Intangible Assets, Net and Goodwill (Schedule of Intangible Assets, Net And Goodwill) (Details) - USD ($) $ in Thousands	May 31, 2019	Nov. 30, 2018
Intangible Assets [Line Items]
Intangible assets, net (excluding goodwill)	$ 181,629	$ 188,291
Goodwill	1,701,301	1,701,840
Total intangible assets, net and goodwill	1,882,930	1,890,131
Other operations
Intangible Assets [Line Items]
Goodwill	3,459	3,459
Jefferies Group
Intangible Assets [Line Items]
Goodwill	1,697,842	1,698,381
Customer and other relationships
Intangible Assets [Line Items]
Intangible assets, net (excluding goodwill)	63,691	67,894
Intangibles, accumulated amortization	106,731	102,579
Trademarks and tradename
Intangible Assets [Line Items]
Intangible assets, net (excluding goodwill)	105,315	107,262
Intangibles, accumulated amortization	22,895	21,086
Other
Intangible Assets [Line Items]
Intangible assets, net (excluding goodwill)	4,068	4,611
Intangibles, accumulated amortization	4,882	4,339
Exchange and clearing organization membership interests and registrations
Intangible Assets [Line Items]
Indefinite lived intangibles	$ 8,555	$ 8,524