Fair Value Disclosures - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Feb. 28, 2021	Feb. 29, 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	$ 75,800	$ 85,300
Transfers of assets from Level 3 to Level 2	44,700	16,800
Transfers of liabilities from Level 2 to Level 3	236,700	102,500
Transfers of liabilities from Level 3 to Level 2	13,300	107,400
Net gains/(losses) on Level 3 assets (realized and unrealized)	12,700	(37,900)
Net gains/(losses) on Level 3 liabilities (realized and unrealized)	(72,100)	26,400
Value of asset excluded from significant unobservable inputs	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	5,400		69,700
Loans and other receivables greater than 90 days past due	4,100		3,800
Cash and securities segregated and on deposit for regulatory purposes with clearing and depository organizations	615,115		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	42,900	6,000
Transfers of assets from Level 3 to Level 2	6,800	4,900
Net gains/(losses) on Level 3 assets (realized and unrealized)	1,642	(3,781)
CDOs and CLOs
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	14,600
Net gains/(losses) on Level 3 assets (realized and unrealized)	3,840	(2,069)
Corporate equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	9,900	55,400
Transfers of assets from Level 3 to Level 2		2,700
Net gains/(losses) on Level 3 assets (realized and unrealized)	1,309	(8,195)
Net gains/(losses) on Level 3 liabilities (realized and unrealized)	(9)	(291)
Other ABS
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	7,500
Transfers of assets from Level 3 to Level 2	14,500	6,300
Net gains/(losses) on Level 3 assets (realized and unrealized)	2,361	(4,159)
Corporate debt securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3		16,500
Transfers of assets from Level 3 to Level 2	17,500
Net gains/(losses) on Level 3 assets (realized and unrealized)	266	1,269
Net gains/(losses) on Level 3 liabilities (realized and unrealized)	(1,430)	189
Net derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of liabilities from Level 2 to Level 3	236,500	83,000
Transfers of liabilities from Level 3 to Level 2	13,300	37,300
Net gains/(losses) on Level 3 liabilities (realized and unrealized)	(43,727)	17,528
Structured notes
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of liabilities from Level 2 to Level 3		13,100
Transfers of liabilities from Level 3 to Level 2		$ 69,100
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	$ 118,500		$ 34,200