Nature Of Operations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Jan. 31, 2015	May 07, 2015
National Beef [Member]
Nature Of Operations [Line Items]
Percentage interest owned in subsidiary	78.90%
Idaho Timber [Member]
Nature Of Operations [Line Items]
Domestic facilities	10
Conwed Plastics [Member]
Nature Of Operations [Line Items]
Foreign facilities	1
Domestic facilities	4
Berkadia [Member]
Nature Of Operations [Line Items]
Percentage of ownership owned	50.00%
Garcadia [Member]
Nature Of Operations [Line Items]
Number of automobile dealerships	26
HomeFed Corporation [Member]
Nature Of Operations [Line Items]
Percentage of ownership owned	65.00%
Linkem [Member]
Nature Of Operations [Line Items]
Percentage of ownership owned	42.00%
Percentage of ownership upon conversion of note	55.00%
HRG [Member]
Nature Of Operations [Line Items]
Percentage of outstanding common stock owned	23.00%	23.00%
Number of operating segments	4
Golden Queen Mining Company, LLC [Member]
Nature Of Operations [Line Items]
Percentage of ownership owned	34.00%
Jefferies LoanCore [Member]
Nature Of Operations [Line Items]
Percentage of ownership owned	48.50%
Jefferies Finance [Member]
Nature Of Operations [Line Items]
Percentage of ownership owned	50.00%
FXCM [Member]
Nature Of Operations [Line Items]
Senior secured term loan receivable	287.6		$ 300.0
FXCM [Member] | Subsequent Event [Member]
Nature Of Operations [Line Items]
Senior secured term loan receivable				$ 228.4
Beef Processing Facility [Member] | National Beef [Member]
Nature Of Operations [Line Items]
Domestic facilities	2
Consumer-Ready Facility [Member] | National Beef [Member]
Nature Of Operations [Line Items]
Domestic facilities	3
Tanning Facility [Member] | National Beef [Member]
Nature Of Operations [Line Items]
Domestic facilities	1