Fair Value Disclosures - Financial Assets and Liabilities Accounted for at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Aug. 31, 2017	Nov. 30, 2016
Financial instruments owned:
Corporate equity securities	$ 1,714,291	$ 1,854,864
Corporate debt securities	2,757,958	2,700,025
Collateralized debt obligations and collateralized loan obligations	92,636	108,660
U.S. government and federal agency securities	1,929,445	2,446,123
Municipal securities	680,634	735,726
Sovereign obligations	2,052,317	2,423,048
Loans and other receivables	2,077,306	1,639,105
Derivatives	173,074	360,534
Investments at fair value	90,417	96,369
Total financial instruments owned, excluding Investments at fair value based on NAV	14,012,498	13,785,203
Counterparty and Cash Collateral Netting	(2,544,283)	(4,255,998)
Financial instruments sold, not yet purchased:
Corporate equity securities	1,334,363	1,594,524
Corporate debt securities	1,575,453	1,718,947
U.S. government and federal agency securities	1,314,800	976,497
Municipal securities	44
Sovereign obligations	2,253,529	2,629,344
Loans	1,437,665	802,355
Derivatives	543,632	637,535
Total financial instruments sold, not yet purchased	8,460,500	8,359,202
Counterparty and Cash Collateral Netting	(2,663,043)	(4,229,213)
Other secured financings		41,768
Short-term borrowings	4,281	0
Long-term debt	553,870	248,856
Residential mortgage-backed securities
Financial instruments owned:
Mortgage- and asset-backed securities, assets	1,691,819	999,266
Commercial mortgage-backed securities
Financial instruments owned:
Mortgage- and asset-backed securities, assets	526,301	316,985
Financial instruments sold, not yet purchased:
Commercial mortgage-backed securities	1,014
Other asset-backed securities
Financial instruments owned:
Mortgage- and asset-backed securities, assets	226,300	104,498
Level 1
Financial instruments owned:
Corporate equity securities	1,616,600	1,742,463
Corporate debt securities	0	0
Collateralized debt obligations and collateralized loan obligations	0	0
U.S. government and federal agency securities	1,834,270	2,389,397
Municipal securities	0	0
Sovereign obligations	1,384,264	1,432,556
Loans and other receivables	0	0
Derivatives	67,400	3,825
Investments at fair value	0	0
Total financial instruments owned, excluding Investments at fair value based on NAV	4,902,534	5,568,241
Financial instruments sold, not yet purchased:
Corporate equity securities	1,310,423	1,577,405
Corporate debt securities	0	0
U.S. government and federal agency securities	1,314,800	976,497
Municipal securities	0
Sovereign obligations	1,600,423	1,375,590
Loans	0	0
Derivatives	147,101	568
Total financial instruments sold, not yet purchased	4,372,747	3,930,060
Other secured financings		0
Short-term borrowings	0
Long-term debt	0	0
Level 1 | Residential mortgage-backed securities
Financial instruments owned:
Mortgage- and asset-backed securities, assets	0	0
Level 1 | Commercial mortgage-backed securities
Financial instruments owned:
Mortgage- and asset-backed securities, assets	0	0
Financial instruments sold, not yet purchased:
Commercial mortgage-backed securities	0
Level 1 | Other asset-backed securities
Financial instruments owned:
Mortgage- and asset-backed securities, assets	0	0
Level 2
Financial instruments owned:
Corporate equity securities	75,517	90,662
Corporate debt securities	2,732,943	2,675,020
Collateralized debt obligations and collateralized loan obligations	54,433	54,306
U.S. government and federal agency securities	95,175	56,726
Municipal securities	680,634	708,469
Sovereign obligations	668,053	990,492
Loans and other receivables	2,014,650	1,557,233
Derivatives	2,647,286	4,606,278
Investments at fair value	0	0
Total financial instruments owned, excluding Investments at fair value based on NAV	11,305,880	12,059,672
Financial instruments sold, not yet purchased:
Corporate equity securities	23,821	16,806
Corporate debt securities	1,574,931	1,718,424
U.S. government and federal agency securities	0	0
Municipal securities	44
Sovereign obligations	653,106	1,253,754
Loans	1,434,380	801,977
Derivatives	3,051,821	4,856,310
Total financial instruments sold, not yet purchased	6,739,082	8,647,271
Other secured financings		41,350
Short-term borrowings	4,281
Long-term debt	553,870	248,856
Level 2 | Residential mortgage-backed securities
Financial instruments owned:
Mortgage- and asset-backed securities, assets	1,671,170	960,494
Level 2 | Commercial mortgage-backed securities
Financial instruments owned:
Mortgage- and asset-backed securities, assets	508,665	296,405
Financial instruments sold, not yet purchased:
Commercial mortgage-backed securities	979
Level 2 | Other asset-backed securities
Financial instruments owned:
Mortgage- and asset-backed securities, assets	157,354	63,587
Level 3
Financial instruments owned:
Corporate equity securities	22,174	21,739
Corporate debt securities	25,015	25,005
Collateralized debt obligations and collateralized loan obligations	38,203	54,354
U.S. government and federal agency securities	0	0
Municipal securities	0	27,257
Sovereign obligations	0	0
Loans and other receivables	62,656	81,872
Derivatives	2,671	6,429
Investments at fair value	90,417	96,369
Total financial instruments owned, excluding Investments at fair value based on NAV	348,367	413,288
Financial instruments sold, not yet purchased:
Corporate equity securities	119	313
Corporate debt securities	522	523
U.S. government and federal agency securities	0	0
Municipal securities	0
Sovereign obligations	0	0
Loans	3,285	378
Derivatives	7,753	9,870
Total financial instruments sold, not yet purchased	11,714	11,084
Other secured financings		418
Short-term borrowings	0
Long-term debt	0	0
Level 3 | Residential mortgage-backed securities
Financial instruments owned:
Mortgage- and asset-backed securities, assets	20,649	38,772
Level 3 | Commercial mortgage-backed securities
Financial instruments owned:
Mortgage- and asset-backed securities, assets	17,636	20,580
Financial instruments sold, not yet purchased:
Commercial mortgage-backed securities	35
Level 3 | Other asset-backed securities
Financial instruments owned:
Mortgage- and asset-backed securities, assets	$ 68,946	$ 40,911