Investments Of Operating Entities And Consolidated Funds - Operating Entities - Receivable On And Payable For Derivative Contracts, At Fair Value (Details)		Mar. 31, 2020 USD ($) contract	Dec. 31, 2019 USD ($) contract
Derivative [Line Items]
Receivable on derivative contracts, at fair value		$ 83,867,000	$ 62,977,000
Payable for derivative contracts, at fair value		72,385,000	60,761,000
Futures
Derivative [Line Items]
Derivative Liability, Notional Amount		5,045,000	10,224,000
Payable for derivative contracts, at fair value		87,000	217,000
Currency Forwards
Derivative [Line Items]
Derivative Asset, Notional Amount		58,737,000	0
Receivable on derivative contracts, at fair value		1,010,000	0
Derivative Liability, Notional Amount		108,189,000	77,790,000
Payable for derivative contracts, at fair value		1,883,000	851,000
Swaps
Derivative [Line Items]
Derivative Asset, Notional Amount		232,713,000	383,752,000
Receivable on derivative contracts, at fair value		24,523,000	2,911,000
Derivative Liability, Notional Amount		202,650,000	607,717,000
Payable for derivative contracts, at fair value		$ 9,469,000	$ 23,169,000
Options
Derivative [Line Items]
Derivative Asset, Number of Instruments Held | contract	[1]	402,281	550,188
Receivable on derivative contracts, at fair value	[1]	$ 58,334,000	$ 60,066,000
Option
Derivative [Line Items]
Derivative Liability, Number of Instruments Held | contract	[2]	222,709	306,306
Payable for derivative contracts, at fair value	[2]	$ 60,946,000	$ 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.