Segment Information (Schedule Of Segment Reporting Information, By Segment) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Net Revenues	$ 2,366,096	$ 3,003,643	$ 8,390,242	$ 8,798,130
Total consolidated pre-tax income from continuing operations	(272,185)	118,159	315,385	393,174
Depreciation and amortization	58,466	46,464	166,146	132,594
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net Revenues	2,447,086	2,833,849	7,716,002	8,383,338
Total consolidated pre-tax income from continuing operations	(54,316)	55,792	942	286,554
Depreciation and amortization	47,617	42,453	137,964	122,498
Parent Company [Member]
Segment Reporting Information [Line Items]
Total consolidated pre-tax income from continuing operations	(22,598)	(24,281)	(71,208)	(73,824)
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net Revenues	0	0	(21,000)	0
Jefferies [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net Revenues	580,484	840,350	1,964,356	2,460,165
Total consolidated pre-tax income from continuing operations	3,337	133,917	107,606	415,855
Depreciation and amortization	24,165	19,495	68,741	54,909
National Beef [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net Revenues	1,864,030	1,983,349	5,714,914	5,879,820
Total consolidated pre-tax income from continuing operations	(31,680)	26,308	(74,665)	4,813
Depreciation and amortization	22,529	21,479	66,397	63,434
Corporate and Other [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net Revenues	2,572	10,150	36,732	43,353
Total consolidated pre-tax income from continuing operations	(25,973)	(104,433)	(31,999)	(134,114)
Depreciation and amortization	923	1,479	2,826	4,155
All other (Member) [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net Revenues	(80,990)	169,794	695,240	414,792
Total consolidated pre-tax income from continuing operations	(195,271)	86,648	385,651	180,444
Depreciation and amortization	$ 10,849	$ 4,011	$ 28,182	$ 10,096