Investments - Jefferies Finance - Narrative (Details) - Jefferies Finance, LLC - USD ($) $ in Millions	3 Months Ended
	Feb. 28, 2021	Nov. 30, 2020
Guarantee Obligations [Line Items]
Equity commitment	$ 750.0
Total committed equity capitalization of JFIN	1,500.0
Funded portion of equity commitment to subsidiary	652.4
Unfunded portion of equity commitment to subsidiary	$ 97.6
Extension period	1 year
Termination notice period	60 days
Funded portion of loan commitment	$ 0.0
Loan commitment	250.0
Other assets
Guarantee Obligations [Line Items]
Receivables under service agreement	12.4	$ 24.2
Accrued expense and other liabilities
Guarantee Obligations [Line Items]
Due to related parties	13.7	$ 13.7
Corporate debt securities
Guarantee Obligations [Line Items]
Committed line of credit facility amount	$ 500.0