Long-Term Debt (Narrative) (Details)	6 Months Ended
May 31, 2019 USD ($) Contract
Structured Notes \| Jefferies Group
Debt Instrument [Line Items]
Principal amount of debt issued, net of retirements	$ 119,600,000
8.50% Senior Notes, due July 15, 2019
Debt Instrument [Line Items]
Interest rate	8.50%
8.50% Senior Notes, due July 15, 2019 \| Jefferies Group
Debt Instrument [Line Items]
Repayments of debt	$ 36,000,000.0
Revolving Credit Facility \| Jefferies Group
Debt Instrument [Line Items]
Debt face amount	$ 190,000,000.0
Secured Debt \| Foursight Capital Credit Facilities
Debt Instrument [Line Items]
Number of warehouse credit commitment \| Contract	2
Credit facility maximum amount	$ 175,000,000.0
Line of Credit \| Foursight Capital Credit Facilities \| Foursight Capital
Debt Instrument [Line Items]
Assets pledged for indebtedness	$ 148,300,000

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