Commitments, Contingencies and Guarantees - Narrative (Details) $ in Millions	9 Months Ended
	Aug. 31, 2024 USD ($)
Loss Contingencies [Line Items]
Fair value of derivative contracts approximated deemed to meet the definition of a guarantee	$ 200.4
HomeFed LLC
Loss Contingencies [Line Items]
Aggregate amount of infrastructure improvement bonds, outstanding	50.1
Standby letters of credit
Loss Contingencies [Line Items]
Letters of credit commitments	$ 221.4
Standby letters of credit | Maximum
Loss Contingencies [Line Items]
Standby letters of credit expiration period	1 year
Outstanding loan commitments to clients
Loss Contingencies [Line Items]
Loan commitments outstanding to clients	$ 515.4
Outstanding loan commitments to strategic affiliates
Loss Contingencies [Line Items]
Loan commitments outstanding to clients	7.4
Jefferies Capital Partners LLC
Loss Contingencies [Line Items]
Outstanding equity commitments	9.9
Strategic Affiliates
Loss Contingencies [Line Items]
Outstanding equity commitments	265.6
Other Investments
Loss Contingencies [Line Items]
Outstanding equity commitments	$ 45.3