Consolidated Statements of Operations and Comprehensive Income (Loss) (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Consolidated Statements of Operations and Comprehensive Income (Loss) [Abstract]
Revenue	$ 51,239	$ 35,142	$ 132,947	$ 104,424
Operating expenses
Cost of revenue	30,950	21,128	81,593	63,893
Selling, general and administrative	20,255	10,387	49,045	34,089
Research and development	5,572	3,091	12,924	9,545
Amortization of intangible assets	2,525	338	4,385	1,013
Impairment related and other	739	484	1,026	603
Total operating expenses	60,041	35,428	148,973	109,143
Operating income (loss)	(8,802)	(286)	(16,026)	(4,719)
Other income (loss), net	31,570	(374)	33,021	26,184
Interest income	105	90	335	298
Interest expense	(202)	(145)	(398)	(477)
Income (loss) before income taxes and equity loss	22,671	(715)	16,932	21,286
Income tax (expense) benefit	(109)	1,338	(1,041)	(639)
Equity loss	(1,608)	(3,245)	(7,147)	(10,006)
Less: Net income (loss) attributable to the non controlling interest	(387)	335	417	941
Net income (loss) attributable to ICG Group, Inc.	21,341	(2,957)	8,327	9,700
Basic income (loss) per share attributable to ICG Group, Inc.	$ 0.60	$ (0.08)	$ 0.23	$ 0.26
Shares used in computation of basic income (loss) per share	35,650	36,556	35,907	36,819
Diluted income (loss) per share attributable to ICG Group, Inc.	$ 0.59	$ (0.08)	$ 0.23	$ 0.26
Shares used in computation of diluted income (loss) per share	36,273	36,556	36,435	37,738
Net income (loss)	20,954	(2,622)	8,744	10,641
Other comprehensive income (loss)
Unrealized holding gains (losses) in marketable securities	(13)		1,552
Reclassification adjustments/realized net gains on marketable securities	(106)		(1,552)
Other accumulated other comprehensive income (loss)	(56)	24	(47)	9
Comprehensive income (loss)	20,779	(2,598)	8,697	10,650
Less: Comprehensive income attributable to the noncontrolling interest	(443)	359	370	950
Comprehensive income (loss) attributable to ICG Group, Inc.	$ 21,222	$ (2,957)	$ 8,327	$ 9,700