Investments - Summary of Selected Financial Information for Jefferies Finance (Details) - USD ($) $ in Thousands	12 Months Ended
	Nov. 30, 2020	Nov. 30, 2019	Nov. 30, 2018
Schedule of Equity Method Investments [Line Items]
Total assets	$ 47,751,997	$ 43,516,115
Total liabilities	41,385,865	37,386,368
Net earnings (loss)	874,706	244,385	$ 159,017
Jefferies Finance
Schedule of Equity Method Investments [Line Items]
Interest income	2,400	0	1,200
Unfunded commitment fees	1,100	1,300	1,200
Total assets	7,199,500	7,112,400
Total liabilities	5,990,400	5,828,300
Total equity	1,209,100	1,284,100
Our total equity balance	604,600	642,000
Net earnings (loss)	(74,900)	44,500	197,200
Origination and syndication fee revenues	198,100	176,300	377,700
Origination fee expenses	27,300	27,600	56,600
CLO placement fee revenues	1,700	6,000	3,700
Derivative gains (losses)	0	0	(1,600)
Underwriting fees	1,700	3,900	0
Service fees	$ 65,100	$ 60,800	$ 61,700