Consolidated Statements of Changes in Equity - USD ($)	Total	Common Shares	Preferred Shares	Treasury Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings/(Accumulated deficit)	Retained Earnings/(Accumulated deficit) Cumulative Effect, Period of Adoption, Adjustment	Cowen Inc Equity	Nonredeemable Noncontrolling Interests
Common stock outstanding, beginning balance (in shares) at Dec. 31, 2019		28,610,357
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock awards issued (in shares)		2,174,859
Common stock issuance for purchase of investment		0
Common stock issuance upon acquisition (in shares)		74,694
Purchase of treasury stock, at cost (in shares)		(4,014,282)
Share settlement of convertible notes (in shares)		0
Common stock outstanding, ending balance (in shares) at Dec. 31, 2020		26,845,628
Preferred stock outstanding, beginning balance (in shares) at Dec. 31, 2019			120,750
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Modification of Series A Convertible Preferred Stock (in shares)			0
Preferred stock outstanding, ending balance (in shares) at Dec. 31, 2020			120,750
Balance, start at Dec. 31, 2019		$ 334,000	$ 1,000	$ (284,301,000)	$ 1,110,635,000	$ (5,000)	$ (16,809,000)	$ (10,000)	$ 809,855,000	$ 94,320,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification of Series A Convertible Preferred Stock			0		0
Purchase of treasury stock, at cost				(62,569,000)
Common stock issuance for purchase of investment	$ 0				0
Common stock issuance upon acquisition	926,000				926,000
Equity portion of convertible note extinguishment					(29,645,000)
Amortization of share based awards					48,222,000
Foreign currency translation						(2,000)
Net income (loss) attributable to Cowen Inc.	216,363,000						216,363,000
Preferred dividends paid							(6,792,000)
Cash dividends declared	(6,851)						(6,851,000)
Net income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds										23,625,000
Capital contributions										201,223,000
Capital withdrawals										(78,251,000)
Consolidation of entity										48,596,000
Deconsolidation of entity										(89,889,000)
Balance, end at Dec. 31, 2020	$ 1,169,121,000	$ 334,000	$ 1,000	(346,870,000)	1,130,138,000	(7,000)	185,901,000	0	969,497,000	199,624,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock awards issued (in shares)		2,710,719
Common stock issuance for purchase of investment		68,980
Common stock issuance upon acquisition (in shares)		642,862
Purchase of treasury stock, at cost (in shares)		(5,428,066)
Share settlement of convertible notes (in shares)		2,938,841
Common stock outstanding, ending balance (in shares) at Dec. 31, 2021		27,778,964
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Modification of Series A Convertible Preferred Stock (in shares)			(120,750)
Preferred stock outstanding, ending balance (in shares) at Dec. 31, 2021	120,750		0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification of Series A Convertible Preferred Stock			$ (1,000)		(120,749,000)
Purchase of treasury stock, at cost				(200,242,000)
Common stock issuance for purchase of investment	$ 2,500,000				2,500,000
Common stock issuance upon acquisition	23,060,000				23,060,000
Equity portion of convertible note extinguishment					0
Amortization of share based awards					65,718,000
Foreign currency translation						5,000
Net income (loss) attributable to Cowen Inc.	295,611,000						295,611,000
Preferred dividends paid							(6,792,000)
Cash dividends declared	(12,738,000)						(12,738,000)
Net income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds										8,380,000
Capital contributions										55,556,000
Capital withdrawals										(29,012,000)
Consolidation of entity										0
Deconsolidation of entity										(74,813,000)
Balance, end at Dec. 31, 2021	$ 1,175,604,000	$ 334,000	$ 0	(547,112,000)	1,100,667,000	(2,000)	461,982,000		1,015,869,000	159,735,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Restricted stock awards issued (in shares)		2,524,673
Common stock issuance for purchase of investment		0
Common stock issuance upon acquisition (in shares)		58,587
Purchase of treasury stock, at cost (in shares)		(2,127,935)
Share settlement of convertible notes (in shares)		0
Common stock outstanding, ending balance (in shares) at Dec. 31, 2022		28,234,289
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Modification of Series A Convertible Preferred Stock (in shares)			0
Preferred stock outstanding, ending balance (in shares) at Dec. 31, 2022	120,750		0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification of Series A Convertible Preferred Stock			$ 0		0
Purchase of treasury stock, at cost				(67,160,000)
Common stock issuance for purchase of investment	$ 0				0
Common stock issuance upon acquisition	1,881,000				1,881,000
Equity portion of convertible note extinguishment					0
Amortization of share based awards					60,166,000
Foreign currency translation						3,000
Net income (loss) attributable to Cowen Inc.	76,458,000						76,458,000
Preferred dividends paid							(6,792,000)
Cash dividends declared	(16,253,000)						(16,253,000)
Net income (loss) attributable to non-controlling interests in consolidated subsidiaries and investment funds										(10,603,000)
Capital contributions										24,417,000
Capital withdrawals										(10,626,000)
Consolidation of entity										0
Deconsolidation of entity										0
Balance, end at Dec. 31, 2022	$ 1,227,095,000	$ 334,000	$ 0	$ (614,272,000)	$ 1,162,714,000	$ 1,000	$ 515,395,000	$ 0	$ 1,064,172,000	$ 162,923,000