Short-Term Borrowings (Details) - USD ($)	6 Months Ended
	May 31, 2020	Nov. 30, 2019
Short-term Debt [Line Items]
Short-term borrowings	$ 656,855,000	$ 548,490,000
Interest rates on short-term borrowings outstanding	2.38%	3.24%
Floating rate puttable notes
Short-term Debt [Line Items]
Short-term borrowings	$ 6,800,000	$ 0
Principal amount of short-term debt issued	6,800,000
Equity-linked notes
Short-term Debt [Line Items]
Short-term borrowings	15,671,000	20,981,000
Equity-linked notes due March 13, 2020
Short-term Debt [Line Items]
Short-term debt matured	5,200,000
Jefferies Group credit facility | Line of Credit | JPMorgan Chase Bank, N.A.
Short-term Debt [Line Items]
Credit facility, maximum borrowing capacity	296,000,000.0
Intraday Credit Facility | Revolving Credit Facility
Short-term Debt [Line Items]
Credit facility, maximum borrowing capacity	$ 150,000,000.0
Debt instrument, interest rate	0.12%
Intraday Credit Facility | Revolving Credit Facility | Base rate
Short-term Debt [Line Items]
Basis spread on variable rate (as a percent)	3.00%
Intraday Credit Facility | Revolving Credit Facility | Federal funds effective rate
Short-term Debt [Line Items]
Basis spread on variable rate (as a percent)	0.50%
Bank loans
Short-term Debt [Line Items]
Short-term borrowings	$ 634,384,000	$ 527,509,000