Investments - Jefferies Finance - Additional Information (Detail) (USD $)	3 Months Ended			6 Months Ended
	May 31, 2014	May 31, 2013	Feb. 28, 2013	May 31, 2014	Nov. 30, 2013
Guarantee Obligations [Line Items]
Equity commitments to JFIN	$ 600,000,000			$ 600,000,000
Total committed equity capitalization of JIFN	1,200,000,000			1,200,000,000
Funded portion of equity commitment to subsidiary	331,100,000			331,100,000
Unfunded portion of equity commitment to subsidiary	268,900,000			268,900,000
Investment expiry date				Mar. 01, 2016
Committed line of credit facility amount	700,000,000			700,000,000
Loan maturity description				Scheduled to mature on March 1, 2016 with automatic one year extensions absent a 60 day termination notice by either party.
Extension period				1 year
Termination notice period				60 days
Loan commitment	350,000,000			350,000,000
Interest income	600,000	400,000	4,100,000
Unfunded commitment fees	400,000	400,000	300,000
Funded portion of loan commitment	0			0	123,800,000
Net underwriting fees paid by JFIN related to originations of loans by JFIN	38,800,000	35,200,000	39,900,000	86,400,000
Fees paid to JFIN related to origination of loans by JFIN	3,400,000	6,200,000	800,000	7,700,000
Secured Revolving Credit Facility [Member]
Guarantee Obligations [Line Items]
Interest income				1,100,000
Unfunded commitment fees				1,100,000
Jefferies Finance, LLC [Member]
Guarantee Obligations [Line Items]
Net income earnings	29,300,000	20,300,000	36,700,000	58,500,000
Administrative services provided	7,000,000	5,400,000	15,700,000	28,700,000
Receivables under service agreement	$ 14,200,000			$ 14,200,000	$ 31,100,000