Investments Of Operating Entities And Consolidated Funds - Operating Entities - Receivable On And Payable For Derivative Contracts, At Fair Value (Details)		Dec. 31, 2020 USD ($) contract	Dec. 31, 2019 USD ($) contract
Derivative [Line Items]
Receivable on derivative contracts, at fair value		$ 51,482,000	$ 62,977,000
Payable for derivative contracts, at fair value		76,160,000	60,761,000
Receivable on derivatives contracts, at fair value [Member]
Derivative [Line Items]
Receivable on derivative contracts, at fair value		51,482,000	62,977,000
Derivative Asset, Fair Value, Amount Offset Against Collateral	[1],[2]	(62,269,000)	(3,240,000)
Payable for derivatives contracts, at fair value [Member]
Derivative [Line Items]
Payable for derivative contracts, at fair value		76,160,000	60,761,000
Derivative Liability, Fair Value, Amount Offset Against Collateral	[2]	(37,033,000)	(3,240,000)
Futures
Derivative [Line Items]
Derivative Liability, Notional Amount		0	10,224,000
Payable for derivative contracts, at fair value		0	217,000
Currency Forwards
Derivative [Line Items]
Derivative Asset, Notional Amount		4,902,000	0
Receivable on derivative contracts, at fair value		15,000	0
Derivative Liability, Notional Amount		123,346,000	77,790,000
Payable for derivative contracts, at fair value		3,067,000	851,000
Swaps
Derivative [Line Items]
Derivative Asset, Notional Amount		944,544,000	383,752,000
Receivable on derivative contracts, at fair value		64,634,000	6,151,000
Derivative Liability, Notional Amount		896,863,000	607,717,000
Payable for derivative contracts, at fair value		$ 43,560,000	$ 26,409,000
Options
Derivative [Line Items]
Derivative Asset, Number of Instruments Held | contract	[3]	371,188	550,188
Receivable on derivative contracts, at fair value	[3]	$ 49,102,000	$ 60,066,000
Option
Derivative [Line Items]
Derivative Liability, Number of Instruments Held | contract	[3]	198,320	306,306
Payable for derivative contracts, at fair value	[3]	$ 66,566,000	$ 36,524,000

[1] Derivatives are reported on a net basis, by counterparty, when a legal right of offset exists under an enforceable netting agreement as well as net of cash collateral received or posted under enforceable credit support agreements. See Note 2g for further information on offsetting of derivative financial instruments.

[2] Includes financial instruments subject to enforceable master netting provisions that are permitted to be offset to the extent an event of default has occurred

[3] Includes the volume of contracts for index, equity, commodity future and cash conversion options.