Revised Financial Statements - Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended									9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Sep. 30, 2015	Sep. 30, 2014
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net revenues	$ 33,480		$ 58,583							$ 107,975	$ 155,666
Gross profits	6,991		17,183							21,923	42,244
Net income (loss) from continuing operations	(14,263)		75							(32,339)	9,699
Net income (loss)	(14,263)		75							(32,339)	9,699
Net income (loss) attributable to Steel Excel Inc.	$ (14,474)		$ (163)							$ (32,260)	$ 9,798
Basic (in dollars per share)	$ (1.27)		$ (0.01)							$ (2.81)	$ 0.83
Diluted (in dollars per share)	$ (1.27)		$ (0.01)							$ (2.81)	$ 0.83
Valuation Allowance of Deferred Tax Assets
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net revenues		$ 54,482	$ 58,583	$ 51,924	$ 45,159	$ 33,496	$ 31,420	$ 28,761	$ 26,351
Gross profits		13,799	17,183	15,003	10,058	9,120	8,010	8,041	6,983
Net income (loss) from continuing operations		(33,968)	75	7,657	1,967	8,150	2,383	732	1,602
Net income (loss)		(33,462)	75	7,657	1,967	4,087	1,495	538	1,207		$ 9,699
Net income (loss) attributable to Steel Excel Inc.		(33,605)	(163)	7,668	2,293	6,599	1,806	723	1,543		$ 9,798
Net income (loss) from continuing operations attributable to Steel Excel Inc.		$ (33,832)	$ (163)	$ 7,668	$ 2,293	$ 8,428	$ 2,205	$ 768	$ 1,622
Basic (in dollars per share)		$ (2.97)	$ (0.01)	$ 0.64	$ 0.19	$ 0.69	$ 0.18	$ 0.06	$ 0.13		$ 0.83
Diluted (in dollars per share)		$ (2.97)	$ (0.01)	$ 0.64	$ 0.19	$ 0.69	$ 0.18	$ 0.06	$ 0.13		$ 0.83