Consolidated Statements Of Operations (USD $) In Thousands, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Consolidated Statements Of Operations [Abstract]
Revenues	$ 35,142	$ 30,222	$ 104,424	$ 82,634
Operating expenses
Cost of revenue	21,128	18,056	63,893	52,381
Selling, general and administrative	10,387	9,989	34,089	31,211
Research and development	3,091	2,729	9,545	7,798
Amortization of intangible assets	338	342	1,013	1,020
Impairment related and other	484	1,004	603	1,172
Total operating expenses	35,428	32,120	109,143	93,582
Operating income (loss)	(286)	(1,898)	(4,719)	(10,948)
Other income (loss), net	(374)	9,196	26,184	74,119
Interest income	90	56	298	255
Interest expense	(145)	(123)	(477)	(192)
Income (loss) from continuing operations before income taxes, equity loss and noncontrolling interest	(715)	7,231	21,286	63,234
Income tax (expense) benefit	1,338	(2,860)	(639)	(3,065)
Equity loss	(3,245)	(2,952)	(10,006)	(13,867)
Income (loss) from continuing operations	(2,622)	1,419	10,641	46,302
Income (loss) from discontinued operations		601		802
Net income (loss)	(2,622)	2,020	10,641	47,104
Less: Net income attributable to the noncontrolling interest	335	229	941	781
Net income (loss) attributable to ICG Group, Inc.	(2,957)	1,791	9,700	46,323
Amounts attributable to ICG Group, Inc.:
Net income (loss) from continuing operations	(2,957)	1,339	9,700	45,711
Net income (loss) from discontinued operations		452		612
Net income (loss)	$ (2,957)	$ 1,791	$ 9,700	$ 46,323
Basic income (loss) per share attributable to ICG Group, Inc.:
Income (loss) from continuing operations	$ (0.08)	$ 0.04	$ 0.26	$ 1.25
Income (loss) from discontinued operations		$ 0.01		$ 0.02
Net income (loss)	$ (0.08)	$ 0.05	$ 0.26	$ 1.27
Shares used in computation of basic income (loss) per share	36,556	36,368	36,819	36,340
Diluted income (loss) per share attributable to ICG Group, Inc.:
Income (loss) from continuing operations	$ (0.08)	$ 0.04	$ 0.26	$ 1.24
Income (loss) from discontinued operations		$ 0.01		$ 0.02
Net income (loss)	$ (0.08)	$ 0.05	$ 0.26	$ 1.26
Shares used in computation of diluted income (loss) per share	36,556	36,956	37,738	36,679