Commitments, Contingencies and Guarantees - Additional Information (Detail) (USD $)	3 Months Ended
	Feb. 28, 2013
Commitments Contingencies And Guarantees [Line Items]
Loan commitments outstanding to clients	$ 411,600,000
Revolving credit facility	1,000,000,000
Fair value of mortgage-related commitments	49,200,000
Noncancelable agreements expiring at various dates through	2029
Global headquarters and executive offices lease term extended years	15 years
Fair value of derivative contracts approximated deemed to meet the definition of a guarantee	142,900,000
Unrated [Member]
Commitments Contingencies And Guarantees [Line Items]
Unfunded loan commitments	283,100,000
Corporate Lending Commitments	626,100,000
Jefferies Employee Partners IV, LLC [Member]
Commitments Contingencies And Guarantees [Line Items]
Funded loan commitments	28,200,000
Unfunded loan commitments	4,800,000
Corporate Lending Commitments	33,000,000
Revolving credit facility [Member]
Commitments Contingencies And Guarantees [Line Items]
Funded loan commitments	221,700,000
Unfunded loan commitments	278,300,000
Jefferies Finance, LLC [Member]
Commitments Contingencies And Guarantees [Line Items]
Equity Commitments	500,000,000
Funded Equity Commitments	107,500,000
Jefferies LoanCore, LLC [Member]
Commitments Contingencies And Guarantees [Line Items]
Equity Commitments	291,000,000
Funded Equity Commitments	193,400,000
Jefferies Capital Partners LLC [Member]
Commitments Contingencies And Guarantees [Line Items]
Equity Commitments	5,900,000
Funded Equity Commitments	1,000,000
Unfunded equity commitments	4,900,000
USA Fund and Jefferies Capital Partners LP [Member]
Commitments Contingencies And Guarantees [Line Items]
Equity Commitments	85,000,000
Jefferies Capital Partners IV L.P.[Member]
Commitments Contingencies And Guarantees [Line Items]
Equity Commitments	45,900,000
Funded Equity Commitments	43,600,000
Jefferies Capital Partners IV LLC [Member]
Commitments Contingencies And Guarantees [Line Items]
Equity Commitments	3,100,000
Funded Equity Commitments	2,200,000
Jefferies Capital Partners IV L.P and Jefferies Capital Partners IV LLC [Member]
Commitments Contingencies And Guarantees [Line Items]
Unfunded equity commitments	3,200,000
Other Investments [Member]
Commitments Contingencies And Guarantees [Line Items]
Equity Commitments	29,800,000
Unfunded equity commitments	2,000,000
USA Fund [Member]
Commitments Contingencies And Guarantees [Line Items]
Equity Commitments	75,000,000
Funded Equity Commitments	36,800,000
Jefferies Capital Partners V L.P.[Member]
Commitments Contingencies And Guarantees [Line Items]
Equity Commitments	10,000,000
Funded Equity Commitments	4,900,000
USA Fund and Jefferies Capital Partners V L.P [Member]
Commitments Contingencies And Guarantees [Line Items]
Unfunded equity commitments	$ 43,300,000