Revised Financials Revised Financials - Statement of Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013
Net income (loss)	$ (7,613)		$ 1,967
Foreign currency translation adjustment	2		0
Reclassification to realized gains	0		0
Net foreign currency translation adjustment	2	[1]	0	[1]
Gross unrealized gains on marketable securities, net of tax	1,114	[2]	8,023	[2]
Reclassification to realized gains, net of tax	(185)	[3]	(1,934)	[3]
Net unrealized gain on marketable securities, net of taxes	929		6,089
Comprehensive income (loss)	(6,682)		8,056
Comprehensive loss attributable to non-controlling interest	363		326
Comprehensive income (loss) attributable to Steel Excel Inc.	(6,319)		8,382
Tax provision on gross unrealized gains	(548)		0
Tax benefit on reclassifications to realized gains (losses)	91		0
Valuation Allowance of Deferred Tax Assets
Net income (loss)			1,967		(33,462)	75	7,657	4,087	1,495	538	1,207
Foreign currency translation adjustment			0
Reclassification to realized gains			0
Net foreign currency translation adjustment			0
Gross unrealized gains on marketable securities, net of tax			8,023
Reclassification to realized gains, net of tax			(1,934)
Net unrealized gain on marketable securities, net of taxes			6,089
Comprehensive income (loss)			8,056
Comprehensive loss attributable to non-controlling interest			326
Comprehensive income (loss) attributable to Steel Excel Inc.			8,382
Tax provision on gross unrealized gains			0
Tax benefit on reclassifications to realized gains (losses)			0
Valuation Allowance of Deferred Tax Assets | Previously Reported
Net income (loss)			4,065
Foreign currency translation adjustment			0
Reclassification to realized gains			0
Net foreign currency translation adjustment			0
Gross unrealized gains on marketable securities, net of tax			5,259
Reclassification to realized gains, net of tax			(1,268)
Net unrealized gain on marketable securities, net of taxes			3,991
Comprehensive income (loss)			8,056
Comprehensive loss attributable to non-controlling interest			326
Comprehensive income (loss) attributable to Steel Excel Inc.			8,382
Tax provision on gross unrealized gains			(2,764)
Tax benefit on reclassifications to realized gains (losses)			666
Valuation Allowance of Deferred Tax Assets | Adjustments
Net income (loss)			(2,098)
Foreign currency translation adjustment			0
Reclassification to realized gains			0
Net foreign currency translation adjustment			0
Gross unrealized gains on marketable securities, net of tax			2,764
Reclassification to realized gains, net of tax			(666)
Net unrealized gain on marketable securities, net of taxes			2,098
Comprehensive income (loss)			0
Comprehensive loss attributable to non-controlling interest			0
Comprehensive income (loss) attributable to Steel Excel Inc.			0
Tax provision on gross unrealized gains			2,764
Tax benefit on reclassifications to realized gains (losses)			$ (666)

[1] No tax effect on cumulative translation adjustments

[2] Tax provision on gross unrealized gains: $(548) $0

[3] Tax benefit on reclassifications to realized gains: $91 $0