Fair Value Disclosures - Quantitative Information about Significant Unobservable Inputs Used in Level 3 Fair Value Measurements (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Feb. 29, 2020 $ / shares	Nov. 30, 2019 $ / shares	Feb. 29, 2020 € / shares	Feb. 29, 2020	Feb. 29, 2020 USD ($)	Nov. 30, 2019 € / shares	Nov. 30, 2019	Nov. 30, 2019 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, excluding Investments at fair value based on NAV					$ 17,007,249			$ 15,793,064
Securities purchased under agreements to resell								25,000
Financial instruments sold, not yet purchased, at fair value ($4,240 and $0 at February 29, 2020 and November 30, 2019, respectively, related to consolidated VIEs)					9,877,182			10,532,460
Long-term debt					1,354,714			1,215,285
Value of asset excluded from significant unobservable inputs					54,000			31,900
Value of liability excluded from significant unobservable inputs					3,600			400
Corporate debt securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, excluding Investments at fair value based on NAV					2,866,112			2,479,703
Financial instruments sold, not yet purchased, at fair value ($4,240 and $0 at February 29, 2020 and November 30, 2019, respectively, related to consolidated VIEs)					1,773,257			1,471,482
Corporate debt securities | Scenario analysis | Volatility
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input							0.44
CDOs and CLOs
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, excluding Investments at fair value based on NAV					118,277			144,306
RMBS
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, excluding Investments at fair value based on NAV					1,097,665			1,086,806
CMBS
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, excluding Investments at fair value based on NAV					445,933			430,170
Financial instruments sold, not yet purchased, at fair value ($4,240 and $0 at February 29, 2020 and November 30, 2019, respectively, related to consolidated VIEs)					35			35
Other ABS
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, excluding Investments at fair value based on NAV					301,912			346,410
Loans and other receivables
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, excluding Investments at fair value based on NAV					2,705,430			2,459,451
Corporate equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, excluding Investments at fair value based on NAV					3,604,461			2,601,820
Financial instruments sold, not yet purchased, at fair value ($4,240 and $0 at February 29, 2020 and November 30, 2019, respectively, related to consolidated VIEs)					2,132,054			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 ($4,240 and $0 at February 29, 2020 and November 30, 2019, respectively, related to consolidated VIEs)					1,820,886			1,609,691
Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, excluding Investments at fair value based on NAV					345,657			307,152
Derivative assets								13,826
Securities purchased under agreements to resell								25,000
Financial instruments sold, not yet purchased, at fair value ($4,240 and $0 at February 29, 2020 and November 30, 2019, respectively, related to consolidated VIEs)					147,023			106,382
Derivative liability					134,087			92,057
Long-term debt					543,463			480,069
Level 3 | Non-exchange-traded securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, excluding Investments at fair value based on NAV					78,543			29,017
Level 3 | Non-exchange-traded securities | Market approach | Price | Minimum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments 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 instruments owned, measurement input | $ / shares	213	140
Level 3 | Non-exchange-traded securities | Market approach | Price | Weighted Average
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input | $ / shares	105	55
Level 3 | Non-exchange-traded securities | Market approach | Underlying stock price | Minimum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input | $ / shares	3	3
Level 3 | Non-exchange-traded securities | Market approach | Underlying stock price | Maximum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input | $ / shares	5	5
Level 3 | Non-exchange-traded securities | Market approach | Underlying stock price | Weighted Average
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input | $ / shares	4	4
Level 3 | Corporate debt securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, excluding Investments at fair value based on NAV					25,090			7,490
Financial instruments sold, not yet purchased, at fair value ($4,240 and $0 at February 29, 2020 and November 30, 2019, respectively, related to consolidated VIEs)					767			340
Level 3 | Corporate debt securities | Scenario analysis | Underlying stock price
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input | $ / shares		0.4
Level 3 | Corporate debt securities | Scenario analysis | Estimated recovery percentage | Minimum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input				0.22			0.23
Level 3 | Corporate debt securities | Scenario analysis | Estimated recovery percentage | Maximum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input				0.85			0.85
Level 3 | Corporate debt securities | Scenario analysis | Estimated recovery percentage | Weighted Average
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input				0.41			0.46
Level 3 | Corporate debt securities | Scenario analysis | Credit Spread
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input							750
Level 3 | Corporate debt securities | Market approach | Price | Minimum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input | € / shares			69
Level 3 | Corporate debt securities | Market approach | Price | Maximum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input | € / shares			78
Level 3 | Corporate debt securities | Market approach | Price | Weighted Average
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input | $ / shares	69
Level 3 | CDOs and CLOs
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, excluding Investments at fair value based on NAV					20,952			20,081
Level 3 | CDOs and CLOs | Discounted cash flows | Constant prepayment rate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input				0.20			0.20
Level 3 | CDOs and CLOs | Discounted cash flows | Constant default rate | Minimum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input				0.01			0.01
Level 3 | CDOs and CLOs | Discounted cash flows | Constant default rate | Maximum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input				0.02			0.02
Level 3 | CDOs and CLOs | Discounted cash flows | Constant default rate | Weighted Average
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input				0.02			0.02
Level 3 | CDOs and CLOs | Discounted cash flows | Loss severity | Minimum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input				0.25			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 instruments owned, measurement input				0.70			0.37
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 instruments owned, measurement input				0.28			0.29
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 instruments owned, measurement input				0.13			0.12
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 instruments owned, measurement input				0.30			0.21
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 instruments owned, measurement input				0.17			0.15
Level 3 | RMBS
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, excluding Investments at fair value based on NAV					16,970			17,740
Level 3 | RMBS | Discounted cash flows
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input							0.03
Financial instruments owned, measurement input, term	6 years	6 years 3 months 18 days
Level 3 | RMBS | Discounted cash flows | Discount rate/yield
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input				0.03
Level 3 | RMBS | Discounted cash flows | Cumulative loss rate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input				0.02			0.02
Level 3 | CMBS
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, excluding Investments at fair value based on NAV					4,264			6,110
Financial instruments sold, not yet purchased, at fair value ($4,240 and $0 at February 29, 2020 and November 30, 2019, respectively, related to consolidated VIEs)					35			35
Level 3 | CMBS | Discounted cash flows
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input							0.85
Financial instruments owned, measurement input, term		2 months 12 days
Level 3 | CMBS | Discounted cash flows | Cumulative loss rate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input							0.073
Level 3 | CMBS | Scenario analysis | Estimated recovery percentage
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input				0.44			0.44
Level 3 | Other ABS
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, excluding Investments at fair value based on NAV					41,903			42,563
Level 3 | Other ABS | Discounted cash flows | Minimum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input, term	6 months	6 months
Level 3 | Other ABS | Discounted cash flows | Maximum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input, term	2 years 9 months 18 days	3 years
Level 3 | Other ABS | Discounted cash flows | Weighted Average
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input, term	1 year 7 months 6 days	1 year 6 months
Level 3 | Other ABS | Discounted cash flows | Discount rate/yield | Minimum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input				0.07			0.07
Level 3 | Other ABS | Discounted cash flows | Discount rate/yield | Maximum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input				0.14			0.15
Level 3 | Other ABS | Discounted cash flows | Discount rate/yield | Weighted Average
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input				0.11			0.11
Level 3 | Other ABS | Discounted cash flows | Cumulative loss rate | Minimum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input				0.07			0.07
Level 3 | Other ABS | Discounted cash flows | Cumulative loss rate | Maximum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input				0.31			0.31
Level 3 | Other ABS | Discounted cash flows | Cumulative loss rate | Weighted Average
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input				0.14			0.16
Level 3 | Other ABS | Market approach | Price
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input | $ / shares	100
Level 3 | Loans and other receivables
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, excluding Investments at fair value based on NAV					54,321			64,240
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, excluding Investments at fair value based on NAV					52,815			62,734
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 instruments owned, measurement input				0.63			0.87
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 instruments owned, measurement input				1			1.04
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 instruments owned, measurement input				0.79			0.99
Level 3 | Loans and other receivables | Market approach | Price | Minimum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input | $ / shares	29	36
Level 3 | Loans and other receivables | Market approach | Price | Maximum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input | $ / shares	101	100
Level 3 | Loans and other receivables | Market approach | Price | Weighted Average
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input | $ / shares	89	90
Level 3 | Interest rate swaps
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative assets					22,216
Level 3 | Interest rate swaps | Market approach | Basis points upfront
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative asset, measurement input							0
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				0
Derivative liability, measurement input				0			0
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				12			16
Derivative liability, measurement input				18			22
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			6
Derivative liability, measurement input				9			13
Level 3 | Equity options | Volatility benchmarking | Volatility
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative liability, measurement input							0.45
Level 3 | Equity options | Volatility benchmarking | Volatility | Minimum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative liability, measurement input				0.21			0.21
Level 3 | Equity options | Volatility benchmarking | Volatility | Maximum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative liability, measurement input				0.60			0.61
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				0.42			0.43
Level 3 | Cross currency swaps | Market approach | Basis points upfront
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative liability, measurement input				2			2
Level 3 | Unfunded commitments | Market approach | Price
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input | $ / shares		88
Derivative liability, measurement input | $ / shares	83	88
Level 3 | Private equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, excluding Investments at fair value based on NAV					28,927			75,736
Level 3 | Private equity securities | Market approach | Price | Minimum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input | $ / shares	8	8
Level 3 | Private equity securities | Market approach | Price | Maximum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input | $ / shares	168	250
Level 3 | Private equity securities | Market approach | Price | Weighted Average
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments owned, measurement input | $ / shares	132	125
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 | 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 | Market approach | Spread to 6 month LIBOR
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, excluding Investments at fair value based on NAV					103,643			58,301
Financial instruments sold, not yet purchased, at fair value ($4,240 and $0 at February 29, 2020 and November 30, 2019, respectively, related to consolidated VIEs)					4,275			4,487
Level 3 | Corporate equity securities | Market approach | Transaction level
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt instrument, measurement input | $ / shares		1
Financial instruments sold, not yet purchased, measurement input | $ / shares	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 ($4,240 and $0 at February 29, 2020 and November 30, 2019, respectively, related to consolidated VIEs)					7,859			9,463
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 ($4,240 and $0 at February 29, 2020 and November 30, 2019, respectively, related to consolidated VIEs)					5,074
Level 3 | Loans | Scenario analysis | Estimated recovery percentage
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt instrument, measurement input				0.63			0.01
Level 3 | Loans | Market approach | Price
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt instrument, measurement input | $ / shares	50
Level 3 | Loans | Market approach | Price | Minimum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt instrument, measurement input | $ / shares		50
Level 3 | Loans | Market approach | Price | Maximum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt instrument, measurement input | $ / shares		100
Level 3 | Loans | Market approach | Price | Weighted Average
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt instrument, measurement input | $ / shares		88
Level 3 | Long-term debt
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instruments sold, not yet purchased, at fair value ($4,240 and $0 at February 29, 2020 and November 30, 2019, respectively, related to consolidated VIEs)								$ 480,069
Long-term debt					$ 543,463
Level 3 | Long-term debt | Market approach | Price | Minimum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Long-term debt, measurement input	90	84	72			74
Level 3 | Long-term debt | Market approach | Price | Maximum
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Long-term debt, measurement input	102	108	105			103
Level 3 | Long-term debt | Market approach | Price | Weighted Average
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Long-term debt, measurement input	94	96	91			91