Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income (loss)		$ (97,783)	$ (23,763)	$ 7,327
Other comprehensive income (loss):
Foreign currency translation adjustment		(8)	20	(63)
Reclassification to realized gains		0	0	(361)
Net foreign currency translation adjustment (A)	[1]	(8)	20	(424)
Marketable securities:
Gross unrealized gains (losses) on marketable securities, net of tax (B)	[2]	(24,927)	(20,043)	12,126
Reclassification to realized losses (gains), net of tax (C)	[3]	34,595	(5,223)	(2,608)
Net unrealized gain (loss) on marketable securities, net of taxes		9,668	(25,266)	9,518
Comprehensive income (loss)		(88,123)	(49,009)	16,421
Comprehensive loss (income) attributable to non-controlling interest		376	(44)	3,344
Comprehensive income (loss) attributable to Steel Excel Inc.		(87,747)	(49,053)	19,765
Tax provision on gross unrealized gains (losses)		13,990	0	0
Tax benefit on reclassifications to realized gains (losses)		$ (19,416)	$ 0	$ 0

[1] No tax effect on cumulative translation adjustments

[2] Tax provision on gross unrealized gains (losses)

[3] Tax benefit on reclassifications to realized gains (losses)