Intangible Assets, Net and Goodwill (Schedule of Intangible Assets, Net And Goodwill) (Details) - USD ($) $ in Thousands	Feb. 28, 2019	Nov. 30, 2018
Intangible Assets [Line Items]
Intangible assets, net (excluding goodwill)	$ 185,843	$ 188,291
Goodwill	1,705,105	1,701,840
Total intangible assets, net and goodwill	1,890,948	1,890,131
Other operations
Intangible Assets [Line Items]
Goodwill	3,459	3,459
Jefferies Group
Intangible Assets [Line Items]
Goodwill	1,701,646	1,698,381
Customer and other relationships
Intangible Assets [Line Items]
Intangible assets, net (excluding goodwill)	66,009	67,894
Intangibles, accumulated amortization	104,929	102,579
Trademarks and tradename
Intangible Assets [Line Items]
Intangible assets, net (excluding goodwill)	106,894	107,262
Intangibles, accumulated amortization	22,116	21,086
Other
Intangible Assets [Line Items]
Intangible assets, net (excluding goodwill)	4,349	4,611
Intangibles, accumulated amortization	4,601	4,339
Exchange and clearing organization membership interests and registrations
Intangible Assets [Line Items]
Indefinite lived intangibles	$ 8,591	$ 8,524