Pro Forma Information (Detail) (FolioDynamix, NuCivic, KMI, USD $)	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
FolioDynamix, NuCivic, KMI
Business Acquisition [Line Items]
Revenue	$ 30,600	$ 26,600
Net income (loss) from continuing operations attributable to Actua Corporation	$ (14,800)	$ (11,800)
Net income (loss) from continuing operations per diluted share attributable to Actua Corporation	$ (0.40)	$ (0.32)

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

+ References

+ Details

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- Definition

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

+ References

+ Details

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