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, 2020 USD ($)	Nov. 30, 2019 USD ($)	May 31, 2020 $ / shares	May 31, 2020 $ / Bond	May 31, 2020	May 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	$ 17,629,541	$ 16,308,807
Derivative assets	640,593	418,408
Financial instruments sold, not yet purchased, at fair value	9,646,023	10,532,460
Derivative liability	417,900	527,205
Long-term debt, fair value	1,245,486	1,215,285
Corporate debt securities
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	3,004,979	2,479,735
Financial instruments sold, not yet purchased, at fair value	1,491,252	1,471,482
CDOs and CLOs
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	100,299	153,013
Residential mortgage-backed securities
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	1,710,718	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	359,622	430,170
Financial instruments sold, not yet purchased, at fair value	140	35
Other asset-backed securities
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	378,220	346,410
Loans and other receivables
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	2,692,523	2,574,631
Corporate equity securities
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	2,724,291	2,783,993
Financial instruments sold, not yet purchased, at fair value	1,778,244	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	1,807,265	1,609,691
Level 3
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	617,987	554,618
Derivative assets	41,769	13,826
Financial instruments sold, not yet purchased, at fair value	103,422	106,382
Derivative liability	83,576	92,057
Long-term debt, fair value	497,040	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				78		63		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				94		109		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				84		85		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	75,712	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			94				55
Level 3 | Non-exchange-traded securities | Underlying stock price | Market approach
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 | 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			8
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			4
Level 3 | Corporate debt securities
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	25,178	7,490
Financial instruments sold, not yet purchased, at fair value	163	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 | 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 | 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 | 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	31,551	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					0.03				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					0.10
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					0.16
Level 3 | CDOs and CLOs | Constant default 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 | 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
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
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
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					0.30				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					0.14				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					0.32				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					0.22				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	$ 22,339	$ 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					0.15
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					0.03
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					0.33
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					0.11
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	2 years
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	6 years 1 month 6 days
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	5 years 7 months 6 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	$ 4,461	$ 6,110
Financial instruments sold, not yet purchased, at fair value	140	$ 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	$ 86,062	$ 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					0.05				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					0.09				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					0.31				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					0.14				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	4 months 24 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	2 years 9 months 18 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 4 months 24 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	$ 121,129	$ 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	67,207	$ 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				1				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				81				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					0.01				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					0.61				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 | 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					1				0
Derivative liability, measurement input					0				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					16				16
Derivative liability, measurement input					16				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					8				6
Derivative liability, measurement input					7				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				90				88
Level 3 | Equity options | Volatility | Volatility benchmarking
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Derivative asset, measurement input					0.49				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					0.33				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					0.62				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					0.47				0.43
Level 3 | Private equity securities
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial instruments owned, at fair value	92,194	$ 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			40				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					0.86
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	$ 53,765	$ 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 8 months 12 days	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 8 months 12 days	1 year 2 months 12 days
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	$ 76,140	$ 58,426
Financial instruments sold, not yet purchased, at fair value	4,190	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	10,674	9,463
Debt instrument, fair value	$ 10,674	$ 9,463
Level 3 | Loans | Price | Market approach | Minimum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Debt instrument, measurement input | $ / Bond				1				50
Level 3 | Loans | Price | Market approach | Maximum
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Debt instrument, measurement input | $ / Bond				50				100
Level 3 | Loans | Price | Market approach | Weighted Average
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Debt instrument, measurement input | $ / Bond				33				88
Level 3 | Loans | Estimated recovery percentage | Scenario analysis
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Debt instrument, measurement input					0.01				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