Loans to and Investments in Associated Companies - Jefferies Finance (Details) - USD ($)		11 Months Ended	12 Months Ended
	May 15, 2019	Nov. 30, 2018	Nov. 30, 2020	Nov. 30, 2019	Mar. 28, 2019
Schedule of Equity Method Investments [Line Items]
Other assets			$ 2,189,257,000	$ 2,450,109,000
Payables, expense accruals and other liabilities			10,388,072,000	8,179,013,000
Interest expense		$ 89,249,000	84,870,000	87,177,000
Jefferies Group
Schedule of Equity Method Investments [Line Items]
Interest expense		1,245,694,000	$ 945,056,000	1,465,680,000
Jefferies Finance
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage			50.00%
Equity commitment			$ 750,000,000.0
Funded equity commitments			$ 652,400,000
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
Credit facility termination notice period			60 days
Funded portion of line of credit commitment			$ 50,000,000.0
Line of credit facility commitment of Jefferies			$ 250,000,000.0
Jefferies Finance
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage			50.00%
Credit facility, extension period			1 year
Other assets			$ 24,200,000	17,200,000
Payables, expense accruals and other liabilities			13,700,000	13,700,000
Jefferies Finance | Lending transactions
Schedule of Equity Method Investments [Line Items]
Payables, expense accruals and other liabilities				17,600,000
Jefferies Finance | Jefferies Group
Schedule of Equity Method Investments [Line Items]
Interest income and unfunded commitment fees related to facility commitment		$ 2,400,000	$ 3,500,000	1,300,000
Promissory note | Jefferies Group
Schedule of Equity Method Investments [Line Items]
Debt principal amount					$ 1,000,000,000.0
Interest expense	$ 3,800,000
Jefferies Finance | Affiliated entity
Schedule of Equity Method Investments [Line Items]
Purchases of loan receivables				$ 65,300,000