Operating Results and Other Key Financial Measures of Operating Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Segment Reporting Information [Line Items]
Expenses	$ 12,838	$ 10,770	$ 36,753	$ 19,363
Other income (expense)	(846)	4,636	1,208	6,215
Earnings (loss) from continuing operations before reorganization items, net and income taxes	(2,346)	1,199	(4,907)	(3,041)
Reorganization items, net		63	80	1,388
Earnings (loss) before income taxes and loss attributable to noncontrolling interest	(2,346)	1,136	(4,987)	(4,429)
Income tax expense (benefit)	(60)	(2,650)	25	(2,762)
Net earnings (loss)	(2,628)	1,244	(7,765)	(9,185)
Earnings (loss) from continuing operations	(2,286)	3,786	(5,012)	(1,667)
Loss attributable to noncontrolling interest		(31)		(93)
Earnings (loss) from discontinued operations, net of income taxes	(342)	(2,542)	(2,753)	(7,518)
Net earnings (loss) attributable to Signature Group Holdings, Inc.	(2,628)	1,275	(7,765)	(9,092)
Earnings (loss) from continuing operations attributable to Signature Group Holdings, Inc.	(2,286)	3,817	(5,012)	(1,574)
Assets	127,029		127,029		143,018
Liabilities	69,399		69,399		79,181
Continuing Operations
Segment Reporting Information [Line Items]
Revenues from external customers	11,338	7,333	30,638	10,107
Expenses	12,838	10,770	36,753	19,363
Other income (expense)	(846)	4,636	1,208	6,215
Earnings (loss) from continuing operations before reorganization items, net and income taxes	(2,346)	1,199	(4,907)	(3,041)
Reorganization items, net		63	80	1,388
Earnings (loss) before income taxes and loss attributable to noncontrolling interest	(2,346)	1,136	(4,987)	(4,429)
Income tax expense (benefit)	(60)	(2,650)	25	(2,762)
Earnings (loss) from continuing operations	(2,286)	3,786	(5,012)	(1,667)
Loss attributable to noncontrolling interest		(31)		(93)
Earnings (loss) from continuing operations attributable to Signature Group Holdings, Inc.	(2,286)	3,817	(5,012)	(1,574)
Assets	123,792		123,792		122,202
Liabilities	59,012		59,012		67,645
Continuing Operations | Signature Special Situations
Segment Reporting Information [Line Items]
Revenues from external customers	1,041	1,013	3,145	2,924
Intersegment revenues	161	256	479	256
Expenses	305	(17)	788	(48)
Other income (expense)	80	492	2,486	1,117
Earnings (loss) from continuing operations before reorganization items, net and income taxes	977	1,778	5,322	4,345
Earnings (loss) before income taxes and loss attributable to noncontrolling interest	977	1,778	5,322	4,345
Income tax expense (benefit)	664	54	696	60
Earnings (loss) from continuing operations	313	1,724	4,626	4,285
Earnings (loss) from continuing operations attributable to Signature Group Holdings, Inc.	313	1,724	4,626	4,285
Assets	45,311		45,311		35,341
Liabilities	23,250		23,250		9,411
Continuing Operations | NABCO
Segment Reporting Information [Line Items]
Revenues from external customers	10,203	6,082	27,107	6,082
Expenses	8,490	5,239	22,926	5,239
Other income (expense)	(76)	(47)	(225)	(47)
Earnings (loss) from continuing operations before reorganization items, net and income taxes	1,637	796	3,956	796
Earnings (loss) before income taxes and loss attributable to noncontrolling interest	1,637	796	3,956	796
Income tax expense (benefit)	741	317	1,668	317
Earnings (loss) from continuing operations	896	479	2,288	479
Earnings (loss) from continuing operations attributable to Signature Group Holdings, Inc.	896	479	2,288	479
Assets	36,673		36,673		39,428
Liabilities	25,539		25,539		30,582
Continuing Operations | Cosmed
Segment Reporting Information [Line Items]
Revenues from external customers	77	227	332	1,067
Expenses	256	617	830	2,224
Other income (expense)			(2)	281
Earnings (loss) from continuing operations before reorganization items, net and income taxes	(179)	(390)	(500)	(876)
Earnings (loss) before income taxes and loss attributable to noncontrolling interest	(179)	(390)	(500)	(876)
Income tax expense (benefit)			3
Earnings (loss) from continuing operations	(179)	(390)	(503)	(876)
Loss attributable to noncontrolling interest		(31)		(93)
Earnings (loss) from continuing operations attributable to Signature Group Holdings, Inc.	(179)	(359)	(503)	(783)
Assets	1,375		1,375		1,735
Liabilities	2,509		2,509		2,367
Continuing Operations | Corporate and Other
Segment Reporting Information [Line Items]
Revenues from external customers	17	11	54	34
Intersegment revenues	270	38	679	83
Expenses	4,218	5,225	13,367	12,287
Other income (expense)	(850)	4,191	(1,051)	4,864
Earnings (loss) from continuing operations before reorganization items, net and income taxes	(4,781)	(985)	(13,685)	(7,306)
Reorganization items, net		63	80	1,388
Earnings (loss) before income taxes and loss attributable to noncontrolling interest	(4,781)	(1,048)	(13,765)	(8,694)
Income tax expense (benefit)	(1,465)	(3,021)	(2,342)	(3,139)
Earnings (loss) from continuing operations	(3,316)	1,973	(11,423)	(5,555)
Earnings (loss) from continuing operations attributable to Signature Group Holdings, Inc.	(3,316)	1,973	(11,423)	(5,555)
Assets	76,466		76,466		64,481
Liabilities	43,747		43,747		44,068
Continuing Operations | Eliminations
Segment Reporting Information [Line Items]
Intersegment revenues	(431)	(294)	(1,158)	(339)
Expenses	(431)	(294)	(1,158)	(339)
Assets	(36,033)		(36,033)		(18,783)
Liabilities	(36,033)		(36,033)		(18,783)
Discontinued Operations
Segment Reporting Information [Line Items]
Revenues from external customers	113	655	1,769	1,476
Expenses	1,234	2,610	4,425	8,333
Other income (expense)	569	34	(199)	387
Earnings (loss) before reorganization items, net and income taxes	(552)	(1,921)	(2,855)	(6,470)
Reorganization items, net	(210)		(102)
Earnings (loss) before income taxes and loss attributable to noncontrolling interest	(342)	(1,921)	(2,753)	(6,470)
Income tax expense (benefit)		621		1,048
Net earnings (loss)	(342)	(2,542)	(2,753)	(7,518)
Earnings attributable to noncontrolling interest
Earnings (loss) from discontinued operations, net of income taxes	(342)	(2,542)	(2,753)	(7,518)
Assets	3,237		3,237		20,816
Liabilities	10,387		10,387		11,536
Total
Segment Reporting Information [Line Items]
Revenues from external customers	11,451	7,988	32,407	11,583
Expenses	14,072	13,380	41,178	27,696
Other income (expense)	(277)	4,670	1,009	6,602
Earnings (loss) before reorganization items, net and income taxes	(2,898)	(722)	(7,762)	(9,511)
Reorganization items, net	(210)	63	(22)	1,388
Earnings (loss) before income taxes and loss attributable to noncontrolling interest	(2,688)	(785)	(7,740)	(10,899)
Income tax expense (benefit)	(60)	(2,029)	25	(1,714)
Net earnings (loss)	(2,628)	1,244	(7,765)	(9,185)
Loss attributable to noncontrolling interest		(31)		(93)
Net earnings (loss) attributable to Signature Group Holdings, Inc.	$ (2,628)	$ 1,275	$ (7,765)	$ (9,092)