Investments - Jefferies Finance - Narrative (Detail) (USD $)	3 Months Ended
	Feb. 28, 2015	Feb. 28, 2014	Nov. 30, 2014
Guarantee Obligations [Line Items]
Equity commitments to JFIN	$ 600,000,000
Total committed equity capitalization of JIFN	1,200,000,000
Funded portion of equity commitment to subsidiary	506,700,000
Unfunded portion of equity commitment to subsidiary	93,300,000
Extension period	1 year
Termination notice period	60 days
Committed line of credit facility amount	1,000,000,000
Maturity date	Mar. 01, 2016
Funded portion of loan commitment	0		0
Loan commitment	350,000,000
Interest income	500,000	500,000
Unfunded commitment fees	400,000	700,000
Net underwriting fees paid by JFIN related to originations of loans by JFIN	15,600,000	47,600,000
Fees paid to JFIN related to origination of loans by JFIN	700,000	4,300,000
Revenue in Connection of Execution of JFIN CLO	166,922,000	162,063,000
Committed Advances [Member]
Guarantee Obligations [Line Items]
Committed line of credit facility amount	700,000,000
Discretionary Advances [Member]
Guarantee Obligations [Line Items]
Committed line of credit facility amount	300,000,000
Jefferies Finance, LLC [Member]
Guarantee Obligations [Line Items]
Net income earnings	21,100,000	29,100,000
Revenue in Connection of Execution of JFIN CLO		400,000
Administrative services provided	27,800,000	21,700,000
Receivables under service agreement	$ 15,500,000		$ 41,500,000