Fair Value Disclosures - Quantitative Information About Significant Unobservable Inputs Used in Level 3 Fair Value Measurements (Details)
$ in Thousands
 6 Months Ended 12 Months Ended
May 31, 2022
USD ($)
Nov. 30, 2021
USD ($)
May 31, 2022
$ / shares
May 31, 2022
May 31, 2022
$ / Bond
May 31, 2022
€ / shares
May 31, 2022
€ / Bond
Nov. 30, 2021
$ / shares
Nov. 30, 2021
Nov. 30, 2021
$ / Bond
Nov. 30, 2021
€ / shares
Nov. 30, 2021
€ / Bond
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value $ 18,942,955 $ 18,802,730                    
Derivative assets 408,100 570,472                    
Loans to and investments in associated companies 16,590 30,842                    
Financial instruments sold, not yet purchased, at fair value 13,665,037 11,699,467                    
Derivative liability 1,286,189 1,412,176                    
Other secured financings 2,362 102,788                    
Long-term debt, fair value 1,617,020 1,843,598                    
Corporate debt securities                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value 3,252,318 3,848,144                    
Financial instruments sold, not yet purchased, at fair value 2,309,216 2,112,259                    
CDOs and CLOs                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value 373,485 611,464                    
Commercial mortgage-backed securities                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value 345,614 198,752                    
Financial instruments sold, not yet purchased, at fair value 385 210                    
Other asset-backed securities                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value 287,287 430,546                    
Loans and other receivables                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value 2,962,624 3,498,289                    
Corporate equity securities                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value 4,225,424 3,082,220                    
Financial instruments sold, not yet purchased, at fair value 1,838,161 1,695,985                    
Loans                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments sold, not yet purchased, at fair value 2,484,257 2,491,857                    
Level 3                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value 739,734 579,045                    
Loans to and investments in associated companies 14,795 30,842                    
Financial instruments sold, not yet purchased, at fair value 124,734 99,114                    
Other secured financings 2,362 25,905                    
Long-term debt, fair value 739,353 881,732                    
Level 3 | Market approach and volatility benchmarking                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Derivative assets 18,755 6,501                    
Derivative liability 97,612 76,533                    
Level 3 | Scenario analysis                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Other secured financings 2,362 25,905                    
Level 3 | Non-exchange-traded securities | Market approach and volatility benchmarking                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value 200,961 86,961                    
Level 3 | Non-exchange-traded securities | Market approach | Price | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / shares     1         1        
Level 3 | Non-exchange-traded securities | Market approach | Price | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / shares     366         366        
Level 3 | Non-exchange-traded securities | Market approach | Price | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / shares     80         183        
Level 3 | Non-exchange-traded securities | Volatility benchmarking | Volatility | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.50         0.40      
Level 3 | Non-exchange-traded securities | Volatility benchmarking | Volatility | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.70         0.53      
Level 3 | Non-exchange-traded securities | Volatility benchmarking | Volatility | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.60         0.45      
Level 3 | Corporate debt securities                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value 20,813 11,803                    
Financial instruments sold, not yet purchased, at fair value 401 482                    
Level 3 | Corporate debt securities | Market approach                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value   11,803                    
Level 3 | Corporate debt securities | Market approach | Price                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / Bond         23              
Level 3 | Corporate debt securities | Market approach | Price | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / Bond                   13    
Level 3 | Corporate debt securities | Market approach | Price | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / Bond                   100    
Level 3 | Corporate debt securities | Market approach | Price | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / Bond                   86    
Level 3 | Corporate debt securities | Market approach | EBITDA multiple                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       3.3                
Level 3 | Corporate debt securities | Market approach and scenario analysis                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value 20,813                      
Level 3 | Corporate debt securities | Scenario analysis | Estimated recovery percentage                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.06                
Level 3 | CDOs and CLOs                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value 49,858 31,946                    
Level 3 | CDOs and CLOs | Market approach | Price | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / Bond         69         86    
Level 3 | CDOs and CLOs | Market approach | Price | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / Bond         102         103    
Level 3 | CDOs and CLOs | Market approach | Price | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / Bond         92         93    
Level 3 | CDOs and CLOs | Discounted cash flows and market approach                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value 49,858 31,944                    
Level 3 | CDOs and CLOs | Discounted cash flows | Constant prepayment rate                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.20         0.20      
Level 3 | CDOs and CLOs | Discounted cash flows | Constant default rate                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.02         0.02      
Level 3 | CDOs and CLOs | Discounted cash flows | Loss severity                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.70                
Level 3 | CDOs and CLOs | Discounted cash flows | Loss severity | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 0.25      
Level 3 | CDOs and CLOs | Discounted cash flows | Loss severity | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 0.30      
Level 3 | CDOs and CLOs | Discounted cash flows | Loss severity | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 0.26      
Level 3 | CDOs and CLOs | Discounted cash flows | Discount rate/yield | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.10         0.08      
Level 3 | CDOs and CLOs | Discounted cash flows | Discount rate/yield | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.22         0.19      
Level 3 | CDOs and CLOs | Discounted cash flows | Discount rate/yield | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.19         0.16      
Level 3 | Commercial mortgage-backed securities                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value 1,870 2,333                    
Financial instruments sold, not yet purchased, at fair value 385 210                    
Level 3 | Commercial mortgage-backed securities | Scenario analysis                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value 1,870 2,333                    
Level 3 | Commercial mortgage-backed securities | Scenario analysis | Estimated recovery percentage                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.81         0.81      
Level 3 | Other asset-backed securities                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value 84,778 93,524                    
Level 3 | Other asset-backed securities | Market approach | Price                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / Bond         37              
Level 3 | Other asset-backed securities | Market approach | Price | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / Bond                   37    
Level 3 | Other asset-backed securities | Market approach | Price | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / Bond                   100    
Level 3 | Other asset-backed securities | Market approach | Price | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / Bond                   94    
Level 3 | Other asset-backed securities | Discounted cash flows and market approach                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value $ 66,623 $ 86,099                    
Level 3 | Other asset-backed securities | Discounted cash flows | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input, term 9 months 18 days 8 months 12 days                    
Level 3 | Other asset-backed securities | Discounted cash flows | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input, term 1 year 7 months 6 days 1 year 4 months 24 days                    
Level 3 | Other asset-backed securities | Discounted cash flows | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input, term 1 year 3 months 18 days 1 year 1 month 6 days                    
Level 3 | Other asset-backed securities | Discounted cash flows | Constant prepayment rate | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 0      
Level 3 | Other asset-backed securities | Discounted cash flows | Constant prepayment rate | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 0.35      
Level 3 | Other asset-backed securities | Discounted cash flows | Constant prepayment rate | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 0.31      
Level 3 | Other asset-backed securities | Discounted cash flows | Constant default rate                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.02                
Level 3 | Other asset-backed securities | Discounted cash flows | Constant default rate | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 0.02      
Level 3 | Other asset-backed securities | Discounted cash flows | Constant default rate | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 0.04      
Level 3 | Other asset-backed securities | Discounted cash flows | Constant default rate | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 0.04      
Level 3 | Other asset-backed securities | Discounted cash flows | Loss severity                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.88                
Level 3 | Other asset-backed securities | Discounted cash flows | Loss severity | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 0.60      
Level 3 | Other asset-backed securities | Discounted cash flows | Loss severity | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 0.85      
Level 3 | Other asset-backed securities | Discounted cash flows | Loss severity | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 0.55      
Level 3 | Other asset-backed securities | Discounted cash flows | Discount rate/yield | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.05         0.03      
Level 3 | Other asset-backed securities | Discounted cash flows | Discount rate/yield | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.17         0.16      
Level 3 | Other asset-backed securities | Discounted cash flows | Discount rate/yield | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.12         0.10      
Level 3 | Other asset-backed securities | Discounted cash flows | Cumulative loss rate | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.05         0.07      
Level 3 | Other asset-backed securities | Discounted cash flows | Cumulative loss rate | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.21         0.20      
Level 3 | Other asset-backed securities | Discounted cash flows | Cumulative loss rate | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.17         0.14      
Level 3 | Loans and other receivables                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value $ 137,752 $ 135,239                    
Level 3 | Loans and other receivables | Market approach | Price | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / Bond         7         31    
Level 3 | Loans and other receivables | Market approach | Price | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / Bond         136         101    
Level 3 | Loans and other receivables | Market approach | Price | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / Bond         108         54    
Level 3 | Loans and other receivables | Market approach and scenario analysis                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value 137,752 134,015                    
Level 3 | Loans and other receivables | Scenario analysis | Estimated recovery percentage | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.05         0.09      
Level 3 | Loans and other receivables | Scenario analysis | Estimated recovery percentage | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.94         1      
Level 3 | Loans and other receivables | Scenario analysis | Estimated recovery percentage | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.35         0.76      
Level 3 | Equity options | Volatility benchmarking | Volatility                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Derivative asset, measurement input       0.53         0.46      
Level 3 | Equity options | Volatility benchmarking | Volatility | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Derivative liability, measurement input       0.29         0.26      
Level 3 | Equity options | Volatility benchmarking | Volatility | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Derivative liability, measurement input       0.63         0.77      
Level 3 | Equity options | Volatility benchmarking | Volatility | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Derivative liability, measurement input       0.49         0.40      
Level 3 | Interest rate swaps | Market approach | Basis points upfront | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Derivative asset, measurement input       2.8         0.1      
Derivative liability, measurement input       2.8         0.1      
Level 3 | Interest rate swaps | Market approach | Basis points upfront | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Derivative asset, measurement input       11.1         8.7      
Derivative liability, measurement input       11.1         8.7      
Level 3 | Interest rate swaps | Market approach | Basis points upfront | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Derivative asset, measurement input       6.7         3.3      
Derivative liability, measurement input       6.7         3.1      
Level 3 | Total return swaps | Market approach | Price                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Derivative asset, measurement input | $ / Bond                   100    
Derivative liability, measurement input | $ / Bond         99         100    
Level 3 | Private equity securities | Market approach | Price | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / shares     1         1        
Level 3 | Private equity securities | Market approach | Price | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / shares     15,852         152        
Level 3 | Private equity securities | Market approach | Price | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input | $ / shares     548         32        
Level 3 | Private equity securities | Market approach | EBITDA multiple                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       15.7         16.9      
Level 3 | Private equity securities | Market approach | Revenue multiple | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 4.9      
Level 3 | Private equity securities | Market approach | Revenue multiple | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 5.1      
Level 3 | Private equity securities | Market approach | Revenue multiple | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 5.0      
Level 3 | Private equity securities | Discounted cash flows | Discount rate/yield | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.10                
Level 3 | Private equity securities | Discounted cash flows | Discount rate/yield | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.14                
Level 3 | Private equity securities | Discounted cash flows | Discount rate/yield | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.12                
Level 3 | Private equity securities | Market approach and scenario analysis                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value   128,152                    
Level 3 | Private equity securities | Scenario analysis | Discount rate/yield                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input       0.12                
Level 3 | Private equity securities | Scenario analysis | Discount rate/yield | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 0.13      
Level 3 | Private equity securities | Scenario analysis | Discount rate/yield | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 0.21      
Level 3 | Private equity securities | Scenario analysis | Discount rate/yield | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 0.17      
Level 3 | Private equity securities | Scenario analysis | Estimated recovery percentage                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 0.07      
Level 3 | Private equity securities | Scenario analysis | Revenue growth                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instrument owned, measurement input                 0      
Level 3 | Private equity securities | Market approach, discounted cash flows and scenario analysis                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value 158,312                      
Level 3 | FXCM term loan | Discounted cash flows                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value $ 51,880 $ 50,455                    
Level 3 | FXCM term loan | Discounted cash flows | Measurement Input, Expected Term [Member] | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial Instruments Owned, Measurement Input, Expected Term 0 months 0 months                    
Level 3 | FXCM term loan | Discounted cash flows | Measurement Input, Expected Term [Member] | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial Instruments Owned, Measurement Input, Expected Term 1 year 8 months 12 days 2 years 2 months 12 days                    
Level 3 | FXCM term loan | Discounted cash flows | Measurement Input, Expected Term [Member] | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial Instruments Owned, Measurement Input, Expected Term 1 year 8 months 12 days 2 years 2 months 12 days                    
Level 3 | Non-exchange-traded warrants | Market approach                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Loans to and investments in associated companies $ 14,795 $ 30,842                    
Level 3 | Non-exchange-traded warrants | Market approach | Volatility | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Loans to and investments in associated companies, measurement input       0.25         0.25      
Level 3 | Non-exchange-traded warrants | Market approach | Volatility | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Loans to and investments in associated companies, measurement input       0.49         0.59      
Level 3 | Non-exchange-traded warrants | Market approach | Volatility | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Loans to and investments in associated companies, measurement input       0.30         0.31      
Level 3 | Non-exchange-traded warrants | Market approach | Underlying stock price                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Loans to and investments in associated companies, measurement input | $ / shares     723         662        
Level 3 | Non-exchange-traded warrants | Market approach | Underlying stock price | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Loans to and investments in associated companies, measurement input | € / shares           11         15  
Level 3 | Non-exchange-traded warrants | Market approach | Underlying stock price | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Loans to and investments in associated companies, measurement input | € / shares           14         18  
Level 3 | Non-exchange-traded warrants | Market approach | Underlying stock price | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Loans to and investments in associated companies, measurement input | € / shares           13         16  
Level 3 | Corporate equity securities                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments owned, at fair value 200,961 87,647                    
Financial instruments sold, not yet purchased, at fair value 3,749 4,635                    
Level 3 | Corporate equity securities | Market approach                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments sold, not yet purchased, at fair value 3,749 4,635                    
Level 3 | Corporate equity securities | Market approach | Price                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments sold, not yet purchased, measurement input | $ / shares     1         1        
Level 3 | Loans                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments sold, not yet purchased, at fair value 18,283 15,770                    
Level 3 | Loans | Market approach | Price                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments sold, not yet purchased, measurement input | $ / Bond         91              
Level 3 | Loans | Market approach | Price | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments sold, not yet purchased, measurement input | $ / Bond                   31    
Level 3 | Loans | Market approach | Price | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments sold, not yet purchased, measurement input | $ / Bond                   100    
Level 3 | Loans | Market approach | Price | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments sold, not yet purchased, measurement input | $ / Bond                   43    
Level 3 | Loans | Market approach and scenario analysis                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments sold, not yet purchased, at fair value 18,283 15,770                    
Level 3 | Loans | Scenario analysis | Estimated recovery percentage                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Financial instruments sold, not yet purchased, measurement input       0.05         0.50      
Level 3 | Other secured financings | Scenario analysis | Estimated recovery percentage | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Other secured financings, measurement input       0.13         0.13      
Level 3 | Other secured financings | Scenario analysis | Estimated recovery percentage | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Other secured financings, measurement input       0.36         0.98      
Level 3 | Other secured financings | Scenario analysis | Estimated recovery percentage | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Other secured financings, measurement input       0.29         0.92      
Level 3 | Structured notes | Market approach                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Long-term debt, fair value $ 739,353 $ 881,732                    
Level 3 | Structured notes | Market approach | Price | Minimum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Long-term debt, measurement input         52   60     76   81
Level 3 | Structured notes | Market approach | Price | Maximum                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Long-term debt, measurement input         108   102     115   113
Level 3 | Structured notes | Market approach | Price | Weighted Average                        
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]                        
Long-term debt, measurement input         75   80     94   103