Commitments, Contingencies and Guarantees - Additional Information (Details) $ in Millions	9 Months Ended
	Aug. 31, 2019 USD ($)
Loss Contingencies [Line Items]
Loan commitments outstanding to clients	$ 66.1
Fair value of derivative contracts approximated deemed to meet the definition of a guarantee	239.0
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	17.7
Other Investments
Loss Contingencies [Line Items]
Outstanding equity commitments	$ 11.0
Maximum | Standby Letters of Credit
Loss Contingencies [Line Items]
Standby letters of credit expiration period	1 year