The Company	9 Months Ended
Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
The Company	The Company Description of the Company Actua Corporation (together with its subsidiaries, "Actua"), which was formed on March 4, 1996, is a multi-vertical cloud technology company with offerings that it believes create unique and compelling value for its customers and provide transformative efficiency to vertical markets worldwide. As of September 30, 2017, Actua owned majority interests in three businesses, each of which addresses the needs of a specific vertical market or industry: BOLT Solutions, Inc. ("Bolt"), Folio Dynamics Holdings, Inc. ("FolioDynamix") and VelocityEHS Holdings, Inc. ("VelocityEHS"). Actua has entered into a Membership Interest Purchase Agreement, dated as of September 23, 2017, by and among Actua, Actua Holdings, Inc., Arsenal Acquisition Holdings, LLC, and Velocity Holdco III Inc. (formerly Arsenal Buyer Inc.), an affiliate of CVC Growth Fund (“CVC”) (such agreement, the “Velocity/Bolt Sale Agreement”). Under the Velocity/Bolt Sale Agreement, CVC has agreed to purchase all of Actua’s interests in VelocityEHS and Bolt based on a total enterprise values of $354 million (such transaction, the “Velocity/Bolt Sale”). FolioDynamix has entered into an Agreement and Plan of Merger, dated as of September 25, 2017, by and among FolioDynamix, Envestnet, Inc. (“Envestnet”), FCD Merger Sub, Inc. and Actua USA Corporation, as the representative of FolioDynamix’s stockholders (such agreement, the “Folio Sale Agreement”). Under the Folio Sale Agreement, Envestnet has agreed to acquire FolioDynamix through the merger of FolioDynamix into a wholly-owned subsidiary of Envestnet for $195 million of cash, subject to adjustments for working capital, cash, debt and other items (including a potential downward adjustment of up to $130 million relating to the receipt of certain third part consents) (such transaction, the “Folio Sale,” and together with the Velocity/Bolt Sale, the “Transactions”). Actua filed a proxy statement with the SEC on November 7, 2017 describing the Transactions in detail and soliciting the vote of Actua’s stockholders to, among other things, approve both the Velocity/Bolt Sale and the Folio Sale, which together constitute a sale of substantially all of Actua’s assets. The closing of each of the Velocity/Bolt Sale and the Folio Sale is subject to a number of conditions, including, in the case of the Velocity/Bolt Sale, the approval of Actua’s stockholders. A number of these conditions are outside of Actua’s control. There can be no assurance that either the Velocity/Bolt Sale or the Folio Sale will be consummated. Assuming that the Transactions are consummated, Actua intends to distribute substantially all of the net proceeds from the Velocity/Bolt Sale and the Folio Sale to its stockholders as soon as practicable following the closing of both the Velocity/Bolt Sale and the Folio Sale. There can be no assurance, however, of the exact amount of cash proceeds to be distributed to Actua’s stockholders or of the exact timing of any such distributions. Following the consummation of the Velocity/Bolt Sale and the Folio Sale, Actua intends to monetize its remaining assets, which consist largely of minority ownership stakes (generally less than 10%) in relatively small private companies, and to discharge its outstanding obligations as it winds down its operations. Actua intends to significantly reduce its operating costs during this wind-down stage. Actua’s goal is to monetize its remaining holdings during the 12- to 18-month period following the later to occur of the closing of the Velocity/Bolt Sale and the closing of the Folio Sale. As part of the process of winding down its operations and liquidating its remaining assets, following the distribution of substantially all of the net proceeds from the Velocity/Bolt Sale and the Folio Sale, Actua intends to delist its common stock with NASDAQ and to deregister its common stock with the SEC in connection with the adoption of a plan of liquidation. There can be no assurance as to how long this process will take. Please refer to Item 1, "Business," in Actua’s Annual Report on Form 10-K for the year ended December 31, 2016 for a more detailed description of Actua and its businesses. Basis of Presentation On October 18, 2016, the sale of GovDelivery Holdings, Inc. ("GovDelivery") to affiliates of Vista Equity Partners ("Vista") (such transaction, the "GovDelivery Sale") was consummated. Accordingly, the financial results of GovDelivery are presented as discontinued operations in the consolidated financial statements for the three and nine months ended September 30, 2016 (the "Consolidated Financial Statements".) As a result of the execution of the Velocity/Bolt Sale Agreement and the Folio Sale Agreement, as well as other relevant factors, the criteria for held-for-sale classification and discontinued operations presentation were met on September 30, 2017. Accordingly, the financial results and financial positions of Bolt, FolioDynamix and VelocityEHS are presented as discontinued operations in the Consolidated Financial Statements for all periods presented. The Consolidated Financial Statements contained herein include the accounts of Actua Corporation and its wholly-owned and majority-owned subsidiaries.

The Company

Description of the Company

Actua Corporation (together with its subsidiaries, "Actua"), which was formed on March 4, 1996, is a multi-vertical cloud technology company with offerings that it believes create unique and compelling value for its customers and provide transformative efficiency to vertical markets worldwide. As of September 30, 2017, Actua owned majority interests in three businesses, each of which addresses the needs of a specific vertical market or industry: BOLT Solutions, Inc. ("Bolt"), Folio Dynamics Holdings, Inc. ("FolioDynamix") and VelocityEHS Holdings, Inc. ("VelocityEHS").

Actua has entered into a Membership Interest Purchase Agreement, dated as of September 23, 2017, by and among Actua, Actua Holdings, Inc., Arsenal Acquisition Holdings, LLC, and Velocity Holdco III Inc. (formerly Arsenal Buyer Inc.), an affiliate of CVC Growth Fund (“CVC”) (such agreement, the “Velocity/Bolt Sale Agreement”). Under the Velocity/Bolt Sale Agreement, CVC has agreed to purchase all of Actua’s interests in VelocityEHS and Bolt based on a total enterprise values of $354 million (such transaction, the “Velocity/Bolt Sale”).

FolioDynamix has entered into an Agreement and Plan of Merger, dated as of September 25, 2017, by and among FolioDynamix, Envestnet, Inc. (“Envestnet”), FCD Merger Sub, Inc. and Actua USA Corporation, as the representative of FolioDynamix’s stockholders (such agreement, the “Folio Sale Agreement”). Under the Folio Sale Agreement, Envestnet has agreed to acquire FolioDynamix through the merger of FolioDynamix into a wholly-owned subsidiary of Envestnet for $195 million of cash, subject to adjustments for working capital, cash, debt and other items (including a potential downward adjustment of up to $130 million relating to the receipt of certain third part consents) (such transaction, the “Folio Sale,” and together with the Velocity/Bolt Sale, the “Transactions”).

Actua filed a proxy statement with the SEC on November 7, 2017 describing the Transactions in detail and soliciting the vote of Actua’s stockholders to, among other things, approve both the Velocity/Bolt Sale and the Folio Sale, which together constitute a sale of substantially all of Actua’s assets. The closing of each of the Velocity/Bolt Sale and the Folio Sale is subject to a number of conditions, including, in the case of the Velocity/Bolt Sale, the approval of Actua’s stockholders. A number of these conditions are outside of Actua’s control. There can be no assurance that either the Velocity/Bolt Sale or the Folio Sale will be consummated.

Assuming that the Transactions are consummated, Actua intends to distribute substantially all of the net proceeds from the Velocity/Bolt Sale and the Folio Sale to its stockholders as soon as practicable following the closing of both the Velocity/Bolt Sale and the Folio Sale. There can be no assurance, however, of the exact amount of cash proceeds to be distributed to Actua’s stockholders or of the exact timing of any such distributions.

Following the consummation of the Velocity/Bolt Sale and the Folio Sale, Actua intends to monetize its remaining assets, which consist largely of minority ownership stakes (generally less than 10%) in relatively small private companies, and to discharge its outstanding obligations as it winds down its operations. Actua intends to significantly reduce its operating costs during this wind-down stage. Actua’s goal is to monetize its remaining holdings during the 12- to 18-month period following the later to occur of the closing of the Velocity/Bolt Sale and the closing of the Folio Sale.

As part of the process of winding down its operations and liquidating its remaining assets, following the distribution of substantially all of the net proceeds from the Velocity/Bolt Sale and the Folio Sale, Actua intends to delist its common stock with NASDAQ and to deregister its common stock with the SEC in connection with the adoption of a plan of liquidation. There can be no assurance as to how long this process will take.

Please refer to Item 1, "Business," in Actua’s Annual Report on Form 10-K for the year ended December 31, 2016 for a more detailed description of Actua and its businesses.

Basis of Presentation

On October 18, 2016, the sale of GovDelivery Holdings, Inc. ("GovDelivery") to affiliates of Vista Equity Partners ("Vista") (such transaction, the "GovDelivery Sale") was consummated. Accordingly, the financial results of GovDelivery are presented as discontinued operations in the consolidated financial statements for the three and nine months ended September 30, 2016 (the "Consolidated Financial Statements".)

As a result of the execution of the Velocity/Bolt Sale Agreement and the Folio Sale Agreement, as well as other relevant factors, the criteria for held-for-sale classification and discontinued operations presentation were met on September 30, 2017. Accordingly, the financial results and financial positions of Bolt, FolioDynamix and VelocityEHS are presented as discontinued operations in the Consolidated Financial Statements for all periods presented.

The Consolidated Financial Statements contained herein include the accounts of Actua Corporation and its wholly-owned and majority-owned subsidiaries.