Fair Value Disclosures - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	May 31, 2021	May 31, 2020	May 31, 2021	May 31, 2020	Nov. 30, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	$ 57,800	$ 127,500	$ 99,700	$ 148,500
Transfers of assets from Level 3 to Level 2	21,800	33,700	46,100	14,600
Transfers of liabilities from Level 2 to Level 3	78,100	23,700	162,900	37,000
Transfers of liabilities from Level 3 to Level 2	154,700	98,600	17,300	98,500
Net gains/(losses) on Level 3 assets (realized and unrealized)	21,800	(39,500)	35,300	(69,800)
Net gains/(losses) on Level 3 liabilities (realized and unrealized)	(7,000)	124,300	(60,700)	144,700
Value of asset excluded from significant unobservable inputs	2,500		2,500		$ 17,300
Value of liability excluded from significant unobservable inputs					800
Aggregate fair value of loans and other receivables on nonaccrual status and/or 90 days or greater past due	67,400		67,400		69,700
Loans and other receivables greater than 90 days past due	26,200		26,200		3,800
Cash and securities segregated and on deposit for regulatory purposes with clearing and depository organizations	901,381		901,381		604,321
Loans and other receivables
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	20,900	20,700	58,300	33,500
Transfers of assets from Level 3 to Level 2			6,700	4,000
Transfers of liabilities from Level 2 to Level 3				10,800
Net gains/(losses) on Level 3 assets (realized and unrealized)	1,981	(4,891)	4,312	(8,600)
CDOs and CLOs
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	20,100	29,600	18,200	22,900
Transfers of assets from Level 3 to Level 2		4,400
Net gains/(losses) on Level 3 assets (realized and unrealized)	6,557	(12,879)	9,695	(14,223)
Corporate equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3			11,000	37,000
Transfers of assets from Level 3 to Level 2		26,200		7,300
Net gains/(losses) on Level 3 assets (realized and unrealized)	12,057	(5,319)	14,329	(12,860)
Net gains/(losses) on Level 3 liabilities (realized and unrealized)	(42)	60	(64)	(216)
Residential mortgage-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 3 to Level 2	15,300		14,700
Net gains/(losses) on Level 3 assets (realized and unrealized)	205	(1,773)	33	(2,248)
Other ABS
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	13,500	44,500	10,500	31,100
Transfers of assets from Level 3 to Level 2	4,400		6,700
Net gains/(losses) on Level 3 assets (realized and unrealized)	3,575	(2,380)	6,373	(2,848)
Corporate debt securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3				18,300
Transfers of assets from Level 3 to Level 2			17,500
Net gains/(losses) on Level 3 assets (realized and unrealized)	1,292	(1,480)	2,466	1,560
Net gains/(losses) on Level 3 liabilities (realized and unrealized)	22	23	(1,349)	27
Net derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of liabilities from Level 2 to Level 3	50,500	11,400	134,800	26,200
Transfers of liabilities from Level 3 to Level 2	154,200	66,100	17,300	40,200
Net gains/(losses) on Level 3 liabilities (realized and unrealized)	8,965	32,744	(16,813)	44,729
Structured notes
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of liabilities from Level 2 to Level 3	27,400	11,100	27,700
Transfers of liabilities from Level 3 to Level 2		31,900		57,300
US treasury securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash and securities segregated and on deposit for regulatory purposes with clearing and depository organizations	58,000		58,000		$ 34,200
Investments at fair value
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3		19,200
Net gains/(losses) on Level 3 assets (realized and unrealized)	$ (4,037)	$ (10,805)	$ (2,098)	$ (30,496)