Loans to and Investments in Associated Companies - Jefferies Finance (Details)	3 Months Ended		6 Months Ended
	May 31, 2021 USD ($)	May 31, 2020 USD ($)	May 31, 2021 USD ($) businessLine	May 31, 2020 USD ($)	Nov. 30, 2020 USD ($)
Investments In Associated Companies [Line Items]
Other assets	$ 2,383,096,000		$ 2,383,096,000		$ 2,189,257,000
Payables, expense accruals and other liabilities	12,394,362,000		12,394,362,000		10,388,072,000
Jefferies Finance
Investments In Associated Companies [Line Items]
Equity commitment	750,000,000.0		750,000,000.0
Funded equity commitments	676,800,000		$ 676,800,000
Investment commitment extension			1 year
Investment commitment termination notice period			60 days
Total line of credit facility commitment under joint venture	500,000,000.0		$ 500,000,000.0
Termination notice			60 days
Line of credit facility, commitment of Jefferies, funded	0.0		$ 0.0
Line of credit facility commitment of Jefferies	250,000,000.0		$ 250,000,000.0
Jefferies Finance
Investments In Associated Companies [Line Items]
Extension period			1 year
Other assets	31,600,000		$ 31,600,000		24,200,000
Payables, expense accruals and other liabilities	$ 1,800,000		$ 1,800,000		$ 13,700,000
Jefferies Finance | Jefferies Finance
Investments In Associated Companies [Line Items]
Equity method investment, ownership percentage	50.00%		50.00%
Number of business lines | businessLine			2
Jefferies Finance | Jefferies Finance | Jefferies Credit Partners
Investments In Associated Companies [Line Items]
Amount managed under private credit platform			$ 10,000,000,000.0
Jefferies Finance | Jefferies Finance | Minimum | Leveraged Finance Arrangement
Investments In Associated Companies [Line Items]
Transaction range			250,000,000
Jefferies Finance | Jefferies Finance | Maximum | Leveraged Finance Arrangement
Investments In Associated Companies [Line Items]
Transaction range			1,500,000,000
Jefferies Finance | Jefferies Group
Investments In Associated Companies [Line Items]
Interest income and unfunded commitment fees related to facility commitment	$ 1,300,000	$ 1,500,000	$ 1,900,000	$ 2,600,000