Revised Financial Statements - Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended									6 Months Ended
	Jun. 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	Jun. 30, 2015	Jun. 30, 2014
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net revenues	$ 35,610			$ 51,924						$ 74,495	$ 97,083
Gross profits	8,235			15,003						14,932	25,061
Net income (loss) from continuing operations	(10,463)			7,657						(18,076)	9,624
Net income (loss)	(10,463)			7,657						(18,076)	9,624
Net income (loss) attributable to Steel Excel Inc.	$ (10,536)			$ 7,668						$ (17,786)	$ 9,961
Basic (in dollars per share)	$ (0.91)			$ 0.64						$ (1.54)	$ 0.83
Diluted (in dollars per share)	$ (0.91)			$ 0.64						$ (1.54)	$ 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		$ 9,624
Net income (loss) attributable to Steel Excel Inc.		(33,605)	(163)	7,668	2,293	6,599	1,806	723	1,543		$ 9,961
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
Diluted (in dollars per share)		$ (2.97)	$ (0.01)	$ 0.64	$ 0.19	$ 0.69	$ 0.18	$ 0.06	$ 0.13