Equity Method Investments (Details Textual) (USD $)	1 Months Ended	3 Months Ended		12 Months Ended
	Nov. 30, 2011	Feb. 29, 2012	Feb. 28, 2011	Nov. 30, 2011
Guarantor Obligations [Line Items]
Funded portion of equity commitment to subsidiary		$ 107,500,000
Aggregate commitment		500,000,000
Reimbursed administrative services		10,900,000
Equity Method Investments (Textual) [Abstract]
Increase in equity commitment to JFIN			250,000,000
Total committed equity capitalization of JFIN			1,000,000,000
Unfunded portion of equity commitment to subsidiary		392,500,000
Line of credit facility commitment under joint venture			1,000,000,000
Additional Funded portion of equity commitment to subsidiary		79,900,000
Additional Aggregate commitment	500,000,000			500,000,000
Maturity date description		Scheduled to mature on March 1, 2014 with an automatic one year extensions subject to a 60 day termination notice by either party
Payment for the purchase of participation certificates in loans originated by JFIN		0	477,200,000
Fees paid to JFIN related to originations of loans by JFIN		3,800,000	600,000
Fees earned to JFIN related to originations of loans by JFIN		23,700,000	18,600,000
Extension period		1
Termination notice period		60
Jefferies Loan Core LLC [Member]
Guarantor Obligations [Line Items]
Aggregate commitment		600,000,000
Funded portion of equity commitment to subsidiary		168,500,000		163,300,000
Administrative services		200,000
Equity Commitment		291,000,000
Percentage of the Variable Interest Entity's (VIE) voting interest		48.50%
Net income earnings		13,600,000	0
Receivables from loan core under service agreement	300,000	200,000		300,000
Aggregate fair market value of derivative transactions outstanding		25,600,000
Recognized gains within Principal transaction revenues		7,900,000
Jefferies Finance LLC [Member]
Guarantor Obligations [Line Items]
Administrative services	16,600,000	31,000,000		10,900,000
Net income earnings		30,100,000	26,400,000
Secured Revolving Credit Facility [Member]
Guarantor Obligations [Line Items]
Interest Income		$ 3,000,000