Revised Financial Statements - Statement of Operations (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]
Income before income taxes and equity method income	$ (3,717)		$ 5,435							$ (31,788)	$ 14,195
Benefit from (provision for) income taxes	(2,393)		(517)							4,267	(1,094)
Loss from equity method investees, net of taxes	(8,153)		(4,843)							(4,818)	(3,402)
Net income (loss)	(14,263)		75							(32,339)	9,699
Net loss (income) attributable to non-controlling interests in consolidated entities	(211)		(238)							79	99
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]
Income before income taxes and equity method income			$ 5,435								$ 14,195
Benefit from (provision for) income taxes			(517)								(1,094)
Loss from equity method investees, net of taxes			(4,843)								(3,402)
Net income (loss)		$ (33,462)	75	$ 7,657	$ 1,967	$ 4,087	$ 1,495	$ 538	$ 1,207		9,699
Net loss (income) attributable to non-controlling interests in consolidated entities			(238)								99
Net income (loss) attributable to Steel Excel Inc.		$ (33,605)	$ (163)	$ 7,668	$ 2,293	$ 6,599	$ 1,806	$ 723	$ 1,543		$ 9,798
Basic and diluted income (loss) per share attributable to Steel Excel Inc.: (in dollars per share)			$ (0.01)
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
Valuation Allowance of Deferred Tax Assets | Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income before income taxes and equity method income			$ 5,435								$ 14,195
Benefit from (provision for) income taxes			(1,537)								1,059
Loss from equity method investees, net of taxes			(4,843)								(3,402)
Net income (loss)			(945)								11,852
Net loss (income) attributable to non-controlling interests in consolidated entities			(238)								99
Net income (loss) attributable to Steel Excel Inc.			$ (1,183)								$ 11,951
Basic and diluted income (loss) per share attributable to Steel Excel Inc.: (in dollars per share)			$ (0.10)
Basic (in dollars per share)											$ 1.02
Diluted (in dollars per share)											$ 1.01
Valuation Allowance of Deferred Tax Assets | Adjustments
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income before income taxes and equity method income			$ 0								$ 0
Benefit from (provision for) income taxes		$ 2,200	1,020	$ (1,100)	$ (2,100)	$ (700)	$ (700)	$ (300)	$ (1,800)		(2,153)
Loss from equity method investees, net of taxes			0								0
Net income (loss)			1,020								(2,153)
Net loss (income) attributable to non-controlling interests in consolidated entities			0								0
Net income (loss) attributable to Steel Excel Inc.			$ 1,020								$ (2,153)
Basic and diluted income (loss) per share attributable to Steel Excel Inc.: (in dollars per share)			$ 0.09
Basic (in dollars per share)											$ (0.18)
Diluted (in dollars per share)											$ (0.18)