Entity Central Index Key Document and entity information. Document And Entity Information [Abstract] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Statement Of Financial Position [Abstract] ASSETS Assets [Abstract] Current Assets Assets Current [Abstract] Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Restricted Cash Restricted Cash And Cash Equivalents At Carrying Value Accounts receivables, net of allowance ($1,143-2015; $790-2014) Accounts Receivable Net Current Deferred tax asset Deferred Tax Assets Liabilities Net Current Prepaid expenses and other current assets Prepaid Expense And Other Assets Current Total current assets Assets Current Fixed assets, net of accumulated depreciation and amortization ($14,974-2015; $13,757-2014) Property Plant And Equipment Net Goodwill Goodwill Intangible, net Intangible Assets Net Excluding Goodwill Equity and cost method businesses Long Term Investments Deferred tax asset Deferred Tax Assets Net Noncurrent Other assets, net Other Assets Noncurrent Total assets Assets LIABILITIES Liabilities [Abstract] Current Liabilities Liabilities Current [Abstract] Current maturities of long-term debt Long Term Debt Current Accounts payable Accounts Payable Current Accrued expenses Accrued Liabilities Current Accrued compensation and benefits Employee Related Liabilities Current Deferred revenue Deferred Revenue Current Total current liabilities Liabilities Current Long-term debt Long Term Debt Noncurrent Deferred tax liability Deferred Tax Liabilities Noncurrent Deferred revenue Deferred Revenue Noncurrent Other liabilities Other Liabilities Noncurrent Total liabilities Liabilities Redeemable noncontrolling interest (Note 4, Consolidated Businesses) Temporary Equity Carrying Amount Including Portion Attributable To Noncontrolling Interests Actua Corporation’s Stockholders’ Equity Stockholders Equity [Abstract] Preferred stock, $0.01 par value; 10,000 shares authorized, none issued or outstanding Preferred Stock Value Common stock, $0.001 par value; 2,000,000 shares authorized, 46,601 shares (2015) and 46,405 shares (2014) issued Common Stock Value Treasury stock, at cost, 5,988 shares (2015) and 5,892 shares (2014) Treasury Stock Value Additional paid-in capital Additional Paid In Capital Common Stock Accumulated deficit Retained Earnings Accumulated Deficit Accumulated other comprehensive income Accumulated Other Comprehensive Income Loss Net Of Tax Total Actua Corporation’s Stockholders’ Equity Stockholders Equity Noncontrolling interests Minority Interest Total equity Stockholders Equity Including Portion Attributable To Noncontrolling Interest Total Liabilities, Redeemable noncontrolling interest and Equity Liabilities And Stockholders Equity Accounts receivable, allowance Allowance For Doubtful Accounts Receivable Current Accumulated depreciation and amortization Accumulated Depreciation Depletion And Amortization Property Plant And Equipment Preferred stock, par value Preferred Stock Par Or Stated Value Per Share Preferred stock, shares authorized Preferred Stock Shares Authorized Preferred stock, shares issued Preferred Stock Shares Issued Preferred stock, shares outstanding Preferred Stock Shares Outstanding Common stock, par value Common Stock Par Or Stated Value Per Share Common stock, shares authorized Common Stock Shares Authorized Common stock, shares issued Common Stock Shares Issued Treasury stock, shares at cost Treasury Stock Shares Income Statement [Abstract] Revenue Revenues Operating expenses Operating Expenses [Abstract] Cost of Revenue Cost Of Revenue Sales and marketing Selling And Marketing Expense General and administrative General And Administrative Expense Research and development Research And Development Expense Amortization of intangibles assets Amortization Of Intangible Assets Impairment related and other Asset Impairment Charges Total operating expenses Operating Expenses Operating income (loss) Operating Income Loss Other income (loss), net Other Nonoperating Income Expense Interest income Investment Income Interest Interest expense Interest Expense Income (loss) before income taxes, equity loss and noncontrolling interest Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments Income tax (expense) benefit Income Tax Expense Benefit Equity loss Income Loss From Equity Method Investments Income (loss) from continuing operations Income Loss From Continuing Operations Including Portion Attributable To Noncontrolling Interest Income (loss) from discontinued operations, including gain on sale, net of tax Income Loss From Discontinued Operations Net Of Tax Net income (loss) Profit Loss Less: Net income (loss) attributable to the noncontrolling interest Net Income Loss Attributable To Noncontrolling Interest Net income (loss) attributable to Actua Corporation Net Income Loss Amounts attributable to Actua Corporation: Income Amounts Attributable To Reporting Entity Disclosures [Abstract] Net income (loss) from continuing operations Income Loss From Continuing Operations Net income (loss) from discontinued operations Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity Basic income (loss) per share attributable to Actua Corporation: Earnings Per Share Basic [Abstract] Income (loss) from continuing operations Income Loss From Continuing Operations Per Basic Share Income (loss) from discontinued operations Income Loss From Discontinued Operations Net Of Tax Per Basic Share Net income (loss) Earnings Per Share Basic Shares used in computation of basic income (loss) per share Weighted Average Number Of Shares Outstanding Basic Diluted income (loss) per share attributable to Actua Corporation: Earnings Per Share Diluted [Abstract] Income (loss) from continuing operations Income Loss From Continuing Operations Per Diluted Share Income (loss) from discontinued operations Income Loss From Discontinued Operations Net Of Tax Per Diluted Share Net income (loss) Earnings Per Share Diluted Shares used in computation of diluted income (loss) per share Weighted Average Number Of Diluted Shares Outstanding Net income (loss) Other comprehensive income Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent [Abstract] Unrealized holding gain (loss) in marketable securities Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax Reclassified adjustments/realized net (gains) loss on marketable securities Other Comprehensive Income Loss Reclassification Adjustment From A O C I For Sale Of Securities Net Of Tax Other accumulated other comprehensive income (loss) Other Comprehensive Income Other Net Of Tax Comprehensive income (loss) Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest Less: Comprehensive income (loss) attributable to noncontrolling interests Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest Comprehensive income (loss) attributable to Actua Corporation Comprehensive Income Net Of Tax Other activity regarding equity transfers among controlling entity (ACTUA) and noncontrolling owners. Net income excluding impact of redeemable noncontrolling interest. Statement Of Stockholders Equity [Abstract] Statement [Table] Statement [Table] Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Common Stock Common Stock [Member] Treasury Stock Treasury Stock [Member] Additional Paid-In Capital Additional Paid In Capital [Member] Accumulated Deficit Retained Earnings [Member] Accumulated Other Comprehensive Income (AOCI) Accumulated Other Comprehensive Income [Member] Non-controlling Interest Noncontrolling Interest [Member] Statement [Line Items] Statement [Line Items] Beginning balance Beginning balance (in shares) Shares Outstanding Equity-based compensation expense related to stock appreciation rights (SARs) and stock options Adjustments To Additional Paid In Capital Share Based Compensation Stock Options Requisite Service Period Recognition Equity-based compensation related to deferred stock units (DSUs) Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Equity-based compensation related to restricted stock (RS) Adjustments To Additional Paid In Capital Share Based Compensation Restricted Stock Units Requisite Service Period Recognition Issuance of DSUs Stock Issued During Period Value New Issues Issuance of DSUs, shares Stock Issued During Period Shares New Issues Issuance of RS, net of forfeitures and surrenders Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures Issuance of RS, net of forfeitures and surrenders, shares Stock Issued During Period Shares Restricted Stock Award Net Of Forfeitures Exercise of SARs and stock options, net of surrenders Stock Issued During Period Value Stock Options Exercised Exercise of SARs and stock options, net of surrenders, shares Stock Issued During Period Shares Stock Options Exercised Impact of redeemable noncontrolling interest accretion Temporary Equity Accretion To Redemption Value Impact of subsidiary equity transactions Impact Of Subsidiary Equity Transactions Repurchase of common stock Treasury Stock Value Acquired Cost Method Repurchase of common stock, shares Treasury Stock Shares Acquired Net income (loss) Net Income Excluding Impact Of Redeemable Noncontrolling Interest Ending balance Ending balance (in shares) Statement Of Cash Flows [Abstract] OPERATING ACTIVITIES - continuing operations Net Cash Provided By Used In Operating Activities Continuing Operations [Abstract] (Income) loss from discontinued operations, including gain on sale, net of tax Adjustments to reconcile net loss to cash provided by (used in) operating activities: Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Depreciation and amortization Depreciation Depletion And Amortization Equity-based compensation Share Based Compensation Other (income) loss Equity loss Deferred tax asset Deferred Income Tax Expense Benefit Changes in operating assets and liabilities - net of acquisitions: Increase Decrease In Operating Capital [Abstract] Accounts receivable, net Increase Decrease In Accounts Receivable Prepaid expenses and other assets Increase Decrease In Prepaid Deferred Expense And Other Assets Accounts payable Increase Decrease In Accounts Payable Accrued expenses Increase Decrease In Accrued Liabilities Accrued compensation and benefits Increase Decrease In Employee Related Liabilities Deferred revenue Increase Decrease In Deferred Revenue Other liabilities Increase Decrease In Other Operating Liabilities Cash flows provided by (used in) operating activities Net Cash Provided By Used In Operating Activities Continuing Operations INVESTING ACTIVITIES - continuing operations Net Cash Provided By Used In Investing Activities Continuing Operations [Abstract] Capital expenditures, net Payments To Acquire Property Plant And Equipment Change in restricted cash Increase Decrease In Restricted Cash Proceeds from sales/distributions of ownership interests Proceeds From Sale Of Equity Method Investments Ownership acquisition, net of cash acquired Payments To Acquire Business Two Net Of Cash Acquired Cash flows provided by (used in) investing activities Net Cash Provided By Used In Investing Activities Continuing Operations FINANCING ACTIVITIES – continuing operations Net Cash Provided By Used In Financing Activities Continuing Operations [Abstract] Acquisition of noncontrolling interest in subsidiary equity Payments To Acquire Interest In Subsidiaries And Affiliates Borrowings of long-term debt Proceeds From Issuance Of Long Term Debt Repayment of long-term debt and capital lease obligations Proceeds From Repayments Of Long Term Debt And Capital Securities Purchase of treasury stock Payments For Repurchase Of Common Stock Tax withholdings related to equity-based awards Payments Related To Tax Withholding For Share Based Compensation Other financing activities Proceeds From Payments For Other Financing Activities Cash flows provided by (used in) financing activities Net Cash Provided By Used In Financing Activities Continuing Operations Effect of exchange rate on cash flows and cash equivalents Effect Of Exchange Rate On Cash And Cash Equivalents Discontinued Operations Net Cash Provided By Used In Discontinued Operations [Abstract] Cash flows provided by (used in) operating activities Cash Provided By Used In Operating Activities Discontinued Operations Net increase (decrease) in cash and cash equivalents from discontinued operations Net Cash Provided By Used In Discontinued Operations Net increase (decrease) in cash and cash equivalents Cash And Cash Equivalents Period Increase Decrease Cash and cash equivalents at beginning of period Cash And Cash Equivalents At Carrying Value Including Discontinued Operations Cash and cash equivalents at end of period - continuing operations Organization Consolidation And Presentation Of Financial Statements [Abstract] The Company Organization Consolidation And Presentation Of Financial Statements Disclosure [Text Block] Accounting Policies [Abstract] Significant Accounting Policies Significant Accounting Policies [Text Block] Goodwill And Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Goodwill And Intangible Assets Disclosure [Text Block] Business Combinations [Abstract] Consolidated Businesses Business Combination Disclosure [Text Block] Equity Method Investments And Joint Ventures [Abstract] Equity and Cost Method Businesses Cost And Equity Method Investments Disclosure [Text Block] Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Debt Disclosure [Abstract] Debt Debt Disclosure [Text Block] Equity [Abstract] Treasury Stock Treasury Stock [Text Block] Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] Equity-Based Compensation Disclosure Of Compensation Related Costs Share Based Payments [Text Block] Other Income And Expenses [Abstract] Other Income (Loss) Other Income And Other Expense Disclosure [Text Block] Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Earnings Per Share [Abstract] Net Income (Loss) per Share Earnings Per Share [Text Block] Segment Reporting [Abstract] Segment Information Segment Reporting Disclosure [Text Block] Commitments And Contingencies Disclosure [Abstract] Contingencies Commitments And Contingencies Disclosure [Text Block] Principles of Accounting for Ownership Interests Basis Of Accounting Policy Policy [Text Block]