Investments - Jefferies Finance - Narrative (Details) - USD ($)		12 Months Ended
	May 15, 2019	Nov. 30, 2019	Nov. 30, 2018	Nov. 30, 2017	Mar. 28, 2019
Schedule of Equity Method Investments [Line Items]
Payables to brokers, dealers and clearing organizations		$ 2,555,178,000	$ 2,448,059,000
Financial instruments sold, not yet purchased, at fair value		10,532,460,000	9,478,944,000
Interest expense		1,472,002,000	1,246,256,000	$ 980,473,000
Promissory Note
Schedule of Equity Method Investments [Line Items]
Debt principal amount					$ 1,000,000,000.0
Interest expense	$ 3,800,000
Jefferies Finance
Schedule of Equity Method Investments [Line Items]
Equity commitment		750,000,000.0
Total committed equity capitalization		1,500,000,000
Funded portion of equity commitment to subsidiary		643,700,000
Unfunded portion of equity commitment to subsidiary		$ 106,300,000
Extension period		1 year
Termination notice period		60 days
Funded portion of loan commitment		$ 0.0
Loan commitment		250,000,000.0
Payables to brokers, dealers and clearing organizations		4,700,000	200,000
Financial instruments sold, not yet purchased, at fair value		200,000	400,000
Jefferies Finance | Committed advances
Schedule of Equity Method Investments [Line Items]
Committed line of credit facility amount		500,000,000.0
Jefferies Finance | Other Assets
Schedule of Equity Method Investments [Line Items]
Receivables under service agreement		17,200,000	35,200,000
Jefferies Finance | Accounts expenses and other liabilities
Schedule of Equity Method Investments [Line Items]
Payables under service agreement		13,700,000	$ 14,100,000
Jefferies Finance | Payables to customers
Schedule of Equity Method Investments [Line Items]
Payables under service agreement		$ 17,600,000