Derivative Instruments - Fair Value of Derivative Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Equities futures | Derivative instruments not designated as hedging instruments | Receivables from broker-dealers and clearing organizations
Derivatives Assets
Fair Value	$ (741)	$ (575)
Notional	1,944,872	663,110
Equities futures | Derivative instruments not designated as hedging instruments | Payables to broker-dealers and clearing organizations
Derivatives Liabilities
Fair Value	(558)	1,819
Notional	501,978	3,238,651
Commodity futures | Derivative instruments not designated as hedging instruments | Receivables from broker-dealers and clearing organizations
Derivatives Assets
Fair Value	(7,017)	(31,007)
Notional	6,489,328	7,597,057
Commodity futures | Derivative instruments not designated as hedging instruments | Payables to broker-dealers and clearing organizations
Derivatives Liabilities
Fair Value	(4)	597
Notional	25,462	39,046
Currency futures | Derivative instruments not designated as hedging instruments | Receivables from broker-dealers and clearing organizations
Derivatives Assets
Fair Value	707	(24,023)
Notional	6,964,937	7,460,531
Currency futures | Derivative instruments not designated as hedging instruments | Payables to broker-dealers and clearing organizations
Derivatives Liabilities
Fair Value	12,031	8
Notional	1,518,087	6,386
Fixed income futures | Derivative instruments not designated as hedging instruments | Receivables from broker-dealers and clearing organizations
Derivatives Assets
Fair Value	1	(360)
Notional	5,989	30,292
Fixed income futures | Derivative instruments not designated as hedging instruments | Payables to broker-dealers and clearing organizations
Derivatives Liabilities
Fair Value	165	(264)
Notional	82,044	123,043
Options
Derivatives Assets
Fair Value	3,485	5,200
Derivatives Liabilities
Fair Value	3,186	3,889
Options | Derivative instruments not designated as hedging instruments | Financial instruments owned
Derivatives Assets
Fair Value	3,485	5,200
Notional	1,167,643	691,737
Options | Derivative instruments not designated as hedging instruments | Financial instruments sold, not yet purchased
Derivatives Liabilities
Fair Value	3,186	3,889
Notional	1,173,351	742,531
Currency forwards
Derivatives Assets
Fair Value	377,279	500,553
Derivatives Liabilities
Fair Value	339,085	497,799
Currency forwards | Derivative instruments not designated as hedging instruments | Financial instruments owned
Derivatives Assets
Fair Value	377,279	500,553
Notional	33,579,641	30,286,330
Currency forwards | Derivative instruments not designated as hedging instruments | Financial instruments sold, not yet purchased
Derivatives Liabilities
Fair Value	339,085	497,799
Notional	33,560,544	30,284,952
Interest rate swap
Derivatives Assets
Fair Value		87,268
Derivatives Liabilities
Fair Value	7,661
Interest rate swap | Derivative instruments designated as hedging instruments | Payables to broker-dealers and clearing organizations
Derivatives Liabilities
Fair Value	7,661	0
Notional	1,525,000	0
Interest rate swap | Derivative instruments designated as hedging instruments | Receivables from broker-dealers and clearing organizations
Derivatives Assets
Fair Value	0	87,268
Notional	$ 0	$ 1,525,000