Investments Of Operating Entities And Consolidated Funds - Operating Entities - Receivable On And Payable For Derivative Contracts, At Fair Value (Details)		Sep. 30, 2020 USD ($) contract	Dec. 31, 2019 USD ($) contract
Derivative [Line Items]
Receivable on derivative contracts, at fair value		$ 58,194,000	$ 62,977,000
Payable for derivative contracts, at fair value		62,054,000	60,761,000
Futures
Derivative [Line Items]
Derivative Liability, Notional Amount		9,895,000	10,224,000
Payable for derivative contracts, at fair value		123,000	217,000
Currency Forwards
Derivative [Line Items]
Derivative Asset, Notional Amount		82,100,000	0
Receivable on derivative contracts, at fair value		870,000	0
Derivative Liability, Notional Amount		103,500,000	77,790,000
Payable for derivative contracts, at fair value		717,000	851,000
Swaps
Derivative [Line Items]
Derivative Asset, Notional Amount		244,090,000	383,752,000
Receivable on derivative contracts, at fair value		4,644,000	2,911,000
Derivative Liability, Notional Amount		376,331,000	607,717,000
Payable for derivative contracts, at fair value		$ 7,514,000	$ 23,169,000
Options
Derivative [Line Items]
Derivative Asset, Number of Instruments Held | contract	[1]	256,841	550,188
Receivable on derivative contracts, at fair value	[1]	$ 52,680,000	$ 60,066,000
Option
Derivative [Line Items]
Derivative Liability, Number of Instruments Held | contract	[2]	252,576	306,306
Payable for derivative contracts, at fair value	[2]	$ 53,700,000	$ 36,524,000

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

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