Fair Value Disclosures - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	May 31, 2016	May 31, 2015	May 31, 2016	May 31, 2015	Nov. 30, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments at fair value	$ 30,300		$ 30,300		$ 36,700
Transfers of assets from Level 2 to Level 3	107,100	$ 98,400	155,900	$ 155,000
Transfers of assets from Level 3 to Level 2	62,700	96,400	92,900	87,000
Transfers of liabilities from Level 3 to Level 2				3,000
Net gains/(losses) on Level 3 assets (realized and unrealized)	(21,400)	2,400	(51,900)	(17,300)
Net gains/(losses) on Level 3 liabilities (realized and unrealized)	300	5,000	(9,500)	(1,900)
Unadjusted net asset value of the funds	97,000		97,000		156,200
Unadjusted net liability value of the funds	500		500		600
Aggregate fair value of loans and other receivables	23,300		23,300		11,300
Loan and other receivables on nonaccrual status	51,800		51,800		$ 307,500
Long-term Debt [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Other changes in fair value	3,489	0	10,305	0
Long-term Debt [Member] | Principal Transactions Revenue [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Other changes in fair value	3,900		10,700
Long-term Debt [Member] | Interest Expense [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Other changes in fair value	400		400
Collateralized debt obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3		48,000	30,600	27,300
Transfers of assets from Level 3 to Level 2		54,400	22,300	52,300
Net gains/(losses) on Level 3 assets (realized and unrealized)	1,797	(5,120)	(20,455)	(17,229)
Residential mortgage-backed securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	19,300	30,000	21,700	20,300
Transfers of assets from Level 3 to Level 2	19,500	23,000	16,700	15,100
Net gains/(losses) on Level 3 assets (realized and unrealized)	(4,915)	(1,820)	(8,337)	(3,735)
Investments at fair value [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3			26,100	69,200
Transfers of assets from Level 3 to Level 2			16,100
Net gains/(losses) on Level 3 assets (realized and unrealized)	(1,574)	3,380	(6,090)	4,615
Other asset-backed securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	30,700	2,100	28,000	2,100
Transfers of assets from Level 3 to Level 2	16,000	5,400
Net gains/(losses) on Level 3 assets (realized and unrealized)	(7,284)	(19)	(202)	(258)
Corporate equity securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	22,000	1,400		1,600
Transfers of assets from Level 3 to Level 2		7,000		10,300
Net gains/(losses) on Level 3 assets (realized and unrealized)	(927)	8,030	1,571	7,066
Commercial mortgage-backed securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3		7,700		10,200
Transfers of assets from Level 3 to Level 2		5,500		3,500
Net gains/(losses) on Level 3 assets (realized and unrealized)	(1,140)	(789)	(2,589)	(1,124)
Loans and other receivables [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3	15,900	1,000	20,200	13,900
Transfers of assets from Level 3 to Level 2			16,800	5,300
Net gains/(losses) on Level 3 assets (realized and unrealized)	(7,792)	(748)	(13,376)	(5,795)
Corporate debt securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers of assets from Level 2 to Level 3		8,200		10,400
Net gains/(losses) on Level 3 assets (realized and unrealized)	$ 474	$ (532)	$ (2,378)	$ (796)
3.875% Convertible Senior Debentures due 2029 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt instrument interest rate	3.875%		3.875%
3.875% Convertible Senior Debentures due 2029 [Member] | Leucadia [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Debt instrument interest rate	3.875%		3.875%
Long-term debt embedded conversion option [Member] | Leucadia [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Volatility curve used in valuing embedded option			252 days