Fair Value Disclosures - Financial Assets and Liabilities Accounted for at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Nov. 30, 2020	Nov. 30, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Alternative investment	$ 955,984	$ 570,310
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	16,730,068	15,793,064
Counterparty and cash collateral netting	(1,556,136)	(1,432,806)
Securities purchased under agreements to resell		25,000
Securities received as collateral	7,517	9,500
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	10,017,522	10,532,460
Counterparty and Cash Collateral Netting	(1,798,659)	(1,631,787)
Short-term borrowings	5,067	20,981
Other secured financings	1,543
Obligation to return securities received as collateral	7,517	9,500
Long-term debt	1,712,245	1,215,285
Corporate equity securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	2,465,396	2,601,820
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	2,059,921	2,767,526
Corporate debt securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	2,977,347	2,479,703
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	1,237,772	1,471,482
Collateralized debt obligations and collateralized loan obligations
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	74,668	144,306
U.S. government and federal agency securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	2,931,678	2,260,242
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	2,609,660	1,851,981
Municipal securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	453,881	742,326
Sovereign obligations
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	2,553,688	2,735,853
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	1,675,511	2,304,540
Residential mortgage-backed securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	1,122,675	1,086,806
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	477
Commercial mortgage-backed securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	738,294	430,170
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	35	35
Other asset-backed securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	183,606	346,410
Loans and other receivables
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	2,687,788	2,459,451
Loans
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	1,793,081	1,609,691
Derivative, assets
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	467,817	397,551
Derivatives, liabilities
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	641,065	527,205
Investments at fair value
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	73,230	108,426
Fair value based on net asset value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Alternative investment	956,000	570,300
Level 1
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	7,135,334	5,759,575
Securities purchased under agreements to resell		0
Securities received as collateral	7,517	9,500
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	5,707,423	5,971,928
Short-term borrowings	0	0
Other secured financings	0
Obligation to return securities received as collateral	7,517	9,500
Long-term debt	0	0
Level 1 | Corporate equity securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	2,331,440	2,325,116
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	2,046,441	2,755,601
Level 1 | Corporate debt securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	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:
Total financial instruments owned, excluding Investments at fair value based on NAV	0	0
Level 1 | U.S. government and federal agency securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	2,840,025	2,101,624
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	2,609,660	1,851,981
Level 1 | Municipal securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	0	0
Level 1 | Sovereign obligations
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	1,962,346	1,330,026
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	1,050,771	1,363,475
Level 1 | Residential mortgage-backed securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	0	0
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	0
Level 1 | Commercial mortgage-backed securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	0	0
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	0	0
Level 1 | Other asset-backed securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	0	0
Level 1 | Loans and other receivables
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	0	0
Level 1 | Loans
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	0	0
Level 1 | Derivative, assets
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	1,523	2,809
Level 1 | Derivatives, liabilities
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	551	871
Level 1 | Investments at fair value
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	0	0
Level 2
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	10,771,762	11,159,143
Securities purchased under agreements to resell		0
Securities received as collateral	0	0
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	6,039,818	6,085,937
Short-term borrowings	5,067	20,981
Other secured financings	0
Obligation to return securities received as collateral	0	0
Long-term debt	1,036,217	735,216
Level 2 | Corporate equity securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	58,159	218,403
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	9,046	7,438
Level 2 | Corporate debt securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	2,954,201	2,472,213
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	1,237,631	1,471,142
Level 2 | Collateralized debt obligations and collateralized loan obligations
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	64,155	124,225
Level 2 | U.S. government and federal agency securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	91,653	158,618
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	0	0
Level 2 | Municipal securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	453,881	742,326
Level 2 | Sovereign obligations
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	591,342	1,405,827
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	624,740	941,065
Level 2 | Residential mortgage-backed securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	1,100,849	1,069,066
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	477
Level 2 | Commercial mortgage-backed securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	736,291	424,060
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	0	0
Level 2 | Other asset-backed securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	103,611	303,847
Level 2 | Loans and other receivables
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	2,610,746	2,395,211
Level 2 | Loans
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	1,776,446	1,600,228
Level 2 | Derivative, assets
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	2,000,752	1,812,659
Level 2 | Derivatives, liabilities
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	2,391,478	2,066,064
Level 2 | Investments at fair value
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	6,122	32,688
Level 3
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	379,108	307,152
Securities purchased under agreements to resell		25,000
Securities received as collateral	0	0
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	68,940	106,382
Short-term borrowings	0	0
Other secured financings	1,543
Obligation to return securities received as collateral	0	0
Long-term debt	676,028	480,069
Level 3 | Corporate equity securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	75,797	58,301
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	4,434	4,487
Level 3 | Corporate debt securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	23,146	7,490
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	141	340
Level 3 | Collateralized debt obligations and collateralized loan obligations
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	10,513	20,081
Level 3 | U.S. government and federal agency securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	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:
Total financial instruments owned, excluding Investments at fair value based on NAV	0	0
Level 3 | Sovereign obligations
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	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:
Total financial instruments owned, excluding Investments at fair value based on NAV	21,826	17,740
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	0
Level 3 | Commercial mortgage-backed securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	2,003	6,110
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	35	35
Level 3 | Other asset-backed securities
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	79,995	42,563
Level 3 | Loans and other receivables
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	77,042	64,240
Level 3 | Loans
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	16,635	9,463
Level 3 | Derivative, assets
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	21,678	14,889
Level 3 | Derivatives, liabilities
Financial instruments sold, not yet purchased:
Financial instruments sold, not yet purchased, at fair value	47,695	92,057
Level 3 | Investments at fair value
Financial instruments owned:
Total financial instruments owned, excluding Investments at fair value based on NAV	$ 67,108	$ 75,738