Investments - Summary of Selected Financial Information for Jefferies Finance (Detail) - USD ($) $ in Thousands	12 Months Ended
	Nov. 30, 2017	Nov. 30, 2016	Nov. 30, 2015
Schedule of Equity Method Investments [Line Items]
CLO placement fee revenues	$ 593,257	$ 611,574	$ 659,002
Jefferies Finance
Schedule of Equity Method Investments [Line Items]
Interest income	2,900	100	900
Unfunded commitment fees	1,000	1,200	1,600
Total assets	8,164,900	7,293,300
Total liabilities	6,892,600	6,352,300
Total equity	1,272,300	941,100
Our total equity balance	636,200	470,500
Net earnings (loss)	181,700	(19,600)	83,400
Origination and syndication fee revenues	327,900	112,600	122,700
Origination fee expenses	2,400	500	5,900
CLO placement fee revenues	6,100	2,600	6,200
Derivative gains (losses)	(1,100)	500	0
Underwriting fees	0	0	1,300
Service fees	$ 50,700	$ 46,100	$ 51,700