Investments - Summary of Selected Financial Information for Jefferies LoanCore (Detail) - Jefferies LoanCore, LLC [Member] - USD ($) $ in Millions	May 31, 2016	Nov. 30, 2015
Schedule of Equity Method Investments [Line Items]
Total assets	$ 1,215.3	$ 2,069.1
Total liabilities	886.1	1,469.8
Total equity	329.2	599.3
Our total equity balance	$ 159.7	$ 290.7