CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Statement [Abstract]
Revenue	$ 33,536	$ 19,029	$ 64,128	$ 37,451
Operating expenses
Cost of Revenue	9,783	5,519	19,515	10,418
Sales and marketing	12,163	9,585	23,399	18,116
General and administrative	15,966	12,915	31,402	22,924
Research and development	7,373	3,547	14,466	6,800
Amortization of intangibles assets	3,706	2,293	7,722	4,594
Impairment related and other	166	836	340	836
Total operating expenses	49,157	34,695	96,844	63,688
Operating income (loss)	(15,621)	(15,666)	(32,716)	(26,237)
Other income (loss), net	(425)	637	940	937
Interest income	35	146	54	232
Interest expense	(31)	(1,080)	(68)	(1,591)
Income (loss) before income taxes, equity loss and noncontrolling interest	(16,042)	(15,963)	(31,790)	(26,659)
Income tax (expense) benefit	(1)	599	(178)	505
Equity loss	0	(320)	0	(632)
Income (loss) from continuing operations	(16,043)	(15,684)	(31,968)	(26,786)
Income (loss) from discontinued operations, including gain on sale, net of tax	0	1,315	0	1,363
Net income (loss)	(16,043)	(14,369)	(31,968)	(25,423)
Less: Net income (loss) attributable to the noncontrolling interest	(761)	(1,475)	(1,921)	(2,379)
Net income (loss) attributable to Actua Corporation	(15,282)	(12,894)	(30,047)	(23,044)
Amounts attributable to Actua Corporation:
Net income (loss) from continuing operations	(15,282)	(14,209)	(30,047)	(24,407)
Net income (loss) from discontinued operations	0	1,315	0	1,363
Net income (loss) attributable to Actua Corporation	$ (15,282)	$ (12,894)	$ (30,047)	$ (23,044)
Basic and diluted income (loss) per share attributable to Actua Corporation:
Income (loss) from continuing operations	$ (0.41)	$ (0.38)	$ (0.81)	$ (0.66)
Income (loss) from discontinued operations	0.00	0.03	0.00	0.04
Net income (loss)	$ (0.41)	$ (0.35)	$ (0.81)	$ (0.62)
Shares used in computation of basic and diluted income (loss) per share	37,123	37,313	36,983	37,205
Net income (loss)	$ (16,043)	$ (14,369)	$ (31,968)	$ (25,423)
Other comprehensive income
Unrealized holding gain (loss) in marketable securities	0	0	0	0
Reclassified adjustments/realized net (gains) loss on marketable securities	0	0	0	0
Other accumulated other comprehensive income (loss)	0	0	0	0
Comprehensive income (loss)	(16,043)	(14,369)	(31,968)	(25,423)
Less: Comprehensive income (loss) attributable to noncontrolling interests	(761)	(1,475)	(1,921)	(2,379)
Comprehensive income (loss) attributable to Actua Corporation	$ (15,282)	$ (12,894)	$ (30,047)	$ (23,044)