Commitments, Contingencies and Guarantees - Additional Information (Details) $ in Millions	3 Months Ended
	Feb. 29, 2020 USD ($)
Loss Contingencies [Line Items]
Loan commitments outstanding to clients	$ 70.0
Fair value of derivative contracts approximated deemed to meet the definition of a guarantee	690.8
Standby Letters of Credit
Loss Contingencies [Line Items]
Letters of credit commitments	36.9
Jefferies Capital Partners LLC
Loss Contingencies [Line Items]
Outstanding equity commitments	11.3
Other Investments
Loss Contingencies [Line Items]
Outstanding equity commitments	$ 7.3
Maximum | Standby Letters of Credit
Loss Contingencies [Line Items]
Standby letters of credit expiration period	1 year