Investments - Summary of Selected Financial Information for Jefferies Finance (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2017	Aug. 31, 2016	Nov. 30, 2016
Schedule of Equity Method Investments [Line Items]
CLO placement fee revenues	$ 139,082	$ 152,044	$ 437,547	$ 454,025
Jefferies Finance, LLC
Schedule of Equity Method Investments [Line Items]
Interest income	200	0	2,500	0
Unfunded commitment fees	300	300	800	900
Our total equity balance	612,100		612,100		$ 470,500
Net earnings (loss)	40,800	22,800	133,500	(55,000)
Origination and syndication fee revenues	104,200	19,000	243,500	42,100
Origination fee expenses	0	0	2,500	1,600
CLO placement fee revenues	800	1,300	4,700	1,300
Derivative gains (losses)	(200)	0	(600)	1,300
Service fees	$ 7,900	$ 7,200	$ 37,400	$ 35,800