Investments - Summary of Selected Financial Information for Jefferies LoanCore (Detail) - Jefferies LoanCore, LLC [Member] - USD ($) $ in Millions	Nov. 30, 2016	Nov. 30, 2015
Schedule of Equity Method Investments [Line Items]
Total assets	$ 1,827.2	$ 2,069.1
Total liabilities	1,505.0	1,469.8
Total equity	322.2	599.3
Our total equity balance	$ 156.3	$ 290.7