Contingencies	9 Months Ended
Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Contingencies	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 would be paid in connection with a liquidity event or income receipt at any of the businesses in which the carried interest plans hold debt or equity interests, subject to an aggregate specified hurdle threshold and hold back and clawback criteria. Actua allocated approximately $76.6 million to date with respect to these plans (primarily with respect to Bolt). In connection with the execution of the Velocity/Bolt Sale Agreement, the interest in Bolt held by the 2009 carried interest plan was contributed to a wholly-owned subsidiary of Actua; the participants in the 2009 carried interest plan did not receive any payment under the carried interest plan in connection with the contribution and will not receive any payment under the carried interest plan in connection with the Velocity/Bolt Sale. The remaining assets held by the carried interest plans are immaterial to Actua, and Actua does not expect any payments to be made under either of these plans. Accordingly, Actua has not recorded a liability with respect to these plans.

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 would be paid in connection with a liquidity event or income receipt at any of the businesses in which the carried interest plans hold debt or equity interests, subject to an aggregate specified hurdle threshold and hold back and clawback criteria. Actua allocated approximately $76.6 million to date with respect to these plans (primarily with respect to Bolt). In connection with the execution of the Velocity/Bolt Sale Agreement, the interest in Bolt held by the 2009 carried interest plan was contributed to a wholly-owned subsidiary of Actua; the participants in the 2009 carried interest plan did not receive any payment under the carried interest plan in connection with the contribution and will not receive any payment under the carried interest plan in connection with the Velocity/Bolt Sale. The remaining assets held by the carried interest plans are immaterial to Actua, and Actua does not expect any payments to be made under either of these plans. Accordingly, Actua has not recorded a liability with respect to these plans.