Investments - Summary of Selected Financial Information for Jefferies LoanCore (Detail) - Jefferies LoanCore, LLC [Member] - USD ($) $ in Millions	Aug. 31, 2015	Nov. 30, 2014
Schedule of Equity Method Investments [Line Items]
Total assets	$ 1,789.3	$ 1,500.9
Total liabilities	1,277.9	962.7
Total equity	511.5	538.2
Our total equity balance	$ 248.1	$ 261.0