Revised Financial Statements - Statement of Operations (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]
Income before income taxes and equity method income	$ (22,196)			$ 5,165						$ (28,071)	$ 8,760
Benefit from (provision for) income taxes	6,288			(382)						6,660	(577)
Income from equity method investees, net of taxes	5,445			2,874						3,335	1,441
Net income (loss)	(10,463)			7,657						(18,076)	9,624
Net loss (income) attributable to non-controlling interests in consolidated entities	(73)			11						290	337
Net income 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]
Income before income taxes and equity method income				$ 5,165							$ 8,760
Benefit from (provision for) income taxes				(382)							(577)
Income from equity method investees, net of taxes				2,874							1,441
Net income (loss)		$ (33,462)	$ 75	7,657	$ 1,967	$ 4,087	$ 1,495	$ 538	$ 1,207		9,624
Net loss (income) attributable to non-controlling interests in consolidated entities				11							337
Net income attributable to Steel Excel Inc.		$ (33,605)	$ (163)	$ 7,668	$ 2,293	$ 6,599	$ 1,806	$ 723	$ 1,543		$ 9,961
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
Basic and diluted income (loss) per share attributable to Steel Excel Inc.: (in dollars per share)											$ 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				$ 5,165							$ 8,760
Benefit from (provision for) income taxes				693							2,596
Income from equity method investees, net of taxes				2,874							1,441
Net income (loss)				8,732							12,797
Net loss (income) attributable to non-controlling interests in consolidated entities				11							337
Net income attributable to Steel Excel Inc.				$ 8,743							$ 13,134
Basic (in dollars per share)				$ 0.74
Diluted (in dollars per share)				$ 0.73
Basic and diluted income (loss) per share attributable to Steel Excel Inc.: (in dollars per share)											$ 1.10
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	$ 1,000	(1,075)	$ (2,100)	$ (700)	$ (700)	$ (300)	$ (1,800)		(3,173)
Income from equity method investees, net of taxes				0							0
Net income (loss)				(1,075)							(3,173)
Net loss (income) attributable to non-controlling interests in consolidated entities				0							0
Net income attributable to Steel Excel Inc.				$ (1,075)							$ (3,173)
Basic (in dollars per share)				$ (0.09)
Diluted (in dollars per share)				$ (0.09)
Basic and diluted income (loss) per share attributable to Steel Excel Inc.: (in dollars per share)											$ (0.27)