Fair Value Disclosures - Financial Assets and Liabilities Accounted for at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Feb. 28, 2015	Nov. 30, 2014
Financial instruments owned:
Corporate equity securities	$ 2,377,580	$ 2,426,242
Corporate debt securities	3,429,984	3,398,194
Collateralized debt obligations	244,797	397,716
U.S. government and federal agency securities	3,890,072	2,775,541
Municipal securities	772,940	590,849
Sovereign obligations	2,580,183	2,759,511
Loans and other receivables	1,460,611	1,556,018
Derivatives	497,092	406,268
Investments at fair value	169,964	168,541
Physical commodities	58,715	62,234
Total financial instruments owned	19,098,646	18,636,612
Cash and cash equivalents	3,339,965	4,079,968
Investments in managed funds	54,679jef_InvestmentsInManagedFunds	74,365jef_InvestmentsInManagedFunds
Cash and securities segregated and on deposit for regulatory purposes	3,186,319	3,444,674
Securities received as collateral	4,821us-gaap_SecuritiesReceivedAsCollateral	5,418us-gaap_SecuritiesReceivedAsCollateral
Financial instruments sold, not yet purchased:
Corporate equity securities	2,056,407	1,985,864
Corporate debt securities	1,766,453	1,612,217
Collateralized debt obligations		4,557
U.S. government and federal agency securities	1,466,111	2,253,055
Sovereign obligations	1,367,690	1,791,085
Loans	919,896jef_FairValueOfLoanObligations	870,975jef_FairValueOfLoanObligations
Derivatives	322,341	363,515
Total financial instruments sold, not yet purchased	7,910,823	8,881,268
Obligation to return securities received as collateral	4,821	5,418
Other secured financings	65,602us-gaap_SecuredDebtOther	30,825us-gaap_SecuredDebtOther
Embedded conversion option	825	693
Residential mortgage-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	2,904,453	2,962,511
Financial instruments sold, not yet purchased:
Residential mortgage-backed securities	11,925
Commercial mortgage-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	566,718	993,306
Other asset-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	145,537	139,681
Level 1 [Member]
Financial instruments owned:
Corporate equity securities	2,150,032	2,178,837
Corporate debt securities	0	0
Collateralized debt obligations	0	0
U.S. government and federal agency securities	3,783,645	2,694,268
Municipal securities	0	0
Sovereign obligations	1,522,227	1,968,747
Loans and other receivables	0	0
Derivatives	96,660	65,145
Investments at fair value	0	0
Physical commodities	0	0
Total financial instruments owned	7,552,564	6,906,997
Cash and cash equivalents	3,339,965	4,079,968
Investments in managed funds	0	0
Cash and securities segregated and on deposit for regulatory purposes	3,186,319	3,444,674
Securities received as collateral	4,821	5,418
Financial instruments sold, not yet purchased:
Corporate equity securities	1,996,335	1,911,145
Corporate debt securities	0	0
Collateralized debt obligations		0
U.S. government and federal agency securities	1,366,689	2,253,055
Sovereign obligations	707,844	1,217,075
Loans	0	0
Derivatives	71,707	52,778
Total financial instruments sold, not yet purchased	4,142,575	5,434,053
Obligation to return securities received as collateral	4,821	5,418
Other secured financings	0	0
Embedded conversion option	0	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
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	209,338	226,441
Corporate debt securities	3,399,249	3,342,276
Collateralized debt obligations	153,900	306,218
U.S. government and federal agency securities	106,427	81,273
Municipal securities	772,940	590,849
Sovereign obligations	1,057,623	790,764
Loans and other receivables	1,349,201	1,458,760
Derivatives	5,083,829	5,046,278
Investments at fair value	3	73,152
Physical commodities	58,715	62,234
Total financial instruments owned	15,696,205	15,962,237
Cash and cash equivalents	0	0
Investments in managed funds	23,839	19,383
Cash and securities segregated and on deposit for regulatory purposes	0	0
Securities received as collateral	0	0
Financial instruments sold, not yet purchased:
Corporate equity securities	60,034	74,681
Corporate debt securities	1,766,453	1,611,994
Collateralized debt obligations		4,557
U.S. government and federal agency securities	99,422	0
Sovereign obligations	659,846	574,010
Loans	910,569	856,525
Derivatives	5,011,935	5,117,803
Total financial instruments sold, not yet purchased	8,520,184	8,239,570
Obligation to return securities received as collateral	0	0
Other secured financings	0	0
Embedded conversion option	0	0
Level 2 [Member] \| Residential mortgage-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	2,824,500	2,879,954
Financial instruments sold, not yet purchased:
Residential mortgage-backed securities	11,925
Level 2 [Member] \| Commercial mortgage-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	542,089	966,651
Level 2 [Member] \| Other asset-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	138,391	137,387
Level 3 [Member]
Financial instruments owned:
Corporate equity securities	18,210	20,964
Corporate debt securities	30,735	55,918
Collateralized debt obligations	90,897	91,498
U.S. government and federal agency securities	0	0
Municipal securities	0	0
Sovereign obligations	333	0
Loans and other receivables	111,410	97,258
Derivatives	46,136	54,190
Investments at fair value	169,961	95,389
Physical commodities	0	0
Total financial instruments owned	579,410	526,723
Cash and cash equivalents	0	0
Investments in managed funds	30,840	54,982
Cash and securities segregated and on deposit for regulatory purposes	0	0
Securities received as collateral	0	0
Total Level 3 assets	610,250	581,705
Financial instruments sold, not yet purchased:
Corporate equity securities	38	38
Corporate debt securities	0	223
Collateralized debt obligations		0
U.S. government and federal agency securities	0	0
Sovereign obligations	0	0
Loans	9,327	14,450
Derivatives	49,450	49,552
Total financial instruments sold, not yet purchased	58,815	64,263
Obligation to return securities received as collateral	0	0
Other secured financings	65,602	30,825
Embedded conversion option	825	693
Level 3 [Member] \| Residential mortgage-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	79,953	82,557
Financial instruments sold, not yet purchased:
Residential mortgage-backed securities	0
Level 3 [Member] \| Commercial mortgage-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	24,629	26,655
Level 3 [Member] \| Other asset-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	7,146	2,294
Counterparty and Cash Collateral Netting [Member]
Financial instruments owned:
Corporate equity securities	0	0
Corporate debt securities	0	0
Collateralized debt obligations	0	0
U.S. government and federal agency securities	0	0
Municipal securities	0	0
Sovereign obligations	0	0
Loans and other receivables	0	0
Derivatives	(4,729,533)	(4,759,345)
Investments at fair value	0	0
Physical commodities	0	0
Total financial instruments owned	(4,729,533)	(4,759,345)
Cash and cash equivalents	0	0
Investments in managed funds	0	0
Cash and securities segregated and on deposit for regulatory purposes	0	0
Securities received as collateral	0	0
Financial instruments sold, not yet purchased:
Corporate equity securities	0	0
Corporate debt securities	0	0
Collateralized debt obligations		0
U.S. government and federal agency securities	0	0
Sovereign obligations	0	0
Loans	0	0
Derivatives	(4,810,751)	(4,856,618)
Total financial instruments sold, not yet purchased	(4,810,751)	(4,856,618)
Obligation to return securities received as collateral	0	0
Other secured financings	0	0
Embedded conversion option	0	0
Counterparty and Cash Collateral Netting [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
Counterparty and Cash Collateral Netting [Member] \| Commercial mortgage-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	0	0
Counterparty and Cash Collateral Netting [Member] \| Other asset-backed securities [Member]
Financial instruments owned:
Mortgage- and asset-backed securities, assets	$ 0	$ 0

Fair value of loan obligations.

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The fair value as of the balance sheet date of firm holdings in structured asset - backed securities whose value and payments are derived from portfolio of fixed income underlying assets.

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The fair value as of the balance sheet date of firm holdings in corporate loans, participation certificates in GNMA project and construction loans, and escrow and trade claim receivables.

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Financial Instruments Sold Not Yet Purchased Collateralized Debt Obligations

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Level 3 assets carried at fair value for which the entity bears economic exposure.

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The fair value as of the balance sheet date of the firm's investments in funds managed by us and investments in third-party managed funds in which we are entitled to a portion of the management and/or performance fees.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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-Glossary Cash

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Amount of cash subject to withdrawal restrictions, restricted deposits held as compensating balances, and cash and securities segregated in compliance with regulations (such as cash deposited in a special reserve account for the exclusive benefit of customers).

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-Topic 942

-SubTopic 305

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Fair value as of the balance sheet date of the embedded derivative or group of embedded derivatives classified as a liability.

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-Topic 815

-SubTopic 10

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-Paragraph 4B

-Subparagraph (c)

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The aggregate fair value as of the balance sheet date of financial instruments and other positions owned by the entity including: (1) mortgages, mortgage-backed and asset backed securities; (2) US government and agency obligations; (3) state and municipal government obligations; (4) other sovereign government debt; (5) corporate obligations; (6) corporate equities; (7) principal investments; (8) derivative contracts; and (9) physical commodities. Includes both pledged and unpledged holdings.

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-Topic 940

-SubTopic 320

-Section 45

-Paragraph 2

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The fair value as of the balance sheet date of firm holdings in fixed income or other debt securities issued by a corporation or other issuer not elsewhere specified in the taxonomy. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

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The fair value as of the balance sheet date of firm holdings in corporate stocks (common and preferred), stock options, warrants and any other financial instrument which represents, or provides the ability to obtain, ownership rights in a corporation. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

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The fair value as of the balance sheet date of firm holdings in all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments. Their value is derived from the values of one or more underlying assets, reference rates, or indices of asset values. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

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The fair value as of the balance sheet date of firm holdings in mortgages, mortgage backed securities (investment instruments that represent ownership of an undivided interest in a group of mortgages, where principal and interest from the individual mortgages are used to pay investors' principal and interest on the mortgage backed security) and asset-backed securities that are primarily paid from the cash flows of a discrete pool of receivables or other financial assets (such as credit-card receivables), either fixed or revolving, that by their terms convert into cash within a finite time period. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

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The fair value as of the balance sheet date of firm holdings in fixed income obligations issued by foreign governments. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

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The fair value as of the balance sheet date of firm holdings in physical commodity contracts (for example, agricultural products, metals and energy). Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

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The fair value as of the balance sheet date of firm holdings in private equity, mezzanine, venture capital, merchant banking, real estate and special situations investments. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

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The fair value as of the balance sheet date of firm holdings in fixed income obligations issued by state and local governments and authorities. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

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The fair value as of the balance sheet date of firm holdings in debt obligations issued by the US government including short-term Treasury bills, medium-term Treasury notes, and long-term Treasury bonds, as well as debt issued by agencies. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

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Fair value of obligations incurred from short sales.

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-Topic 940

-SubTopic 320

-Section 35

-Paragraph 1

-Subparagraph (b)

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Fair value of obligations arising from corporate debt obligations sold short.

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Fair value of obligations arising from corporate equity sold short.

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Fair value of obligations arising from derivatives and other contracts sold short.

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Fair value of obligations arising from mortgages, mortgage-backed securities and asset-backed securities sold short.

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Fair value of obligations arising from foreign government debt obligations short.

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Fair value of obligations arising from US treasury and other US government and agency debt obligations sold short.

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The fair value of collateral received by the entity associated with securities borrowed that must be returned if the counterparty fulfills its obligations. It appears on the balance sheet as a liability and has a corresponding asset that appears on the balance sheet called Securities Received as Collateral.

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-SubTopic 210

-Section S99

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-Subparagraph (SX 210.7-03.15)

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-Glossary Collateral

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Carrying value as of the balance sheet date of other collateralized debt obligations.

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-Topic 942

-SubTopic 470

-Section 45

-Paragraph 1

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The carrying value as of the balance sheet date of the assets received as collateral against securities loaned to other broker-dealers. Borrowers of securities generally are required to provide collateral to the lenders of securities, commonly cash but sometimes other securities or standby letters of credit, with a value slightly higher than that of the securities borrowed. In instances where the entity is permitted to sell or re-pledge these securities, the entity reports the fair value of the collateral received and the related obligation to return the collateral as a liability.

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-Paragraph 1A

-Subparagraph (b)(1)

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