Investments - Jefferies LoanCore - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended		12 Months Ended
	Feb. 28, 2013	Nov. 30, 2013	Nov. 30, 2011	Nov. 30, 2013	Nov. 30, 2012
Guarantee Obligations [Line Items]
Aggregate commitment					$ 500,000,000
Equity commitment		600,000,000		600,000,000
Jefferies LoanCore, LLC [Member]
Guarantee Obligations [Line Items]
Aggregate commitment		600,000,000		600,000,000
Funded portion of equity commitment to subsidiary				175,500,000	110,000,000
Equity commitment		291,000,000		291,000,000
Percentage of the Variable Interest Entity's (VIE) voting interest		48.50%		48.50%
Net earnings from equity method investment			(2,600,000)	85,200,000	84,200,000
Reimbursed administrative services	600,000	500,000	300,000		500,000
Receivable from loan core under service agreement		230,000		230,000	37,000
Aggregate fair market value of derivative transactions outstanding		0		0	700,000
Recognized net gains within principal transaction revenues	$ 200,000	$ 3,600,000			$ 25,600,000