Fair Value Disclosures (Quantitative Information About Significant Unobservable Inputs Used in Level 3 Fair Value Measurements) (Details) $ in Thousands	9 Months Ended	12 Months Ended
	Aug. 31, 2020 USD ($)	Nov. 30, 2019 USD ($)	Aug. 31, 2020 $ / shares	Aug. 31, 2020 $ / Bond	Aug. 31, 2020	Aug. 31, 2020 € / shares	Aug. 31, 2020 € / Bond	Nov. 30, 2019 $ / shares	Nov. 30, 2019 $ / Bond	Nov. 30, 2019	Nov. 30, 2019 € / Bond	Nov. 30, 2019 gbpPerShare
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	$ 17,058,503	$ 16,308,807
Loans to and investments in associated companies	43,092
Derivative assets	529,684	418,408
Securities purchased under agreements to resell		25,000
Financial instruments sold, not yet purchased, at fair value	10,994,556	10,532,460
Derivative liability	483,335	527,205
Other secured financings	3,402
Long-term debt, fair value	1,522,105	1,215,285
Corporate debt securities
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	2,743,913	2,479,735
Financial instruments sold, not yet purchased, at fair value	1,448,706	1,471,482
CDOs and CLOs
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	104,409	153,013
Residential mortgage-backed securities
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	1,003,483	1,086,806
Commercial mortgage-backed securities
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	1,096,069	430,170
Financial instruments sold, not yet purchased, at fair value	35	35
Other asset-backed securities
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	112,071	346,410
Loans and other receivables
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	2,280,103	2,574,631
Corporate equity securities
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	2,735,919	2,783,993
Financial instruments sold, not yet purchased, at fair value	2,312,291	2,767,526
Loans
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments sold, not yet purchased, at fair value	1,478,707	1,609,691
Level 3
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	677,825	554,618
Loans to and investments in associated companies	34,688
Derivative assets	50,637	13,826
Securities purchased under agreements to resell		25,000
Financial instruments sold, not yet purchased, at fair value	125,764	106,382
Derivative liability	69,615	92,057
Other secured financings	3,402
Long-term debt, fair value	630,260	480,069
Level 3 | Price | Market approach | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Long-term debt, measurement input				77			69		84		74
Level 3 | Price | Market approach | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Long-term debt, measurement input				105			107		108		103
Level 3 | Price | Market approach | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Long-term debt, measurement input				99			91		96		91
Level 3 | Non-exchange-traded securities
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	77,442	29,017
Level 3 | Non-exchange-traded securities | Price | Market approach | 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 | Price | Market approach | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input | $ / shares			213					140
Level 3 | Non-exchange-traded securities | Price | Market approach | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input | $ / shares			84					55
Level 3 | Non-exchange-traded securities | EBITDA multiple | Market approach | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input | $ / shares			3
Level 3 | Non-exchange-traded securities | EBITDA multiple | Market approach | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input | $ / shares			4
Level 3 | Non-exchange-traded securities | EBITDA multiple | Market approach | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input | $ / shares			3
Level 3 | Non-exchange-traded securities | Underlying stock price | Market approach | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input | $ / shares								3
Level 3 | Non-exchange-traded securities | Underlying stock price | Market approach | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input | $ / shares								5
Level 3 | Non-exchange-traded securities | Underlying stock price | Market approach | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input | $ / shares								4
Level 3 | Corporate debt securities
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	23,269	7,490
Financial instruments sold, not yet purchased, at fair value	148	340
Level 3 | Corporate debt securities | Price | Market approach
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input | $ / Bond				69
Level 3 | Corporate debt securities | Estimated recovery percentage | Scenario analysis
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.22
Financial instruments sold, not yet purchased, measurement input					0.22
Level 3 | Corporate debt securities | Estimated recovery percentage | Scenario analysis | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input										0.23
Level 3 | Corporate debt securities | Estimated recovery percentage | Scenario analysis | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input										0.85
Level 3 | Corporate debt securities | Estimated recovery percentage | Scenario analysis | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input										0.46
Level 3 | Corporate debt securities | Volatility | Scenario analysis
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input										0.44
Level 3 | Corporate debt securities | Underlying stock price | Scenario analysis
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input | gbpPerShare												0.4
Level 3 | Corporate debt securities | Credit spread | Scenario analysis
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input										750
Level 3 | CDOs and CLOs
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	36,122	28,788
Level 3 | CDOs and CLOs | Estimated recovery percentage | Scenario analysis | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.02					0.0325
Level 3 | CDOs and CLOs | Estimated recovery percentage | Scenario analysis | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.35					0.365
Level 3 | CDOs and CLOs | Estimated recovery percentage | Scenario analysis | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.24					0.25
Level 3 | CDOs and CLOs | Constant prepayment rate | Discounted cash flows
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input										0.20
Level 3 | CDOs and CLOs | Constant prepayment rate | Discounted cash flows | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.02
Level 3 | CDOs and CLOs | Constant prepayment rate | Discounted cash flows | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.20
Level 3 | CDOs and CLOs | Constant prepayment rate | Discounted cash flows | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.19
Level 3 | CDOs and CLOs | Constant default rate | Discounted cash flows | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.01					0.01
Level 3 | CDOs and CLOs | Constant default rate | Discounted cash flows | Maximum
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 | Constant default rate | Discounted cash flows | Weighted Average
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 | Loss severity | Discounted cash flows | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.25					0.25
Level 3 | CDOs and CLOs | Loss severity | Discounted cash flows | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.50					0.37
Level 3 | CDOs and CLOs | Loss severity | Discounted cash flows | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.28					0.29
Level 3 | CDOs and CLOs | Discount rate/yield | Discounted cash flows | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.06					0.12
Level 3 | CDOs and CLOs | Discount rate/yield | Discounted cash flows | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.26					0.21
Level 3 | CDOs and CLOs | Discount rate/yield | Discounted cash flows | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.17					0.15
Level 3 | Residential mortgage-backed securities
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	$ 28,317	$ 17,740
Level 3 | Residential mortgage-backed securities | Discount rate/yield | Discounted cash flows
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input										0.03
Level 3 | Residential mortgage-backed securities | Discount rate/yield | Discounted cash flows | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.04
Level 3 | Residential mortgage-backed securities | Discount rate/yield | Discounted cash flows | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.14
Level 3 | Residential mortgage-backed securities | Discount rate/yield | Discounted cash flows | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.05
Level 3 | Residential mortgage-backed securities | Cumulative loss rate | Discounted cash flows
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input										0.02
Level 3 | Residential mortgage-backed securities | Cumulative loss rate | Discounted cash flows | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.02
Level 3 | Residential mortgage-backed securities | Cumulative loss rate | Discounted cash flows | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.32
Level 3 | Residential mortgage-backed securities | Cumulative loss rate | Discounted cash flows | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.05
Level 3 | Residential mortgage-backed securities | Duration (years) | Discounted cash flows
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input, term		6 years 3 months 18 days
Level 3 | Residential mortgage-backed securities | Duration (years) | Discounted cash flows | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input, term	1 year
Level 3 | Residential mortgage-backed securities | Duration (years) | Discounted cash flows | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input, term	13 years
Level 3 | Residential mortgage-backed securities | Duration (years) | Discounted cash flows | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input, term	9 years 8 months 12 days
Level 3 | Commercial mortgage-backed securities
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	$ 4,663	$ 6,110
Financial instruments sold, not yet purchased, at fair value	35	$ 35
Level 3 | Commercial mortgage-backed securities | Estimated recovery percentage | Scenario analysis
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.44					0.44
Level 3 | Commercial mortgage-backed securities | Discount rate/yield | Discounted cash flows
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input										0.85
Level 3 | Commercial mortgage-backed securities | Cumulative loss rate | Discounted cash flows
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input										0.073
Level 3 | Commercial mortgage-backed securities | Duration (years) | Discounted cash flows
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input, term		2 months 12 days
Level 3 | Other asset-backed securities
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	$ 63,337	$ 42,563
Level 3 | Other asset-backed securities | Price | Market approach
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 | Discount rate/yield | Discounted cash flows | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.04					0.07
Level 3 | Other asset-backed securities | Discount rate/yield | Discounted cash flows | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.15					0.15
Level 3 | Other asset-backed securities | Discount rate/yield | Discounted cash flows | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.10					0.11
Level 3 | Other asset-backed securities | Cumulative loss rate | Discounted cash flows | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.07					0.07
Level 3 | Other asset-backed securities | Cumulative loss rate | Discounted cash flows | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.72					0.31
Level 3 | Other asset-backed securities | Cumulative loss rate | Discounted cash flows | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.18					0.16
Level 3 | Other asset-backed securities | Duration (years) | Discounted cash flows | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input, term	3 months 18 days	6 months
Level 3 | Other asset-backed securities | Duration (years) | Discounted cash flows | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input, term	4 years 2 months 12 days	3 years
Level 3 | Other asset-backed securities | Duration (years) | 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 9 months 18 days	1 year 6 months
Level 3 | Loans and other receivables
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	$ 162,941	$ 114,080
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	104,212	$ 112,574
Level 3 | Loans and other receivables | Price | Market approach | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input | $ / Bond				6					36
Level 3 | Loans and other receivables | Price | Market approach | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input | $ / Bond				100					100
Level 3 | Loans and other receivables | Price | Market approach | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input | $ / Bond				76					90
Level 3 | Loans and other receivables | Estimated recovery percentage | Scenario analysis | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.02					0.87
Level 3 | Loans and other receivables | Estimated recovery percentage | Scenario analysis | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					1					1.04
Level 3 | Loans and other receivables | Estimated recovery percentage | Scenario analysis | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.62					0.99
Level 3 | Loans and other receivables | Term based on the pay off (years) | Discounted cash flows | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input, term		0 months
Level 3 | Loans and other receivables | Term based on the pay off (years) | Discounted cash flows | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input, term		1 month 6 days
Level 3 | Loans and other receivables | Term based on the pay off (years) | Discounted cash flows | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input, term		1 month 6 days
Level 3 | Total return swaps | Price | Market approach | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Derivative asset, measurement input					97
Level 3 | Total return swaps | Price | Market approach | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Derivative asset, measurement input					99
Level 3 | Total return swaps | Price | Market approach | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Derivative asset, measurement input					98
Level 3 | Equity options | Volatility | Volatility benchmarking
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Derivative asset, measurement input										0.45
Level 3 | Equity options | Volatility | Volatility benchmarking | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Derivative liability, measurement input					0.32					0.21
Level 3 | Equity options | Volatility | Volatility benchmarking | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Derivative liability, measurement input					0.46					0.61
Level 3 | Equity options | Volatility | Volatility benchmarking | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Derivative liability, measurement input					0.39					0.43
Level 3 | Interest rate swaps | Basis points upfront | Market approach | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Derivative asset, measurement input					3					0
Derivative liability, measurement input					3					0
Level 3 | Interest rate swaps | Basis points upfront | Market approach | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Derivative asset, measurement input					20					16
Derivative liability, measurement input					20					22
Level 3 | Interest rate swaps | Basis points upfront | Market approach | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Derivative asset, measurement input					9					6
Derivative liability, measurement input					9					13
Level 3 | Unfunded commitments | Price | Market approach
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Derivative asset, measurement input | $ / Bond									88
Derivative liability, measurement input | $ / Bond									88
Level 3 | Unfunded commitments | Price | Market approach | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Derivative liability, measurement input | $ / Bond				97
Level 3 | Unfunded commitments | Price | Market approach | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Derivative liability, measurement input | $ / Bond				99
Level 3 | Unfunded commitments | Price | Market approach | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Derivative liability, measurement input | $ / Bond				98
Level 3 | Private equity securities
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	76,654	$ 157,504
Level 3 | Private equity securities | Price | Market approach | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input | $ / shares			2					8
Level 3 | Private equity securities | Price | Market approach | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input | $ / shares			169					250
Level 3 | Private equity securities | Price | Market approach | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input | $ / shares			42					80
Level 3 | Private equity securities | Estimated recovery percentage | Scenario analysis
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.33
Level 3 | Private equity securities | Discount rate/yield | Scenario analysis | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.19					0.19
Level 3 | Private equity securities | Discount rate/yield | Scenario analysis | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.21					0.21
Level 3 | Private equity securities | Discount rate/yield | Scenario analysis | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0.20					0.20
Level 3 | Private equity securities | Revenue growth | Scenario analysis
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input					0					0
Level 3 | FXCM term loan
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	$ 56,542	$ 59,120
Level 3 | FXCM term loan | Term based on the pay off (years) | Discounted cash flows | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input, term	0 months	0 months
Level 3 | FXCM term loan | Term based on the pay off (years) | Discounted cash flows | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instrument owned, measurement input, term	1 year 6 months	1 year 2 months 12 days
Level 3 | FXCM term loan | Term based on the pay off (years) | 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 6 months	1 year 2 months 12 days
Level 3 | Non-exchange-traded warrants
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Loans to and investments in associated companies	$ 34,688
Level 3 | Non-exchange-traded warrants | Volatility | Market approach | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Loans to and investments in associated companies, measurement input					0.23
Level 3 | Non-exchange-traded warrants | Volatility | Market approach | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Loans to and investments in associated companies, measurement input					0.59
Level 3 | Non-exchange-traded warrants | Volatility | Market approach | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Loans to and investments in associated companies, measurement input					0.25
Level 3 | Non-exchange-traded warrants | Underlying stock price | Market approach
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Loans to and investments in associated companies, measurement input | $ / shares			506
Level 3 | Non-exchange-traded warrants | Underlying stock price | Market approach | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Loans to and investments in associated companies, measurement input | € / shares						15
Level 3 | Non-exchange-traded warrants | Underlying stock price | Market approach | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Loans to and investments in associated companies, measurement input | € / shares						18
Level 3 | Non-exchange-traded warrants | Underlying stock price | Market approach | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Loans to and investments in associated companies, measurement input | € / shares						17
Level 3 | Securities purchased under agreements to resell
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Securities purchased under agreements to resell		$ 25,000
Level 3 | Securities purchased under agreements to resell | Duration (years) | Market approach
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Securities purchased under agreements to resell, measurement input, term		1 year 6 months
Level 3 | Securities purchased under agreements to resell | Spread to 6 month LIBOR | Market approach
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Securities purchased under agreements to resell, measurement input										500
Level 3 | Corporate equity securities
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	77,941	$ 58,426
Financial instruments sold, not yet purchased, at fair value	4,367	4,487
Level 3 | Corporate equity securities | Transaction level | Market approach
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	$ 46,594	$ 9,463
Level 3 | Loans | Price | Market approach | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments sold, not yet purchased, measurement input | $ / Bond				31					50
Level 3 | Loans | Price | Market approach | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments sold, not yet purchased, measurement input | $ / Bond				97					100
Level 3 | Loans | Price | Market approach | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments sold, not yet purchased, measurement input | $ / Bond				70					88
Level 3 | Loans | Estimated recovery percentage | Scenario analysis
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments sold, not yet purchased, measurement input					0.02					0.01
Level 3 | Cross currency swaps | Basis points upfront | Market approach
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Derivative liability, measurement input										2
Level 3 | Other secured financings | Estimated recovery percentage | Scenario analysis | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Other secured financings, measurement input					0.60
Level 3 | Other secured financings | Estimated recovery percentage | Scenario analysis | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Other secured financings, measurement input					1
Level 3 | Other secured financings | Estimated recovery percentage | Scenario analysis | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Other secured financings, measurement input					0.79