Selected Quarterly Financial Data (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Net revenues	$ 54,482	$ 58,583	$ 51,924	$ 45,159	$ 33,496	$ 31,420	$ 28,761	$ 26,351	$ 210,148	$ 120,028	$ 100,104
Gross profits	14,598	17,984	15,738	10,849	10,172	8,080	8,705	7,686	59,169	34,643	34,040
Net income (loss) from continuing operations	(36,121)	(945)	8,732	4,065	8,895	3,047	1,080	3,369	(24,269)	16,391	22,179
Net income (loss)	(35,615)	(945)	8,732	4,065	4,832	2,159	886	2,974	(23,763)	10,851	20,244
Net income (loss) attributable to Steel Excel Inc.	(35,758)	(1,183)	8,743	4,391	7,344	2,470	1,071	3,310	(23,807)	14,195	20,693
Net income (loss) from continuing operations attributable to Steel Excel Inc.	(35,985)	(1,183)	8,743	4,391	9,173	2,869	1,116	3,389
Net income, basic (in dollars per share)	$ (3.15)	$ (0.10)	$ 0.74	$ 0.37	$ 0.75	$ 0.23	$ 0.09	$ 0.26	$ (2.04)	$ 1.13	$ 1.71
Net income, diluted (in dollars per share)	$ (3.15)	$ (0.10)	$ 0.73	$ 0.37	$ 0.75	$ 0.23	$ 0.09	$ 0.26	$ (2.04)	$ 1.13	$ 1.71
Impairment of goodwill	36,700								36,666	0	192
Income tax benefit	$ 1,700								$ 1,719	$ 7,281	$ 1,373