Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 139,149	$ 293,923
Other comprehensive income (loss):
Net unrealized holding gains (losses) on investments arising during the period, net of income tax provision (benefit) of $(370) and $5,907	(1,226)	10,143
Less: reclassification adjustment for net (gains) losses included in net income (loss), net of income tax provision (benefit) of $(5) and $(11)	15	18
Net change in unrealized holding gains (losses) on investments, net of income tax provision (benefit) of $(365) and $5,918	(1,211)	10,161
Net unrealized foreign exchange gains (losses) arising during the period, net of income tax provision (benefit) of $1,926 and $1,511	17,903	(18)
Less: reclassification adjustment for foreign exchange (gains) losses included in net income (loss), net of income tax provision (benefit) of $0 and $1,097	0	5,290
Net change in unrealized foreign exchange gains (losses), net of income tax provision (benefit) of $1,926 and $414	17,903	5,272
Net change in unrealized instrument specific credit risk gains (losses), net of income tax provision (benefit) of $(4,634) and $(6,345)	(11,569)	(9,695)
Net change in unrealized cash flow hedges gains (losses), net of income tax provision (benefit) of $1,234 and $0	1,248	0
Reclassification adjustment for pension (gains) losses included in net income (loss), net of income tax provision (benefit) of $(151) and $(1,435)	5,806	(798)
Other comprehensive income, net of income taxes	12,177	4,940
Comprehensive income	151,326	298,863
Comprehensive loss attributable to the noncontrolling interests	1,344	523
Comprehensive income attributable to the redeemable noncontrolling interests	(14,796)	(12,022)
Preferred stock dividends	(1,172)	(1,016)
Comprehensive income attributable to Leucadia National Corporation common shareholders	$ 136,702	$ 286,348