Unaudited Quarterly Financial Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Operating revenues:
Total operating revenues	$ 9,369	$ 9,777	$ 14,866	$ 9,576	$ 11,193	$ 11,324	$ 9,340	$ 12,076
Operating costs	11,190	12,170	13,110	10,224	10,256	12,640	12,198	11,244	48,979	52,082
Operating profit (loss)	(1,821)	(2,393)	1,756	(648)	937	(1,316)	(2,858)	832
Earnings (loss) from continuing operations	(383)	(5,687)	(1,873)	(2,163)	718	(2,166)	(3,155)	639	(10,034)	(7,468)
Earnings (loss) from discontinued operations, net of income taxes	900	(172)	(51)	(605)	(422)	(462)	(735)	(1,885)	72	(3,501)
Net loss attributable to Signature Group Holdings, Inc.	517	(5,859)	(1,924)	(2,768)	296	(2,628)	(3,890)	(1,246)	(10,034)	(7,468)
Basic earnings (loss) per share:
Weighted average outstanding shares	11,888,615	11,871,639	11,822,649	11,803,988	11,684,649	11,632,829	11,565,196	11,565,196
Continuing operations	$ (0.03)	$ (0.48)	$ (0.15)	$ (0.18)	$ 0.06	$ (0.19)	$ (0.27)	$ 0.06
Discontinued operations, net of income taxes	$ 0.07	$ (0.01)		$ (0.05)	$ (0.04)	$ (0.04)	$ (0.06)	$ (0.16)
Basic earnings (loss) per share	$ 0.04	$ (0.49)	$ (0.15)	$ (0.23)	$ 0.02	$ (0.23)	$ (0.33)	$ (0.10)
Diluted earnings (loss) per share:
Weighted average outstanding shares	13,220,815	11,871,639	11,822,649	11,803,988	11,867,405	11,632,829	11,565,196	11,565,196
Continuing operations	$ (0.03)	$ (0.48)	$ (0.15)	$ (0.18)	$ 0.06	$ (0.19)	$ (0.27)	$ 0.06
Discontinued operations, net of income taxes	$ 0.07	$ (0.01)		$ (0.05)	$ (0.04)	$ (0.04)	$ (0.06)	$ (0.16)
Diluted earnings (loss) per share	$ 0.04	$ (0.49)	$ (0.15)	$ (0.23)	$ 0.02	$ (0.23)	$ (0.33)	$ (0.10)
Industrial Supply
Operating revenues:
Total operating revenues	8,843	10,230	9,452	8,372	9,134	10,203	9,062	7,843
Special Situations
Operating revenues:
Total operating revenues	526	(453)	5,414	1,204	2,059	1,121	278	4,233
Corporate and Other
Operating revenues:
Total operating revenues