Intangible Assets, Net and Goodwill - Schedule of Intangible Assets and Goodwill (Details) - USD ($) $ in Thousands	Nov. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Amortizable intangibles	$ 188,291	$ 741,030
Goodwill	1,701,840	1,722,150
Total intangible assets, net and goodwill	1,890,131	2,463,180
National Beef
Finite-Lived Intangible Assets [Line Items]
Amortizable intangibles		539,600
Goodwill	0	14,991
Jefferies Group
Finite-Lived Intangible Assets [Line Items]
Goodwill	1,698,381	1,703,300
Customer and other relationships
Finite-Lived Intangible Assets [Line Items]
Amortizable intangibles	67,894	347,767
Intangibles, accumulated amortization	102,579	230,074
Trademarks and tradename
Finite-Lived Intangible Assets [Line Items]
Amortizable intangibles	107,262	293,851
Intangibles, accumulated amortization	21,086	95,627
Supply contracts
Finite-Lived Intangible Assets [Line Items]
Amortizable intangibles	0	86,160
Intangibles, accumulated amortization	0	57,440
Other
Finite-Lived Intangible Assets [Line Items]
Amortizable intangibles	4,611	4,701
Intangibles, accumulated amortization	4,339	3,885
Exchange and clearing organization membership interests and registrations
Finite-Lived Intangible Assets [Line Items]
Indefinite lived intangibles	8,524	8,551
Other Operations [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 3,459	$ 3,859