Derivative Financial Instruments - Unrealized and Realized Gains (Losses) on Derivative Contracts (Details) - USD ($) $ in Thousands	11 Months Ended	12 Months Ended
Nov. 30, 2018	Nov. 30, 2020	Nov. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in interest expense of Jefferies Group	$ 1,824	$ 4,856	$ (2,546)
Unrealized and realized gains (losses) on derivative contracts	(177,436)	58,275	(294,871)
Net investment hedging
Derivative Instruments, Gain (Loss) [Line Items]
Foreign exchange contracts	0	(3,306)	0
Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses) on derivative contracts	67,291	(52,331)	(188,605)
Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses) on derivative contracts	226	2,266	(822)
Foreign exchange contracts \| Net investment hedging
Derivative Instruments, Gain (Loss) [Line Items]
Foreign exchange contracts	0	(3,306)	0
Equity contracts
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses) on derivative contracts	(267,187)	47,631	(108,961)
Commodity contracts
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses) on derivative contracts	21,785	45,491	(5,630)
Credit contracts
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized and realized gains (losses) on derivative contracts	449	15,218	9,147
Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in interest expense of Jefferies Group	(25,539)	41,524	56,385
Long-term debt
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) recognized in interest expense of Jefferies Group	$ 27,363	$ (36,668)	$ (58,931)

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Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

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Total amount of gain (loss) derived from fair value hedges recognized in earnings in the period.

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Amount before tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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