Equity Method Investments (Details Textual) (USD $)	11 Months Ended	12 Months Ended
	Nov. 30, 2010	Nov. 30, 2011	Nov. 30, 2010	Dec. 31, 2009	Aug. 31, 2011	Feb. 28, 2011	Feb. 25, 2011
Guarantor Obligations [Line Items]
Funded portion of equity commitment to subsidiary		$ 107,500,000
Aggregate commitment		500,000,000
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		155,000,000
Additional Aggregate commitment		500,000,000
Maturity date description		Scheduled to mature on March 1, 2014 with an automatic extension subject to a 60 day termination notice by either party
Amount outstanding under the revolving line of credit	0	0	0		100,000,000
Net earnings of JFIN	71,700,000	88,300,000		67,500,000
Payment for the purchase of participation certificates in loans originated by JFIN		477,200,000
Fees paid to JFIN related to originations of loans by JFIN	0	21,500,000
Fees earned to JFIN related to originations of loans by JFIN	10,800,000	60,800,000	35,100,000
Jefferies Loan Core LLC [Member]
Guarantor Obligations [Line Items]
Aggregate commitment		600,000,000
Funded portion of equity commitment to subsidiary		168,400,000
Administrative services		300,000
Equity Commitment		291,000,000
Percentage of the Variable Interest Entity's (VIE) voting interest		48.50%
Receivables from loan core under service agreement		300,000
Jefferies Finance LLC [Member]
Guarantor Obligations [Line Items]
Administrative services		16,600,000	4,300,000
Reimbursed administrative services		20,900,000
Line of Credit [Member]
Guarantor Obligations [Line Items]
Interest Income		200,000
Secured Revolving Credit Facility [Member]
Guarantor Obligations [Line Items]
Interest Income		6,400,000
Maximum [Member]
Guarantor Obligations [Line Items]
Total commitment under revolving line of credit						500,000,000
Minimum [Member]
Guarantor Obligations [Line Items]
Total commitment under revolving line of credit						$ 150,000,000