Fair Value Disclosures - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Nov. 30, 2021	Nov. 30, 2020	Nov. 30, 2019
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	$ 38,300	$ 88,000	$ 58,400
Transfers of assets from Level 3 to Level 2	45,400	24,700	26,700
Transfers of liabilities from Level 2 to Level 3	74,300	1,900
Transfers of liabilities from Level 3 to Level 2	24,700	143,400
Net gains/(losses) on Level 3 assets (realized and unrealized)	35,200	(55,100)	(27,100)
Net gains (losses) on Level 3 liabilities (realized and unrealized)	(12,600)	(82,100)	44,500
Value of asset excluded from significant unobservable inputs	14,300	17,300
Value of liability excluded from significant unobservable inputs	(2,200)	(800)
Aggregate fair value of loans and other receivables on nonaccrual status and/or 90 days or greater past due	56,900	69,700
Loan and other receivables greater than 90 days past due	23,500	3,800
Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations	1,015,107	604,321
Loans and other receivables
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	17,200	10,900	27,400
Transfers of assets from Level 3 to Level 2		7,100	8,600
Net gains/(losses) on Level 3 assets (realized and unrealized)	(1,065)	(20,487)	(5,505)
Other ABS
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	10,200	23,000	12,100
Transfers of assets from Level 3 to Level 2		6,800	2,600
Net gains/(losses) on Level 3 assets (realized and unrealized)	5,335	(3,848)	433
CDOs and CLOs
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	7,600		3,000
Transfers of assets from Level 3 to Level 2			8,800
Net gains/(losses) on Level 3 assets (realized and unrealized)	7,264	(5,703)	(2,342)
Corporate debt securities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	3,300	18,000	8,900
Transfers of assets from Level 3 to Level 2	17,900	3,000
Net gains/(losses) on Level 3 assets (realized and unrealized)	1,565	83	(4,860)
Net gains (losses) on Level 3 liabilities (realized and unrealized)	(1,205)	268	381
RMBS
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 3 to Level 2	19,300
Net gains/(losses) on Level 3 assets (realized and unrealized)	(243)	(934)	(1,669)
Corporate equity securities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3		32,500
Transfers of assets from Level 3 to Level 2	5,400	5,100	6,000
Net gains/(losses) on Level 3 assets (realized and unrealized)	31,273	(3,961)	(10,380)
Net gains (losses) on Level 3 liabilities (realized and unrealized)	83	(456)	2,649
Structured notes
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of liabilities from Level 2 to Level 3	57,900		22,600
Transfers of liabilities from Level 3 to Level 2		80,600	61,700
Net derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of liabilities from Level 2 to Level 3	16,200		57,200
Transfers of liabilities from Level 3 to Level 2	24,700	60,800	14,300
Net gains (losses) on Level 3 liabilities (realized and unrealized)	(7,246)	40	21,452
Loans
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of liabilities from Level 2 to Level 3		1,800
Net gains (losses) on Level 3 liabilities (realized and unrealized)	(1,826)	520	1,382
CMBS
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3			5,600
Net gains/(losses) on Level 3 assets (realized and unrealized)	(1,694)	(827)	(2,888)
Net gains (losses) on Level 3 liabilities (realized and unrealized)	0	0	$ (35)
US Treasury securities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations	$ 0	$ 34,200