Earnings (Loss) Per Common Share (Earnings Per Share Computation) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Line Items]
Net income (loss) attributable to Leucadia National Corporation common shareholders	$ 154,358	$ (173,173)	$ (11,233)	$ 223,992
Allocation of earnings to participating securities	(2,060)	0	0	(3,871)
Net income (loss) attributable to Leucadia National Corporation common shareholders for basic earnings (loss) per share	152,298	(173,173)	(11,233)	220,121
Adjustment to allocation of earnings to participating securities related to diluted shares	6	0	0	(24)
Mandatorily redeemable convertible preferred share dividends	1,016	0	0	0
Net income (loss) attributable to Leucadia National Corporation common shareholders for diluted earnings (loss) per share	$ 153,320	$ (173,173)	$ (11,233)	$ 220,097
Denominator for basic earnings (loss) per share - weighted average shares	370,404,000	372,547,000	371,814,000	373,181,000
Stock options	1,000	0	0	6,000
Warrants	0	0	0	0
Mandatorily redeemable convertible preferred shares	4,162,000	0	0	0
Denominator for diluted earnings (loss) per share	374,567,000	372,547,000	371,814,000	373,187,000
Weighted average shares of participating securities	5,009,500	6,320,200	4,859,900	6,641,100
Dividends declared on participating securities	$ 300	$ 400	$ 900	$ 1,200
3.875% Convertible Senior Debentures, due November 1, 2029 [Member]
Earnings Per Share [Line Items]
Convertible Debenture/Notes	0	0	0	0