Pro Forma Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
FolioDynamix, NuCivic, KMI, Ludwing and Superior Access
Business Acquisition [Line Items]
Revenue	$ 119,071	$ 90,561
Net income (loss) from continuing operations attributable to Actua Corporation	(41,295)	(35,439)
Net income (loss) from continuing operations per basic and diluted share attributable to Actua Corporation	$ (1.11)	$ (0.97)
MSDSonline and Bolt (including Bolt’s acquisition of Superior Access)
Business Acquisition [Line Items]
Revenue		65,995	47,265
Net income (loss) from continuing operations attributable to Actua Corporation		$ (25,591)	$ 10,134
Net income (loss) from continuing operations per basic and diluted share attributable to Actua Corporation		$ (700.00)	$ 280.00

Business acquisition pro forma earnings per share basic and diluted.

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- Definition

The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(2)-(3)

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1392-128463

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

+ References

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