Investments - Jefferies Finance - Narrative (Detail) - USD ($) $ in Thousands	12 Months Ended
	Nov. 30, 2016	Nov. 30, 2015	Nov. 30, 2014
Guarantor Obligations [Line Items]
Equity commitments to JFIN	$ 600,000
Total committed equity capitalization of JIFN	1,200,000
Funded portion of equity commitment to subsidiary	493,900
Unfunded portion of equity commitment to subsidiary	$ 106,100
Extension period	1 year
Termination notice period	60 days
Maturity date	Mar. 01, 2017
Funded portion of loan commitment	$ 0	$ 19,300
Loan commitment	250,000	250,000
Interest income	100	900	$ 2,000
Unfunded commitment fees	1,200	1,600	1,900
Net underwriting fees paid by JFIN related to originations of loans by JFIN	112,600	122,700	199,500
Fees paid to JFIN related to origination of loans by JFIN	500	5,900	10,600
Revenue in Connection of Execution of JFIN CLO	611,574	659,002	668,801
Underwriting fees		1,300	7,700
Committed Advances [Member]
Guarantor Obligations [Line Items]
Committed line of credit facility amount	500,000
Jefferies Finance, LLC [Member]
Guarantor Obligations [Line Items]
Net income earnings	(19,600)	83,400	138,600
Revenue in Connection of Execution of JFIN CLO	2,600	6,200	4,600
Administrative services provided	46,100	51,700	$ 41,600
Accounts Expenses and Other Liabilities [Member] | Jefferies Finance, LLC [Member]
Guarantor Obligations [Line Items]
Due to Related Parties	$ 5,800
Other Assets [Member] | Jefferies Finance, LLC [Member]
Guarantor Obligations [Line Items]
Receivables under service agreement		$ 7,800