Fair Value Disclosures - Financial Assets and Liabilities Accounted for at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	May 31, 2016	Nov. 30, 2015
Financial instruments owned:
Corporate equity securities	$ 2,296,254	$ 2,027,989
Corporate debt securities	2,827,280	2,893,041
Collateralized debt obligations	115,473	174,236
U.S. government and federal agency securities	2,569,421	2,645,651
Municipal securities	638,929	487,141
Sovereign obligations	2,295,884	2,659,441
Loans and other receivables	1,709,718	1,312,333
Derivatives	311,422	251,080
Investments at fair value	86,765	79,344
Total financial instruments owned, excluding Investments at fair value based on NAV	15,089,128	16,522,382
Counterparty and Cash Collateral Netting	(5,030,887)	(4,165,446)
Cash and cash equivalents	2,838,829	3,510,163
Cash and securities segregated and on deposit for regulatory purposes	836,871	751,084
Financial instruments sold, not yet purchased:
Corporate equity securities	1,883,597	1,418,933
Corporate debt securities	1,964,988	1,556,941
U.S. government and federal agency securities	1,349,746	1,488,121
Sovereign obligations	1,772,047	1,342,996
Loans	599,519	769,408
Derivatives	390,871	208,548
Total financial instruments sold, not yet purchased	7,961,813	6,785,064
Counterparty and Cash Collateral Netting	(5,118,214)	(4,257,998)
Other secured financings	46,773	68,345
Long-term debt	92,993	0
US Treasury Securities [Member]
Financial instruments owned:
Cash and securities segregated and on deposit for regulatory purposes	99,900
Residential mortgage-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	1,417,281	2,801,333
Financial instruments sold, not yet purchased:
Residential mortgage-backed securities	1,045	117
Commercial mortgage-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	640,272	1,029,239
Other asset-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	180,429	161,554
Level 1 [Member]
Financial instruments owned:
Corporate equity securities	2,106,323	1,853,351
Corporate debt securities	0	0
Collateralized debt obligations	0	0
U.S. government and federal agency securities	2,476,399	2,555,018
Municipal securities	0	0
Sovereign obligations	1,450,033	1,251,366
Loans and other receivables	0	0
Derivatives	3,914	1,037
Investments at fair value	0	0
Total financial instruments owned, excluding Investments at fair value based on NAV	6,036,669	5,660,772
Cash and cash equivalents	2,838,829	3,510,163
Cash and securities segregated and on deposit for regulatory purposes	836,871	751,084
Financial instruments sold, not yet purchased:
Corporate equity securities	1,794,791	1,382,377
Corporate debt securities	0	0
U.S. government and federal agency securities	1,349,746	1,488,121
Sovereign obligations	678,659	837,614
Loans	0	0
Derivatives	1,383	364
Total financial instruments sold, not yet purchased	3,824,579	3,708,476
Other secured financings	0	0
Long-term debt	0
Level 1 [Member] | Residential mortgage-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	0	0
Financial instruments sold, not yet purchased:
Residential mortgage-backed securities	0	0
Level 1 [Member] | Commercial mortgage-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	0	0
Level 1 [Member] | Other asset-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	0	0
Level 2 [Member]
Financial instruments owned:
Corporate equity securities	141,115	133,732
Corporate debt securities	2,803,167	2,867,165
Collateralized debt obligations	62,763	89,144
U.S. government and federal agency securities	93,022	90,633
Municipal securities	638,929	487,141
Sovereign obligations	845,731	1,407,955
Loans and other receivables	1,605,319	1,123,044
Derivatives	5,322,084	4,395,704
Investments at fair value	29,000	26,224
Total financial instruments owned, excluding Investments at fair value based on NAV	13,647,788	14,485,354
Cash and cash equivalents	0	0
Cash and securities segregated and on deposit for regulatory purposes	0	0
Financial instruments sold, not yet purchased:
Corporate equity securities	88,806	36,518
Corporate debt securities	1,964,988	1,556,941
U.S. government and federal agency securities	0	0
Sovereign obligations	1,093,388	505,382
Loans	597,623	758,939
Derivatives	5,486,967	4,446,639
Total financial instruments sold, not yet purchased	9,232,817	7,304,536
Other secured financings	46,305	67,801
Long-term debt	92,993
Level 2 [Member] | Residential mortgage-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	1,353,973	2,731,070
Financial instruments sold, not yet purchased:
Residential mortgage-backed securities	1,045	117
Level 2 [Member] | Commercial mortgage-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	615,289	1,014,913
Level 2 [Member] | Other asset-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	137,396	118,629
Level 3 [Member]
Financial instruments owned:
Corporate equity securities	48,816	40,906
Corporate debt securities	24,113	25,876
Collateralized debt obligations	52,710	85,092
U.S. government and federal agency securities	0	0
Municipal securities	0	0
Sovereign obligations	120	120
Loans and other receivables	104,399	189,289
Derivatives	16,311	19,785
Investments at fair value	57,765	53,120
Total financial instruments owned, excluding Investments at fair value based on NAV	435,558	541,702
Cash and cash equivalents	0	0
Cash and securities segregated and on deposit for regulatory purposes	0	0
Financial instruments sold, not yet purchased:
Corporate equity securities	0	38
Corporate debt securities	0	0
U.S. government and federal agency securities	0	0
Sovereign obligations	0	0
Loans	1,896	10,469
Derivatives	20,735	19,543
Total financial instruments sold, not yet purchased	22,631	30,050
Other secured financings	468	544
Long-term debt	0
Level 3 [Member] | Residential mortgage-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	63,308	70,263
Financial instruments sold, not yet purchased:
Residential mortgage-backed securities	0	0
Level 3 [Member] | Commercial mortgage-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	24,983	14,326
Level 3 [Member] | Other asset-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	$ 43,033	$ 42,925