Investments - Summary of Selected Financial Information for Jefferies LoanCore (Detail) - Jefferies LoanCore, LLC [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2017	May 31, 2016	Nov. 30, 2016
Schedule of Equity Method Investments [Line Items]
Our total equity balance	$ 219,200		$ 219,200		$ 156,300
Net earnings	2,400	$ 17,300	8,600	$ 22,700
Interest income and fees	3	2,301	589	5,140
Service fees	$ 47	$ 47	$ 95	$ 95
Reverse repurchase agreements					$ 68,100