Contingencies	3 Months Ended
Mar. 31, 2015
Commitments And Contingencies Disclosure [Abstract]
Contingencies	14. Contingencies During 2008 and 2009, two carried interest plans (one in each year) were established, for which a carried interest of 15% is allocable to Actua’s management participants in each plan. Carried interest will be paid in connection with a liquidity event or income receipt at any of the businesses in which the carried interest plans hold interests, subject to an aggregate specified hurdle threshold and holdback and clawback criteria. Actua has deployed approximately $86 million to date with respect to these plans, including approximately $25.5 million in 2014. Actua’s ownership in Bolt acquired prior to 2015 is held in the 2009 carried interest plan, and the activities over the past few years relative to the 2009 carried interest plan primarily relate to cash deployment from Actua to achieve its objectives of increasing its ownership in, and supporting the cash needs of, Bolt. Beginning in 2015, any additional cash deployment to Bolt will not be included in the carried interest plans. Other than the stake in Bolt held by the 2009 carried interest plan, the assets held by the carried interest plans are immaterial to Actua. Actua does not expect a liquidity or income receipt at any of the relevant businesses to occur in the near future, and, accordingly, Actua has not recorded a liability with respect to these plans. Once a liquidity event or income receipt at any of the relevant businesses that would yield proceeds in excess of the calculated hurdle rate occurs, and a payment becomes probable and estimable, Actua would record the appropriate liability. Payments against that liability would occur thereafter subject to relevant holdbacks and clawbacks. As of March 31, 2015, the aggregate specified hurdle thresholds related to both carried interest plans had not been met.

Contingencies

3 Months Ended

Mar. 31, 2015

Commitments And Contingencies Disclosure [Abstract]

14. Contingencies

During 2008 and 2009, two carried interest plans (one in each year) were established, for which a carried interest of 15% is allocable to Actua’s management participants in each plan. Carried interest will be paid in connection with a liquidity event or income receipt at any of the businesses in which the carried interest plans hold interests, subject to an aggregate specified hurdle threshold and holdback and clawback criteria. Actua has deployed approximately $86 million to date with respect to these plans, including approximately $25.5 million in 2014. Actua’s ownership in Bolt acquired prior to 2015 is held in the 2009 carried interest plan, and the activities over the past few years relative to the 2009 carried interest plan primarily relate to cash deployment from Actua to achieve its objectives of increasing its ownership in, and supporting the cash needs of, Bolt. Beginning in 2015, any additional cash deployment to Bolt will not be included in the carried interest plans. Other than the stake in Bolt held by the 2009 carried interest plan, the assets held by the carried interest plans are immaterial to Actua. Actua does not expect a liquidity or income receipt at any of the relevant businesses to occur in the near future, and, accordingly, Actua has not recorded a liability with respect to these plans. Once a liquidity event or income receipt at any of the relevant businesses that would yield proceeds in excess of the calculated hurdle rate occurs, and a payment becomes probable and estimable, Actua would record the appropriate liability. Payments against that liability would occur thereafter subject to relevant holdbacks and clawbacks. As of March 31, 2015, the aggregate specified hurdle thresholds related to both carried interest plans had not been met.