Fair Value Disclosures - Financial Assets and Liabilities Accounted for at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Nov. 30, 2019	Nov. 30, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Alternative investment	$ 570,310	$ 322,909
Financial instruments owned:
Financial instruments owned, at fair value	16,363,374	16,399,526
Derivatives	397,551	130,610
Total financial instruments owned, excluding Investments at fair value based on NAV	15,793,064	16,076,617
Counterparty and Cash Collateral Netting	(1,432,806)	(2,412,486)
Securities purchased under agreements to resell	25,000
Securities received as collateral	9,500	0
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	10,532,460	9,478,944
Derivatives	527,205	1,127,651
Counterparty and Cash Collateral Netting	(1,631,787)	(2,511,605)
Short-term borrowings	20,981	0
Obligation to return securities received as collateral	9,500	0
Long-term debt	1,215,285	686,170
Corporate equity securities
Financial instruments owned:
Financial instruments owned, at fair value	2,601,820	2,077,666
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	2,767,526	1,686,515
Corporate debt securities
Financial instruments owned:
Financial instruments owned, at fair value	2,479,703	2,692,664
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	1,471,482	1,506,140
Collateralized debt obligations and collateralized loan obligations
Financial instruments owned:
Financial instruments owned, at fair value	144,306	98,764
U.S. government and federal agency securities
Financial instruments owned:
Financial instruments owned, at fair value	2,260,242	1,846,206
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	1,851,981	1,384,295
Municipal securities
Financial instruments owned:
Financial instruments owned, at fair value	742,326	894,253
Sovereign obligations
Financial instruments owned:
Financial instruments owned, at fair value	2,735,853	2,812,965
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	2,304,540	2,396,337
Residential mortgage-backed securities
Financial instruments owned:
Financial instruments owned, at fair value	1,086,806	2,183,232
Commercial mortgage-backed securities
Financial instruments owned:
Financial instruments owned, at fair value	430,170	830,292
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	35
Other asset-backed securities
Financial instruments owned:
Financial instruments owned, at fair value	346,410	292,556
Loans and other receivables
Financial instruments owned:
Financial instruments owned, at fair value	2,459,451	2,103,578
Investments at fair value
Financial instruments owned:
Investments at fair value	108,426	113,831
Loans
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	1,609,691	1,378,006
Fair value based on net asset value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Alternative investment	570,300	322,900
Level 1
Financial instruments owned:
Derivatives	2,809	12,186
Total financial instruments owned, excluding Investments at fair value based on NAV	5,759,575	5,479,301
Securities purchased under agreements to resell	0
Securities received as collateral	9,500
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	5,971,928	4,831,079
Derivatives	871	26,471
Short-term borrowings	0
Obligation to return securities received as collateral	9,500
Long-term debt	0	0
Level 1 | Corporate equity securities
Financial instruments owned:
Financial instruments owned, at fair value	2,325,116	1,907,945
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	2,755,601	1,685,071
Level 1 | Corporate debt securities
Financial instruments owned:
Financial instruments owned, at fair value	0	0
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	0	0
Level 1 | Collateralized debt obligations and collateralized loan obligations
Financial instruments owned:
Financial instruments owned, at fair value	0	0
Level 1 | U.S. government and federal agency securities
Financial instruments owned:
Financial instruments owned, at fair value	2,101,624	1,789,614
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	1,851,981	1,384,295
Level 1 | Municipal securities
Financial instruments owned:
Financial instruments owned, at fair value	0	0
Level 1 | Sovereign obligations
Financial instruments owned:
Financial instruments owned, at fair value	1,330,026	1,769,556
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	1,363,475	1,735,242
Level 1 | Residential mortgage-backed securities
Financial instruments owned:
Financial instruments owned, at fair value	0	0
Level 1 | Commercial mortgage-backed securities
Financial instruments owned:
Financial instruments owned, at fair value	0	0
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	0
Level 1 | Other asset-backed securities
Financial instruments owned:
Financial instruments owned, at fair value	0	0
Level 1 | Loans and other receivables
Financial instruments owned:
Financial instruments owned, at fair value	0	0
Level 1 | Investments at fair value
Financial instruments owned:
Investments at fair value	0	0
Level 1 | Loans
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	0	0
Level 2
Financial instruments owned:
Derivatives	1,812,659	2,524,988
Total financial instruments owned, excluding Investments at fair value based on NAV	11,159,143	12,673,061
Securities purchased under agreements to resell	0
Securities received as collateral	0
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	6,085,937	7,125,036
Derivatives	2,066,064	3,585,249
Short-term borrowings	20,981
Obligation to return securities received as collateral	0
Long-term debt	735,216	485,425
Level 2 | Corporate equity securities
Financial instruments owned:
Financial instruments owned, at fair value	218,403	118,681
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	7,438	1,444
Level 2 | Corporate debt securities
Financial instruments owned:
Financial instruments owned, at fair value	2,472,213	2,683,180
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	1,471,142	1,505,618
Level 2 | Collateralized debt obligations and collateralized loan obligations
Financial instruments owned:
Financial instruments owned, at fair value	124,225	72,949
Level 2 | U.S. government and federal agency securities
Financial instruments owned:
Financial instruments owned, at fair value	158,618	56,592
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	0	0
Level 2 | Municipal securities
Financial instruments owned:
Financial instruments owned, at fair value	742,326	894,253
Level 2 | Sovereign obligations
Financial instruments owned:
Financial instruments owned, at fair value	1,405,827	1,043,409
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	941,065	661,095
Level 2 | Residential mortgage-backed securities
Financial instruments owned:
Financial instruments owned, at fair value	1,069,066	2,163,629
Level 2 | Commercial mortgage-backed securities
Financial instruments owned:
Financial instruments owned, at fair value	424,060	819,406
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	0
Level 2 | Other asset-backed securities
Financial instruments owned:
Financial instruments owned, at fair value	303,847	239,381
Level 2 | Loans and other receivables
Financial instruments owned:
Financial instruments owned, at fair value	2,395,211	2,056,593
Level 2 | Investments at fair value
Financial instruments owned:
Investments at fair value	32,688	0
Level 2 | Loans
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	1,600,228	1,371,630
Level 3
Financial instruments owned:
Derivatives	14,889	5,922
Total financial instruments owned, excluding Investments at fair value based on NAV	307,152	336,741
Securities purchased under agreements to resell	25,000
Securities received as collateral	0
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	106,382	34,434
Derivatives	92,057	27,536
Short-term borrowings	0
Obligation to return securities received as collateral	0
Long-term debt	480,069	200,745
Level 3 | Corporate equity securities
Financial instruments owned:
Financial instruments owned, at fair value	58,301	51,040
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	4,487	0
Level 3 | Corporate debt securities
Financial instruments owned:
Financial instruments owned, at fair value	7,490	9,484
Total financial instruments owned, excluding Investments at fair value based on NAV	7,490	9,484
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	340	522
Level 3 | Collateralized debt obligations and collateralized loan obligations
Financial instruments owned:
Financial instruments owned, at fair value	20,081	25,815
Total financial instruments owned, excluding Investments at fair value based on NAV	20,081	25,815
Level 3 | U.S. government and federal agency securities
Financial instruments owned:
Financial instruments owned, at fair value	0	0
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	0	0
Level 3 | Municipal securities
Financial instruments owned:
Financial instruments owned, at fair value	0	0
Level 3 | Sovereign obligations
Financial instruments owned:
Financial instruments owned, at fair value	0	0
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	0	0
Level 3 | Residential mortgage-backed securities
Financial instruments owned:
Financial instruments owned, at fair value	17,740	19,603
Total financial instruments owned, excluding Investments at fair value based on NAV	17,740	19,603
Level 3 | Commercial mortgage-backed securities
Financial instruments owned:
Financial instruments owned, at fair value	6,110	10,886
Total financial instruments owned, excluding Investments at fair value based on NAV	6,110	9,444
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	35
Level 3 | Other asset-backed securities
Financial instruments owned:
Financial instruments owned, at fair value	42,563	53,175
Total financial instruments owned, excluding Investments at fair value based on NAV	42,563	53,175
Level 3 | Loans and other receivables
Financial instruments owned:
Financial instruments owned, at fair value	64,240	46,985
Total financial instruments owned, excluding Investments at fair value based on NAV	62,734	46,078
Level 3 | Investments at fair value
Financial instruments owned:
Investments at fair value	75,738	113,831
Total financial instruments owned, excluding Investments at fair value based on NAV	75,736	113,831
Level 3 | Loans
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	$ 9,463	$ 6,376