, 2013	13,131,160		$	37,517		$	2.86

Earnings_Per_Share

Earnings Per Share	9 Months Ended
	Sep. 30, 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 September 30, 2013, there were 117,411,528 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 three and nine months ended September 30, 2013 and 2012, respectively, as their inclusion would have been anti-dilutive.
	The computation of earnings per share is as follows:
		Three Months Ended September 30,					Nine Months Ended September 30,
		2013		2012			2013		2012
		(dollars in thousands, except per share data)
	Net income (loss)	$	8,370	$	(11,618	)	$	12,637	$	(15,761	)
	Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries	4,759		(1,033		)	10,509		(1,225		)
	Net income (loss) less Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries	$	3,611	$	(10,585	)	$	2,128	$	(14,536	)
	Shares for basic and diluted calculations:
	Weighted average shares used in basic computation	118,359		114,989			116,012		114,587
	Stock options	—		—			—		—
	Stock appreciation rights	311		—			296		—
	Restricted stock	4,038		—			3,583		—
	Weighted average shares used in diluted computation	122,708		114,989			119,891		114,587
	Earnings (loss) per share:
	Basic	$	0.03	$	(0.09	)	$	0.02	$	(0.13	)
	Diluted	$	0.03	$	(0.09	)	$	0.02	$	(0.13	)

Segment_Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 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 condensed 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):
		Three Months Ended September 30, 2013
											Adjustments
		Alternative			Broker-Dealer (1)			Total Economic Income/(Loss)			Funds			Other				US GAAP
		Investment									Consolidation			Adjustments
		(dollars in thousands)
	Revenues
	Investment banking	$	—		$	27,694		$	27,694		$	—		$	—			$	27,694
	Brokerage	—			32,035			32,035			—			(3,573		)	(e)	28,462
	Management fees	14,299			—			14,299			(275		)	(4,697		)	(a)	9,327
	Incentive income	5,666			—			5,666			—			(3,145		)	(a)	2,521
	Investment Income	10,031			2,296			12,327			—			(12,327		)	(c)	—
	Interest and dividends	—			—			—			—			10,969			(c)	10,969
	Reimbursement from affiliates	—			—			—			(75		)	1,461			(b)	1,386
	Other revenue	156			(38		)	118			—			438			(c)	556
	Consolidated Funds revenues	—			—			—			445			—				445
	Total revenues	30,152			61,987			92,139			95			(10,874		)		81,360
	Expenses
	Employee compensation and benefits	13,539			40,291			53,830			—			(216		)		53,614
	Interest and dividends	52			23			75			—			6,058			(c)	6,133
	Non-compensation expenses—Fixed	9,086			16,245			25,331			—			(25,331		)	(c)(d)	—
	Non-compensation expenses—Variable	1,449			5,424			6,873			—			(6,873		)	(c)(d)	—
	Non-compensation expenses	—			—			—			—			31,540			(c)(d)	31,540
	Reimbursement from affiliates	(1,461		)	—			(1,461		)	—			1,461			(b)	—
	Consolidated Funds expenses	—			—			—			450			—				450
	Total expenses	22,665			61,983			84,648			450			6,639				91,737
	Other income (loss)
	Net gain (loss) on securities, derivatives and other investments	—			—			—			—			15,469			(c)	15,469
	Consolidated Funds net gains (losses)	—			—			—			1,230			2,002				3,232
	Total other income (loss)	—			—			—			1,230			17,471				18,701
	Income (loss) before income taxes and non-controlling interests	7,487			4			7,491			875			(42		)		8,324
	Income taxes expense / (benefit)	—			—			—			—			(46		)	(b)	(46		)
	Economic Income (Loss) / Net income (loss) before non-controlling interests	7,487			4			7,491			875			4				8,370
	(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	(3,825		)	—			(3,825		)	(875		)	(59		)		(4,759		)
	Economic Income (Loss) / Net Income (loss) attributable to Cowen Group, Inc. stockholders	$	3,662		$	4		$	3,666		$	—		$	(55	)		$	3,611
	(1) For the three months ended September 30, 2013, the Company has reflected $3.0 million of investment income and related compensation expense of $1.0 million within the broker-dealer segment in proportion to its capital.
		Three Months Ended September 30, 2012
											Adjustments
		Alternative			Broker-Dealer (1)			Total			Funds			Other				US GAAP
		Investment						Economic Income/(Loss)			Consolidation			Adjustments
		(dollars in thousands)
	Revenues
	Investment banking	$	—		$	18,666		$	18,666		$	—		$	—			$	18,666
	Brokerage	—			22,701			22,701			—			—				22,701
	Management fees	13,426			—			13,426			(362		)	(4,198		)	(a)	8,866
	Incentive income	1,699			—			1,699			—			(283		)	(a)	1,416
	Investment Income	6,864			2,288			9,152			—			(9,152		)	(c)	—
	Interest and dividends	—			—			—			—			3,605			(c)	3,605
	Reimbursement from affiliates	—			—			—			(97		)	1,467			(b)	1,370
	Other revenue	168			213			381			—			320			(c)	701
	Consolidated Funds revenues	—			—			—			273			—				273
	Total revenues	22,157			43,868			66,025			(186		)	(8,241		)		57,598
	Expenses
	Employee compensation and benefits	11,759			34,490			46,249			—			1,073				47,322
	Interest and dividends	93			38			131			—			1,925			(c)	2,056
	Non-compensation expenses—Fixed	8,564			15,452			24,016			—			(24,016		)	(c)(d)	—
	Non-compensation expenses—Variable	1,433			4,287			5,720			—			(5,720		)	(c)(d)	—
	Non-compensation expenses	—			—			—			—			29,346			(c)(d)	29,346
	Reimbursement from affiliates	(1,467		)	—			(1,467		)	—			1,467			(b)	—
Consolidated Funds expenses	—			—			—			330			—				330
Total expenses	20,382			54,267			74,649			330			4,075				79,054
Other income (loss)
Net gains (losses) on securities, derivatives and other investments	—			—			—			—			12,510			(c)	12,510
Consolidated Funds net gains (losses)	—			—			—			(815		)	(1,694		)		(2,509		)
Total other income (loss)	—			—			—			(815		)	10,816				10,001
Income (loss) before income taxes and non-controlling interests	1,775			(10,399		)	(8,624		)	(1,331		)	(1,500		)		(11,455		)
Income taxes expense / (benefit)	—			—			—			—			163			(b)	163
Economic Income (Loss) / Net income (loss) before non-controlling interests	1,775			(10,399		)	(8,624		)	(1,331		)	(1,663		)		(11,618		)
(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	(301		)	—			(301		)	1,331			3				1,033
Economic Income (Loss) / Net income (loss) attributable to Cowen Group, Inc. stockholders	$	1,474		$	(10,399	)	$	(8,925	)	$	—		$	(1,660	)		$	(10,585	)
(1) For the three months ended September 30, 2012, the Company has reflected $2.3 million of investment income and related compensation expense of $0.8 million within the broker-dealer segment in proportion to its capital.
	Nine Months Ended September 30, 2013
										Adjustments
	Alternative			Broker-Dealer (1)			Total Economic Income/(Loss)			Funds			Other				US GAAP
	Investment									Consolidation			Adjustments
	(dollars in thousands)
Revenues
Investment banking	$	—		$	70,431		$	70,431		$	—		$	—			$	70,431
Brokerage	—			93,352			93,352			—			(6,769		)	(e)	86,583
Management fees	43,050			—			43,050			(871		)	(13,661		)	(a)	28,518
Incentive income	14,558			—			14,558			—			(7,472		)	(a)	7,086
Investment Income	22,169			4,593			26,762			—			(26,762		)	(c)	—
Interest and dividends	—			—			—			—			30,905			(c)	30,905
Reimbursement from affiliates	—			—			—			(206		)	4,291			(b)	4,085
Other revenue	381			(427		)	(46		)	—			1,565			(c)	1,519
Consolidated Funds revenues	—			—			—			681			—				681
Total revenues	80,158			167,949			248,107			(396		)	(17,903		)		229,808
Expenses
Employee compensation and benefits	37,863			108,202			146,065			—			(721		)		145,344
Interest and dividends	183			88			271			—			20,016			(c)	20,287
Non-compensation expenses—Fixed	26,695			46,197			72,892			—			(72,892		)	(c)(d)	—
Non-compensation expenses—Variable	3,594			19,192			22,786			—			(22,786		)	(c)(d)	—
Non-compensation expenses	—			—			—			—			94,593			(c)(d)	94,593
Reimbursement from affiliates	(4,291		)	—			(4,291		)	—			4,291			(b)	—
Consolidated Funds expenses	—			—			—			1,237			—				1,237
Total expenses	64,044			173,679			237,723			1,237			22,501				261,461
Other income (loss)
Net gains (losses) on securities, derivatives and other investments	—			—			—			—			32,873			(c)	32,873
Consolidated Funds net gains (losses)	—			—			—			4,862			6,843				11,705
Total other income (loss)	—			—			—			4,862			39,716				44,578
Income (loss) before income taxes and non-controlling interests	16,114			(5,730		)	10,384			3,229			(688		)		12,925
Income taxes expense / (benefit)	—			—			—			—			288			(b)	288
Economic Income (Loss) / Net income (loss) before non-controlling interests	16,114			(5,730		)	10,384			3,229			(976		)		12,637
(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	(6,517		)	—			(6,517		)	(3,229		)	(763		)		(10,509		)
Economic Income (Loss) / Net Income (loss) attributable to Cowen Group, Inc. stockholders	$	9,597		$	(5,730	)	$	3,867		$	—		$	(1,739	)		$	2,128
(1) For the nine months ended September 30, 2013, 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.
	Nine Months Ended September 30, 2012
										Adjustments
	Alternative			Broker-Dealer (1)			Total Economic Income/(Loss)			Funds			Other				US GAAP
	Investment									Consolidation			Adjustments
	(dollars in thousands)
Revenues
Investment banking	$	—		$	50,550		$	50,550		$	—		$	—			$	50,550
Brokerage	—			71,282			71,282			—			—				71,282
Management fees	42,032			—			42,032			(1,150		)	(12,367		)	(a)	28,515
Incentive income	8,303			—			8,303			—			(5,616		)	(a)	2,687
Investment Income	30,361			8,182			38,543			—			(38,543		)	(c)	—
Interest and dividends	—			—			—			—			14,845			(c)	14,845
Reimbursement from affiliates	—			—			—			(222		)	4,018			(b)	3,796
Other revenue	508			186			694			—			1,704			(c)	2,398
Consolidated Funds revenues	—			—			—			474			—				474
Total revenues	81,204			130,200			211,404			(898		)	(35,959		)		174,547
Expenses
Employee compensation and benefits	42,705			91,098			133,803			—			3,299				137,102
Interest and dividends	123			155			278			—			6,829			(c)	7,107
Non-compensation expenses—Fixed	24,093			45,655			69,748			—			(69,748		)	(c)(d)	—
Non-compensation expenses—Variable	3,881			15,852			19,733			—			(19,733		)	(c)(d)	—
Non-compensation expenses	—			—			—			—			87,670			(c)(d)	87,670
Reimbursement from affiliates	(4,018		)	—			(4,018		)	—			4,018			(b)	—
Consolidated Funds expenses	—			—			—			1,339			—				1,339
Total expenses	66,784			152,760			219,544			1,339			12,335				233,218
Other income (loss)
Net gains (losses) on securities, derivatives and other investments	—			—			—			—			41,969			(c)	41,969
Consolidated Funds net gains (losses)	—			—			—			119			1,318				1,437
Total other income (loss)	—			—			—			119			43,287				43,406
Income (loss) before income taxes and non-controlling interests	14,420			(22,560		)	(8,140		)	(2,118		)	(5,007		)		(15,265		)
Income taxes expense / (benefit)	—			—			—			—			496			(b)	496
Economic Income (Loss) / Net income (loss) before non-controlling interests	14,420			(22,560		)	(8,140		)	(2,118		)	(5,503		)		(15,761		)
(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	(900		)	—			(900		)	2,118			7				1,225
Economic Income (Loss) / Net Income (loss) attributable to Cowen Group, Inc. stockholders	$	13,520		$	(22,560	)	$	(9,040	)	$	—		$	(5,496	)		$	(14,536	)
(1) For the nine months ended September 30, 2012, the Company has reflected $8.2 million of investment income and related compensation expense of $2.7 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.
For the three and nine months ended September 30, 2013 and 2012, there was no one fund or other customer which represented more than 10% of the Company's total revenues. Primarily all of the revenues earned by the alternative investment segment were from related parties for the three and nine months ended September 30, 2013 and 2012. There were no revenues earned from related parties by the broker dealer segment in the three and nine months ended September 30, 2013 and 2012.

Regulatory_Requirements

Regulatory Requirements	9 Months Ended
	Sep. 30, 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 basic method permitted by the Rule, ATM Execution is required to maintain minimum net capital, as defined, equivalent to the greater of $1.0 million or 6.667% of aggregate indebtedness. ATM USA is required to maintain minimum net capital, as defined, equivalent to the greater of $5,000 or 6.667% of aggregate indebtedness. Cowen Equity Finance is 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 September 30, 2013, Cowen and Company had total net capital of approximately $52.3 million, which was approximately $51.3 million in excess of its minimum net capital requirement of $1.0 million. As of September 30, 2013, ATM Execution had total net capital of approximately $3.5 million, which was approximately $2.5 million in excess of its minimum net capital requirement of $1.0 million. As of September 30, 2013, ATM USA had total net capital of approximately $0.9 million, which was approximately $0.9 million in excess of its minimum net capital requirement of $6,138. As of September 30, 2013, Cowen Equity Finance had total net capital of approximately $11.5 million which was approximately $11.2 million in excess of its minimum net capital requirement of $250,000. As of August 23, 2013, Cowen Securities had been deregistered as a broker dealer and is no longer subject to the SEC's Uniform Net Capital Rule 15c3-1.
	Cowen and Company and ATM Execution are exempt from the provisions of Rule 15c3-3 under the Securities Exchange Act of 1934 as its 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 September 30, 2013, Ramius UK's Financial Resources of $0.5 million exceeded its minimum requirement of $0.2 million by $0.3 million. As of September 30, 2013, CIL's Financial Resources of $4.2 million exceeded its minimum requirement of $2.2 million by $2.0 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 September 30, 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	9 Months Ended
	Sep. 30, 2013
Related Party Transactions [Abstract]	'
Related Party Transactions	'
	Related Party Transactions
	The Company acts as managing member, general partner and/or investment manager to the Ramius managed funds, 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 September 30, 2013 and December 31, 2012, $14.3 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 three months ended September 30, 2013 and 2012, the Company reimbursed the funds it manages $0.4 million and $0.2 million, respectively, and $1.4 million and $1.2 million for the nine months ended September 30, 2013 and 2012, respectively, which were recorded net in management fees and incentive income in the accompanying condensed consolidated statements of operations. As of September 30, 2013 and December 31, 2012, related amounts still payable were $2.0 million and $1.7 million, respectively, and were reflected in fees payable in the accompanying condensed 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 condensed consolidated statements of financial condition. As of September 30, 2013 and December 31, 2012, loans to employees of $7.2 million and $5.1 million, respectively, were included in due from related parties on the condensed consolidated statements of financial condition. Of these amounts $4.6 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 $1.1 million and $0.6 million, respectively, related to the amortization of forgivable loans for the three months ended September 30, 2013 and 2012, and $2.3 million and $1.3 million for the nine months ended September 30, 2013 and 2012, respectively . This expense is included in employee compensation and benefits in the condensed consolidated statement of operations. For the three and nine months ended September 30, 2013 and 2012 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 5), 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 September 30, 2013, $1.5 million is included in due from related parties in the accompanying condensed consolidated statement of financial condition. For the three and nine months ended September 30, 2013 and 2012, interest charged for this loan was insignificant.
	Included in due to related parties is approximately $0.6 million and $0.4 million as of September 30, 2013 and December 31, 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	9 Months Ended
	Sep. 30, 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 condensed 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 condensed 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 condensed consolidated financial statements for these indemnifications.
	Through the Company's securities lending program (see Note 5(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 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 September 30, 2013 was $2.6 million.
	Off-Balance Sheet Arrangements
	The Company has no material off-balance sheet arrangements as of September 30, 2013 and December 31, 2012. However, through indemnification provisions in our clearing agreement, customer activities may expose us to off-balance-sheet credit risk. Pursuant to the clearing agreement, the Company is required to reimburse our 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	9 Months Ended
	Sep. 30, 2013
Subsequent Events [Abstract]	'
Subsequent Events	'
	Subsequent Events
	The Company intends to terminate the defined benefit plan (see Note 11) in standard termination with a proposed termination date of December 31, 2013.
	The Company has evaluated events through November 7, 2013 which is the date the condensed consolidated financial statements were available to be issued and has determined that there were no additional subsequent events requiring adjustment or disclosure in the condensed consolidated financial statements.

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Basis of presentation	'
	Basis of presentation
	These unaudited condensed consolidated financial statements and related notes have been prepared in accordance with US GAAP and the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) related to interim financial statements. Results for interim periods should not be considered indicative of results for any other interim period or for the full year. These financial statements should be read in conjunction with the audited consolidated financial statements as of December 31, 2012 and 2011 and for the years ended December 31, 2012, 2011, and 2010, included in the Form 10-K of Cowen Group as filed with the SEC on March 7, 2013. The financial information contained herein is unaudited; however, management believes all adjustments have been made that are necessary for a fair presentation of the results for the interim periods. The year-end condensed balance sheet data was derived from audited financial statements, but does not include all disclosures required by US GAAP. All material intercompany transactions and balances have been eliminated in consolidation. Certain fund entities that are consolidated in these condensed consolidated financial statements, as further discussed below, are not subject to these consolidation provisions with respect to their own investments pursuant to their specialized accounting.
	The Company serves as the managing member/general partner and/or investment manager to affiliated fund entities which it sponsors and manages. Funds in which the Company has a controlling financial interest are consolidated with the Company pursuant to US GAAP as described below. Consequently, the Company's condensed consolidated financial statements reflect the assets, liabilities, income and expenses of these funds on a gross basis. The ownership interests in these funds that are not owned by the Company are reflected as redeemable non-controlling interests in consolidated subsidiaries in the accompanying condensed consolidated financial statements. The management fees and incentive income earned by the Company from these funds are eliminated in consolidation.
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 September 30, 2013 and December 31, 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 (formerly known as Cowen Bluebird LLC) and Ramius Co-Investment II LLC (formerly known as RCG Ultragenex Holdings 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 September 30, 2013 the Company consolidates three VIEs and as of December 31, 2012 the Company does not consolidate any VIEs. As of September 30, 2013, the total net assets of the consolidated VIEs are $7.1 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 September 30, 2013 and December 31, 2012, the Company holds a variable interest in Ramius Enterprise Master Fund Ltd (“Enterprise Master”) (the “Unconsolidated Master Fund”) through one of its Consolidated Funds, Enterprise LP. 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 Fund.
	In the ordinary course of business, the Company also sponsors various other entities that it has determined to be VIEs. These VIEs are primarily 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 5 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 condensed consolidated statements of financial condition. The Company's share of earnings or losses from equity method investees is included in net gains (losses) on securities, derivatives and other investments in the condensed 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 condensed 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 condensed consolidated statements of financial condition at their estimated fair value, with unrealized gains (losses) resulting from changes in fair value reflected within net realized and unrealized gains (losses) on investments and other transactions. Accordingly, the accompanying condensed consolidated financial statements reflect different accounting policies for investments depending on whether or not they are held through a consolidated investment company. In addition, the Company's broker‑dealer subsidiaries, Cowen and Company, LLC (“Cowen and Company”), 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 condensed consolidated financial statements in conformity with US GAAP requires the management of the Company to make estimates and assumptions that affect the fair value of securities and other investments, the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the accompanying condensed consolidated financial statements, the accounting for goodwill and identifiable intangible assets and the reported amounts of revenues and expenses during the reporting period. Actual results could materially differ from those estimates. Certain reclassifications have been made to prior period amounts in order to conform with current period presentation.
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 condensed consolidated financial statements. Certain of the Company's investments are relatively illiquid or thinly traded and may not be immediately liquidated on demand if needed. Fair values assigned to these investments may differ significantly from the fair values that would have been used had a ready market for the investments existed and such differences could be material.
	The Company primarily uses the “market approach” to value its financial instruments measured at fair value. In determining an instrument's level within the hierarchy, the Company categorizes the Company's financial instruments into three categories: securities, derivative contracts and other investments. To the extent applicable, each of these categories can further be divided between those held long or sold short.
	The Company has the option to measure certain financial assets and financial liabilities at fair value with changes in fair value recognized in earnings each period. The election is made on an instrument by instrument basis at initial recognition of an asset or liability or upon an event that gives rise to a new basis of accounting for that instrument.  The Company has elected the fair value option for 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 condensed consolidated statements of financial condition and all other derivatives are included within securities owned, at fair value on the accompanying condensed 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 5 and 6 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 5 and 6 for further information regarding the Company's investments, including equity method investments, and fair value measurements.
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. 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 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 September 30, 2013 and December 31, 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 September 30, 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 counter party. 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.
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 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 condensed consolidated statements of financial condition, as of September 30, 2013 and December 31, 2012 is $16.2 million and $13.8 million, respectively.
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.
Income tax	'
	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.
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 three and nine months ended September 30, 2013 and 2012, 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 condensed 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.

Investments_of_Operating_Entit1

Investments of Operating Entities and Consolidated Funds (Tables)	9 Months Ended
	Sep. 30, 2013
Operating Entities	'
Investment Holdings [Line Items]	'
Marketable Securities	'
	As of September 30, 2013 and December 31, 2012, securities owned, at fair value consisted of the following:
		As of September 30, 2013				As of December 31, 2012
		(dollars in thousands)
	U.S. Government securities (a)	$	3,506			$	137,478
	Preferred stock	333				2,332
	Common stocks	223,527				259,292
	Convertible bonds (b)	4,129				6,202
	Corporate bonds (c)	134,827				193,078
	Options	10,974				20,546
	Warrants and rights	2,778				2,354
	Mutual funds	525				2,845
		$	380,599			$	624,127
	(a)	As of September 30, 2013, maturities ranged from October 2013 to April 2016 and interest rates ranged between 0.02% and 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 September 30, 2013, the maturity was July 2014 with an interest rate of 5.00%. As of December 31, 2012, maturities ranged from May 2014 to July 2014 with an interest rate of 5.00%.
	(c)	As of September 30, 2013, maturities ranged from December 2013 to February 2046 and interest rates ranged between 2.58% 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 September 30, 2013 and December 31, 2012, other investments consisted of the following:
		As of September 30, 2013				As of December 31, 2012
		(dollars in thousands)
	(1) Portfolio Funds, at fair value	$	70,813			$	55,898
	(2) Real estate investments, at fair value	2,127				1,864
	(3) Equity method investments	24,664				26,462
	(4) Lehman claims, at fair value	558				706
		$	98,162			$	84,930
Schedule of Other Investments, Portfolio Funds	'
	The Portfolio Funds, at fair value as of September 30, 2013 and December 31, 2012, included the following:
		As of September 30, 2013				As of December 31, 2012
		(dollars in thousands)
	HealthCare Royalty Partners (a)(*)	$	10,204			$	7,866
	HealthCare Royalty Partners II (a)(*)	4,510				6,415
	Orchard Square Partners Credit Fund LP (formerly known as Ramius Global Credit Fund LP) (b)(*)	12,417				14,196
	Tapestry Investment Co PCC Ltd (c)	86				194
	Starboard Value and Opportunity Fund LP (d)(*)	17,242				15,706
	Formation 8 Partners Fund I (e)	2,802				1,500
	RCG LV Park Lane LLC (f)	685				708
	RCGL 12E13th LLC (g)	400				—
	RCG Longview Debt Fund V, L.P. (g)	11,679				—
	Other private investment (h)	8,004				7,826
	Other affiliated funds (i)(*)	2,784				1,487
		$	70,813			$	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 13.
	(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 is in the process of liquidation and redemptions will be made periodically at the investment managers' decision as the underlying investments are liquidated.
	(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 September 30, 2013				As of December 31, 2012
		(dollars in thousands)
	RCG Longview Debt Fund IV Management, LLC	$	1,594			$	1,954
	RCG Longview Debt Fund V Partners, LLC	1,010				—
	HealthCare Royalty GP, LLC	832				642
	HealthCare Royalty GP II, LLC	764				1,086
	HealthCare Royalty GP III, LLC	47				—
	CBOE Stock Exchange, LLC	1,810				2,058
	Starboard Value LP	11,692				12,757
	RCG Longview Partners, LLC	2,016				1,535
	RCG Longview Louisiana Manager, LLC	1,327				1,866
	RCG Urban American, LLC	281				1,380
	RCG Urban American Management, LLC	141				545
	RCG Longview Equity Management, LLC	230				285
	Urban American Real Estate Fund II, LLC	1,612				1,636
	RCG Kennedy House, LLC	428				377
	Other	880				341
		$	24,664			$	26,462
Schedule of Results of Operations, Equity Method Investments	'
	The summarized income statement information for the Company's investments in the individually significant investees is as follows:
		Three Months Ended September 30,								Nine Months Ended September 30,
		2013				2012				2013				2012
		(dollars in thousands)
	Revenues	$	6,821			$	3,909			$	17,746			$	16,190
	Expenses	(2,266		)		(2,785		)		(6,945		)		(7,850		)
	Net realized and unrealized gains (losses)	(16		)		26				(116		)		135
	Net Income	$	4,539			$	1,150			$	10,685			$	8,475
Investments Sold, Not yet Purchased	'
	As of September 30, 2013 and December 31, 2012 securities sold, not yet purchased, at fair value consisted of the following:
		As of September 30, 2013				As of December 31, 2012
		(dollars in thousands)
	Common stocks	$	122,211			$	168,797
	Corporate bonds (a)	56				61
	Options	8,862				9,076
	Warrants and rights	—				3
		$	131,129			$	177,937
	(a)	As of September 30, 2013 and December 31, 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 September 30, 2013 and December 31, 2012:
		As of September 30, 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 January 2016	$	6,311
		$	6,311
		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
Consolidated Funds	'
Investment Holdings [Line Items]	'
Marketable Securities	'
	As of September 30, 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 September 30, 2013 and December 31, 2012 other investments, at fair value, held by the Consolidated Funds are comprised of:
		As of September 30, 2013				As of December 31, 2012
		(dollars in thousands)
	(1) Portfolio Funds	$	183,727			$	190,081
	(2) Lehman claims	16,483				14,124
		$	200,210			$	204,205
Schedule of Other Investments, Portfolio Funds	'
	As of September 30, 2013 and December 31, 2012, investments in Portfolio Funds, at fair value, included the following:
		As of September 30, 2013				As of December 31, 2012
		(dollars in thousands)
	Investments of Enterprise LP	$	154,363			$	173,348
	Investments of Merger Fund	22,641				—
	Investments of consolidated fund of funds	6,723				16,733
		$	183,727			$	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 September 30, 2013 and December 31, 2012:
				Fair Value as of September 30, 2013
		Strategy		Ramius Levered Multi-Strategy FOF LP				Ramius Multi-Strategy Master FOF LP				Ramius Vintage Multi-Strategy Master FOF LP				Total
				(dollars in thousands)
	Tapestry Pooled Account V LLC*	Credit-Based		$	254			$	524			$	559			$	1,337	(a)
	Externally Managed Portfolio Funds	Event Driven		1,015				1,522				2,145				4,682		(c)
	Externally Managed Portfolio Funds	Hedged Equity		—				—				704				704		(d)
				$	1,269			$	2,046			$	3,408			$	6,723
				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 September 30, 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 September 30, 2013				As of December 31, 2012
		Strategy		(dollars in thousands)
	RCG Longview Equity Fund, LP*	Real Estate		$	10,599			$	11,027
	RCG Longview II, LP*	Real Estate		819				970
	RCG Longview Debt Fund IV, LP*	Real Estate		18,362				30,572
	RCG Longview, LP*	Real Estate		332				265
	RCG Soundview, LLC*	Real Estate		446				2,374
	RCG Urban American Real Estate Fund, L.P.*	Real Estate		1,936				1,987
	RCG International Sarl*	Multi-Strategy		1,700				752
	RCG Special Opportunities Fund, Ltd*	Multi-Strategy		83,418				80,166
	RCG Endeavour, LLC*	Multi-Strategy		32				43
	RCG Energy, LLC *	Energy		3,363				14,239
	RCG Renergys, LLC*	Energy		1				1
	Other Private Investments	Various		12,396				12,430
	Real Estate Investments	Real Estate		14,970				12,321
				$	148,374			$	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 September 30, 2013				As of December 31, 2012
		(dollars in thousands)
	Bank debt	$	5			$	79
	Common stock	2,703				2,680
	Preferred stock	997				997
	Private equity	309				297
	Restricted stock	137				26
	Rights	2,455				1,714
	Trade claims	128				128
	Warrants	—				2
		$	6,734			$	5,923
Schedule of Derivative Instruments	'
	Derivative contracts, at fair value, owned by Enterprise Master, net
		As of September 30, 2013				As of December 31, 2012
	Description	(dollars in thousands)
	Currency forwards	$	(7	)		$	6
		$	(7	)		$	6
Merger Master	'
Investment Holdings [Line Items]	'
Schedule of Securities Owned and Sold, Not yet Purchased, at Fair Value	'
	Securities owned and securities sold, but not yet purchased by Merger Master, at fair value
		As of September 30, 2013
		(dollars in thousands)
	Common stocks	$	29,408
	Corporate bond (a)	9,580
	Options	376
		$	39,364
	(a)	As of September 30, 2013, maturities ranged from October 2018 to October 2020 and interest rates ranged between 7.75% and 8.13% .
Schedule of Derivative Instruments	'
	Derivative contracts, at fair value, owned by Merger Master, net
		As of September 30, 2013
	Description	(dollars in thousands)
	Equity swap	$	43
	Cross rate	(3		)
		$	40
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

Fair_Value_Measurements_for_Op1

Fair Value Measurements for Operating Entities and Consolidated Funds (Tables)	9 Months Ended
	Sep. 30, 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 condensed consolidated statements of financial condition by caption and by level within the valuation hierarchy as of September 30, 2013 and 2012:
	Operating Entities
		Assets at Fair Value as of September 30, 2013
		Level 1		Level 2				Level 3				Total
				(dollars in thousands)
	Securities owned and derivatives
	US Government securities	$	3,506	$	—			$	—			$	3,506
	Preferred stock	—		—				333				333
	Common stocks	219,315		2,103				2,109				223,527
	Convertible bonds	—		4,129				—				4,129
	Corporate bonds	—		134,827				—				134,827
	Futures	263		—				—				263
	Currency forwards	—		49				—				49
	Equity swaps	—		276				—				276
	Options	10,965		9				—				10,974
	Warrants and rights	111		—				2,667				2,778
	Mutual funds	525		—				—				525
	Other investments
	Portfolio Funds	—		19,110				51,703				70,813
	Real estate investments	—		—				2,127				2,127
	Lehman claim	—		—				558				558
		$	234,685	$	160,503			$	59,497			$	454,685
		Liabilities at Fair Value as of September 30, 2013
		Level 1		Level 2				Level 3				Total
		(dollars in thousands)
	Securities sold, not yet purchased and derivatives
	Common stocks	$	122,211	$	—			$	—			$	122,211
	Corporate bonds	—		56				—				56
	Futures	160		—				—				160
	Currency forwards	—		105				—				105
	Equity swaps	—		4				—				4
	Options	8,603		259				—				8,862
		$	130,974	$	424			$	—			$	131,398
		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
		$	178,157	$	750			$	3			$	178,910
	Consolidated Funds' investments
	Assets at Fair Value as of September 30, 2013
	Level 1		Level 2				Level 3				Total
			(dollars in thousands)
Other investments
Portfolio Funds	$	—	$	22,641			$	161,086			$	183,727
Lehman claims	—		—				16,483				16,483
	$	—	$	22,641			$	177,569			$	200,210
	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 three and nine months ended September 30, 2013 and 2012 for financial instruments classified within level 3. The classification of a financial instrument within level 3 is based upon the significance of the unobservable inputs to the overall fair value measurement.
		Three Months Ended September 30, 2013
		Balance at June 30, 2013		Transfers in				Transfers out				Purchases/(covers)				(Sales)/shorts				Realized gains (losses)				Unrealized gains (losses)				Balance at September 30, 2013
		(dollars in thousands)
	Operating Entities
	Preferred stock	$	333	$	—			$	—			$	—			$	—			$	—			$	—			$	333
	Common stocks	2,273		—				—				—				(2		)		—				(162		)		2,109
	Warrants and Rights	2,136		—				—				—				—				—				531				2,667
	Portfolio Funds	43,343		—				—				6,491				(289		)		712				1,446				51,703
	Real estate	2,158		—				—				—				—				—				(31		)		2,127
	Lehman claim	278		—				—				—				—				—				280				558
	Consolidated Funds
	Portfolio Funds	177,848		—				—				—				(17,886		)		185				939				161,086
	Lehman claim	15,434		—				—				—				—				—				1,049				16,483
		Three Months Ended September 30, 2012
		Balance at June 30, 2012		Transfers in				Transfers out				Purchases/(covers)				(Sales)/shorts				Realized gains (losses)				Unrealized gains (losses)				Balance at September 30, 2012
		(dollars in thousands)
	Operating Entities
	Preferred stock	$	240	$	—			$	—			$	2,000			$	—			$	—			$	34			$	2,274
	Common stocks	719		—				—				—				—				—				(33		)		686
	Warrants and Rights	2,844		—				—				341				—				—				877				4,062
	Warrants and Rights, sold not yet purchased	3		—				—				—				—				(3		)		—				—
	Portfolio Funds	19,876		—				—				320				(361		)		(48		)		706				20,493
	Real estate	2,079		—				—				—				—				—				23				2,102
	Lehman claim	731		—				—				—				—				—				30				761
	Consolidated Funds
	Portfolio Funds	209,507		—				—				—				(19,233		)		182				(2,659		)		187,797
	Lehman claim	6,538		—				—				—				—				—				322				6,860
		Nine Months Ended September 30, 2013
		Balance at December 31, 2012		Transfers in				Transfers out				Purchases/(covers)				(Sales)/shorts				Realized gains (losses)				Unrealized gains (losses)				Balance at September 30, 2013
		(dollars in thousands)
	Operating Entities
	Preferred stock	$	2,332	$	—			$	(2,000	)	(e)	$	—			$	—			$	—			$	1			$	333
	Common stocks	2,549		—				—				—				(275		)		260				(425		)		2,109
	Corporate Bond	515		—				—				2,735				(3,346		)		(914		)		1,010				—
	Warrants and Rights	1,713		290			(c)	—				166				(110		)		—				608				2,667
	Warrants and Rights, sold not yet purchased	3		—				—				—				—				(4		)		1				—
	Portfolio Funds	25,670		13,128			(f)	—				16,560				(7,821		)		(375		)		4,541				51,703
	Real estate	1,864		—				—				—				—				—				263				2,127
	Lehman claim	706		—				—				—				(382		)		—				234				558
	Consolidated Funds
	Portfolio Funds	182,920		—				—				—				(27,835		)		505				5,496				161,086
	Lehman claim	14,124		—				—				—				(1,449		)		1,360				2,448				16,483
		Nine Months Ended September 30, 2012
		Balance at December 31, 2011		Transfers in					Transfers out					Purchases/(covers)				(Sales)/shorts				Realized gains (losses)				Unrealized gains (losses)				Balance at September 30, 2012
		(dollars in thousands)
	Operating Entities
	Preferred stock	$	250	$	—				$	—				$	2,000			$	—			$	—			$	24			$	2,274
	Common stocks	819		—					—					—				(6		)		6				(133		)		686
	Warrants and Rights	1,534		—					(88		)	(b)		623				(65		)		56				2,002				4,062
	Warrants and Rights, sold not yet purchased	—		—					(1,004		)	(d)		(306		)		982				(38		)		366				—
	Portfolio Funds	16,919		—					—					3,171				(1,175		)		(41		)		1,619				20,493
	Real estate	2,353		—					—					152				(501		)		—				98				2,102
	Lehman claim	553		—					—					—				—				—				208				761
	Consolidated Funds
	Portfolio Funds	213,402		16,227			(a)		(17,151		)	(a)		434				(24,259		)		(1,510		)		654				187,797
	Lehman claim	7,340		—					—					—				(2,291		)		1,914				(103		)		6,860
	(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 September 30, 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 September 30, 2013		Valuation techniques		Unobservable Inputs		Range
	Common and preferred stocks	$	2,351	Discounted cash flows, market multiples, recent transactions, bid levels, and comparable transactions		Market multiples and DCF discount rate		DCF discount rates: 15%-25%, Market multiples: 9x-10x
	Warrants and rights, net	2,667		Model based		Volatility		Volatility: 10% to 130%
		$	5,018
	Other level 3 assets and liabilities (a)	232,048
	Total level 3 assets and liabilities	$	237,066
	(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.

Redeemable_NonControlling_Inte1

Redeemable Non-Controlling Interests in Consolidated Subsidiaries (Tables)	9 Months Ended
	Sep. 30, 2013
Noncontrolling Interest [Abstract]	'
Redeemable non-controlling interests in consolidated subsidiaries	'
	Redeemable non-controlling interests in consolidated subsidiaries and the related net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries are comprised as follows:
		As of September 30, 2013		As of December 31, 2012
		(dollars in thousands)
	Redeemable non-controlling interests in consolidated subsidiaries
	Operating companies	$	9,606	$	4,106
	Consolidated funds	80,573		81,597
		$	90,179	$	85,703
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries	'
		Three Months Ended September 30,					Nine Months Ended September 30,
		2013		2012			2013		2012
		(dollars in thousands)
	Income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries
	Operating companies	$	3,884	$	298		$	7,280	$	893
	Consolidated funds	875		(1,331		)	3,229		(2,118		)
		$	4,759	$	(1,033	)	$	10,509	$	(1,225	)

ShareBased_Compensation_and_Em1

Share-Based Compensation and Employee Ownership Plans (Tables)	9 Months Ended
	Sep. 30, 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 nine months ended September 30, 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	773,763		$	12.58	1.6	$	—
	Options granted	—		—		—	—
	Options acquired	—		—		—	—
	Options expired	(473.757	)	16		—	—
	Balance outstanding at September 30, 2013	300.006		$	7.18	2.66	$	—
	Options exercisable at September 30, 2013	200.004		$	9.04	1.94	$	—
	-1	Based on the Company's closing stock price of $3.44 on September 30, 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 nine months ended September 30, 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 September 30, 2013	400,000		$	2.9	4.46	$	467,640
	SAR's exercisable at September 30, 2013	—		$	—	—	$	—
	-1	Based on the Company's closing stock price of $3.44 on September 30, 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 nine months ended September 30, 2013:
		Nonvested Restricted Shares and Restricted Stock Units		Weighted-Average
				Grant Date
				Fair Value
	Balance outstanding at December 31, 2012	10,252,023		$	4.15
	Granted	7,234,924		2.66
	Vested	(4,178,314	)	3.94
	Cancelled	—		—
	Forfeited	(176,413	)	3.15
	Balance outstanding at September 30, 2013	13,132,220		$	3.41

Defined_Benefit_Plans_Tables

Defined Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 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 for the three and nine months ended September 30, 2013 and 2012:
		Three Months Ended September 30,						Nine Months Ended September 30,
		2013			2012			2013			2012
		(dollars in thousands)
	Components of net periodic benefit cost included in employee compensation and benefits
	Service cost	$	—		$	—		$	—		$	—
	Interest cost	54			53			152			159
	Expected return on plan assets	(64		)	(60		)	(186		)	(176		)
	Amortization of (loss) / gain	—			—			—			—
	Amortization of prior service cost	5			5			16			15
	Effect of settlement	—			(17		)	(95		)	(20		)
	Net periodic benefit cost	$	(5	)	$	(19	)	$	(113	)	$	(22	)

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Future Minimum Annual Lease and Service Payments	'
	As of September 30, 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)
	2013	$	825	$	3,520	$	4,899
	2014	1,548		11,577		19,223
	2015	1,051		3,876		16,181
	2016	194		247		13,069
	2017	—		—		9,946
	Thereafter	—		—		43,733
		$	3,618	$	19,220	$	107,051
	(a)	Equipment Leases include the Company's commitments relating to operating and capital leases. See Note 14 for further information on the capital lease minimum payments which are included in the table.
	(b)	The Company has entered into various agreements to sublease certain of its premises. The Company recorded sublease income related to these leases of $0.4 million and $0.3 million for the three months ended September 30, 2013 and 2012, respectively, and $1.0 million and $1.0 million for the nine months ended September 30, 2013 and 2012, respectively.

ShortTerm_Borrowings_and_Other1

Short-Term Borrowings and Other Debt (Tables)	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Schedule of Debt	'
	As of September 30, 2013 and December 31, 2012, short term borrowings and other debt of the Company were as follows:
		As of September 30, 2013			As of December 31, 2012
		(dollars in thousands)
	Notes payable	$	491		$	206
	Capital lease obligations	2,878			3,926
		$	3,369		$	4,132
Schedule of Letters of Credit	'
	As of September 30, 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		12-May-14
	New York		$	1,191		3-Sep-14
	New York		$	6,746		12-Dec-13
	New York		$	1,000		22-Feb-14
	New York		$	1,861		19-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 September 30, 2013, are as follows:
		Capital Lease			Short Term
		Obligation			Borrowings
		(dollars in thousands)
	2013	$	385		$	464
	2014	1,402			46
	2015	1,051			—
	2016	194			—
	2017	—			—
	Thereafter	—			—
	Subtotal	3,032			510
	Less: Amount representing interest (a)	(154		)	(19		)
	Total	$	2,878		$	491
	(a)	Amount necessary to reduce net minimum lease payments to present value calculated at the Company's implicit rate at lease inception.

Treasury_stock_Tables

Treasury stock (Tables)	9 Months Ended
	Sep. 30, 2013
Equity [Abstract]	'
Treasury Stock Activity	'
	The following represents the activity relating to the treasury stock held by the Company during the nine months ended September 30, 2013:
		Treasury stock shares		Cost			Average cost
				(dollars in thousands)			per share
	Balance outstanding at December 31, 2012	11,292,220		$	31,728		$	2.81
	Shares purchased for minimum tax withholding under the Equity Plan	1,049,740		3,156			3.01
	Treasury stock reissued	(24,744	)	(90		)	3.64
	Purchase of treasury stock	813,944		2,723			3.35
	Balance outstanding at September 30, 2013	13,131,160		$	37,517		$	2.86

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Earnings Per Share, Basic and Diluted	'
	The computation of earnings per share is as follows:
		Three Months Ended September 30,					Nine Months Ended September 30,
		2013		2012			2013		2012
		(dollars in thousands, except per share data)
	Net income (loss)	$	8,370	$	(11,618	)	$	12,637	$	(15,761	)
	Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries	4,759		(1,033		)	10,509		(1,225		)
	Net income (loss) less Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries	$	3,611	$	(10,585	)	$	2,128	$	(14,536	)
	Shares for basic and diluted calculations:
	Weighted average shares used in basic computation	118,359		114,989			116,012		114,587
	Stock options	—		—			—		—
	Stock appreciation rights	311		—			296		—
	Restricted stock	4,038		—			3,583		—
	Weighted average shares used in diluted computation	122,708		114,989			119,891		114,587
	Earnings (loss) per share:
	Basic	$	0.03	$	(0.09	)	$	0.02	$	(0.13	)
	Diluted	$	0.03	$	(0.09	)	$	0.02	$	(0.13	)

Segment_Reporting_Tables

Segment Reporting (Tables)	9 Months Ended
	Sep. 30, 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):
		Three Months Ended September 30, 2013
											Adjustments
		Alternative			Broker-Dealer (1)			Total Economic Income/(Loss)			Funds			Other				US GAAP
		Investment									Consolidation			Adjustments
		(dollars in thousands)
	Revenues
	Investment banking	$	—		$	27,694		$	27,694		$	—		$	—			$	27,694
	Brokerage	—			32,035			32,035			—			(3,573		)	(e)	28,462
	Management fees	14,299			—			14,299			(275		)	(4,697		)	(a)	9,327
	Incentive income	5,666			—			5,666			—			(3,145		)	(a)	2,521
	Investment Income	10,031			2,296			12,327			—			(12,327		)	(c)	—
	Interest and dividends	—			—			—			—			10,969			(c)	10,969
	Reimbursement from affiliates	—			—			—			(75		)	1,461			(b)	1,386
	Other revenue	156			(38		)	118			—			438			(c)	556
	Consolidated Funds revenues	—			—			—			445			—				445
	Total revenues	30,152			61,987			92,139			95			(10,874		)		81,360
	Expenses
	Employee compensation and benefits	13,539			40,291			53,830			—			(216		)		53,614
	Interest and dividends	52			23			75			—			6,058			(c)	6,133
	Non-compensation expenses—Fixed	9,086			16,245			25,331			—			(25,331		)	(c)(d)	—
	Non-compensation expenses—Variable	1,449			5,424			6,873			—			(6,873		)	(c)(d)	—
	Non-compensation expenses	—			—			—			—			31,540			(c)(d)	31,540
	Reimbursement from affiliates	(1,461		)	—			(1,461		)	—			1,461			(b)	—
	Consolidated Funds expenses	—			—			—			450			—				450
	Total expenses	22,665			61,983			84,648			450			6,639				91,737
	Other income (loss)
	Net gain (loss) on securities, derivatives and other investments	—			—			—			—			15,469			(c)	15,469
	Consolidated Funds net gains (losses)	—			—			—			1,230			2,002				3,232
	Total other income (loss)	—			—			—			1,230			17,471				18,701
	Income (loss) before income taxes and non-controlling interests	7,487			4			7,491			875			(42		)		8,324
	Income taxes expense / (benefit)	—			—			—			—			(46		)	(b)	(46		)
	Economic Income (Loss) / Net income (loss) before non-controlling interests	7,487			4			7,491			875			4				8,370
	(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	(3,825		)	—			(3,825		)	(875		)	(59		)		(4,759		)
	Economic Income (Loss) / Net Income (loss) attributable to Cowen Group, Inc. stockholders	$	3,662		$	4		$	3,666		$	—		$	(55	)		$	3,611
	(1) For the three months ended September 30, 2013, the Company has reflected $3.0 million of investment income and related compensation expense of $1.0 million within the broker-dealer segment in proportion to its capital.
		Three Months Ended September 30, 2012
											Adjustments
		Alternative			Broker-Dealer (1)			Total			Funds			Other				US GAAP
		Investment						Economic Income/(Loss)			Consolidation			Adjustments
		(dollars in thousands)
	Revenues
	Investment banking	$	—		$	18,666		$	18,666		$	—		$	—			$	18,666
	Brokerage	—			22,701			22,701			—			—				22,701
	Management fees	13,426			—			13,426			(362		)	(4,198		)	(a)	8,866
	Incentive income	1,699			—			1,699			—			(283		)	(a)	1,416
	Investment Income	6,864			2,288			9,152			—			(9,152		)	(c)	—
	Interest and dividends	—			—			—			—			3,605			(c)	3,605
	Reimbursement from affiliates	—			—			—			(97		)	1,467			(b)	1,370
	Other revenue	168			213			381			—			320			(c)	701
	Consolidated Funds revenues	—			—			—			273			—				273
	Total revenues	22,157			43,868			66,025			(186		)	(8,241		)		57,598
	Expenses
	Employee compensation and benefits	11,759			34,490			46,249			—			1,073				47,322
	Interest and dividends	93			38			131			—			1,925			(c)	2,056
	Non-compensation expenses—Fixed	8,564			15,452			24,016			—			(24,016		)	(c)(d)	—
	Non-compensation expenses—Variable	1,433			4,287			5,720			—			(5,720		)	(c)(d)	—
	Non-compensation expenses	—			—			—			—			29,346			(c)(d)	29,346
	Reimbursement from affiliates	(1,467		)	—			(1,467		)	—			1,467			(b)	—
	Consolidated Funds expenses	—			—			—			330			—				330
	Total expenses	20,382			54,267			74,649			330			4,075				79,054
	Other income (loss)
	Net gains (losses) on securities, derivatives and other investments	—			—			—			—			12,510			(c)	12,510
Consolidated Funds net gains (losses)	—			—			—			(815		)	(1,694		)		(2,509		)
Total other income (loss)	—			—			—			(815		)	10,816				10,001
Income (loss) before income taxes and non-controlling interests	1,775			(10,399		)	(8,624		)	(1,331		)	(1,500		)		(11,455		)
Income taxes expense / (benefit)	—			—			—			—			163			(b)	163
Economic Income (Loss) / Net income (loss) before non-controlling interests	1,775			(10,399		)	(8,624		)	(1,331		)	(1,663		)		(11,618		)
(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	(301		)	—			(301		)	1,331			3				1,033
Economic Income (Loss) / Net income (loss) attributable to Cowen Group, Inc. stockholders	$	1,474		$	(10,399	)	$	(8,925	)	$	—		$	(1,660	)		$	(10,585	)
(1) For the three months ended September 30, 2012, the Company has reflected $2.3 million of investment income and related compensation expense of $0.8 million within the broker-dealer segment in proportion to its capital.
	Nine Months Ended September 30, 2013
										Adjustments
	Alternative			Broker-Dealer (1)			Total Economic Income/(Loss)			Funds			Other				US GAAP
	Investment									Consolidation			Adjustments
	(dollars in thousands)
Revenues
Investment banking	$	—		$	70,431		$	70,431		$	—		$	—			$	70,431
Brokerage	—			93,352			93,352			—			(6,769		)	(e)	86,583
Management fees	43,050			—			43,050			(871		)	(13,661		)	(a)	28,518
Incentive income	14,558			—			14,558			—			(7,472		)	(a)	7,086
Investment Income	22,169			4,593			26,762			—			(26,762		)	(c)	—
Interest and dividends	—			—			—			—			30,905			(c)	30,905
Reimbursement from affiliates	—			—			—			(206		)	4,291			(b)	4,085
Other revenue	381			(427		)	(46		)	—			1,565			(c)	1,519
Consolidated Funds revenues	—			—			—			681			—				681
Total revenues	80,158			167,949			248,107			(396		)	(17,903		)		229,808
Expenses
Employee compensation and benefits	37,863			108,202			146,065			—			(721		)		145,344
Interest and dividends	183			88			271			—			20,016			(c)	20,287
Non-compensation expenses—Fixed	26,695			46,197			72,892			—			(72,892		)	(c)(d)	—
Non-compensation expenses—Variable	3,594			19,192			22,786			—			(22,786		)	(c)(d)	—
Non-compensation expenses	—			—			—			—			94,593			(c)(d)	94,593
Reimbursement from affiliates	(4,291		)	—			(4,291		)	—			4,291			(b)	—
Consolidated Funds expenses	—			—			—			1,237			—				1,237
Total expenses	64,044			173,679			237,723			1,237			22,501				261,461
Other income (loss)
Net gains (losses) on securities, derivatives and other investments	—			—			—			—			32,873			(c)	32,873
Consolidated Funds net gains (losses)	—			—			—			4,862			6,843				11,705
Total other income (loss)	—			—			—			4,862			39,716				44,578
Income (loss) before income taxes and non-controlling interests	16,114			(5,730		)	10,384			3,229			(688		)		12,925
Income taxes expense / (benefit)	—			—			—			—			288			(b)	288
Economic Income (Loss) / Net income (loss) before non-controlling interests	16,114			(5,730		)	10,384			3,229			(976		)		12,637
(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	(6,517		)	—			(6,517		)	(3,229		)	(763		)		(10,509		)
Economic Income (Loss) / Net Income (loss) attributable to Cowen Group, Inc. stockholders	$	9,597		$	(5,730	)	$	3,867		$	—		$	(1,739	)		$	2,128
(1) For the nine months ended September 30, 2013, 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.
	Nine Months Ended September 30, 2012
										Adjustments
	Alternative			Broker-Dealer (1)			Total Economic Income/(Loss)			Funds			Other				US GAAP
	Investment									Consolidation			Adjustments
	(dollars in thousands)
Revenues
Investment banking	$	—		$	50,550		$	50,550		$	—		$	—			$	50,550
Brokerage	—			71,282			71,282			—			—				71,282
Management fees	42,032			—			42,032			(1,150		)	(12,367		)	(a)	28,515
Incentive income	8,303			—			8,303			—			(5,616		)	(a)	2,687
Investment Income	30,361			8,182			38,543			—			(38,543		)	(c)	—
Interest and dividends	—			—			—			—			14,845			(c)	14,845
Reimbursement from affiliates	—			—			—			(222		)	4,018			(b)	3,796
Other revenue	508			186			694			—			1,704			(c)	2,398
Consolidated Funds revenues	—			—			—			474			—				474
Total revenues	81,204			130,200			211,404			(898		)	(35,959		)		174,547
Expenses
Employee compensation and benefits	42,705			91,098			133,803			—			3,299				137,102
Interest and dividends	123			155			278			—			6,829			(c)	7,107
Non-compensation expenses—Fixed	24,093			45,655			69,748			—			(69,748		)	(c)(d)	—
Non-compensation expenses—Variable	3,881			15,852			19,733			—			(19,733		)	(c)(d)	—
Non-compensation expenses	—			—			—			—			87,670			(c)(d)	87,670
Reimbursement from affiliates	(4,018		)	—			(4,018		)	—			4,018			(b)	—
Consolidated Funds expenses	—			—			—			1,339			—				1,339
Total expenses	66,784			152,760			219,544			1,339			12,335				233,218
Other income (loss)
Net gains (losses) on securities, derivatives and other investments	—			—			—			—			41,969			(c)	41,969
Consolidated Funds net gains (losses)	—			—			—			119			1,318				1,437
Total other income (loss)	—			—			—			119			43,287				43,406
Income (loss) before income taxes and non-controlling interests	14,420			(22,560		)	(8,140		)	(2,118		)	(5,007		)		(15,265		)
Income taxes expense / (benefit)	—			—			—			—			496			(b)	496
Economic Income (Loss) / Net income (loss) before non-controlling interests	14,420			(22,560		)	(8,140		)	(2,118		)	(5,503		)		(15,761		)
(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	(900		)	—			(900		)	2,118			7				1,225
Economic Income (Loss) / Net Income (loss) attributable to Cowen Group, Inc. stockholders	$	13,520		$	(22,560	)	$	(9,040	)	$	—		$	(5,496	)		$	(14,536	)
(1) For the nine months ended September 30, 2012, the Company has reflected $8.2 million of investment income and related compensation expense of $2.7 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.

Organization_and_Business_Deta

Organization and Business (Details)	9 Months Ended
	Sep. 30, 2013
	segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Number of business segments	2

Significant_Accounting_Policie2

Significant Accounting Policies (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified	cowenfund
Organization [Line Items]	'	'
Number of funds, Consolidated	8	'
Deferred rent	$16.20	$13.80
Total net assets of consolidated VIEs	$7.10	'
Investment Company	'	'
Organization [Line Items]	'	'
Number of funds, Consolidated	3	'

Cash_collateral_pledged_Detail

Cash collateral pledged (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Cash and Cash Equivalents [Abstract]	'	'
Cash collateral pledged	$10,899	$9,160

Investments_of_Operating_Entit2

Investments of Operating Entities and Consolidated Funds - Securities Owned at Fair Value (Details) (USD $)

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Consolidated Funds

Consolidated Funds

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 Master

Enterprise Master

Enterprise Master

Enterprise Master

Enterprise Master

Enterprise Master

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Merger Master

Merger Master

Merger Master

Merger Master

Merger Master

Merger Master

Merger Master

Merger Master

Government Sponsored Securities

Government Sponsored Securities

Government Sponsored Securities

Commercial Paper

Currency Forwards

Currency Forwards

Debt

Debt

Common Stock

Common Stock

Preferred Stock

Preferred Stock

Private Equity

Private Equity

Restricted Stock

Restricted Stock

Rights

Rights

Warrants and Rights

Warrants and Rights

Trade Claims

Trade Claims

Other Income

Other Income

Other Income

Other Income

Derivative contracts, at fair value

Derivative contracts, at fair value

US Government Securities

US Government Securities

US Government Securities

US Government Securities

US Government Securities

US Government Securities

Convertible Bonds

Convertible Bonds

Convertible Bonds

Common Stock

Common Stock

Preferred Stock

Preferred Stock

Corporate Bonds

Corporate Bonds

Corporate Bonds

Corporate Bonds

Corporate Bonds

Corporate Bonds

Options Held

Options Held

Warrants and Rights

Warrants and Rights

Credit Default Swaps, Futures and Equity Swap Contracts

Credit Default Swaps, Futures and Equity Swap Contracts

Futures and Equity Swap Contracts

Futures and Equity Swap Contracts

Mutual Funds

Mutual Funds

Common Stock

Corporate Bonds

Corporate Bonds

Corporate Bonds

Options Held

Currency Forwards

Cross Currency Interest Rate Contract

Minimum

Maximum

Receivables from Brokers-Dealers and Clearing Organizations

Receivables from Brokers-Dealers and Clearing Organizations

Minimum

Minimum

Maximum

Maximum

Minimum

Minimum

Minimum

Maximum

Maximum

Other

Other

Accounts Payable, Accrued Expenses and Other Liabilities

Accounts Payable, Accrued Expenses and Other Liabilities

Minimum

Maximum

Schedule of Trading Securities and Other Trading Assets [Line Items]

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Trading Securities, Debt

'

'

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'

$1,911,000

[1]

'

'

$1,614,000

[2]

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$3,506,000

[3]

$137,478,000

[3]

'

'

'

'

$6,202,000

[4]

$4,129,000

[4]

'

'

'

$333,000

$2,332,000

$134,827,000

[5]

$193,078,000

[5]

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Trading Securities, Equity

'

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5,000

79,000

2,703,000

2,680,000

997,000

997,000

309,000

297,000

137,000

26,000

2,455,000

1,714,000

0

2,000

128,000

128,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

223,527,000

259,292,000

'

'

'

'

'

'

'

'

10,974,000

20,546,000

2,778,000

2,354,000

'

'

'

'

525,000

2,845,000

'

'

'

'

'

'

'

'

Securities owned, at fair value

380,599,000

624,127,000

'

3,525,000

'

'

'

'

6,734,000

5,923,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

380,599,000

624,127,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

39,364,000

29,408,000

9,580,000

[6]

'

'

376,000

'

'

Other investments

98,162,000

84,930,000

200,210,000

204,205,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

98,162,000

84,930,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Derivative, Fair Value, Net

'

'

'

'

'

'

'

'

-7,000

6,000

-7,000

6,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

40,000

'

'

'

'

'

43,000

-3,000

Debt securities, interest rate

'

'

'

'

'

0.28%

4.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.02%

0.25%

5.95%

5.95%

5.00%

'

5.00%

'

'

'

'

'

'

2.58%

3.09%

11.75%

12.50%

'

'

'

'

'

'

'

'

'

'

'

'

'

7.75%

8.13%

'

'

'

Derivative assets

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

600,000

200,000

'

'

'

'

'

'

'

'

'

'

'

'

Derivative liabilities

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

300,000

1,000,000

'

'

'

'

'

'

'

'

'

'

Realized and unrealized gains/(losses) related to derivatives trading activities

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

800,000

3,000,000

3,100,000

5,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Collateral posted

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$8,900,000

$6,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

[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 SeptemberB 30, 2013, maturities ranged from October 2013 to April 2016 and interest rates ranged between 0.02% and 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 SeptemberB 30, 2013, the maturity was July 2014 with an interest rate of 5.00%. As of DecemberB 31, 2012, maturities ranged from May 2014 to July 2014 with an interest rate of 5.00%.

[5]

As of SeptemberB 30, 2013, maturities ranged from December 2013 to February 2046 and interest rates ranged between 2.58% 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 SeptemberB 30, 2013, maturities ranged from October 2018 to October 2020 and interest rates ranged between 7.75% and 8.13%

Investments_of_Operating_Entit3

Investments of Operating Entities and Consolidated Funds - Other Investments (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Investment Holdings [Line Items]	'	'
Other investments	$98,162,000	$84,930,000
Operating Entities	'	'
Investment Holdings [Line Items]	'	'
Other investments	98,162,000	84,930,000
Operating Entities | Portfolio Funds	'	'
Investment Holdings [Line Items]	'	'
Other investments	70,813,000	55,898,000
Operating Entities | Real Estate Investments	'	'
Investment Holdings [Line Items]	'	'
Other investments	2,127,000	1,864,000
Operating Entities | Equity Method Investments	'	'
Investment Holdings [Line Items]	'	'
Other investments	24,664,000	26,462,000
Operating Entities | Lehman Claim	'	'
Investment Holdings [Line Items]	'	'
Other investments	558,000	706,000
Consolidated Funds	'	'
Investment Holdings [Line Items]	'	'
Other investments	200,210,000	204,205,000
Consolidated Funds | Portfolio Funds	'	'
Investment Holdings [Line Items]	'	'
Other investments	183,727,000	190,081,000
Consolidated Funds | Lehman Claim	'	'
Investment Holdings [Line Items]	'	'
Other investments	$16,483,000	$14,124,000

Investments_of_Operating_Entit4

Investments of Operating Entities and Consolidated Funds - Portfolio Funds (Details) (USD $)	9 Months Ended		12 Months Ended
	Sep. 30, 2013		Dec. 31, 2012
Investment Holdings [Line Items]	'		'
Number of funds	8		'
Other investments	$98,162,000		$84,930,000
Operating Entities	'		'
Investment Holdings [Line Items]	'		'
Other investments	98,162,000		84,930,000
Operating Entities | Portfolio Funds	'		'
Investment Holdings [Line Items]	'		'
Other investments	70,813,000		55,898,000
Operating Entities | Portfolio Funds | Healthcare Royalty Partners | Affiliated Entity	'		'
Investment Holdings [Line Items]	'		'
Other investments	10,204,000	[1],[2]	7,866,000	[1],[2]
Operating Entities | Portfolio Funds | Healthcare Royalty Partners II | Affiliated Entity	'		'
Investment Holdings [Line Items]	'		'
Other investments	4,510,000	[1],[2]	6,415,000	[1],[2]
Operating Entities | Portfolio Funds | OSP Credit Fund LP (formerly known as Ramius Global Credit Fund LP ) | Affiliated Entity	'		'
Investment Holdings [Line Items]	'		'
Other investments	12,417,000	[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%
Operating Entities | Portfolio Funds | Tapestry Investment Co PCC Ltd	'		'
Investment Holdings [Line Items]	'		'
Other investments	86,000	[4]	194,000	[4]
Operating Entities | Portfolio Funds | Starboard Value and Opportunity Fund LP | Affiliated Entity	'		'
Investment Holdings [Line Items]	'		'
Other investments	17,242,000	[2],[5]	15,706,000	[2],[5]
Required notice period, withdrawal	'90 days		'90 days
Operating Entities | Portfolio Funds | Formation 8 Partners Fund I	'		'
Investment Holdings [Line Items]	'		'
Other investments	2,802,000	[6]	1,500,000	[6]
Operating Entities | Portfolio Funds | RCG LV Park Lane LLC	'		'
Investment Holdings [Line Items]	'		'
Other investments	685,000	[7]	708,000	[7]
Operating Entities | Portfolio Funds | RCGL 12E13th LLC	'		'
Investment Holdings [Line Items]	'		'
Other investments	400,000	[8]	0	[8]
Operating Entities | Portfolio Funds | RCGLongview Debt Fund V, L.P.	'		'
Investment Holdings [Line Items]	'		'
Other investments	11,679,000	[8]	0	[8]
Operating Entities | Portfolio Funds | Other Funds	'		'
Investment Holdings [Line Items]	'		'
Other investments	8,004,000	[9]	7,826,000	[9]
Operating Entities | Portfolio Funds | Other Funds | Affiliated Entity	'		'
Investment Holdings [Line Items]	'		'
Other investments	2,784,000	[10],[2]	1,487,000	[10],[2]
Consolidated Funds	'		'
Investment Holdings [Line Items]	'		'
Other investments	200,210,000		204,205,000
Consolidated Funds | Portfolio Funds	'		'
Investment Holdings [Line Items]	'		'
Other investments	183,727,000		190,081,000
Enterprise Master | Portfolio Funds	'		'
Investment Holdings [Line Items]	'		'
Other investments	148,374,000		167,147,000
Enterprise Master | Portfolio Funds | Other Private Investment | Various Strategies	'		'
Investment Holdings [Line Items]	'		'
Other investments	12,396,000		12,430,000
Enterprise Master | Portfolio Funds | RCG Longview Equity Fund, LP | Affiliated Entity | Real Estate Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	10,599,000	[11]	11,027,000	[11]
Enterprise Master | Portfolio Funds | RCG Longview II, LP | Affiliated Entity | Real Estate Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	819,000	[11]	970,000	[11]
Enterprise Master | Portfolio Funds | RCG Longview Debt Fund IV, LP | Affiliated Entity | Real Estate Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	18,362,000	[11]	30,572,000	[11]
Enterprise Master | Portfolio Funds | RCG Longview, LP | Affiliated Entity | Real Estate Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	332,000	[11]	265,000	[11]
Enterprise Master | Portfolio Funds | RCG Soundview, LLC | Affiliated Entity | Real Estate Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	446,000	[11]	2,374,000	[11]
Enterprise Master | Portfolio Funds | RCG Urban American Real Estate Fund, L.P. | Affiliated Entity | Real Estate Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	1,936,000	[11]	1,987,000	[11]
Enterprise Master | Portfolio Funds | RCG International Sarl | Affiliated Entity | Multi-strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	1,700,000	[11]	752,000	[11]
Enterprise Master | Portfolio Funds | RCG Special Opportunities Fund, Ltd | Affiliated Entity | Multi-strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	83,418,000	[11]	80,166,000	[11]
Enterprise Master | Portfolio Funds | RCG Endeavour, LLC | Affiliated Entity | Multi-strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	32,000	[11]	43,000	[11]
Enterprise Master | Portfolio Funds | RCG Energy, LLC | Affiliated Entity | Energy Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	3,363,000	[11]	14,239,000	[11]
Enterprise Master | Portfolio Funds | RCG Renergys, LLC | Affiliated Entity | Energy Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	1,000	[11]	1,000	[11]
Enterprise Master | Portfolio Funds | Real Estate Funds | Real Estate Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	14,970,000		12,321,000
Enterprise LP | Portfolio Funds	'		'
Investment Holdings [Line Items]	'		'
Other investments	154,363,000		173,348,000
Merger Fund | Portfolio Funds	'		'
Investment Holdings [Line Items]	'		'
Other investments	22,641,000		0
Consolidated Fund of Funds	'		'
Investment Holdings [Line Items]	'		'
Number of funds	3		'
Consolidated Fund of Funds | Portfolio Funds	'		'
Investment Holdings [Line Items]	'		'
Other investments	6,723,000		16,733,000
Consolidated Fund of Funds | Portfolio Funds | Tapestry Pooled Account V LLC | Affiliated Entity | Credit-Based Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	1,337,000	[11],[12]	1,657,000	[11],[12]
Consolidated Fund of Funds | Portfolio Funds | Independently Advised Portfolio Funds | Affiliated Entity | Futures and Global Macro Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		7,161,000	[11],[13]
Required notice period, redemption	'		'5 days
Required notice period, redemption, intra-month	'		'3 days
Intra-month redemption fee	'		10,000
Consolidated Fund of Funds | Portfolio Funds | Externally Managed Portfolio Funds | Event Driven Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	4,682,000	[14]	7,125,000	[14]
Consolidated Fund of Funds | Portfolio Funds | Externally Managed Portfolio Funds | Hedged Equity Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	704,000	[15]	790,000	[15]
Ramius Levered Multi-Strategy FOF LP | Portfolio Funds	'		'
Investment Holdings [Line Items]	'		'
Other investments	1,269,000		1,860,000
Ramius Levered Multi-Strategy FOF LP | Portfolio Funds | Tapestry Pooled Account V LLC | Affiliated Entity | Credit-Based Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	254,000	[11],[12]	315,000	[11],[12]
Ramius Levered Multi-Strategy FOF LP | Portfolio Funds | Independently Advised Portfolio Funds | Affiliated Entity | Futures and Global Macro Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		0	[11],[13]
Ramius Levered Multi-Strategy FOF LP | Portfolio Funds | Externally Managed Portfolio Funds | Event Driven Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	1,015,000	[14]	1,545,000	[14]
Ramius Levered Multi-Strategy FOF LP | Portfolio Funds | Externally Managed Portfolio Funds | Hedged Equity Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	0	[15]	0	[15]
Ramius Multi-Strategy Master FOF LP | Portfolio Funds	'		'
Investment Holdings [Line Items]	'		'
Other investments	2,046,000		'
Ramius Multi-Strategy Master FOF LP | Portfolio Funds | Tapestry Pooled Account V LLC | Affiliated Entity | Credit-Based Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	524,000	[11],[12]	'
Ramius Multi-Strategy Master FOF LP | Portfolio Funds | Externally Managed Portfolio Funds | Event Driven Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	1,522,000	[14]	'
Ramius Multi-Strategy Master FOF LP | Portfolio Funds | Externally Managed Portfolio Funds | Hedged Equity Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	0	[15]	'
Ramius Vintage Multi-Strategy Master FOF LP | Portfolio Funds	'		'
Investment Holdings [Line Items]	'		'
Other investments	3,408,000		'
Ramius Vintage Multi-Strategy Master FOF LP | Portfolio Funds | Tapestry Pooled Account V LLC | Affiliated Entity | Credit-Based Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	559,000	[11],[12]	'
Ramius Vintage Multi-Strategy Master FOF LP | Portfolio Funds | Externally Managed Portfolio Funds | Event Driven Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	2,145,000	[14]	'
Ramius Vintage Multi-Strategy Master FOF LP | Portfolio Funds | Externally Managed Portfolio Funds | Hedged Equity Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	704,000	[15]	'
Ramius Multi-Strategy FOF LP | Portfolio Funds	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		2,965,000
Ramius Multi-Strategy FOF LP | Portfolio Funds | Tapestry Pooled Account V LLC | Affiliated Entity | Credit-Based Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		649,000	[11],[12]
Ramius Multi-Strategy FOF LP | Portfolio Funds | Independently Advised Portfolio Funds | Affiliated Entity | Futures and Global Macro Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		0	[11],[13]
Ramius Multi-Strategy FOF LP | Portfolio Funds | Externally Managed Portfolio Funds | Event Driven Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		2,316,000	[14]
Ramius Multi-Strategy FOF LP | Portfolio Funds | Externally Managed Portfolio Funds | Hedged Equity Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		0	[15]
Ramius Vintage Multi-Strategy FOF LP | Portfolio Funds	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		4,747,000
Ramius Vintage Multi-Strategy FOF LP | Portfolio Funds | Tapestry Pooled Account V LLC | Affiliated Entity | Credit-Based Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		693,000	[11],[12]
Ramius Vintage Multi-Strategy FOF LP | Portfolio Funds | Independently Advised Portfolio Funds | Affiliated Entity | Futures and Global Macro Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		0	[11],[13]
Ramius Vintage Multi-Strategy FOF LP | Portfolio Funds | Externally Managed Portfolio Funds | Event Driven Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		3,264,000	[14]
Ramius Vintage Multi-Strategy FOF LP | Portfolio Funds | Externally Managed Portfolio Funds | Hedged Equity Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		790,000	[15]
RTS Global 3X Fund LP	'		'
Investment Holdings [Line Items]	'		'
Number of funds	6		'
RTS Global 3X Fund LP | Portfolio Funds	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		7,161,000
Derivative asset (liability)	'		338,000
RTS Global 3X Fund LP | Portfolio Funds | Futures	'		'
Investment Holdings [Line Items]	'		'
Derivative asset (liability)	'		239,000
RTS Global 3X Fund LP | Portfolio Funds | Bond Futures	'		'
Investment Holdings [Line Items]	'		'
Derivative asset (liability)	'		489,000
RTS Global 3X Fund LP | Portfolio Funds | Commodity Futures	'		'
Investment Holdings [Line Items]	'		'
Derivative asset (liability)	'		47,000
RTS Global 3X Fund LP | Portfolio Funds | Currency Futures	'		'
Investment Holdings [Line Items]	'		'
Derivative asset (liability)	'		264,000
RTS Global 3X Fund LP | Portfolio Funds | Equity Futures	'		'
Investment Holdings [Line Items]	'		'
Derivative asset (liability)	'		-27,000
RTS Global 3X Fund LP | Portfolio Funds | NASDAQ Index Future [Member]	'		'
Investment Holdings [Line Items]	'		'
Derivative asset (liability)	'		-257,000
RTS Global 3X Fund LP | Portfolio Funds | Interest Rate Futures	'		'
Investment Holdings [Line Items]	'		'
Derivative asset (liability)	'		40,000
RTS Global 3X Fund LP | Portfolio Funds | Commodity Forwards	'		'
Investment Holdings [Line Items]	'		'
Derivative asset (liability)	'		-659,000
RTS Global 3X Fund LP | Portfolio Funds | Currency Forwards	'		'
Investment Holdings [Line Items]	'		'
Derivative asset (liability)	'		202,000
RTS Global 3X Fund LP | Portfolio Funds | Tapestry Pooled Account V LLC | Affiliated Entity | Credit-Based Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		0	[11],[12]
RTS Global 3X Fund LP | Portfolio Funds | Independently Advised Portfolio Funds | Affiliated Entity | Futures and Global Macro Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		7,161,000	[11],[13]
RTS Global 3X Fund LP | Portfolio Funds | Externally Managed Portfolio Funds | Event Driven Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		0	[14]
RTS Global 3X Fund LP | Portfolio Funds | Externally Managed Portfolio Funds | Hedged Equity Strategy	'		'
Investment Holdings [Line Items]	'		'
Other investments	'		$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 is in the process of liquidation and redemptions will be made periodically at the investment managers' decision as the underlying investments are liquidated.
[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 $)	Sep. 30, 2013	Dec. 31, 2012
Investment Holdings [Line Items]	'	'
Other investments	$98,162,000	$84,930,000
Operating Entities	'	'
Investment Holdings [Line Items]	'	'
Other investments	98,162,000	84,930,000
Operating Entities | Real Estate Investments	'	'
Investment Holdings [Line Items]	'	'
Other investments	2,127,000	1,864,000
RCG RE Manager, LLC | Operating Entities | Real Estate Equity Investment	'	'
Investment Holdings [Line Items]	'	'
Other investments	$2,100,000	$1,900,000

Investments_of_Operating_Entit6

Investments of Operating Entities and Consolidated Funds - Equity Method Investments (Details) (USD $)

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Clawback Obligation

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

Operating Entities

cowenfund

Net Gains (Losses) on Securities, Derivatives and Other Investments

Net Gains (Losses) on Securities, Derivatives and Other Investments

Net Gains (Losses) on Securities, Derivatives and Other Investments

Net Gains (Losses) on Securities, Derivatives and Other Investments

CBOE Stock Exchange, LLC

RCG Longview Partners II, LLC

Equity Method Investee, Exceeded Threshold for Income Test

Equity Method Investee, Exceeded Threshold for Income Test

Equity Method Investee, Exceeded Threshold for Income Test

Equity Method Investee, Exceeded Threshold for Income Test

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Equity Method Investments

Minimum

Maximum

Clawback Obligation

RCG Longview Debt Fund IV Management, LLC

RCG Longview Debt Fund IV Management, LLC

RCG Longview Debt Fund V Partners, LLC

RCG Longview Debt Fund V Partners, LLC

Healthcare Royalty GP, LLC

Healthcare Royalty GP, LLC

Healthcare Royalty GP II, LLC

Healthcare Royalty GP II, LLC

Healthcare Royalty GP III, LLC [Member]

Healthcare Royalty GP III, LLC [Member]

CBOE Stock Exchange, LLC

CBOE Stock Exchange, LLC

Starboard Value L.P.

Starboard Value L.P.

RCG Longview Partners, LLC

RCG Longview Partners, LLC

RCG Longview Louisiana Manager, LLC

RCG Longview Louisiana Manager, LLC

RCG Urban American, LLC

RCG Urban American, LLC

RCG Urban American Management, LLC

RCG Urban American Management, LLC

RCG Longview Equity Management, LLC

RCG Longview Equity Management, LLC

Urban American Real Estate Fund II, LLC

Urban American Real Estate Fund II, LLC

RCG Kennedy House, LLC

RCG Kennedy House, LLC

Equity Method Investee, Other

Equity Method Investee, Other

Accounts Payable, Accrued Expenses and Other Liabilities

Schedule of Equity Method Investments [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Equity method investment, ownership percentage

'

'

'

'

'

'

'

'

'

9.60%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

20.00%

55.00%

Number of entities in which Company holds a majority

'

'

'

3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Other investments

$98,162,000

$84,930,000

'

$98,162,000

$84,930,000

'

'

'

'

'

'

'

'

'

'

$24,664,000

$26,462,000

$1,594,000

$1,954,000

$1,010,000

$0

$832,000

$642,000

$764,000

$1,086,000

$47,000

$0

$1,810,000

$2,058,000

$11,692,000

$12,757,000

$2,016,000

$1,535,000

$1,327,000

$1,866,000

$281,000

$1,380,000

$141,000

$545,000

$230,000

$285,000

$1,612,000

$1,636,000

$428,000

$377,000

$880,000

$341,000

'

'

Contractual obligation

'

'

6,200,000

'

'

'

'

'

'

'

6,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Income (loss) from equity method investments

'

'

'

'

'

5,200,000

1,500,000

12,600,000

9,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Equity Method Investment, Summarized Financial Information [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revenues

'

'

'

'

'

'

'

'

'

'

'

6,821,000

3,909,000

17,746,000

16,190,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Expenses

'

'

'

'

'

'

'

'

'

'

'

-2,266,000

-2,785,000

-6,945,000

-7,850,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net realized and unrealized gains (losses)

'

'

'

'

'

'

'

'

'

'

'

-16,000

26,000

-116,000

135,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net Income

'

'

'

'

'

'

'

'

'

'

'

$4,539,000

$1,150,000

$10,685,000

$8,475,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Investments_of_Operating_Entit7

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

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Nov. 30, 2012

Nov. 02, 2012

Sep. 15, 2008

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 26, 2013

Feb. 29, 2012

Dec. 31, 2011

Jul. 31, 2010

Jun. 30, 2010

Sep. 30, 2013

Feb. 28, 2013

Nov. 30, 2012

Nov. 02, 2012

Sep. 15, 2008

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Jul. 31, 2013

Sep. 30, 2013

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 Claim

Lehman Claim

Lehman Claim

Lehman Claim

Lehman Claim

Lehman Claim

Lehman Claim

Lehman Claim

Lehman Claim

Lehman Claim

Lehman Claim

Lehman Claim

Lehman Claim

Lehman Claim

Lehman Claim

Lehman Claim

Lehman Claim

Trust Assets

Foreign Denominated Assets

Cash

Cash

Lehman Claim

Investment Holdings [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Initial value

'

'

'

'

'

'

'

'

$1,000,000

'

'

'

'

'

'

'

'

'

$11,700,000

'

'

'

$24,300,000

'

'

$4,900,000

$4,900,000

'

Claim settlement receivable

'

'

'

'

'

'

'

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

'

'

'

'

43.30%

'

25.20%

'

'

'

'

'

'

'

'

'

'

'

'

'

25.20%

'

'

'

'

'

'

'

Dividend amount received

'

'

'

'

400,000

'

200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

300,000

'

'

'

'

'

'

'

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

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net Equity Claim

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

12,400,000

'

'

'

'

'

'

'

'

'

Other investments

98,162,000

84,930,000

98,162,000

84,930,000

558,000

706,000

'

'

'

200,210,000

204,205,000

16,483,000

14,124,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

16,500,000

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

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

20,700,000

'

'

'

'

'

'

'

'

'

Claim Resolution Agreement fee

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1.00%

1.00%

'

'

'

Other Investments, not within control of LBIE

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$4,700,000

'

'

'

Recoverable claims assigned to variable interest entities

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100.00%

'

'

'

'

'

'

'

'

'

Percentage of Net Equity Claim

'

'

'

'

127.50%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Investments_of_Operating_Entit8

Investments of Operating Entities and Consolidated Funds - Securities Sold, Not Yet Purchased (Details) (USD $)	Sep. 30, 2013		Dec. 31, 2012
Investments Sold, Not yet Purchased [Line Items]	'		'
Securities owned, at fair value	$380,599,000		$624,127,000
Operating Entities	'		'
Investments Sold, Not yet Purchased [Line Items]	'		'
Securities owned, at fair value	380,599,000		624,127,000
Securities sold, not yet purchased, at fair value	131,129,000		177,937,000
Operating Entities | Corporate Bonds	'		'
Investments Sold, Not yet Purchased [Line Items]	'		'
Securities sold, not yet purchased, at fair value	56,000	[1]	61,000	[1]
Securities sold, not yet purchased, interest rate	5.55%		5.55%
Operating Entities | Common Stock	'		'
Investments Sold, Not yet Purchased [Line Items]	'		'
Securities sold, not yet purchased, at fair value	122,211,000		168,797,000
Operating Entities | Options Held	'		'
Investments Sold, Not yet Purchased [Line Items]	'		'
Securities sold, not yet purchased, at fair value	8,862,000		9,076,000
Operating Entities | Warrants and Rights	'		'
Investments Sold, Not yet Purchased [Line Items]	'		'
Securities sold, not yet purchased, at fair value	0		3,000
Merger Master	'		'
Investments Sold, Not yet Purchased [Line Items]	'		'
Securities owned, at fair value	39,364,000		'
Merger Master | Common Stock	'		'
Investments Sold, Not yet Purchased [Line Items]	'		'
Securities owned, at fair value	29,408,000		'
Merger Master | Corporate Bonds	'		'
Investments Sold, Not yet Purchased [Line Items]	'		'
Securities owned, at fair value	9,580,000	[2]	'
Merger Master | Options Held	'		'
Investments Sold, Not yet Purchased [Line Items]	'		'
Securities owned, at fair value	$376,000		'
[1]	As of SeptemberB 30, 2013 and DecemberB 31, 2012, the maturity was January 2026 with an interest rate of 5.55%
[2]	As of SeptemberB 30, 2013, maturities ranged from October 2018 to October 2020 and interest rates ranged between 7.75% and 8.13%

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 $)	Sep. 30, 2013	Dec. 31, 2012
Assets Purchased Under Agreements to Resell or Sold under Agreements to Repurchase [Line Items]	'	'
Securities sold under agreements to repurchase	$6,311,000	$165,945,000
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	7,700,000	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	6,311,000	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]	'	'
Securities sold under agreements to repurchase	6,311,000	29,039,000
Interest rates on repurchase agreements	1.75%	'
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%

Recovered_Sheet1

Investments of Operating Entities and Consolidated Funds - Securities Lending and Borrowing Transactions (Details) (USD $)	Sep. 30, 2013
In Millions, unless otherwise specified
Investments, Debt and Equity Securities [Abstract]	'
Securities Loaned, Fair Value	$856.30
Securities Borrowed, Fair Value	$866.70

Recovered_Sheet2

Investments of Operating Entities and Consolidated Funds - Variable Interest Entities (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Variable Interest Entity [Line Items]	'	'
Total assets of nonconsolidated variable interest entities	$1,600,000,000	$1,400,000,000
Total liabilities of nonconsolidated variable interest entities	228,300,000	22,800,000
Variable Interest Entity, Not Primary Beneficiary	'	'
Variable Interest Entity [Line Items]	'	'
Maximum exposure regarding nonconsolidated variable interest entities	$205,800,000	$220,900,000

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 $)	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Securities sold, not yet purchased, at fair value	$131,129,000	'	$177,937,000	'	'	'
Operating Entities | Level 3	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	5,018,000	'	'	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Total Estimated Fair Value	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Assets at fair value	454,685,000	'	682,797,000	'	'	'
Liabilities at fair value	131,398,000	'	178,910,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Assets at fair value	234,685,000	'	413,843,000	'	'	'
Liabilities at fair value	130,974,000	'	178,157,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Level 2	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Assets at fair value	160,503,000	'	233,605,000	'	'	'
Liabilities at fair value	424,000	'	750,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Level 3	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Assets at fair value	59,497,000	'	35,349,000	'	'	'
Liabilities at fair value	0	'	3,000	'	'	'
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]	'	'	'	'	'	'
Securities sold, not yet purchased, at fair value	122,211,000	'	168,797,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Common Stock | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Securities sold, not yet purchased, at fair value	122,211,000	'	168,797,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Common Stock | Level 2	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Securities sold, not yet purchased, at fair value	0	'	0	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Common Stock | Level 3	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Securities sold, not yet purchased, at fair value	0	'	0	'	'	'
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]	'	'	'	'	'	'
Securities sold, not yet purchased, at fair value	56,000	'	61,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Corporate Bonds | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Securities sold, not yet purchased, at fair value	0	'	0	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Corporate Bonds | Level 2	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Securities sold, not yet purchased, at fair value	56,000	'	61,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Corporate Bonds | Level 3	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Securities sold, not yet purchased, at fair value	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]	'	'	'	'	'	'
Securities sold, not yet purchased, at fair value	'	'	3,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Warrants and Rights | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Securities sold, not yet purchased, at fair value	'	'	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]	'	'	'	'	'	'
Securities sold, not yet purchased, at fair value	'	'	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]	'	'	'	'	'	'
Securities sold, not yet purchased, at fair value	'	'	3,000	'	'	'
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]	'	'	'	'	'	'
Derivative liabilities	160,000	'	370,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Futures | Derivative Liabilities | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Derivative liabilities	160,000	'	370,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Futures | Derivative Liabilities | Level 2	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Derivative liabilities	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]	'	'	'	'	'	'
Derivative liabilities	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]	'	'	'	'	'	'
Derivative liabilities	105,000	'	603,000	'	'	'
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]	'	'	'	'	'	'
Derivative liabilities	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]	'	'	'	'	'	'
Derivative liabilities	105,000	'	603,000	'	'	'
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]	'	'	'	'	'	'
Derivative liabilities	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]	'	'	'	'	'	'
Derivative liabilities	4,000	'	'	'	'	'
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]	'	'	'	'	'	'
Derivative liabilities	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]	'	'	'	'	'	'
Derivative liabilities	4,000	'	'	'	'	'
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]	'	'	'	'	'	'
Derivative liabilities	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]	'	'	'	'	'	'
Derivative liabilities	8,862,000	'	9,076,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Options | Derivative Liabilities | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Derivative liabilities	8,603,000	'	8,990,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Options | Derivative Liabilities | Level 2	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Derivative liabilities	259,000	'	86,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Options | Derivative Liabilities | Level 3	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Derivative liabilities	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]	'	'	'	'	'	'
Investments at fair value	333,000	'	2,332,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Preferred Stock | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	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]	'	'	'	'	'	'
Investments at fair value	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]	'	'	'	'	'	'
Investments at fair value	333,000	333,000	2,332,000	2,274,000	240,000	250,000
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]	'	'	'	'	'	'
Investments at fair value	3,506,000	'	137,478,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | US Government Securities | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	3,506,000	'	137,478,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | US Government Securities | Level 2	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	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]	'	'	'	'	'	'
Investments at fair value	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]	'	'	'	'	'	'
Investments at fair value	4,129,000	'	6,202,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Convertible Bonds | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	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]	'	'	'	'	'	'
Investments at fair value	4,129,000	'	6,202,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Convertible Bonds | Level 3	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	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]	'	'	'	'	'	'
Investments at fair value	134,827,000	'	193,078,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Corporate Bonds | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	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]	'	'	'	'	'	'
Investments at fair value	134,827,000	'	192,563,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Corporate Bonds | Level 3	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	0	'	515,000	'	'	'
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]	'	'	'	'	'	'
Investments at fair value	223,527,000	'	259,292,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Common Stock | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	219,315,000	'	254,606,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Common Stock | Level 2	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	2,103,000	'	2,137,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Common Stock | Level 3	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	2,109,000	2,273,000	2,549,000	686,000	719,000	819,000
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]	'	'	'	'	'	'
Investments at fair value	525,000	'	2,845,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Mutual Funds | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	525,000	'	2,845,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Mutual Funds | Level 2	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	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]	'	'	'	'	'	'
Investments at fair value	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]	'	'	'	'	'	'
Derivative assets	263,000	'	'	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Futures | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Derivative assets	263,000	'	'	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Futures | Level 2	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Derivative assets	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]	'	'	'	'	'	'
Derivative assets	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]	'	'	'	'	'	'
Derivative assets	49,000	'	202,000	'	'	'
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]	'	'	'	'	'	'
Derivative assets	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]	'	'	'	'	'	'
Derivative assets	49,000	'	202,000	'	'	'
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]	'	'	'	'	'	'
Derivative assets	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]	'	'	'	'	'	'
Derivative assets	276,000	'	'	'	'	'
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]	'	'	'	'	'	'
Derivative assets	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]	'	'	'	'	'	'
Derivative assets	276,000	'	'	'	'	'
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]	'	'	'	'	'	'
Derivative assets	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]	'	'	'	'	'	'
Derivative assets	10,974,000	'	20,546,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Options | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Derivative assets	10,965,000	'	18,273,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Options | Level 2	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Derivative assets	9,000	'	2,273,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Derivative Assets | Options | Level 3	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Derivative assets	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]	'	'	'	'	'	'
Investments at fair value	2,778,000	'	2,354,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Warrants and Rights | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	111,000	'	641,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Warrants and Rights | Level 2	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	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]	'	'	'	'	'	'
Investments at fair value	2,667,000	'	1,713,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Portfolio Funds | Total Estimated Fair Value	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	70,813,000	'	55,898,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Portfolio Funds | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	0	'	0	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Portfolio Funds | Level 2	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	19,110,000	'	30,228,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Portfolio Funds | Level 3	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	51,703,000	43,343,000	25,670,000	20,493,000	19,876,000	16,919,000
Operating Entities | Fair Value, Measurements, Recurring | Real Estate Investments | Total Estimated Fair Value	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	2,127,000	'	1,864,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Real Estate Investments | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	0	'	0	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Real Estate Investments | Level 2	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	0	'	0	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Real Estate Investments | Level 3	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	2,127,000	2,158,000	1,864,000	2,102,000	2,079,000	2,353,000
Operating Entities | Fair Value, Measurements, Recurring | Lehman Claim | Total Estimated Fair Value	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	558,000	'	706,000	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Lehman Claim | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	0	'	0	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Lehman Claim | Level 2	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	0	'	0	'	'	'
Operating Entities | Fair Value, Measurements, Recurring | Lehman Claim | Level 3	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	558,000	278,000	706,000	761,000	731,000	553,000
Consolidated Funds | Fair Value, Measurements, Recurring | Total Estimated Fair Value	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Assets at fair value	200,210,000	'	207,730,000	'	'	'
Consolidated Funds | Fair Value, Measurements, Recurring | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Assets at fair value	0	'	1,911,000	'	'	'
Consolidated Funds | Fair Value, Measurements, Recurring | Level 2	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Assets at fair value	22,641,000	'	8,775,000	'	'	'
Consolidated Funds | Fair Value, Measurements, Recurring | Level 3	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Assets at fair value	177,569,000	'	197,044,000	'	'	'
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]	'	'	'	'	'	'
Investments at fair value	'	'	1,911,000	'	'	'
Consolidated Funds | Fair Value, Measurements, Recurring | US Government Securities | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	'	'	1,911,000	'	'	'
Consolidated Funds | Fair Value, Measurements, Recurring | US Government Securities | Level 2	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	'	'	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]	'	'	'	'	'	'
Investments at fair value	'	'	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]	'	'	'	'	'	'
Investments at fair value	'	'	1,614,000	'	'	'
Consolidated Funds | Fair Value, Measurements, Recurring | Commercial Paper | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	'	'	0	'	'	'
Consolidated Funds | Fair Value, Measurements, Recurring | Commercial Paper | Level 2	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	'	'	1,614,000	'	'	'
Consolidated Funds | Fair Value, Measurements, Recurring | Commercial Paper | Level 3	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	'	'	0	'	'	'
Consolidated Funds | Fair Value, Measurements, Recurring | Portfolio Funds	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	161,086,000	'	'	'	'	'
Consolidated Funds | Fair Value, Measurements, Recurring | Portfolio Funds | Total Estimated Fair Value	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	183,727,000	'	190,081,000	'	'	'
Consolidated Funds | Fair Value, Measurements, Recurring | Portfolio Funds | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	0	'	0	'	'	'
Consolidated Funds | Fair Value, Measurements, Recurring | Portfolio Funds | Level 2	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	22,641,000	'	7,161,000	'	'	'
Consolidated Funds | Fair Value, Measurements, Recurring | Portfolio Funds | Level 3	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	161,086,000	177,848,000	182,920,000	187,797,000	209,507,000	213,402,000
Consolidated Funds | Fair Value, Measurements, Recurring | Lehman Claim | Total Estimated Fair Value	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	16,483,000	'	14,124,000	'	'	'
Consolidated Funds | Fair Value, Measurements, Recurring | Lehman Claim | Level 1	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	0	'	0	'	'	'
Consolidated Funds | Fair Value, Measurements, Recurring | Lehman Claim | Level 2	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	0	'	0	'	'	'
Consolidated Funds | Fair Value, Measurements, Recurring | Lehman Claim | Level 3	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'
Investments at fair value	$16,483,000	$15,434,000	$14,124,000	$6,860,000	$6,538,000	$7,340,000

Fair_Value_Measurements_for_Op3

Fair Value Measurements for Operating Entities and Consolidated Funds Unobservable Input Roll Forward (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012
Level 3 | Operating Entities	'	'	'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'		'
Investments at fair value, end of period	$5,018,000	'	$5,018,000		'
Fair Value, Measurements, Recurring | Consolidated Funds | Portfolio Funds	'	'	'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'		'
Investments at fair value, end of period	161,086,000	'	161,086,000		'
Fair Value, Measurements, Recurring | Level 3 | Operating Entities | Preferred Stock	'	'	'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'		'
Investments at fair value, beginning of period	333,000	240,000	2,332,000		250,000
Transfers In	0	0	0		0
Transfers Out	0	0	-2,000,000	[1]	0
Purchases/(covers)	0	2,000,000	0		2,000,000
(Sales)/short buys	0	0	0		0
Realized gains (losses)	0	0	0		0
Unrealized gains (losses)	0	34,000	1,000		24,000
Investments at fair value, end of period	333,000	2,274,000	333,000		2,274,000
Fair Value, Measurements, Recurring | Level 3 | Operating Entities | Common Stock	'	'	'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'		'
Investments at fair value, beginning of period	2,273,000	719,000	2,549,000		819,000
Transfers In	0	0	0		0
Transfers Out	0	0	0		0
Purchases/(covers)	0	0	0		0
(Sales)/short buys	-2,000	0	-275,000		-6,000
Realized gains (losses)	0	0	260,000		6,000
Unrealized gains (losses)	-162,000	-33,000	-425,000		-133,000
Investments at fair value, end of period	2,109,000	686,000	2,109,000		686,000
Fair Value, Measurements, Recurring | Level 3 | Operating Entities | Corporate Bonds	'	'	'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'		'
Investments at fair value, beginning of period	'	'	515,000		'
Transfers In	'	'	0		'
Transfers Out	'	'	0		'
Purchases/(covers)	'	'	2,735,000		'
(Sales)/short buys	'	'	-3,346,000		'
Realized gains (losses)	'	'	-914,000		'
Unrealized gains (losses)	'	'	1,010,000		'
Investments at fair value, end of period	0	'	0		'
Fair Value, Measurements, Recurring | Level 3 | Operating Entities | Warrants and Rights	'	'	'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'		'
Investments at fair value, beginning of period	2,136,000	2,844,000	1,713,000		1,534,000
Transfers In	0	0	290,000	[2]	0
Transfers Out	0	0	0		-88,000	[3]
Purchases/(covers)	0	341,000	166,000		623,000
(Sales)/short buys	0	0	-110,000		-65,000
Realized gains (losses)	0	0	0		56,000
Unrealized gains (losses)	531,000	877,000	608,000		2,002,000
Investments at fair value, end of period	2,667,000	4,062,000	2,667,000		4,062,000
Fair Value, Measurements, Recurring | Level 3 | Operating Entities | Warrants and Rights, sold not yet purchased	'	'	'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'		'
Investments at fair value, beginning of period	'	3,000	3,000		0
Transfers In	'	0	0		0
Transfers Out	'	0	0		-1,004,000	[4]
Purchases/(covers)	'	0	0		-306,000
(Sales)/short buys	'	0	0		982,000
Realized gains (losses)	'	-3,000	-4,000		-38,000
Unrealized gains (losses)	'	0	1,000		366,000
Investments at fair value, end of period	0	0	0		0
Fair Value, Measurements, Recurring | Level 3 | Operating Entities | Portfolio Funds	'	'	'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'		'
Investments at fair value, beginning of period	43,343,000	19,876,000	25,670,000		16,919,000
Transfers In	0	0	13,128,000	[5]	0
Transfers Out	0	0	0		0
Purchases/(covers)	6,491,000	320,000	16,560,000		3,171,000
(Sales)/short buys	-289,000	-361,000	-7,821,000		-1,175,000
Realized gains (losses)	712,000	-48,000	-375,000		-41,000
Unrealized gains (losses)	1,446,000	706,000	4,541,000		1,619,000
Investments at fair value, end of period	51,703,000	20,493,000	51,703,000		20,493,000
Fair Value, Measurements, Recurring | Level 3 | Operating Entities | Real Estate Investments	'	'	'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'		'
Investments at fair value, beginning of period	2,158,000	2,079,000	1,864,000		2,353,000
Transfers In	0	0	0		0
Transfers Out	0	0	0		0
Purchases/(covers)	0	0	0		152,000
(Sales)/short buys	0	0	0		-501,000
Realized gains (losses)	0	0	0		0
Unrealized gains (losses)	-31,000	23,000	263,000		98,000
Investments at fair value, end of period	2,127,000	2,102,000	2,127,000		2,102,000
Fair Value, Measurements, Recurring | Level 3 | Operating Entities | Lehman Claim	'	'	'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'		'
Investments at fair value, beginning of period	278,000	731,000	706,000		553,000
Transfers In	0	0	0		0
Transfers Out	0	0	0		0
Purchases/(covers)	0	0	0		0
(Sales)/short buys	0	0	-382,000		0
Realized gains (losses)	0	0	0		0
Unrealized gains (losses)	280,000	30,000	234,000		208,000
Investments at fair value, end of period	558,000	761,000	558,000		761,000
Fair Value, Measurements, Recurring | Level 3 | Consolidated Funds | Portfolio Funds	'	'	'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'		'
Investments at fair value, beginning of period	177,848,000	209,507,000	182,920,000		213,402,000
Transfers In	0	0	0		16,227,000	[6]
Transfers Out	0	0	0		-17,151,000	[6]
Purchases/(covers)	0	0	0		434,000
(Sales)/short buys	-17,886,000	-19,233,000	-27,835,000		-24,259,000
Realized gains (losses)	185,000	182,000	505,000		-1,510,000
Unrealized gains (losses)	939,000	-2,659,000	5,496,000		654,000
Investments at fair value, end of period	161,086,000	187,797,000	161,086,000		187,797,000
Fair Value, Measurements, Recurring | Level 3 | Consolidated Funds | Lehman Claim	'	'	'		'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'	'		'
Investments at fair value, beginning of period	15,434,000	6,538,000	14,124,000		7,340,000
Transfers In	0	0	0		0
Transfers Out	0	0	0		0
Purchases/(covers)	0	0	0		0
(Sales)/short buys	0	0	-1,449,000		-2,291,000
Realized gains (losses)	0	0	1,360,000		1,914,000
Unrealized gains (losses)	1,049,000	322,000	2,448,000		-103,000
Investments at fair value, end of period	$16,483,000	$6,860,000	$16,483,000		$6,860,000
[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, Level 3, USD $)

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Other Assets and Liabilities

Income Approach and Market Approach Valuation Techniques

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

Fair Value, Measurements, Recurring

Fair Value, Measurements, Recurring

Fair Value, Measurements, Recurring

Fair Value, Measurements, Recurring

Common and Preferred Stock

Common and Preferred Stock

Common and Preferred Stock

Warrants and Rights

Warrants and Rights

Warrants and Rights

Corporate Bonds

Corporate Bonds

Warrants and Rights

Warrants and Rights

Minimum

Maximum

Minimum

Maximum

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

'

'

'

'

'

'

'

'

'

'

'

'

DCF discount rate

'

'

'

15.00%

25.00%

'

'

'

'

'

'

'

Market multiple

'

'

'

9

10

'

'

'

'

'

'

'

Volatility

'

'

'

'

'

'

10.00%

130.00%

'

'

'

'

Investments at fair value

$5,018,000

'

$2,351,000

'

'

$2,667,000

'

'

$0

$515,000

$2,667,000

$1,713,000

Assets and liabilities at fair value

$237,066,000

$232,048,000

[1]

'

'

'

'

'

'

'

'

'

'

[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 $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Brokers and Dealers [Abstract]	'	'
Receivable from brokers	$67,966	$71,306
Payable to brokers	$149,276	$188,788

Goodwill_Schedule_of_Goodwill_

Goodwill Schedule of Goodwill by Segment (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Goodwill [Line Items]	'	'	'	'	'
Goodwill, Impairment Loss	$0	$0	$0	$0	'
Goodwill	36,207	'	36,207	'	28,545
Dahlman Rose & Company, LLC	'	'	'	'	'
Goodwill [Line Items]	'	'	'	'	'
Goodwill	$7,700	'	$7,700	'	'

Redeemable_NonControlling_Inte2

Redeemable Non-Controlling Interests in Consolidated Subsidiaries (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Noncontrolling Interest [Line Items]	'	'	'	'	'
Redeemable non-controlling interests in consolidated subsidiaries	$90,179	'	$90,179	'	$85,703
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries	4,759	-1,033	10,509	-1,225	'
Operating Entities	'	'	'	'	'
Noncontrolling Interest [Line Items]	'	'	'	'	'
Redeemable non-controlling interests in consolidated subsidiaries	9,606	'	9,606	'	4,106
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries	3,884	298	7,280	893	'
Consolidated Funds	'	'	'	'	'
Noncontrolling Interest [Line Items]	'	'	'	'	'
Redeemable non-controlling interests in consolidated subsidiaries	80,573	'	80,573	'	81,597
Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries	$875	($1,331)	$3,229	($2,118)	'

ShareBased_Compensation_and_Em2

Share-Based Compensation and Employee Ownership Plans Narrative (Details) (USD $)

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

1 Months Ended

9 Months Ended

In Millions, except Share data, unless otherwise specified

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2012

Sep. 30, 2013

Feb. 28, 2013

Sep. 30, 2013

Equity Plans

Equity Plans

Equity Plans

Equity Plans

Equity Plans

Equity Plans

Equity Plans

Equity Plans

Equity Plans

Equity Plans

Equity Plans

Equity Plans

RCG Grants

RCG Grants

RCG Grants

Deferred Cash Award

Deferred Cash Award

Employee Stock Option

Employee Stock Option

Restricted Shares and Restricted Stock Units (RSUs)

Stock Appreciation Rights (SARs)

Restricted Stock

Restricted Stock

Restricted Stock Units (RSUs)

Restricted Stock Units (RSUs)

Restricted Stock

Cowen Group, Inc. 2010 Equity and Incentive Plan

Cowen Group, Inc. 2010 Equity and Incentive Plan

Minimum

Maximum

Minimum

Maximum

Non-employee Director

Non-employee Director

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Shares authorized under compensation plan, in shares

17,725,000

'

17,725,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stock compensation award, vesting period

'

'

'

'

'2 years

'5 years

'

'

'2 years

'5 years

'

'

'

'

'3 years

'

'

Stock options, initial term

'

'

'7 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

SAR's, initial term

'

'

'

'

'

'

'

'5 years

'

'

'

'

'

'

'

'

'

Shares available for issuance under compensation plan, in shares

1,400,000

'

1,400,000

'

'

'

'

'

'

'

482,522

482,522

'

'

'

'

'

Deferred cash awards granted

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$27.70

'

Deferred cash awards, vesting period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'5 years

Deferred cash award, interest rate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.75%

Deferred cash awards, unrecognized compensation expense

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

29.8

Stock-compensation expense recognized in connection with compensation plan

4.3

5.7

13.8

16.2

'

'

'

'

'

'

'

'

1.3

4.4

'

'

'

Tax benefit of stock-compensation expense recognized in connection with compensation plan

$2.90

$4.40

$8.50

$9

'

'

'

'

'

'

'

'

$0.50

$1.70

'

'

'

Units awarded

'

'

'

'

'

'

7,234,924

400,000

'

'

'

'

'

'

'

'

'

Vested, shares

'

'

'

'

'

'

4,178,314

0

'

'

112,320

112,320

'

'

'

'

'

Granted, shares

'

'

'

'

'

'

'

'

'

'

257,947

257,947

'

'

'

'

'

ShareBased_Compensation_and_Em3

Share-Based Compensation and Employee Ownership Plans Stock Options (Details) (USD $)	9 Months Ended		12 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
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 7 months 28 days		'1 year 7 months 6 days
Weighted average remaining term, options exercisable	'1 year 11 months 9 days		'
Aggregate Intrinsic Value	'		'
Closing stock price, in dollars per share	$3.44		$2.45
Equity Plans	'		'
Shares Subject to Option	'		'
Balance outstanding, beginning of period, shares	773,763		'
Options granted, shares	0		'
Options acquired, shares	0		'
Options expired, shares	-473,757		'
Balance outstanding, end of period, shares	300,006		'
Options exercisable, shares	200,004		'
Weighted Average Exercise Price/Share	'		'
Balance outstanding, beginning of period, in dollars per share	$12.58		'
Options granted, in dollars per share	$0		'
Options acquired, in dollars per share	$0		'
Options expired, in dollars per share	$16		'
Balance outstanding, end of period, in dollars per share	$7.18		'
Options exercisable, in dollars per share	$9.04		'
Aggregate Intrinsic Value	'		'
Balance outstanding, beginning of period	$0	[1]	'
Balance outstanding, end of period	0	[1]	'
Options exercisable	$0	[1]	'
[1]	Based on the Company's closing stock price of $3.44 on SeptemberB 30, 2013 and $2.45 on DecemberB 31, 2012.

ShareBased_Compensation_and_Em4

Share-Based Compensation and Employee Ownership Plans SARs (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013		Sep. 30, 2013
In Millions, except Share data, unless otherwise specified			Stock Appreciation Rights (SARs)		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 5 months 16 days		'
Aggregate Intrinsic Value	'	'	'		'
Balance outstanding, beginning of period	'	'	'		$0	[1]
Granted	'	'	$0	[1]	'
Acquired	'	'	$0	[1]	'
Expired	'	'	$0	[1]	'
Balance outstanding, end of period	'	'	'		$467,640,000	[1]
Balance, exercisable	'	'	'		$0	[1]
Closing stock price, in dollars per share	$3.44	$2.45	'		'
Unrecognized compensation expense	'	'	'		$0.30
[1]	Based on the Company's closing stock price of $3.44 on SeptemberB 30, 2013.

ShareBased_Compensation_and_Em5

Share-Based Compensation and Employee Ownership Plans Restricted Shares and Restricted Stock Units (Details) (Equity Plans, Restricted Shares and Restricted Stock Units (RSUs), USD $)	9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013
Equity Plans | Restricted Shares and Restricted Stock Units (RSUs)	'
Nonvested Restricted Shares and Restricted Stock Units	'
Balance outstanding, beginning of period, shares	10,252,023
Granted, shares	7,234,924
Vested, shares	-4,178,314
Cancelled, shares	0
Forfeited, shares	-176,413
Balance outstanding, end of period, shares	13,132,220
Weighted-Average Grant Date Fair Value	'
Balance outstanding, beginning of period, in dollars per share	$4.15
Granted, in dollars per share	$2.66
Vested, in dollars per share	$3.94
Cancelled, in dollars per share	$0
Forfeited, in dollars per share	$3.15
Balance outstanding, end of period, in dollars per share	$3.41
Unrecognized compensation expense	$30
Weighted-average recognition period for unrecognized compensation expense	'1 year 9 months 29 days

Defined_Benefit_Plans_Details

Defined Benefit Plans (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Components of net periodic benefit cost included in employee compensation and benefits	'	'	'	'
Service cost	$0	$0	$0	$0
Interest cost	54,000	53,000	152,000	159,000
Expected return on plan assets	-64,000	-60,000	-186,000	-176,000
Amortization of (loss) / gain	0	0	0	0
Amortization of prior service cost	5,000	5,000	16,000	15,000
Effect of settlement	0	-17,000	-95,000	-20,000
Net periodic benefit cost	($5,000)	($19,000)	($113,000)	($22,000)

Income_Taxes_Income_Tax_Expens

Income Taxes Income Tax Expense (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Income Taxes [Line Items]	'	'
Effective income tax rate	2.22%	-3.26%
Statutory tax rate	35.00%	35.00%
Undistributed earnings of foreign subsidiaries	$1.20	'
Undistributed Earnings of Foreign Subsidiaries	'	'
Income Taxes [Line Items]	'	'
Tax effect if undistributed foreign earnings were repatriated	$0.10	'

Commitments_and_Contingencies_1

Commitments and Contingencies (Details) (USD $)

3 Months Ended

9 Months Ended

9 Months Ended

1 Months Ended

9 Months Ended

1 Months Ended

9 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Dec. 31, 2011

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Apr. 30, 2011

Apr. 30, 2013

Sep. 30, 2013

Jan. 31, 2013

Sep. 30, 2012

Sep. 30, 2013

Equipment Leases

Service Payments

Facility Leases

Buildings, Avenue of Americas

Buildings, Avenue of Americas

Clawback Obligation

Unfunded Commitments

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

cowenfund

Healthcare Royalty Partners

Healthcare Royalty Partners

Healthcare Royalty Partners

Starboard Value L.P.

Starboard Leaders Fund LP

Starboard Leaders Fund LP

OSP Credit Fund LP (formerly known as Ramius Global Credit Fund LP )

Formation 8 Partners Fund I

Formation 8 Partners Fund I

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

$4,300,000

$3,600,000

$12,300,000

$11,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Future Rent Payments Liability

'

'

'

'

5,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Liability relating to vacating premises

'

'

'

'

'

'

'

'

300,000

2,800,000

'

'

'

'

'

'

'

'

'

'

'

Future minimum annual lease and service payments

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2013

'

'

'

'

'

825,000

[1]

3,520,000

4,899,000

[2]

'

'

'

'

'

'

'

'

'

'

'

'

'

2014

'

'

'

'

'

1,548,000

[1]

11,577,000

19,223,000

[2]

'

'

'

'

'

'

'

'

'

'

'

'

'

2015

'

'

'

'

'

1,051,000

[1]

3,876,000

16,181,000

[2]

'

'

'

'

'

'

'

'

'

'

'

'

'

2016

'

'

'

'

'

194,000

[1]

247,000

13,069,000

[2]

'

'

'

'

'

'

'

'

'

'

'

'

'

2017

'

'

'

'

'

0

[1]

0

9,946,000

[2]

'

'

'

'

'

'

'

'

'

'

'

'

'

Thereafter

'

'

'

'

'

0

[1]

0

43,733,000

[2]

'

'

'

'

'

'

'

'

'

'

'

'

'

Future minimum annual lease and service payments

'

'

'

'

'

3,618,000

[1]

19,220,000

107,051,000

[2]

'

'

'

'

'

'

'

'

'

'

'

'

'

Sublease income related to operating leases

400,000

300,000

1,000,000

1,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contractual obligation

'

'

'

'

'

'

'

'

'

'

6,200,000

19,400,000

42,400,000

'

'

'

'

'

'

'

'

Number of real estate investments, in investments

'

'

'

'

'

'

'

'

'

'

'

4

'

'

'

'

'

'

'

'

'

Expected call period

'

'

'

'

'

'

'

'

'

'

'

'

'

'2 years

'5 years

'

'

'

'

'

'

Funding toward commitments

'

'

'

'

'

'

'

'

'

'

'

'

29,300,000

'

'

'

'

500,000

'

'

3,000,000

Commitments made

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$15,000,000

$1,000,000

'

$10,000,000

$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 14 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 $0.4 million and $0.3 million for the three months ended SeptemberB 30, 2013 and 2012, respectively, and $1.0 million and $1.0 million for the nine months ended SeptemberB 30, 2013 and 2012, respectively.

ShortTerm_Borrowings_and_Other2

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

3 Months Ended

9 Months Ended

9 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Dec. 31, 2010

Sep. 30, 2013

Sep. 30, 2012

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Jan. 31, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

letters_of_credit

letters_of_credit

Minimum

Maximum

Insurance Note

Insurance Note

Letter of Credit, San Francisco Office, Expires May 2014

Letter of Credit, Expires September 2014

Letter of Credit, Expires December 2013

Letter of Credit, Expires February 2014

Letter of Credit, 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]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of Letters of Credit

5

'

'

5

'

'

'

'

'

'

'

'

'

'

'

Components of short-term borrowings and other debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Notes payable

$491,000

'

'

$491,000

'

$206,000

'

'

$500,000

$2,000,000

'

'

'

'

'

Capital lease obligations

2,878,000

'

'

2,878,000

'

3,926,000

'

'

'

'

'

'

'

'

'

Short-term borrowings and other debt

3,369,000

'

'

3,369,000

'

4,132,000

'

'

'

'

'

'

'

'

'

Interest rate

'

'

'

'

'

'

'

'

2.22%

'

'

'

'

'

'

Monthly payment

'

'

'

'

'

'

'

'

200,000

'

'

'

'

'

'

Capital leases entered into

'

'

6,300,000

'

'

'

'

'

'

'

'

'

'

'

'

Capital leases, term

'

'

'

'

'

'

'48 months

'60 months

'

'

'

'

'

'

'

Capital leases, interest rate

'

'

'

'

'

'

0.60%

6.14%

'

'

'

'

'

'

'

Capital lease interest expense

100,000

100,000

'

100,000

100,000

'

'

'

'

'

'

'

'

'

'

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

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2013

385,000

'

'

385,000

'

'

'

'

'

'

'

'

'

'

'

2014

1,402,000

'

'

1,402,000

'

'

'

'

'

'

'

'

'

'

'

2015

1,051,000

'

'

1,051,000

'

'

'

'

'

'

'

'

'

'

'

2016

194,000

'

'

194,000

'

'

'

'

'

'

'

'

'

'

'

2017

0

'

'

0

'

'

'

'

'

'

'

'

'

'

'

Thereafter

0

'

'

0

'

'

'

'

'

'

'

'

'

'

'

Subtotal

3,032,000

'

'

3,032,000

'

'

'

'

'

'

'

'

'

'

'

Less: Amount representing interest

-154,000

[1]

'

'

-154,000

[1]

'

'

'

'

'

'

'

'

'

'

'

Total

2,878,000

'

'

2,878,000

'

'

'

'

'

'

'

'

'

'

'

Repayments on long-term and short-term borrowings

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2013

464,000

'

'

464,000

'

'

'

'

'

'

'

'

'

'

'

2014

46,000

'

'

46,000

'

'

'

'

'

'

'

'

'

'

'

2015

0

'

'

0

'

'

'

'

'

'

'

'

'

'

'

2016

0

'

'

0

'

'

'

'

'

'

'

'

'

'

'

2017

0

'

'

0

'

'

'

'

'

'

'

'

'

'

'

Thereafter

0

'

'

0

'

'

'

'

'

'

'

'

'

'

'

Subtotal

510,000

'

'

510,000

'

'

'

'

'

'

'

'

'

'

'

Less: Amount representing interest

-19,000

[1]

'

'

-19,000

[1]

'

'

'

'

'

'

'

'

'

'

'

Notes payable

$491,000

'

'

$491,000

'

$206,000

'

'

$500,000

$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.

Treasury_stock_Details

Treasury stock (Details) (USD $)	9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Treasury Stock, Cost [Roll Forward]	'	'
Shares purchased for minimum tax withholding, cost	$3,156	$2,652
Treasury stock reissued, cost	-65	'
Treasury Stock	'	'
Treasury Stock, Shares [Roll Forward]	'	'
Treasury stock, shares, beginning of period	11,292,220	'
Shares purchased for minimum tax withholding, shares	1,049,740	'
Treasury stock reissued, shares	-24,744	'
Purchase of treasury stock, shares	813,944	'
Treasury stock, shares, end of period	13,131,160	'
Treasury Stock, Cost [Roll Forward]	'	'
Treasury stock, cost, beginning of period	31,728	'
Shares purchased for minimum tax withholding, cost	3,156	'
Treasury stock reissued, cost	-90	'
Purchase of treasury stock, cost	2,723	'
Treasury stock, cost, end of period	$37,517	'
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	$3.01	'
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	$3.35	'
Treasury stock, average cost per share, end of period, in dollars per share	$2.86	'

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

In Thousands, except Share data, unless otherwise specified

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Stock Options [Member]

Stock Options [Member]

Stock Options [Member]

Stock Options [Member]

Stock Appreciation Rights (SARs)

Stock Appreciation Rights (SARs)

Stock Appreciation Rights (SARs)

Stock Appreciation Rights (SARs)

Restricted Stock

Restricted Stock

Restricted Stock

Restricted Stock

Non-employee Director

Common Stock Class A

Common Stock Class A

Equity Plans

Restricted Stock Units (RSUs)

Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]

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Common stock, shares outstanding, shares

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117,411,528

112,447,892

Common stock, restricted shares, shares

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482,522

482,522

336,895

Computation of earnings per share:

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Net income (loss)

$8,370

($11,618)

$12,637

($15,761)

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

4,759

-1,033

10,509

-1,225

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Net income (loss) from continuing operations less Net income (loss) attributable to redeemable non-controlling interests in consolidated subsidiaries

$3,611

($10,585)

$2,128

($14,536)

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Shares for basic and diluted calculations:

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Weighted average shares used in basic computation, shares

118,359,000

114,989,000

116,012,000

114,587,000

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Shares attributable to share-based payment awards, shares

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0

0

0

0

311,000

0

296,000

0

4,038,000

0

3,583,000

0

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Weighted average shares used in diluted computation, shares

122,708,000

114,989,000

119,891,000

114,587,000

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Earnings (loss) per share:

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Basic (in dollars per share)

$0.03

($0.09)

$0.02

($0.13)

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Diluted (in dollars per share)

$0.03

($0.09)

$0.02

($0.13)

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Segment_Reporting_Details

Segment Reporting (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
	customer		customer		segment		customer
					customer
Segment Reporting Information [Line Items]	'		'		'		'
Number of Operating Segments	'		'		2		'
Revenues	'		'		'		'
Investment banking	$27,694,000		$18,666,000		$70,431,000		$50,550,000
Brokerage	28,462,000		22,701,000		86,583,000		71,282,000
Management fees	9,327,000		8,866,000		28,518,000		28,515,000
Incentive income	2,521,000		1,416,000		7,086,000		2,687,000
Interest and dividends	10,969,000		3,605,000		30,905,000		14,845,000
Reimbursement from affiliates	1,386,000		1,370,000		4,085,000		3,796,000
Total revenues	81,360,000		57,598,000		229,808,000		174,547,000
Expenses	'		'		'		'
Employee compensation and benefits	53,614,000		47,322,000		145,344,000		137,102,000
Interest and dividends	6,133,000		2,056,000		20,287,000		7,107,000
Total expenses	91,737,000		79,054,000		261,461,000		233,218,000
Other income (loss)	'		'		'		'
Net gain (losses) on securities, derivatives and other investments	15,469,000		12,510,000		32,873,000		41,969,000
Total other income (loss)	18,701,000		10,001,000		44,578,000		43,406,000
Income (loss) before income taxes and non-controlling interests	8,324,000		-11,455,000		12,925,000		-15,265,000
Income taxes expense / (benefit)	-46,000		163,000		288,000		496,000
Economic income (loss)/ net income (loss) before non-controlling interests	8,370,000		-11,618,000		12,637,000		-15,761,000
Net income (loss) attributable to Cowen Group, Inc. stockholders	3,611,000		-10,585,000		2,128,000		-14,536,000
Number of major customers	0		0		0		0
Reported Under U.S. GAAP	'		'		'		'
Revenues	'		'		'		'
Investment banking	27,694,000		18,666,000		70,431,000		50,550,000
Brokerage	28,462,000		22,701,000		86,583,000		71,282,000
Management fees	9,327,000		8,866,000		28,518,000		28,515,000
Incentive income	2,521,000		1,416,000		7,086,000		2,687,000
Investment Income	0		0		0		0
Interest and dividends	10,969,000		3,605,000		30,905,000		14,845,000
Reimbursement from affiliates	1,386,000		1,370,000		4,085,000		3,796,000
Other revenue	556,000		701,000		1,519,000		2,398,000
Total revenues	81,360,000		57,598,000		229,808,000		174,547,000
Expenses	'		'		'		'
Employee compensation and benefits	53,614,000		47,322,000		145,344,000		137,102,000
Interest and dividends	6,133,000		2,056,000		20,287,000		7,107,000
Non-compensation expenses - Fixed	0		0		0		0
Non-compensation expenses - Variable	0		0		0		0
Non-compensation expenses	31,540,000		29,346,000		94,593,000		87,670,000
Reimbursement from affiliates	0		0		0		0
Total expenses	91,737,000		79,054,000		261,461,000		233,218,000
Other income (loss)	'		'		'		'
Net gain (losses) on securities, derivatives and other investments	15,469,000		12,510,000		32,873,000		41,969,000
Total other income (loss)	18,701,000		10,001,000		44,578,000		43,406,000
Income (loss) before income taxes and non-controlling interests	8,324,000		-11,455,000		12,925,000		-15,265,000
Income taxes expense / (benefit)	-46,000		163,000		288,000		496,000
Economic income (loss)/ net income (loss) before non-controlling interests	8,370,000		-11,618,000		12,637,000		-15,761,000
(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	-4,759,000		1,033,000		-10,509,000		1,225,000
Net income (loss) attributable to Cowen Group, Inc. stockholders	3,611,000		-10,585,000		2,128,000		-14,536,000
Operating Segments | Reported Under Economic Income/(Loss)	'		'		'		'
Revenues	'		'		'		'
Investment banking	27,694,000		18,666,000		70,431,000		50,550,000
Brokerage	32,035,000		22,701,000		93,352,000		71,282,000
Management fees	14,299,000		13,426,000		43,050,000		42,032,000
Incentive income	5,666,000		1,699,000		14,558,000		8,303,000
Investment Income	12,327,000		9,152,000		26,762,000		38,543,000
Interest and dividends	0		0		0		0
Reimbursement from affiliates	0		0		0		0
Other revenue	118,000		381,000		-46,000		694,000
Total revenues	92,139,000		66,025,000		248,107,000		211,404,000
Expenses	'		'		'		'
Employee compensation and benefits	53,830,000		46,249,000		146,065,000		133,803,000
Interest and dividends	75,000		131,000		271,000		278,000
Non-compensation expenses - Fixed	25,331,000		24,016,000		72,892,000		69,748,000
Non-compensation expenses - Variable	6,873,000		5,720,000		22,786,000		19,733,000
Non-compensation expenses	0		0		0		0
Reimbursement from affiliates	-1,461,000		-1,467,000		-4,291,000		-4,018,000
Total expenses	84,648,000		74,649,000		237,723,000		219,544,000
Other income (loss)	'		'		'		'
Net gain (losses) on securities, derivatives and other investments	0		0		0		0
Total other income (loss)	0		0		0		0
Income (loss) before income taxes and non-controlling interests	7,491,000		-8,624,000		10,384,000		-8,140,000
Income taxes expense / (benefit)	0		0		0		0
Economic income (loss)/ net income (loss) before non-controlling interests	7,491,000		-8,624,000		10,384,000		-8,140,000
(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	-3,825,000		-301,000		-6,517,000		-900,000
Net income (loss) attributable to Cowen Group, Inc. stockholders	3,666,000		-8,925,000		3,867,000		-9,040,000
Alternative Investment | Reported Under Economic Income/(Loss)	'		'		'		'
Revenues	'		'		'		'
Investment banking	0		0		0		0
Brokerage	0		0		0		0
Management fees	14,299,000		13,426,000		43,050,000		42,032,000
Incentive income	5,666,000		1,699,000		14,558,000		8,303,000
Investment Income	10,031,000		6,864,000		22,169,000		30,361,000
Interest and dividends	0		0		0		0
Reimbursement from affiliates	0		0		0		0
Other revenue	156,000		168,000		381,000		508,000
Total revenues	30,152,000		22,157,000		80,158,000		81,204,000
Expenses	'		'		'		'
Employee compensation and benefits	13,539,000		11,759,000		37,863,000		42,705,000
Interest and dividends	52,000		93,000		183,000		123,000
Non-compensation expenses - Fixed	9,086,000		8,564,000		26,695,000		24,093,000
Non-compensation expenses - Variable	1,449,000		1,433,000		3,594,000		3,881,000
Non-compensation expenses	0		0		0		0
Reimbursement from affiliates	-1,461,000		-1,467,000		-4,291,000		-4,018,000
Total expenses	22,665,000		20,382,000		64,044,000		66,784,000
Other income (loss)	'		'		'		'
Net gain (losses) on securities, derivatives and other investments	0		0		0		0
Total other income (loss)	0		0		0		0
Income (loss) before income taxes and non-controlling interests	7,487,000		1,775,000		16,114,000		14,420,000
Income taxes expense / (benefit)	0		0		0		0
Economic income (loss)/ net income (loss) before non-controlling interests	7,487,000		1,775,000		16,114,000		14,420,000
(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	-3,825,000		-301,000		-6,517,000		-900,000
Net income (loss) attributable to Cowen Group, Inc. stockholders	3,662,000		1,474,000		9,597,000		13,520,000
Broker-Dealer | Reported Under Economic Income/(Loss)	'		'		'		'
Revenues	'		'		'		'
Investment banking	27,694,000	[1]	18,666,000	[2]	70,431,000	[3]	50,550,000	[4]
Brokerage	32,035,000	[1]	22,701,000	[2]	93,352,000	[3]	71,282,000	[4]
Management fees	0	[1]	0	[2]	0	[3]	0	[4]
Incentive income	0	[1]	0	[2]	0	[3]	0	[4]
Investment Income	2,296,000	[1]	2,288,000	[2]	4,593,000	[3]	8,182,000	[4]
Interest and dividends	0	[1]	0	[2]	0	[3]	0	[4]
Reimbursement from affiliates	0	[1]	0	[2]	0	[3]	0	[4]
Other revenue	-38,000	[1]	213,000	[2]	-427,000	[3]	186,000	[4]
Total revenues	61,987,000	[1]	43,868,000	[2]	167,949,000	[3]	130,200,000	[4]
Expenses	'		'		'		'
Employee compensation and benefits	40,291,000	[1]	34,490,000	[2]	108,202,000	[3]	91,098,000	[4]
Interest and dividends	23,000	[1]	38,000	[2]	88,000	[3]	155,000	[4]
Non-compensation expenses - Fixed	16,245,000	[1]	15,452,000	[2]	46,197,000	[3]	45,655,000	[4]
Non-compensation expenses - Variable	5,424,000	[1]	4,287,000	[2]	19,192,000	[3]	15,852,000	[4]
Non-compensation expenses	0	[1]	0	[2]	0	[3]	0	[4]
Reimbursement from affiliates	0	[1]	0	[2]	0	[3]	0	[4]
Total expenses	61,983,000	[1]	54,267,000	[2]	173,679,000	[3]	152,760,000	[4]
Other income (loss)	'		'		'		'
Net gain (losses) on securities, derivatives and other investments	0	[1]	0	[2]	0	[3]	0	[4]
Total other income (loss)	0	[1]	0	[2]	0	[3]	0	[4]
Income (loss) before income taxes and non-controlling interests	4,000	[1]	-10,399,000	[2]	-5,730,000	[3]	-22,560,000	[4]
Income taxes expense / (benefit)	0	[1]	0	[2]	0	[3]	0	[4]
Economic income (loss)/ net income (loss) before non-controlling interests	4,000	[1]	-10,399,000	[2]	-5,730,000	[3]	-22,560,000	[4]
(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	0	[1]	0	[2]	0	[3]	0	[4]
Net income (loss) attributable to Cowen Group, Inc. stockholders	4,000	[1]	-10,399,000	[2]	-5,730,000	[3]	-22,560,000	[4]
Investment Income from Entity's Capital	3,000,000		2,300,000		5,600,000		8,200,000
Compensation Expense Related to Investment of Entity's Capital	1,000,000		800,000		1,800,000		2,700,000
Funds Consolidation | Reconciliation from Economic Income/(Loss) to U.S. GAAP	'		'		'		'
Revenues	'		'		'		'
Investment banking	0		0		0		0
Brokerage	0		0		0		0
Management fees	-275,000		-362,000		-871,000		-1,150,000
Incentive income	0		0		0		0
Investment Income	0		0		0		0
Interest and dividends	0		0		0		0
Reimbursement from affiliates	-75,000		-97,000		-206,000		-222,000
Other revenue	0		0		0		0
Total revenues	95,000		-186,000		-396,000		-898,000
Expenses	'		'		'		'
Employee compensation and benefits	0		0		0		0
Interest and dividends	0		0		0		0
Non-compensation expenses - Fixed	0		0		0		0
Non-compensation expenses - Variable	0		0		0		0
Non-compensation expenses	0		0		0		0
Reimbursement from affiliates	0		0		0		0
Total expenses	450,000		330,000		1,237,000		1,339,000
Other income (loss)	'		'		'		'
Net gain (losses) on securities, derivatives and other investments	0		0		0		0
Total other income (loss)	1,230,000		-815,000		4,862,000		119,000
Income (loss) before income taxes and non-controlling interests	875,000		-1,331,000		3,229,000		-2,118,000
Income taxes expense / (benefit)	0		0		0		0
Economic income (loss)/ net income (loss) before non-controlling interests	875,000		-1,331,000		3,229,000		-2,118,000
(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	-875,000		1,331,000		-3,229,000		2,118,000
Net income (loss) attributable to Cowen Group, Inc. stockholders	0		0		0		0
Other Adjustments | Reconciliation from Economic Income/(Loss) to U.S. GAAP	'		'		'		'
Revenues	'		'		'		'
Investment banking	0		0		0		0
Brokerage	-3,573,000	[5]	0		-6,769,000	[5]	0
Management fees	-4,697,000	[6]	-4,198,000	[6]	-13,661,000	[6]	-12,367,000	[6]
Incentive income	-3,145,000	[6]	-283,000	[6]	-7,472,000	[6]	-5,616,000	[6]
Investment Income	-12,327,000	[7]	-9,152,000	[7]	-26,762,000	[7]	-38,543,000	[7]
Interest and dividends	10,969,000	[7]	3,605,000	[7]	30,905,000	[7]	14,845,000	[7]
Reimbursement from affiliates	1,461,000	[8]	1,467,000	[8]	4,291,000	[8]	4,018,000	[8]
Other revenue	438,000	[7]	320,000	[7]	1,565,000	[7]	1,704,000	[7]
Total revenues	-10,874,000		-8,241,000		-17,903,000		-35,959,000
Expenses	'		'		'		'
Employee compensation and benefits	-216,000		1,073,000		-721,000		3,299,000
Interest and dividends	6,058,000	[7]	1,925,000	[7]	20,016,000	[7]	6,829,000	[7]
Non-compensation expenses - Fixed	-25,331,000	[7],[9]	-24,016,000	[7],[9]	-72,892,000	[7],[9]	-69,748,000	[7],[9]
Non-compensation expenses - Variable	-6,873,000	[7],[9]	-5,720,000	[7],[9]	-22,786,000	[7],[9]	-19,733,000	[7],[9]
Non-compensation expenses	31,540,000	[7],[9]	29,346,000	[7],[9]	94,593,000	[7],[9]	87,670,000	[7],[9]
Reimbursement from affiliates	1,461,000	[8]	1,467,000	[8]	4,291,000	[8]	4,018,000	[8]
Total expenses	6,639,000		4,075,000		22,501,000		12,335,000
Other income (loss)	'		'		'		'
Net gain (losses) on securities, derivatives and other investments	15,469,000	[7]	12,510,000	[7]	32,873,000	[7]	41,969,000	[7]
Total other income (loss)	17,471,000		10,816,000		39,716,000		43,287,000
Income (loss) before income taxes and non-controlling interests	-42,000		-1,500,000		-688,000		-5,007,000
Income taxes expense / (benefit)	-46,000	[8]	163,000	[8]	288,000	[8]	496,000	[8]
Economic income (loss)/ net income (loss) before non-controlling interests	4,000		-1,663,000		-976,000		-5,503,000
(Income) loss attributable to redeemable non-controlling interests in consolidated subsidiaries	-59,000		3,000		-763,000		7,000
Net income (loss) attributable to Cowen Group, Inc. stockholders	-55,000		-1,660,000		-1,739,000		-5,496,000
Consolidated Funds | Reported Under U.S. GAAP	'		'		'		'
Revenues	'		'		'		'
Total revenues	445,000		273,000		681,000		474,000
Expenses	'		'		'		'
Total expenses	450,000		330,000		1,237,000		1,339,000
Other income (loss)	'		'		'		'
Net gain (losses) on securities, derivatives and other investments	3,232,000		-2,509,000		11,705,000		1,437,000
Consolidated Funds | Operating Segments | Reported Under Economic Income/(Loss)	'		'		'		'
Revenues	'		'		'		'
Total revenues	0		0		0		0
Expenses	'		'		'		'
Total expenses	0		0		0		0
Other income (loss)	'		'		'		'
Net gain (losses) on securities, derivatives and other investments	0		0		0		0
Consolidated Funds | Alternative Investment | Reported Under Economic Income/(Loss)	'		'		'		'
Revenues	'		'		'		'
Total revenues	0		0		0		0
Expenses	'		'		'		'
Total expenses	0		0		0		0
Other income (loss)	'		'		'		'
Net gain (losses) on securities, derivatives and other investments	0		0		0		0
Consolidated Funds | Broker-Dealer | Reported Under Economic Income/(Loss)	'		'		'		'
Revenues	'		'		'		'
Total revenues	0	[1]	0	[2]	0	[3]	0	[4]
Expenses	'		'		'		'
Total expenses	0	[1]	0	[2]	0	[3]	0	[4]
Other income (loss)	'		'		'		'
Net gain (losses) on securities, derivatives and other investments	0	[1]	0	[2]	0	[3]	0	[4]
Consolidated Funds | Funds Consolidation | Reconciliation from Economic Income/(Loss) to U.S. GAAP	'		'		'		'
Revenues	'		'		'		'
Total revenues	445,000		273,000		681,000		474,000
Expenses	'		'		'		'
Total expenses	450,000		330,000		1,237,000		1,339,000
Other income (loss)	'		'		'		'
Net gain (losses) on securities, derivatives and other investments	1,230,000		-815,000		4,862,000		119,000
Consolidated Funds | Other Adjustments | Reconciliation from Economic Income/(Loss) to U.S. GAAP	'		'		'		'
Revenues	'		'		'		'
Total revenues	0		0		0		0
Expenses	'		'		'		'
Total expenses	0		0		0		0
Other income (loss)	'		'		'		'
Net gain (losses) on securities, derivatives and other investments	$2,002,000		($1,694,000)		$6,843,000		$1,318,000
[1]	For the three months ended SeptemberB 30, 2013, the Company has reflected $3.0 million of investment income and related compensation expense of $1.0 million within the broker-dealer segment in proportion to its capital.
[2]	For the three months ended SeptemberB 30, 2012, the Company has reflected $2.3 million of investment income and related compensation expense of $0.8 million within the broker-dealer segment in proportion to its capital
[3]	For the nine months ended SeptemberB 30, 2013, 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]	For the nine months ended SeptemberB 30, 2012, the Company has reflected $8.2 million of investment income and related compensation expense of $2.7 million within the broker-dealer segment in proportion to its capital.
[5]	Economic Income (Loss) recognizes stock borrow/loan activity and other brokerage dividends as brokerage revenue.
[6]	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.
[7]	Economic Income (Loss) recognizes Company income from proprietary trading net of related expenses.
[8]	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.
[9]	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.

Regulatory_Requirements_Detail

Regulatory Requirements (Details) (USD $)	Sep. 30, 2013
U.S. Securities and Exchange Commission | Cowen and Company	'
Regulatory Requirements for Broker-Dealers [Line Items]	'
Net capital requirement under alternative method	$1,000,000
Net capital	52,300,000
Excess net capital under alternative method	51,300,000
U.S. Securities and Exchange Commission | Cowen and Company | Minimum	'
Regulatory Requirements for Broker-Dealers [Line Items]	'
Net capital requirement under alternative method	1,000,000
U.S. Securities and Exchange Commission | ATM Execution	'
Regulatory Requirements for Broker-Dealers [Line Items]	'
Minimum net capital required	1,000,000
Net capital	3,500,000
Excess capital	2,500,000
U.S. Securities and Exchange Commission | ATM Execution | Minimum	'
Regulatory Requirements for Broker-Dealers [Line Items]	'
Minimum net capital required	1,000,000
Net capital requirement as a percentage of indebtedness	6.67%
U.S. Securities and Exchange Commission | ATM USA	'
Regulatory Requirements for Broker-Dealers [Line Items]	'
Minimum net capital required	6,138
Net capital	900,000
Excess capital	900,000
U.S. Securities and Exchange Commission | ATM USA | Minimum	'
Regulatory Requirements for Broker-Dealers [Line Items]	'
Minimum net capital required	5,000
Net capital requirement as a percentage of indebtedness	6.67%
U.S. Securities and Exchange Commission | Cowen Equity Finance	'
Regulatory Requirements for Broker-Dealers [Line Items]	'
Minimum net capital required	250,000
Net capital	11,500,000
Excess capital	11,200,000
U.K. Financial Services Authority | Raimus U.K., Ltd.	'
Regulatory Requirements for Broker-Dealers [Line Items]	'
Financial resources	500,000
Financial resources requirement	200,000
Excess financial resources	300,000
U.K. Financial Services Authority | Cowen International Limited	'
Regulatory Requirements for Broker-Dealers [Line Items]	'
Financial resources	4,200,000
Financial resources requirement	2,200,000
Excess financial resources	2,000,000
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 $)

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Apr. 30, 2011

Apr. 30, 2011

Sep. 30, 2013

Sep. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Affiliated Entity

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

Asset Management Income

Asset Management Income

Asset Management Income

Asset Management Income

Fees Receivable

Fees Receivable

Fees Payable

Fees Payable

Starboard Value L.P.

Starboard Value L.P.

Due from Related Parties

LIBOR

Starboard Value L.P.

Related Party Transaction [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fees receivable from related parties

'

'

'

'

'

'

'

'

$14,300,000

$13,600,000

'

'

'

'

'

'

'

'

'

'

'

Reimbursement to affiliated funds

'

'

'

'

400,000

200,000

1,400,000

1,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Fees payable to related parties

'

'

'

'

'

'

'

'

'

'

2,000,000

1,700,000

'

'

'

'

'

'

'

'

'

Due from employees

'

'

'

'

'

'

'

'

'

'

'

'

7,200,000

5,100,000

'

'

'

'

'

'

'

Forgivable Loan Balances

'

'

'

'

'

'

'

'

'

'

'

'

4,600,000

2,300,000

'

'

'

'

'

'

'

Forgivable Loans, Vesting Period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'1 year

'3 years

Amortization on Forgivable Loans

1,100,000

600,000

2,300,000

1,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Credit agreement with related party, maximum loan amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3,000,000

'

'

'

'

'

'

Credit agreement with related party, interest rate spread

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3.75%

'

'

'

'

'

Credit agreement with related party, loan receivable

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,500,000

'

'

'

'

Due to Affiliate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$600,000

$400,000

'

'

Guarantees_and_OffBalance_Shee1

Guarantees and Off-Balance Sheet Arrangements (Details) (USD $)	Sep. 30, 2013
Securities Lending	'
Guaranty loans	$150,000,000
Employee Loans	'
Guaranty loans	$2,600,000