Investments - Summary of Selected Financial Information for Jefferies Finance (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	May 31, 2020	May 31, 2019	May 31, 2020	May 31, 2019	Nov. 30, 2019
Schedule of Equity Method Investments [Line Items]
Net earnings (loss)	$ 128,896	$ 109,819	$ 300,261	$ 156,184
Jefferies Finance, LLC
Schedule of Equity Method Investments [Line Items]
Interest income	1,400	0	2,200	0
Unfunded commitment fees	100	300	400	600
Our total equity balance	602,800		602,800		$ 642,000
Origination and syndication fee revenues	43,800	69,300	81,500	91,200
Origination fee expenses	3,000	8,200	8,600	13,600
CLO placement fee revenues	0	0	400	1,300
Underwriting fees	0	1,000	300	1,000
Service fees	10,700	11,200	35,900	38,300
Jefferies Finance, LLC | Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Net earnings (loss)	$ (99,200)	$ 50,200	$ (78,500)	$ 47,800