Term of automatic extension Debt Instrument, Term Of Automatic Extension Debt Instrument, Term Of Automatic Extension Assets: Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] VIBSQ VIBSQ [Member] VIBSQ Aggregate value of ownership based on quoted market price Equity Method Investment, Quoted Market Value Cash paid during the period: Supplemental Cash Flow Information [Abstract] Letter of Credit Letter of Credit [Member] Earnings Per Share Earnings Per Share, Policy [Policy Text Block] Tailwind Subscription Agreement, Purchase of Common Stock Tailwind Subscription Agreement, Purchase of Common Stock [Member] Tailwind Subscription Agreement, Purchase of Common Stock Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Net (loss) earnings attributable to Cannae Holdings, Inc. common shareholders Net Income (Loss) Attributable to Parent Consolidated Entities [Axis] Consolidated Entities [Axis] Entity Emerging Growth Company Entity Emerging Growth Company Lease assets Operating Lease, Right-of-Use Asset Fixed maturity securities available for sale, at fair value Debt Securities, Available-for-sale, Current Number of restaurants Number of Restaurants Preferred stock outstanding (in shares) Preferred Stock, Shares Outstanding Unrealized (losses) gain of investments in unconsolidated affiliates Other comprehensive earnings — unrealized losses of investments in unconsolidated affiliates, net of tax Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) On Equity Method Investments Arising During Period, Net Of Tax Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) On Equity Method Investments Arising During Period, Net Of Tax Receivable Type [Axis] Receivable Type [Axis] Entity Address, Address Line One Entity Address, Address Line One Gross Principal Maturities of Notes Payable Schedule of Maturities of Long-term Debt [Table Text Block] Equity securities: Equity Securities, FV-NI, Current Consideration for sale of disposal group Disposal Group, Including Discontinued Operation, Consideration Proceeds from sales of property and equipment Proceeds from Sale of Property, Plant, and Equipment Revenue from Contract with Customer [Abstract] Revenue from Contract with Customer [Abstract] Contract Balances Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block] Entity Filer Category Entity Filer Category Purchase Redeemable Warrants Forward Purchase Agreement, Purchase Redeemable Warrants [Member] Forward Purchase Agreement, Purchase Redeemable Warrants Other assets Other Assets, Noncurrent Number of businesses Number of Businesses Acquired Investment, Name [Axis] Investment, Name [Axis] Segments [Axis] Segments [Axis] Subscription Agreements Subscription Agreements [Member] Subscription Agreements Net decrease in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Proceeds from partial sale of shares Proceeds from Sale of Equity Method Investments Trebia Trebia [Member] Trebia 2023 Long-Term Debt, Maturity, Year Two Stock-based compensation APIC, Share-based Payment Arrangement, Increase for Cost Recognition Net change in income taxes Increase (Decrease) in Income Taxes Payable Equity investment, units received (in shares) Equity Method Investment, Number of Shares of Units Received Equity Method Investment, Number of Shares of Units Received NV Brasada FNF NV Brasada, LLC [Member] FNF NV Brasada, LLC [Member] 2021 (remaining) Long-Term Debt, Maturity, Remainder of Fiscal Year Loss on disposal group previously recorded Disposal Group, Not Discontinued Operation, Loss (Gain) on Write-down (Loss) earnings before equity in earnings (losses) of unconsolidated affiliates (Loss) earnings before equity in earnings of unconsolidated affiliates Income (Loss) From Continuing Operations Before Minority Interest And Income (Loss) On Equity Method Investments, Net Of Income Tax Income (Loss) From Continuing Operations Before Minority Interest And Income (Loss) On Equity Method Investments, Net Of Income Tax Document Fiscal Year Focus Document Fiscal Year Focus Unrealized (losses) gains on investments in unconsolidated affiliates, tax expense (benefit) Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) On Equity Method Investments Arising During Period, Tax Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) On Equity Method Investments Arising During Period, Tax Subsequent Event Type [Domain] Subsequent Event Type [Domain] Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Antidilutive shares excluded from calculation of diluted earnings per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Revenue recognized that was included in deferred revenue Contract with Customer, Liability, Revenue Recognized Sale of Stock [Axis] Sale of Stock [Axis] Real estate and resort Real Estate And Resort [Member] Real Estate And Resort [Member] Other Other Investments In Unconsolidated Affiliates [Member] Other Investments In Unconsolidated Affiliates [Member] Other than temporary impairment of investment Equity Method Investment, Other than Temporary Impairment Variable interest rate, increase Debt Instrument, Basis Spread on Variable Rate, Increase Debt Instrument, Basis Spread on Variable Rate, Increase Restricted Cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Business Acquisition [Axis] Business Acquisition [Axis] Unrealized gain on investments and other financial instruments, net (excluding investments in unconsolidated affiliates) Other comprehensive earnings — unrealized gain on investments and other financial instruments, net of tax OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax Backstop subscription, sponsors of Trebia , class B ordinary shares forfeited, exchanged for Trebia class B ordinary shares as consideration Backstop Subscription, Sponsors of Trebia , Class B Ordinary Shares Forfeited, Exchanged for Trebia Class B Ordinary Share Backstop Subscription, Sponsors of Trebia , Class B Ordinary Shares Forfeited, Exchanged for Trebia Class B Ordinary Share Disposal Group Name [Axis] Disposal Group Name [Axis] Net valuation gain included in earnings Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Backstop subscription, placement fee Backstop Subscription, Placement Fee Backstop Subscription, Placement Fee Credit Facility [Domain] Credit Facility [Domain] ASSETS Assets [Abstract] Schedule of Carrying Amounts and Fair Values of Available for Sale Securities Schedule of Available-for-sale Securities Reconciliation [Table Text Block] 2024 Long-Term Debt, Maturity, Year Three Forward purchase agreement, commitment to purchase, warrants, price per share (in usd per share) Forward Purchase Agreement, Commitment to Purchase, Warrants, Share Price Forward Purchase Agreement, Commitment to Purchase, Warrants, Share Price Preferred stock, 0.0001 par value; authorized 10,000,000 shares; issued and outstanding, none as of September 30, 2021 and December 31, 2020 Preferred Stock, Value, Issued Subsidiary dividends paid to noncontrolling interests Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Optimal Blue Optimal Blue [Member] Optimal Blue Entity Address, City or Town Entity Address, City or Town Variable Interest Entity, Not Primary Beneficiary Variable Interest Entity, Not Primary Beneficiary [Member] Bakery sales Bakery Sales [Member] Bakery Sales [Member] Retained Earnings Retained Earnings [Member] Debt Instrument [Axis] Debt Instrument [Axis] Number of business records (more than) Number Of Business Records Number Of Business Records Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] 2024 Recorded Unconditional Purchase Obligation, to be Paid, Year Three Franchise and other Franchise And Other [Member] Franchise And Other [Member] Distributions from investments in unconsolidated affiliates Proceeds from Equity Method Investment, Distribution Triple Tree Holdings, LLC Triple Tree Holdings, LLC [Member] Triple Tree Holdings, LLC Recognized (losses) gains, net Nonoperating Gains (Losses) Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Comprehensive (loss) earnings Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Entity Interactive Data Current Entity Interactive Data Current Interest expense Interest Expense, Related Party Amount available to be drawn Line of Credit Facility, Remaining Borrowing Capacity Net (loss) earnings per share (in usd per share) Earnings Per Share, Basic Unrealized gains recognized during the reporting period on equity securities still held at the reporting date Equity Securities, FV-NI, Realized Gain (Loss) Revenue Recognition Revenue from Contract with Customer [Text Block] Document Type Document Type Investments in Alight, net of subscription fees earned Subscription and forward purchase agreement funding Payments to Acquire Equity Securities, FV-NI 2022 Long-Term Debt, Maturity, Year One Acquisition Loan, A Note Notes Payable To Banks, Acquisition Loan, A Note [Member] Notes Payable To Banks, Acquisition Loan, A Note [Member] Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] QOMPLX QOMPLX, Inc. [Member] QOMPLX, Inc. [Member] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Diluted Earnings Per Share, Diluted [Abstract] Entity Current Reporting Status Entity Current Reporting Status Interest, investment and other income Investment Income, Interest and Dividend Senator JV Senator Focused Strategies [Member] Senator Focused Strategies Total Long Term Debt Long-term Debt, Gross Gains on Equity Securities Included in Recognized Gains and Losses Gain (Loss) on Securities [Table Text Block] Long-term debt Long-term debt Notes payable, total Long-term debt Long-term Debt Total Assets Assets, Fair Value Disclosure Equity securities received in exchange for investment holdings of corporate debt securities (in shares) Equity Securities Received in Exchange for Investment in Corporate Debt Securities Equity Securities Received in Exchange for Investment in Corporate Debt Securities Distributions from investments in unconsolidated affiliates Proceeds from Equity Method Investment, Distribution, Return of Capital Level 1 Fair Value, Inputs, Level 1 [Member] Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Goodwill impairment Goodwill, Impairment Loss Document Transition Report Document Transition Report Cash deconsolidated through the Blue Ribbon Reorganization Cash Deconsolidated From Reorganization Cash Deconsolidated From Reorganization Base Rate Base Rate [Member] Liabilities: Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Total liabilities and equity Liabilities and Equity Sponsor of Austerlitz I Sponsor of Austerlitz I [Member] Sponsor of Austerlitz I Investments, Debt and Equity Securities [Abstract] Investments, Debt and Equity Securities [Abstract] Trade receivables, net Accounts Receivable, after Allowance for Credit Loss Deferred revenue Contract with Customer, Liability, Current 99 Revolver 99 Restaurants Credit Facility 99 Restaurants Credit Facility [Member] 99 Restaurants Credit Facility [Member] Scenario [Axis] Scenario [Axis] Colt Colt Holdings, LLC [Member] Restricted cash Restricted Cash Additional paid-in capital Additional Paid in Capital Supplemental Cash Flow Elements [Abstract] Supplemental Cash Flow Elements [Abstract] LIABILITIES AND EQUITY Liabilities and Equity [Abstract] Accounts payable and other accrued liabilities, current Accounts Payable and Accrued Liabilities, Current Acquisition Loan, C Note Notes Payable To Banks, Acquisition Loan, C Note [Member] Notes Payable To Banks, Acquisition Loan, C Note Income Tax Contingency [Table] Income Tax Contingency [Table] Recognized gain on settlement Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) on Settlement Included in Earnings Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) on Settlement Included in Earnings Treasury stock repurchases Stock repurchases Treasury Stock, Value, Acquired, Cost Method Operating expenses: Operating Expenses [Abstract] Net gains recognized during the period on equity securities Equity Securities, FV-NI, Gain (Loss) Stock repurchase, average price per share (in usd per share) Treasury Stock Acquired, Average Cost Per Share Ownership percentage Ownership (as percentage) Equity Method Investment, Ownership Percentage Condensed Consolidated Balance Sheets Equity Method Investment, Summarized Financial Information [Abstract] Fixed maturity securities available for sale: Debt Securities, Available-for-Sale, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract] Maximum borrowing increment Line Of Credit Facility, Maximum Borrowing Increment Line Of Credit Facility, Maximum Borrowing Increment Sale of noncontrolling interest in consolidated subsidiary Proceeds from Contributions from Affiliates Basis of Financial Statements Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Line of credit outstanding balance Long-term Line of Credit Balance Sheet Location [Domain] Balance Sheet Location [Domain] Total Liabilities Financial and Nonfinancial Liabilities, Fair Value Disclosure Less: Comprehensive earnings (loss) attributable to noncontrolling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest (Loss) earnings before income taxes and equity in earnings (losses) of unconsolidated affiliates (Loss) earnings before income taxes and equity in earnings (losses) of unconsolidated affiliates Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Preferred stock authorized (in shares) Preferred Stock, Shares Authorized FTAC Foley Trasimene Acquisition Corp [Member] Foley Trasimene Acquisition Corp Unrealized Gains Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Legendary Baking Legendary Baking [Member] Legendary Baking Sale of noncontrolling interest in consolidated subsidiary Noncontrolling Interest, Increase from Sale of Parent Equity Interest D & B Dun & Bradstreet Dun And Bradstreet Corporation Dun And Bradstreet Corporation [Member] Dun And Bradstreet Corporation [Member] Trading Symbol Trading Symbol 2022 Recorded Unconditional Purchase Obligation, to be Paid, Year One Ownership after business acquisition, percentage Business Acquisition, Percentage of Voting Interests Acquired AmeriLife AmeriLife Joint Venture [Member] Equity Funding To AmeriLife Joint Venture [Member] Current liabilities: Liabilities, Current [Abstract] 2025 Long-Term Debt, Maturity, Year Four Receivable [Domain] Receivable [Domain] Equity offering, net of offering costs Stock Issued During Period, Value, New Issues Management fee expenses Management Fee Expense Supplemental Cash Flow Information Cash Flow, Supplemental Disclosures [Text Block] Notes Payable Debt Disclosure [Text Block] Beginning balance (in shares) Ending balance (in shares) Shares, Outstanding Line of Credit Loan Line of Credit [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Difference between carrying amount and underlying equity Equity Method Investment, Difference Between Carrying Amount and Underlying Equity Alight Warrants Alight Warrants [Member] Alight Warrants Accounts payable and other accrued liabilities, long term Accounts Payable and Accrued Liabilities, Noncurrent Note receivable received through sale of RC Noncash or Part Noncash Divestiture, Amount of Consideration Received Equity offering, net of offering costs (in shares) Stock Issued During Period, Shares, New Issues Senior Lien Senior Lien [Member] Cannae common stock, 0.0001 par value; authorized 115,000,000 shares as of September 30, 2021 and December 31, 2020; outstanding of 88,912,864 and 91,651,257 shares as of September 30, 2021 and December 31, 2020, respectively, and issued of 92,381,740 and 92,391,965 shares as of September 30, 2021 and December 31, 2020, respectively Common Stock, Value, Issued Dividends attributable to preferred equity and (income) expense attributable to noncontrolling interest Preferred Stock Dividends and Other Adjustments Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Total other (expense) income Nonoperating Income (Expense) Additions to notes receivable Payments to Acquire Notes Receivable Commitments and contingencies - see Note G Commitments and Contingencies Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Number of directors to be appointed Number of Directors Number of Directors Acquisition Loan, B Note Notes Payable To Banks, Acquisition Loan, B Note [Member] Notes Payable To Banks, Acquisition Loan, B Note [Member] Ceska zbrojovka Group SE Ceska zbrojovka Group SE [Member] Ceska zbrojovka Group SE Disposal Group Classification [Axis] Disposal Group Classification [Axis] Ownership [Axis] Ownership [Axis] Document Period End Date Document Period End Date Total operating expenses Costs and Expenses Entity Registrant Name Entity Registrant Name Treasury shares (in shares) Treasury Stock, Shares Restaurant Group Restaurant Group [Member] Restaurant Group [Member] Income Tax Contingency [Line Items] Income Tax Contingency [Line Items] Proceeds from sale of stock Sale of Stock, Consideration Received on Transaction Additions to property and equipment and other intangible assets Payments to Acquire Productive Assets Unrealized gain on investments and other financial instruments, net, income tax expense OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, Tax Financial Instrument [Axis] Financial Instrument [Axis] Income from related party Revenue from Related Parties Shares issued in business combination (in shares) Business Acquisition, Equity Interest Issued or Issuable, Number of Shares Total operating revenues Total operating revenues Revenues from external customers Revenue from Contract with Customer, Excluding Assessed Tax Alight, Inc./FTAC Sponsor Alight, Inc. and FTAC Sponsor [Member] Alight, Inc. and FTAC Sponsor Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Consolidation Items [Domain] Consolidation Items [Domain] Carrying Value Reported Value Measurement [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Contribution of CSA services from FNF Stock Issued During Period, Value, Issued for Services Alight Alight, Inc. [Member] Alight, Inc. Ninety-Nine Restaurants, LLC 99 Restaurants Ninety-Nine Restaurants [Member] Ninety-Nine Restaurants [Member] Notes payable Notes Payable, Other Payables [Member] Common Stock Common stock Common Stock [Member] Variable Rate [Axis] Variable Rate [Axis] Segment Information Segment Reporting Disclosure [Text Block] Operating loss Operating income (loss) Operating Income (Loss) Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-sale [Line Items] Stock repurchase program, period Stock Repurchase Program, Period in Force Lease liabilities, current Operating Lease, Liability, Current Unrealized Losses Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Stock-based compensation cost Share-based Payment Arrangement, Noncash Expense Variable Rate [Domain] Variable Rate [Domain] Purchases of other long term investments Payments to Acquire Other Investments Reclassification to investments in unconsolidated affiliates and Warrants, transfers to Level 2 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 Additional Paid-in Capital Additional Paid-in Capital [Member] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Change in deferred taxes Increase (Decrease) in Deferred Income Taxes Forward purchase agreement, number of shares called by each warrant Forward Purchase Agreement, Common Stock, Number Of Securities Called By Each Warrant or Right Forward Purchase Agreement, Common Stock, Number Of Securities Called By Each Warrant or Right Treasury Stock Treasury Stock [Member] Equity Method Investment, Nonconsolidated Investee [Axis] Equity Method Investment, Nonconsolidated Investee [Axis] 2021 (remaining) Recorded Unconditional Purchase Obligation, to be Paid, Remainder of Fiscal Year Equity securities, at fair value Equity Securities, FV-NI, Noncurrent Forward purchase agreement, sale of stock, proceeds Forward Purchase Agreement, Sale of Stock, Consideration Received on Transaction Forward Purchase Agreement, Sale of Stock, Consideration Received on Transaction Net other investing activities Payments for (Proceeds from) Other Investing Activities Investments Investments In Available-For-Sale Debt Securities And Equity Method Investments [Text Block] Investments In Available-For-Sale Debt Securities And Equity Method Investments [Text Block] Reclassification from accumulated other comprehensive income for gain, tax benefit Reclassification from accumulated other comprehensive income for gain, tax Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax Total liabilities Total liabilities Liabilities Legal Entity [Axis] Legal Entity [Axis] DLOC Loan Development Line Of Credit Loan [Member] Development Line Of Credit Loan [Member] Thereafter Recorded Unconditional Purchase Obligation, to be Paid, After Year Four Recorded Unconditional Purchase Obligation, to be Paid, After Year Four Probability of consummation of business combination, percentage Probability, Consummation of Business Combination, Percentage Probability, Consummation of Business Combination, Percentage Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Consolidation Items [Axis] Consolidation Items [Axis] Forward purchase agreement, investment, shares sold (in shares) Forward Purchase Agreement, Investment, Number of Shares Sold in Transaction Forward Purchase Agreement, Investment, Number of Shares Sold in Transaction Total Cannae shareholders' equity Stockholders' Equity Attributable to Parent Forward purchase agreement, investment, shares purchased (in shares) Forward Purchase Agreement, Investment, Number of Shares Purchased, Shares Forward Purchase Agreement, Investment, Number of Shares Purchased, Shares Common stock issued (in shares) Common Stock, Shares, Issued Investments in Paysafe, net of subscription fees earned Payments To Acquire Stock Subscription Agreement, Net of Fees Payments To Acquire Stock Subscription Agreement, Net of Fees Common stock shares issued, additional shares (in shares) Common Stock Shares Issued, Accordion Feature, Increase Shares Common Stock Shares Issued, Accordion Feature, Increase Shares Preferred stock issued (in shares) Preferred Stock, Shares Issued Investments in unconsolidated affiliates Equity Method Investments [Member] Schedule of Supplemental Cash Flow information Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Treasury stock repurchases Payments for Repurchase of Common Stock Purchase of warrants of Austerlitz II Payments to Acquire Equity Method Investments, Warrants Payments to Acquire Equity Method Investments, Warrants Noncash Investing and Financing Items [Abstract] Noncash Investing and Financing Items [Abstract] Loss on sale of disposal group Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal Balance Sheet Location [Axis] Balance Sheet Location [Axis] Interest investment and other income (expense), including recognized gains and losses, net Investment Income, Net Lease liabilities, long term Operating Lease, Liability, Noncurrent Austerlitz II Austerlitz II [Member] Austerlitz II Notes, face amounts Debt Instrument, Face Amount Interest expense Interest Expense Variable rate interest Debt Instrument, Interest Rate, Effective Percentage Notes Receivable Notes Receivable [Member] City Area Code City Area Code Retained earnings Accumulated deficit Retained Earnings (Accumulated Deficit) Operating Segments Operating Segments [Member] Line of credit borrowing capacity increase Line of Credit Facility, Borrowing Capacity, Increase Line of Credit Facility, Borrowing Capacity, Increase Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Schedule of Investments and Equity in Earnings of Unconsolidated Affiliates Equity Method Investments [Table Text Block] Other-than-temporary impairment charges related to corporate debt securities Other-than-temporary Impairment Loss, Debt Securities, Available-for-sale Subscription for Trebia Class A Common Stock Subscription for Trebia Class A Common Stock [Member] Subscription for Trebia Class A Common Stock Condensed Consolidated Statements of Operations Income Statement [Abstract] Investments in unconsolidated affiliates Aggregate investment value Equity Method Investments Amendment Flag Amendment Flag Asset Class [Domain] Asset Class [Domain] Distributions from Unconsolidated Affiliates Distributions from Unconsolidated Affiliates Policy [Policy Text Block] Distributions from Unconsolidated Affiliates Policy Paysafe Warrants Paysafe Warrants [Member] Paysafe Warrants 2025 Recorded Unconditional Purchase Obligation, to be Paid, Year Four Income tax (benefit) expense Income tax (benefit) expense Income Tax Expense (Benefit) Total equity Beginning balance Ending balance Total equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Forward Purchase Agreements Forward Purchase Agreements and Subscription Agreements [Member] Forward Purchase Agreements and Subscription Agreements Other Commitments [Domain] Other Commitments [Domain] Borrowings Proceeds from Issuance of Long-term Debt Equity Components [Axis] Equity Components [Axis] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Tailwind Acquisition Corp Tailwind Acquisition Corp [Member] Tailwind Acquisition Corp Forward Purchase Agreements Forward Purchase Agreement, Purchase of Common Stock [Member] Forward Purchase Agreement, Purchase of Common Stock Total current assets Total current assets Assets, Current Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Sale of Stock [Domain] Sale of Stock [Domain] Summary of Financial Information Concerning Reportable Segments Schedule of Segment Reporting Information, by Segment [Table Text Block] Gain on sale of stock Gain (Loss) on Disposition of Stock in Subsidiary or Equity Method Investee Entity File Number Entity File Number Equity Method Investment, Nonconsolidated Investee [Domain] Equity Method Investment, Nonconsolidated Investee [Domain] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Net (decrease) increase in accounts payable, accrued liabilities, deferred revenue and other liabilities Increase (Decrease) In Accounts Payable, Accrued Liabilities, Contract Liabilities, And Other Operating Liabilities Increase (Decrease) In Accounts Payable, Accrued Liabilities, Contract Liabilities, And Other Operating Liabilities Settlement/redemption of corporate debt securities Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Notes payable, current Less: Notes payable, current Long-term Debt, Current Maturities Product and Service [Axis] Product and Service [Axis] Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Small Business Entity Small Business Investment without readily determinable fair value Equity Securities without Readily Determinable Fair Value, Amount Preferred stock par value (in usd per share) Preferred Stock, Par or Stated Value Per Share Equity Component [Domain] Equity Component [Domain] Notes payable to banks Notes Payable to Banks [Member] Disposal Group Name [Domain] Disposal Group Name [Domain] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Statement [Line Items] Statement [Line Items] Other Other [Member] Other Corporate debt securities Fair Value Debt Securities, Available-for-sale Convertible note funded Payment to Acquire Equity Method Investment, Convertible Note Payment to Acquire Equity Method Investment, Convertible Note Net purchases of short-term investment securities Payments for (Proceeds from) Short-term Investments Debt Disclosure [Abstract] Debt Disclosure [Abstract] Entity Address, State or Province Entity Address, State or Province Earnings (loss) before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Level 2 Fair Value, Inputs, Level 2 [Member] Segment Reporting [Abstract] Segment Reporting [Abstract] Entity [Domain] Entity [Domain] Cost Basis Debt Securities, Available-for-sale, Amortized Cost Management Estimates Use of Estimates, Policy [Policy Text Block] Entity Shell Company Entity Shell Company Asset Class [Axis] Asset Class [Axis] Local Phone Number Local Phone Number Forecast Forecast [Member] Bisnode Business Information Group AB Bisnode Business Information Group AB [Member] Bisnode Business Information Group AB Increase in difference between carrying amount and underlying equity Equity Method Investment, Increase in Difference Between Carrying Amount and Underlying Equity, Increase Equity Method Investment, Increase in Difference Between Carrying Amount and Underlying Equity Other operating revenue Total other operating revenue Total Other Operating Revenue [Member] Total Other Operating Revenue [Member] Proceeds from equity offering, net of offering expenses Proceeds from Issuance of Common Stock Total assets Assets Assets Investment, Name [Domain] Investment, Name [Domain] Common stock authorized (in shares) Common Stock, Shares Authorized Interest Interest Paid, Excluding Capitalized Interest, Operating Activities Net income (loss) Net Income (Loss) Available to Common Stockholders, Basic Backstop subscription, facility investment commitment Backstop Subscription, Maximum Commitment, Amount Backstop Subscription, Maximum Commitment, Amount Non-controlling Interests Noncontrolling Interest [Member] Product and Service [Domain] Product and Service [Domain] Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Interest rate incurred Debt Instrument, Interest Rate, Stated Percentage Less: Net earnings (loss) attributable to non-controlling interests Income attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Revolving credit facility Revolver Note Revolving Credit Facility [Member] Unconsolidated affiliates Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member] Net cash used in operating activities Net Cash Provided by (Used in) Operating Activities Reclassification adjustments for unrealized gains and losses on investments and other financial instruments, net of tax, (excluding investments in unconsolidated affiliates) included in net earnings Reclassification adjustments for unrealized gains and losses on investments and other financial instruments, net of tax, (excluding investments in unconsolidated affiliates) included in net earnings Reclassification from accumulated other comprehensive income for gain Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax Other noncurrent assets: Other Assets, Noncurrent, Fair Value Other Assets, Noncurrent, Fair Value Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Entity Tax Identification Number Entity Tax Identification Number Purchase Obligations Recorded Unconditional Purchase Obligations [Table Text Block] Basic Earnings Per Share, Basic [Abstract] Thereafter Long-Term Debt, Maturity, after Year Four Long-Term Debt, Maturity, after Year Four Equity investment , warrants received (in shares) Equity Method Investment, Number of Shares of Warrants Received Equity Method Investment, Number of Shares of Warrants Received Corporate and Other Corporate and Other [Member] Weighted average shares outstanding Cannae Holdings common stock, basic basis (in shares) Weighted Average Number of Shares Outstanding, Basic Net (loss) earnings per share (in usd per share) Earnings Per Share, Diluted Segments [Domain] Segments [Domain] Repayment of outstanding balance under Margin Facility Repayments of Long-term Lines of Credit Fifth Third Bank Fifth Third Bank [Member] Fifth Third Bank [Member] Lease asset amortization Operating Lease, Right-of-Use Asset, Amortization Expense Income taxes Income Taxes Paid, Net Austerlitz I Austerlitz I [Member] Austerlitz I Net decrease in lease liabilities Increase (Decrease) In Lease Liabilities Increase (Decrease) In Lease Liabilities Deferred Tax Liability Deferred Tax Liability [Member] Deferred Tax Liability Comprehensive (loss) earnings attributable to Cannae Holdings, Inc. common shareholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent Other intangible assets, net Intangible Assets, Net (Excluding Goodwill) Deferred revenue (contract liabilities) Contract with Customer, Liability Proceeds from investment in PIPE, fees Proceeds from Investment in Private Placement in Public Equity, Fees Proceeds from Investment in Private Placement in Public Equity, Fees Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Operating leases Cash Paid For Operating Leases Cash Paid For Operating Leases Other comprehensive earnings (loss), net of tax: Other Comprehensive Income (Loss), Net of Tax [Abstract] Less: Treasury stock, 3,468,876 and 740,708 shares as of September 30, 2021 and December 31, 2020, respectively, at cost Treasury Stock, Value Weighted Average Shares Outstanding Weighted Average Number of Shares Outstanding, Diluted [Abstract] Deferred tax liability Deferred Income Tax Liabilities, Net Equity in earnings (losses) of unconsolidated affiliates Equity in earnings of unconsolidated affiliates Income (Loss) from Equity Method Investments Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] O'Charley's O'Charley's [Member] O'Charley's Other operating expenses Other Cost and Expense, Operating Paysafe/FTAC II Sponsor Paysafe/FTAC II Sponsor [Member] Paysafe/FTAC II Sponsor Corporate debt securities Corporate debt securities Corporate Debt Securities [Member] Fair Value Measurements Fair Value Disclosures [Text Block] Depreciation and amortization Depreciation and amortization Depreciation, Depletion and Amortization Schedule of Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Schedule of Variable Interest Entities Schedule of Variable Interest Entities [Table Text Block] Summary of Changes in the Fair Values of Level 3 Assets Measured on a Recurring Basis Fair Value, Assets Measured on Recurring Basis [Table Text Block] FNF Revolver Corporate Revolver Note [Member] Corporate Revolver Note [Member] Accumulated Other Comp (Loss) Earnings AOCI Attributable to Parent [Member] Paysafe Subscription Agreement Paysafe PIPE subscription Paysafe Subscription Agreement, Purchase of Common Stock [Member] Paysafe Subscription Agreement, Purchase of Common Stock Common stock outstanding (in shares) Common Stock, Shares, Outstanding Restaurant Group reorganization and deconsolidation of Legendary Baking and VIBSQ Stockholders' Equity, Increase (Decrease) From Reorganization And Deconsolidation Of Subsidiary Stockholders' Equity, Increase (Decrease) From Reorganization And Deconsolidation Of Subsidiary Financial Instruments [Domain] Financial Instruments [Domain] Tailwind QOMPLX Merger Tailwind QOMPLX Merger [Member] Tailwind QOMPLX Merger Members' equity Members' Equity Percentage of ownership after sale of stock transaction Sale of Stock, Percentage of Ownership after Transaction Recognized losses (gains) and asset impairments, net Gain (Loss) on Sale of Assets and Asset Impairment Charges Cost of restaurant revenue Cost of Goods and Services Sold Revenues: Revenues [Abstract] Cash proceeds from sales of VIBSQ, Legendary Baking, and RCI Cash proceeds, net Proceeds from Divestiture of Businesses Stock repurchase program, number of shares authorized to be repurchased (up to) Stock Repurchase Program, Number of Shares Authorized to be Repurchased Line of Credit Facility, Lender [Domain] Line of Credit Facility, Lender [Domain] Subscription agreement, commitment to purchase, shares (in shares) Subscription Agreement, Commitment to Purchase, Shares Subscription Agreement, Commitment to Purchase, Shares Consolidated Entities [Domain] Consolidated Entities [Domain] Proceeds from sale of other investments in unconsolidated affiliates and other long term investments Proceeds from Sale of Other Investments Forward purchase agreement, commitment to purchase, shares (in shares) Forward Purchase Agreement, Commitment to Purchase, Shares Forward Purchase Agreement, Commitment to Purchase, Shares Subscription agreement, commitment to purchase Subscription Agreement, Commitment to Purchase, Shares, Value Subscription Agreement, Commitment to Purchase, Shares, Value Foley Trasimene Acquisition Corp, Forward Purchase Agreement Foley Trasimene Acquisition Corp, Forward Purchase Agreement [Member] Foley Trasimene Acquisition Corp, Forward Purchase Agreement Debt instrument, term Debt Instrument, Term Equity: Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Bridge Loan Bridge Loan [Member] Disposal Group, Held-for-sale, Not Discontinued Operations Disposal Group, Held-for-sale, Not Discontinued Operations [Member] Sightline Sightline Payments LLC [Member] Sightline Payments LLC Property and equipment, net Property, Plant and Equipment, Net Other non-current liabilities Other Liabilities, Noncurrent Related Party Transactions Related Party Transactions [Policy Text Block] Related Party Transactions Direct interest in private placement warrants (in shares) Equity Method Investment, Direct Interest, Number of Warrants Equity Method Investment, Direct Interest, Number of Warrants Lender Name [Axis] Lender Name [Axis] Schedule of Notes Payable Schedule of Long-term Debt Instruments [Table Text Block] Treasury stock repurchases (in shares) Treasury Stock, Shares, Acquired Debt Instrument [Line Items] Debt Instrument [Line Items] Net valuation gain included in other comprehensive earnings Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Debt service payments Repayments of Long-term Debt Earnings per share Earnings Per Share [Abstract] Reclassification adjustments for unrealized gains and losses of unconsolidated affiliates, net of tax, included in net earnings, tax Other Comprehensive Income Loss Reclassification Adjustment For Net Unrealized Gains Losses On Unconsolidated Affiliates, Net Of Tax, Include Net Earnings. Tax Other Comprehensive Income Loss Reclassification Adjustment For Net Unrealized Gains Losses On Unconsolidated Affiliates, Net Of Tax, Include Net Earnings. Tax Equity Sponsors Equity Sponsors [Member] Equity Sponsors Less: net gains (losses) recognized during the period on equity securities sold or transferred during the period Equity Securities, FV-NI, Unrealized Gain (Loss) Document Quarterly Report Document Quarterly Report Total revenues Total revenues and other income Revenues Net decrease (increase) in other assets Increase (Decrease) in Other Operating Assets Liabilities Other Liabilities, Fair Value Disclosure Line of Credit Facility [Table] Line of Credit Facility [Table] Cash proceeds from settlement of fixed maturity securities and equity in Colt Proceeds from sale of debt securities Proceeds from Sale of Debt Securities, Available-for-sale Foley Trasimene Acquisition Corp. II Foley Trasimene Acquisition Corp. II [Member] Foley Trasimene Acquisition Corp. II Other long term investments and non-current assets Investments and Other Noncurrent Assets Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Noncontrolling interest - nonredeemable Nonredeemable Noncontrolling Interest Paysafe Paysafe/FTAC II Sponsor Paysafe [Member] Paysafe Notes payable, long term Notes payable, long term Long-term Debt, Excluding Current Maturities Goodwill and other intangible assets, net Goodwill and other intangible assets, net Intangible Assets, Net (Including Goodwill) Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Collective voting interest with other equity sponsors (greater than) Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners Document Fiscal Period Focus Document Fiscal Period Focus Percentage of ownership before stock sale transaction Sale of Stock, Percentage of Ownership before Transaction Backstop Agreements Backstop Agreements [Member] Backstop Agreements Effective tax rate Effective Income Tax Rate Reconciliation, Percent Lien Category [Axis] Lien Category [Axis] Personnel costs Labor and Related Expense Net (loss) earnings Net (loss) earnings Net (loss) earnings Net income (loss) Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Acquisition Loan Notes Payable To Banks, Acquisition Loan [Member] Notes Payable To Banks, Acquisition Loan [Member] Other Other Products And Services [Member] Other Products And Services [Member] Forward purchase agreement, investment commitment Forward Purchase Agreement, Commitment To Purchase Equity Interests Forward Purchase Agreement, Commitment To Purchase Equity Interests Ceridian Ceridian Ceridian [Member] Ceridian [Member] Senator JV Senator JV [Member] Senator JV Sale of stock (in shares) Sale of Stock, Number of Shares Issued in Transaction Common stock, par value (in usd per share) Common Stock, Par or Stated Value Per Share Total member's equity Limited Liability Company (LLC) Members' Equity, Including Portion Attributable to Noncontrolling Interest Variable Interest Entities Variable Interest Entity Disclosure [Text Block] Owned investment (in shares) Investment Owned, Balance, Shares Condensed Consolidated Statements of Comprehensive Earnings Statement of Comprehensive Income [Abstract] Current assets: Assets, Current [Abstract] Entity Central Index Key Entity Central Index Key LIBOR London Interbank Offered Rate (LIBOR) [Member] Security Exchange Name Security Exchange Name Disposal Group Classification [Domain] Disposal Group Classification [Domain] Revenue Recognition Revenue from Contract with Customer [Policy Text Block] Weighted average shares outstanding Cannae Holdings common stock, diluted basis (in shares) Weighted Average Number of Shares Outstanding, Diluted Fair value, beginning of period Fair value, end of period Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Other comprehensive (loss) earnings Other Comprehensive Income (Loss), Net of Tax AmeriLife AmeriLife [Member] AmeriLife Collections of notes receivable Proceeds from Collection of Notes Receivable Gain on transaction Debt and Equity Securities, Realized Gain (Loss) Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Current Fiscal Year End Date Current Fiscal Year End Date Interest rate basis Debt Instrument, Basis Spread on Variable Rate Sponsor, FTAC Sponsor, FTAC [Member] Sponsor, FTAC Measurement Basis [Axis] Measurement Basis [Axis] Rock Creek Idaho Holdings, LLC Rock Creek Idaho Holdings, LLC [Member] Rock Creek Idaho Holdings, LLC 2023 Recorded Unconditional Purchase Obligation, to be Paid, Year Two Alight Subscription Agreement, Purchase of Common Stock Alight Subscription Agreement, Purchase of Common Stock [Member] Alight Subscription Agreement, Purchase of Common Stock Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Other income (expense): Nonoperating Income (Expense) [Abstract] Other Other Notes Payable [Member] Other Notes Payable [Member] Maximum Exposure Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount Investment in Dun & Bradstreet, Optimal Blue and additional investments in unconsolidated affiliates Equity investment Equity investment Payments to Acquire Equity Method Investments Credit Facility [Axis] Credit Facility [Axis] Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Changes in assets and liabilities, net of effects from acquisitions: Increase (Decrease) in Operating Capital [Abstract] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Principles of Consolidation and Basis of Presentation Consolidation, Policy [Policy Text Block] Reclassification adjustments for unrealized gains and losses of unconsolidated affiliates, net of tax, included in net earnings Reclassification adjustments for unrealized gains and losses on unconsolidated affiliates, net of tax, included in net earnings Other Comprehensive Income Loss Reclassification Adjustment For Net Unrealized Gains Losses On Unconsolidated Affiliates, Net Of Tax, Include Net Earnings Other Comprehensive Income Loss Reclassification Adjustment For Net Unrealized Gains Losses On Unconsolidated Affiliates, Net Of Tax, Include Net Earnings Total current liabilities Current liabilities Liabilities, Current Affiliate Elimination Intersegment Eliminations [Member] Lien Category [Domain] Lien Category [Domain] Forward Purchase Agreements (as defined in Annual Report) Forward Purchase Agreements Forward Purchase Agreements [Member] Forward Purchase Agreements Equity investment value before impairment adjustment Equity Method Investments Before Impairment Adjustment Equity Method Investments Before Impairment Adjustment Aggregate borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Equity Method Investment, Financial Statement, Reported Amounts [Abstract] Equity Method Investment, Financial Statement, Reported Amounts [Abstract] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Ownership [Domain] Ownership [Domain] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Proceeds equity securities Proceeds from Sale of Equity Securities, FV-NI Underwritten Secondary Public Offering Underwritten Secondary Public Offering [Member] Underwritten Secondary Public Offering [Member] Decrease in borrowing capacity Line of Credit Facility, Increase (Decrease) Borrowing Capacity Line of Credit Facility, Increase (Decrease) Borrowing Capacity Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Title of 12(b) Security Title of 12(b) Security Austerlitz II Warrants Austerlitz II Warrants [Member] Austerlitz II Warrants Statement [Table] Statement [Table] Other current assets Other Assets, Current Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Option to increase limit Line of Credit Facility, Accordion Feature, Increase Limit Line of Credit Facility, Accordion Feature, Increase Limit Other Commitments [Axis] Other Commitments [Axis] 2020 Margin Facility 2020 Margin Facility [Member] 2020 Margin Facility Austerlitz II FPA Austerlitz II Forward Purchase Agreements [Member] Austerlitz II Forward Purchase Agreements Subsequent Event Subsequent Event [Member] Cash and cash equivalents Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations Cover [Abstract] Cover [Abstract] Goodwill Goodwill Goodwill Brasada Interstate Loans Brasada Credit Agreement Brasada Credit Agreement [Member] Brasada Credit Agreement [Member] Total purchase commitments Recorded Unconditional Purchase Obligation Noncontrolling interests Stockholders' Equity Attributable to Noncontrolling Interest Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Restaurant revenue Restaurant sales Restaurant Sales [Member] Restaurant Sales [Member] Net (loss) earnings from continuing operations Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Income taxes payable Accrued Income Taxes, Current Equity investment, shares of common stock received (in shares) Equity Method Investment, Shares of Common Stock Received Equity Method Investment, Shares of Common Stock Received Scenario [Domain] Scenario [Domain] Adjustments to reconcile net (loss) earnings to net cash used in operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subscription for Austerlitz I Class A Ordinary Shares Subscription for Austerlitz I Class A Ordinary Shares [Member] Subscription for Austerlitz I Class A Ordinary Shares Purchase of Austerlitz II Warrants Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases 99 Term Loan 99 Term Loan 99 Term Loan [Member] 99 Term Loan [Member]