Investments - Jefferies Finance - Narrative (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Feb. 28, 2013	Nov. 30, 2013	Nov. 30, 2015	Nov. 30, 2014	Nov. 30, 2013
Guarantee Obligations [Line Items]
Equity commitments to JFIN			$ 600.0
Total committed equity capitalization of JIFN			1,200.0
Funded portion of equity commitment to subsidiary			497.4
Unfunded portion of equity commitment to subsidiary			$ 102.6
Extension period			1 year
Termination notice period			60 days
Maturity date			Mar. 01, 2016
Funded portion of loan commitment			$ 19.3	$ 0.0
Loan commitment			250.0	350.0
Interest income	$ 4.1	$ 1.5	0.9	2.0
Unfunded commitment fees	0.3	1.2	1.6	1.9
Net underwriting fees paid by JFIN related to originations of loans by JFIN	39.9	125.8	122.7	199.5
Fees paid to JFIN related to origination of loans by JFIN	0.8	12.0	5.9	10.6
Underwriting fees			1.3	7.7	$ 6.0
Discretionary Advances [Member]
Guarantee Obligations [Line Items]
Committed line of credit facility amount			1,000.0
Committed Advances [Member]
Guarantee Obligations [Line Items]
Committed line of credit facility amount			500.0
Jefferies Finance, LLC [Member]
Guarantee Obligations [Line Items]
Net income earnings			83.4	138.6	132.7
Revenue in Connection of Execution of JFIN CLO			6.2	4.6	$ 1.9
Placement fees			0.0	0.7
Administrative services provided	$ 15.7	$ 14.2	51.7	41.6
Receivables under service agreement			$ 7.8	$ 41.5