Investments - Summary of Selected Financial Information for Jefferies LoanCore (Detail) - Jefferies LoanCore, LLC [Member] - USD ($) $ in Millions	May. 31, 2015	Nov. 30, 2014
Schedule of Equity Method Investments [Line Items]
Total assets	$ 1,887.2	$ 1,500.9
Total liabilities	1,386.6	962.7
Total equity	500.6	538.2
Our total equity balance	$ 242.8	$ 261.0