Consolidated Statements Of Changes In Equity - USD ($) $ in Thousands	Total	Common Shares $1 Par Value [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Subtotal [Member]	Noncontrolling Interests [Member]
Beginning balance at Dec. 31, 2012	$ 6,767,635	$ 244,583	$ 1,577,528	$ 705,129	$ 4,240,028	$ 6,767,268	$ 367
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	368,078				369,240	369,240	(1,162)
Other comprehensive loss, net of taxes	(167,079)			(167,079)		(167,079)
Acquisition of Jefferies Group LLC	3,741,879	119,363	3,266,336			3,385,699	356,180
Distribution of common shares of Crimson Wine Group, Ltd. to shareholders	(197,000)				(197,000)	(197,000)
Contributions from noncontrolling interests	65,870					0	65,870
Distributions to noncontrolling interests	(355,086)					0	(355,086)
Change in interest in consolidated subsidiary	0		(4,422)			(4,422)	4,422
Share-based compensation expense	87,309		87,309			87,309
Change in fair value of redeemable noncontrolling interests	(16,781)		(16,781)			(16,781)
Issuance of common shares for debt conversion	0
Purchase of common shares for treasury	4,545	184	4,361			4,545
Purchase of common shares for treasury	(40,024)	(1,423)	(38,601)			(40,024)
Dividends ($.25 per common share)	(93,428)				(93,428)	(93,428)
Other	7,135	1,834	5,301			7,135
Ending balance at Dec. 31, 2013	10,173,053	364,541	4,881,031	538,050	4,318,840	10,102,462	70,591
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	203,579				204,306	204,306	(727)
Other comprehensive loss, net of taxes	(90,968)			(90,968)		(90,968)
Contributions from noncontrolling interests	72,221					0	72,221
Distributions to noncontrolling interests	(8,977)					0	(8,977)
Deconsolidation of asset management entities	(77,475)					0	(77,475)
Change in interest in consolidated subsidiary	0		(3,654)			(3,654)	3,654
Share-based compensation expense	109,838		109,838			109,838
Change in fair value of redeemable noncontrolling interests	45,401		45,401			45,401
Issuance of common shares for debt conversion	97,546	4,606	92,940			97,546
Purchase of common shares for treasury	813	36	777			813
Purchase of common shares for treasury	(75,728)	(2,990)	(72,738)			(75,728)
Dividends ($.25 per common share)	(95,077)				(95,077)	(95,077)
Other	15,796	1,306	5,913			7,219	8,577
Ending balance at Dec. 31, 2014	10,370,022	367,499	5,059,508	447,082	4,428,069	10,302,158	67,864
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	274,591				279,587	279,587	(4,996)
Other comprehensive loss, net of taxes	(8,289)			(8,289)		(8,289)
Contributions from noncontrolling interests	16,189					0	16,189
Distributions to noncontrolling interests	(7,277)					0	(7,277)
Deconsolidation of asset management entities	(8,193)					0	(8,193)
Change in interest in consolidated subsidiary	0		(1,092)			(1,092)	1,092
Share-based compensation expense	74,087		74,087			74,087
Change in fair value of redeemable noncontrolling interests	(26,325)		(26,325)			(26,325)
Issuance of common shares for debt conversion	0
Purchase of common shares for treasury	44	2	42			44
Purchase of common shares for treasury	(125,754)	(5,953)	(119,801)			(125,754)
Dividends ($.25 per common share)	(94,674)				(94,674)	(94,674)
Other	1,469	1,069	400			1,469	0
Ending balance at Dec. 31, 2015	$ 10,465,890	$ 362,617	$ 4,986,819	$ 438,793	$ 4,612,982	$ 10,401,211	$ 64,679