Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Trading Arrangement: Trading Arrangement [Axis] New Jersey NEW JERSEY Maximum Maximum [Member] General and administrative General And Administrative, Less Interest, Depreciation and Other Segment Income (Expenses) General And Administrative, Less Interest, Depreciation and Other Segment Income (Expenses) Statistical Measurement [Domain] Statistical Measurement [Domain] Income Tax Jurisdiction, Domestic Federal Income Tax Jurisdiction, Domestic Federal [Member] Title of 12(b) Security Title of 12(b) Security Net loss attributable to common stockholders—diluted Net Income (Loss) Available to Common Stockholders, Diluted Subsequent event Subsequent Event [Member] Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-Sale [Table] Document Fiscal Year Focus Document Fiscal Year Focus Adjustment to Compensation, Amount Adjustment to Compensation Amount Financial Instrument [Axis] Financial Instrument [Axis] Number of Shares Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Segment Reporting [Abstract] Schedule of Fair Value Hierarchy for Financial Assets and Liabilities Fair Value, Assets Measured on Recurring Basis [Table Text Block] Common stock, $0.00001 par value, 200,000,000 shares authorized; 77,326,718 and 75,907,215 shares issued and outstanding as of June 30, 2026 and December 31, 2025, respectively Common Stock, Value, Issued Loss liability Loss Contingency Accrual Guarantees Guarantor Obligations, Maximum Exposure, Undiscounted Line of Credit Line of Credit [Member] Restatement Determination Date Restatement Determination Date Employee compensation Employee-related Liabilities Reinsurance payable Reinsurance Payable Due after five years through ten years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Fair Value Accrued advertising costs Accrued Advertising Warrant, number of shares issuable, common stock (in shares) Class of Warrant or Right, Number of Securities Called by Warrants or Rights Contribution of common stock to related party, fair value (usd per share) Stock Issued During Period, Issued For Charitable Contribution, Fair Value Stock Issued During Period, Issued For Charitable Contribution, Fair Value Unvested, weighted-average exercise price (usd per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Unusual or Infrequent Item, or Both [Axis] Unusual or Infrequent Item, or Both [Axis] Maximum shares that may be issued upon exercise of incentive stock options (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized, Maximum Number Of Shares Issued Upon Exercise Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized, Maximum Number Of Shares Issued Upon Exercise Amendment Flag Amendment Flag Provision for bad debt Accounts Receivable, Credit Loss Expense (Reversal) Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding New York NEW YORK Net investment income Net Investment Income LIC Quota Share Reinsurance Contract LIC Quota Share Reinsurance Contract [Member] LIC Quota Share Reinsurance Contract The Lemonade Foundation Lemonade Foundation [Member] Lemonade Foundation Gross Unrealized Losses Gross unrealized losses (less than for December 31, 2025) Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax Reinsurance Contract [Axis] Reinsurance Arrangement By Type [Axis] Reinsurance Arrangement By Type Asset-backed securities and collateralized loan obligations Asset-backed securities and collateralized loan obligations Asset-backed securities Asset-Backed Securities [Member] Schedule of Amortized Cost and Fair Values of Investment in Fixed Maturities Debt Securities, Available-for-Sale [Table Text Block] Loss Contingencies [Table] Loss Contingencies [Table] Investments [Domain] Investments [Domain] Related Party Transactions Related Party Transactions Disclosure [Text Block] Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Schedule of Cash and Cash Equivalents Schedule of Cash and Cash Equivalents [Table Text Block] Entity Address, State or Province Entity Address, State or Province Gross Unrealized Losses Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss Granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross Gross Unrealized Losses Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract] Foreign currency translation adjustment Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent PEO Total Compensation Amount PEO Total Compensation Amount Common stock, par value (usd per share) Common Stock, Par or Stated Value Per Share Intangible assets Intangible Asset, Excluding Goodwill, after Accumulated Amortization Outstanding (in shares) Outstanding (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number Other liabilities and accrued expenses Increase (Decrease) in Accrued Liabilities and Other Operating Liabilities Weighted average common shares outstanding—basic (in shares) Weighted Average Number of Shares Outstanding, Basic Reinsurance, per risk limit, amount Reinsurance, Per Risk Limit, Amount Reinsurance, Per Risk Limit, Amount Amortization of premium on bonds Accretion (Amortization) of Discounts and Premiums, Investments Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Loss Contingencies [Line Items] Loss Contingencies [Line Items] Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Number of reportable segments Number of Reportable Segments Deferred acquisition costs Increase (Decrease) in Deferred Policy Acquisition Costs Investments Investments [Abstract] Fixed maturities available-for-sale, amortized cost Cost or Amortized Cost Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss Ceded premium payable Increase (Decrease) In Ceded Premiums Payable Increase (Decrease) In Ceded Premiums Payable Entity Address, City or Town Entity Address, City or Town Customer Investment Agreement Customer Investment Agreement [Member] Customer Investment Agreement Granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Statement of Financial Position [Abstract] Title and Position [Domain] Title and Position [Domain] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Vested (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Line of credit facility, funding percentage Line Of Credit Facility, Funding, Percentage Of Monthly Growth Spend Line Of Credit Facility, Funding, Percentage Of Monthly Growth Spend Net loss attributable to common stockholder—basic Net Income (Loss) Available to Common Stockholders, Basic Add: Incurred loss and LAE, net of reinsurance, related to: Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract] Level 2 Fair Value, Inputs, Level 2 [Member] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Maximum amount of borrowings Line of Credit Facility, Maximum Borrowing Capacity Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] 2015 Plan Incentive Share Option Plan 2015 [Member] Incentive Share Option Plan 2015 US UNITED STATES Other expenses Other Expenses Subsequent Event Type [Axis] Subsequent Event Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Uncertain tax position Uncertain Tax Position Uncertain Tax Position Schedule of Long-Term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Sale of Stock [Table] Subsidiary or Equity Method Investee, Sale of Stock, Type [Table] Conversion ratio Business Combination, Consideration Transferred, Equity Interests Issued and Issuable, Share Exchange Ratio Business Combination, Consideration Transferred, Equity Interests Issued and Issuable, Share Exchange Ratio Commission and other income Insurance Commissions and Fees Investment expense Investment Income, Investment Expense Investment Income [Table] Investment Income [Table] New Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Segment Reporting Segment Reporting [Table Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Related Party [Axis] Related and Nonrelated Parties [Axis] Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Payments on borrowings under financing agreement Repayments of Lines of Credit Class of warrant common stock exercise price (usd per share) Class of Warrant or Right, Exercise Price of Warrants or Rights Borrowings outstanding Long-Term Debt Document Period End Date Document Period End Date Investment amount, percent of growth spend up to 80% Investment in Equity Securities, FV-NI, Percentage Of Growth Spend Investment in Equity Securities, FV-NI, Percentage Of Growth Spend MIC Quota Share Reinsurance Contract MIC Quota Share Reinsurance Contract [Member] MIC Quota Share Reinsurance Contract Changes in operating assets and liabilities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Cancelled/Forfeited (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures and Expirations in Period Net cash used in investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Unrecognized tax benefits Unrecognized Tax Benefits Preferred stock, shares outstanding (in shares) Preferred Stock, Shares Outstanding Asset-backed securities and collateralized loan obligations Asset-Backed Securities And Collateralized Loan Obligations [Member] Asset-Backed Securities And Collateralized Loan Obligations Stockholders' Equity Equity [Text Block] Security Exchange Name Security Exchange Name Term of borrowings Debt Instrument, Term Unpaid Loss and Loss Adjustment Expense Insurance Disclosure [Text Block] Amount Premiums Written, Gross Granted (usd per share) Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Funds held for reinsurance treaties Increase (Decrease) in Reinsurance Payables Tax Credit Carryforward [Table] Tax Credit Carryforward [Table] Cost of short-term investments acquired Payments to Acquire Marketable Securities Number of warrant shares vested (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Vested, Number Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Vested, Number Warrant Liability Liabilities, Fair Value Disclosure Accumulated other comprehensive (loss) income Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Shell Company Entity Shell Company 12 Months or More Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer Due after five years through ten years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Amortized Cost Ceded premium payable Ceded Premiums Payable Pennsylvania PENNSYLVANIA Net Loss per Share Earnings Per Share [Text Block] Name Outstanding Recovery, Individual Name Proceeds from short-term investments sold or matured Proceeds from Sale and Maturity of Marketable Securities Per share data: Earnings Per Share [Abstract] Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Document Fiscal Period Focus Document Fiscal Period Focus Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Total liabilities Liabilities Trading Symbol Trading Symbol Schedule of Other Liabilities and Accrued Expenses Other Liabilities [Table Text Block] Fixed maturities available-for-sale, at fair value (amortized cost: $772.4 million and $706.0 million as of June 30, 2026 and December 31, 2025, respectively) Fair Value Total Fixed maturities Debt Securities, Available-for-Sale, Excluding Accrued Interest Geographical [Domain] Geographical [Domain] Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Unrecognized expense, stock options Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount Company Selected Measure Name Company Selected Measure Name Cost of bonds acquired Payments to Acquire Debt Securities, Available-for-Sale Schedule of Restricted Cash Restrictions on Cash and Cash Equivalents [Table Text Block] Income Tax Disclosure [Abstract] Numerator: Earnings Per Share, Diluted [Abstract] Fixed maturities Debt Securities [Member] Unpaid loss and loss adjustment expense Unpaid loss and LAE at beginning of period Unpaid loss and LAE, gross of reinsurance recoverable, at end of period Liability for Claims and Claims Adjustment Expense Related Party Transactions [Abstract] Cash flows from operating activities: Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Compensation Amount Outstanding Recovery Compensation Amount Individual: Individual [Axis] Warrant Liability Warrant shares Warrants for common stock Warrant [Member] Weighted average common shares outstanding—diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Entity Emerging Growth Company Entity Emerging Growth Company Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Schedule of Net Investment Income Investment Income [Table Text Block] Proceeds from borrowings under financing agreement Proceeds from Lines of Credit Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Tax Credit Carryforward, Name [Domain] Tax Credit Carryforward, Name [Domain] Reinsurance, excess retention, amount reinsured, per event Reinsurance, Excess Retention, Amount Reinsured, Per Event Cash, Cash Equivalents and Restricted Cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Asset-backed securities and collateralized loan obligations Debt Securities, Available-for-Sale, Maturity, without Single Maturity Date, Amortized Cost Award Timing Predetermined Award Timing Predetermined [Flag] Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-Sale [Line Items] Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Recoupment assessment term Assessment Charge, Recoupment Approved, Term Assessment Charge, Recoupment Approved, Term Stock-based compensation APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Omnibus Agreement Omnibus Agreement [Member] Omnibus Agreement Level 1 Fair Value, Inputs, Level 1 [Member] Net unpaid loss and LAE at beginning of period Unpaid loss and LAE, net of reinsurance recoverable, at end of period Liability for Unpaid Claims and Claims Adjustment Expense, Net Tax credits received under ERC program Effective Income Tax Rate Reconciliation, Tax Credit, Amount Due after ten years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value Effective tax rate Effective Income Tax Rate Reconciliation, Percent Debt Instrument, Funding Period One Debt Instrument, Funding Period One [Member] Debt Instrument, Funding Period One Organization, Consolidation and Presentation of Financial Statements [Abstract] Outstanding (usd per share) Outstanding (usd per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value All Executive Categories All Executive Categories [Member] Washington WASHINGTON Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Restricted investments Restricted Investments Quota share reinsurance cession percentage Percentage Of Deferred Reinsurance Ceding Commissions Percentage Of Deferred Reinsurance Ceding Commissions Other comprehensive loss, net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Preferred stock, par value (usd per share) Preferred Stock, Par or Stated Value Per Share Other Liabilities and Accrued Expenses Other Liabilities Disclosure [Text Block] Plan Name [Domain] Plan Name [Domain] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Sub-total Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Amortized Cost Outstanding (usd per share) Outstanding (usd per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price Internal rate of return on growth pend Investment In Equity Securities, FV-NI, Internal Rate Of Return, Percent Investment In Equity Securities, FV-NI, Internal Rate Of Return, Percent Sales and marketing Sales and marketing Selling and Marketing Expense Concentration Risk Type [Domain] Concentration Risk Type [Domain] Reinsurance Arrangement By Type [Domain] Reinsurance Arrangement By Type [Domain] Reinsurance Arrangement By Type [Domain] Office leases, payment guarantees Property Lease Guarantee [Member] Deduct: Paid loss and LAE, net of reinsurance, related to: Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Premium taxes payable Premium Taxes Payable Premium Taxes Payable Schedule of Basic and Diluted Net Loss Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Fair Value Disclosures [Abstract] Debt Disclosure [Abstract] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Reinsurance recoverable Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments Segment Information Segment Reporting [Text Block] Investments Investment in Debt and Equity Securities and Other Trading Assets [Text Block] Number of shares available for issuance, annual increase (in shares) Share-Based Compensation Arrangement By Share-Based Payment Award, Number Of Shares Available For Grant, Annual Increase Share-Based Compensation Arrangement By Share-Based Payment Award, Number Of Shares Available For Grant, Annual Increase Minimum Minimum [Member] Borrowings under financing agreement Long-Term Line of Credit Investment Type [Axis] Investment Type [Axis] Expiration Date Trading Arrangement Expiration Date Accrued professional fees Accrued Professional Fees Denominator: Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Effect of exchange rate changes on cash, cash equivalents and restricted cash Effect of Exchange Rate on Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Location, Statement of Income, Balance [Axis] Location, Statement of Income, Balance [Axis] Advance premium Advance Premium Liability Advance Premium Liability Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Outstanding, weighted-average remaining contractual, term Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted-Average Remaining Contractual Term Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Cost or Amortized Cost Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Amortized Cost [Abstract] Affiliated entity Affiliated Entity [Member] Exercisable (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Number Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Common stock, authorized (in shares) Common Stock, Shares Authorized Trade payables Accounts Payable, Trade Antidilutive Security, Excluded EPS Calculation [Table] Antidilutive Security, Excluded EPS Calculation [Table] Nontrade receivables Nontrade Receivables Exercisable, aggregate intrinsic value Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value Schedule of Restricted Stock Units Activity Share-Based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block] Exercise Price Award Exercise Price Cash flows from investing activities: Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Segment Reporting [Line Items] Segment Reporting [Line Items] Proceeds from bonds sold or matured Proceeds from Sale and Maturity of Debt Securities, Available-for-Sale Document Quarterly Report Document Quarterly Report Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Segments [Domain] Segments [Domain] Texas TEXAS Borrowings under Financing Agreement Debt Disclosure [Text Block] Interest payable Interest Payable Prior years Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years Reduction in net unpaid losses Liability for Unpaid Claims and Claims Adjustment Expense, Period Increase (Decrease) Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Deferred ceding commission Increase (Decrease) In Deferred Ceding Commissions Increase (Decrease) In Deferred Ceding Commissions Equity Component [Domain] Equity Component [Domain] Deferred acquisition costs Deferred Policy Acquisition Cost PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Percentage ownership in subsidiary Subsidiary or Equity Method Investee, Cumulative Percentage Ownership after All Transactions Expense Benefits, Losses and Expenses [Abstract] Adoption Date Trading Arrangement Adoption Date Counterparty Name [Domain] Counterparty Name [Domain] Premium receivable, allowance for doubtful accounts Premium Receivable, Allowance for Credit Loss Total stockholders' equity Beginning balance Ending balance Equity, Attributable to Parent Assets Assets [Abstract] Title Trading Arrangement, Individual Title Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Other Liabilities Disclosure [Abstract] Other Liabilities Disclosure [Abstract] Accounting Policies [Abstract] Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Risk-free interest rate Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Lease liabilities Operating Lease, Liability Additional financing Line Of Credit Facility, Additional Borrowing Capacity Line Of Credit Facility, Additional Borrowing Capacity CARES Act, ERC Program CARES Act, ERC Program [Member] CARES Act, ERC Program Insider Trading Policies and Procedures [Line Items] Outstanding (in shares) Outstanding (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Consecutive trading days Share Based Compensation Arrangement, Consecutive Trading Days Stock Price At or Above Threshold Share Based Compensation Arrangement, Consecutive Trading Days Stock Price At or Above Threshold Unusual or Infrequent Item, or Both [Domain] Unusual or Infrequent Item, or Both [Domain] Tax Credit Carryforward [Axis] Tax Credit Carryforward [Axis] Current year Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year Loss and loss adjustment expense, net Total incurred less: Loss and loss adjustment expenses, net Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims Business Combination [Domain] Business Combination [Domain] Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items] Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items] Cancelled/Forfeited (usd per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Number of operating segments Number of Operating Segments Antidilutive potential common stock (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount RSUs with service condition Restricted Stock Units (RSUs) [Member] Schedule of Antidilutive Potential Common Shares Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Entity Central Index Key Entity Central Index Key All Adjustments to Compensation All Adjustments to Compensation [Member] Business Combination [Axis] Business Combination [Axis] Equity [Abstract] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Net cash used in operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Prior years Favorable development on net loss and LAE reserves Prior Year Claims and Claims Adjustment Expense Income Statement [Abstract] Stockholders' equity Equity, Attributable to Parent [Abstract] Document Transition Report Document Transition Report Annual increase in shares reserved for issuance (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Annual Increase In Shares Reserved For Issuance Share-Based Compensation Arrangement by Share-Based Payment Award, Annual Increase In Shares Reserved For Issuance Chief Executive Officer And President Chief Executive Officer And President [Member] Chief Executive Officer And President Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Investment, Name [Axis] Investment, Name [Axis] Line of credit facility maximum borrowing capacity per reference cohort Line Of Credit Facility, Maximum Borrowing Capacity, Per Reference Cohort Line Of Credit Facility, Maximum Borrowing Capacity, Per Reference Cohort Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Schedule of Fair Value Assumptions Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Number of Options Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward] Debt instrument, basis spread on variable rate (as a percent) Debt Instrument, Basis Spread on Variable Rate City Area Code City Area Code Variable Rate [Domain] Variable Rate [Domain] Unvested restricted stock Restricted Stock [Member] Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Geographic Concentration Risk Geographic Concentration Risk [Member] Officer Trading Arrangement [Member] Officer Trading Arrangement All Individuals All Individuals [Member] Schedule of Gross Written Premium by State Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue [Table Text Block] Name Forgone Recovery, Individual Name Unrecognized expense, period for recognition Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Weighted Average Grant Date Fair Value Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Fair Value Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Less than 12 Months [Abstract] Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Less than 12 Months Statement [Line Items] Statement [Line Items] Total assets Assets Entity [Domain] Entity [Domain] Preferred stock, issued (in shares) Preferred Stock, Shares Issued Common stock reserved for issuance (in shares) Common Stock, Capital Shares Reserved for Future Issuance Interest expense Interest Expense, Nonoperating Gross Unrealized Gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax Stock-based Compensation Share-Based Payment Arrangement [Text Block] Asset-backed securities and collateralized loan obligations Debt Securities, Available-for-Sale, Maturity, without Single Maturity Date, Fair Value Other assets Increase (Decrease) in Other Operating Assets Nature of the Business Nature of Operations [Text Block] PEO PEO [Member] Stock-based compensation expense Share-Based Payment Arrangement, Expense Goodwill Goodwill Additional shares authorized (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized Fixed Income Securities Fixed Income Securities [Member] Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Exercised (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period Number of debt securities held, unrealized loss position Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions Total investments Investments Grand date fair value (in dollars per share) Granted (usd per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Subsequent Event Type [Domain] Subsequent Event Type [Domain] Accumulated Deficit Retained Earnings [Member] Cancelled/Forfeited (usd per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Initial limit for each loss occurrence Reinsurance, Amount Retained, Per Event Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Increase (Decrease) in Stockholders' Deficit [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Common stock, outstanding (in shares) Beginning balance (in shares) Ending balance (in shares) Common Stock, Shares, Outstanding Award Timing Disclosures [Line Items] Corporate debt securities Corporate debt securities Corporate debt securities Corporate Debt Securities [Member] Net loss per share attributable to common stockholders—diluted (usd per share) Earnings Per Share, Diluted Entity Current Reporting Status Entity Current Reporting Status Net cash provided by financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Total Shareholder Return Amount Total Shareholder Return Amount Deferred ceding commission Deferred Ceding Commission Deferred Ceding Commission Technology development Technology development Research and Development Expense Adjustments to reconcile net loss to net cash used in operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Share-Based Payment Arrangement [Abstract] Europe and UK Europe and United Kingdom [Member] Europe and United Kingdom Cash flows from financing activities: Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Property and equipment, net Property, Plant, and Equipment, after Accumulated Depreciation, Depletion, and Amortization Net Investment Income [Line Items] Net Investment Income [Line Items] Financial Instruments [Domain] Financial Instruments [Domain] Prepaid reinsurance premium Increase (Decrease) in Prepaid Reinsurance Premiums Ceding commission income Ceded Commission Income Ceded Commission Income Three-Year U.S. Treasury Bill Rate Three-Year U.S. Treasury Bill Rate [Member] Three-Year U.S. Treasury Bill Rate Prepaid reinsurance premium Prepaid Reinsurance Premiums Percentage on recoupment Assessment Charge, Percentage Recoupment Approved Assessment Charge, Percentage Recoupment Approved Financing receivable, allowance for credit loss Financing Receivable, Allowance for Credit Loss Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Share-based compensation equity awards granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Granted Underlying Securities Award Underlying Securities Amount Reinsurance, excess retention, percentage Reinsurance, Excess Retention, Percentage Aggregate Intrinsic Value Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value [Abstract] Depreciation and amortization Cost, Depreciation and Amortization Tax Credit Carryforward [Line Items] Tax Credit Carryforward [Line Items] Due after one year through five years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost Segment Reporting [Table] Segment Reporting [Table] Common stock available for grant (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant Related Party Transaction [Table] Related Party Transaction [Table] Title and Position [Axis] Title and Position [Axis] Weighted-Average Remaining Contractual Term (Years) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Additional Disclosures [Abstract] Commitments and Contingencies Disclosure [Abstract] All Trading Arrangements All Trading Arrangements [Member] Less than 12 Months Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months Other Performance Measure, Amount Other Performance Measure, Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Current Fiscal Year End Date Current Fiscal Year End Date Shares owned by foundation (in shares) Investment Owned, Balance, Shares Contribution to the lemonade foundation (in shares) Stock Issued During Period, Shares, Issued For Charitable Contribution Stock Issued During Period, Shares, Issued For Charitable Contribution Reinsurance Contract [Axis] Reinsurance Contract [Axis] Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Reportable Segment Reportable Segment [Member] Reportable Segment Market condition measurement period Share Based Compensation Arrangement by Share Based Payment Award, Market Condition Measurement Period Share Based Compensation Arrangement by Share Based Payment Award, Market Condition Measurement Period Non-U.S. government obligations Non-U.S. government obligations Non-U.S. government obligations Debt Security, Government, Non-US [Member] Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Entity File Number Entity File Number Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Arizona ARIZONA Due in one year or less Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value Schedule of Contractual Maturities of Bonds Investments Classified by Contractual Maturity Date [Table Text Block] Schedule of Activity In The Liability For Unpaid Loss and LAE Schedule of Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block] Schedule of Stock Options Activity Share-Based Payment Arrangement, Option, Activity [Table Text Block] Weighted- Average Exercise Price Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Common stock, issued (in shares) Common Stock, Shares, Issued Measure: Measure [Axis] Net earned premium Premiums Earned, Net Gross unrealized losses, twelve months or more 12 Months or More Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Unearned premium (Increase) Decrease in Unearned Premiums, Net Equity Components [Axis] Equity Components [Axis] Funds held for reinsurance treaties Funds Held under Reinsurance Agreements, Liability Related Party Related Party [Member] California CALIFORNIA Entity Interactive Data Current Entity Interactive Data Current Variable Rate [Axis] Variable Rate [Axis] Effects of Reinsurance [Line Items] Effects of Reinsurance [Line Items] Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Fair Value Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Fair Value [Abstract] Entity Small Business Entity Small Business Comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Unearned premium Unearned Premiums Termination Date Trading Arrangement Termination Date Grant date fair value Share-Based Compensation Arrangement By Share-Based Payment Award, Equity Instruments Other Than Options, Grants In Period, Fair Value Share-Based Compensation Arrangement By Share-Based Payment Award, Equity Instruments Other Than Options, Grants In Period, Fair Value Market condition, share price threshold (at or above) Share Based Compensation By Share Based Payment Award, Market Condition, Threshold Share Price, Minimum Share Based Compensation By Share Based Payment Award, Market Condition, Threshold Share Price, Minimum Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Current year Current accident year incurred loss and LAE Current Year Claims and Claims Adjustment Expense Expiration period Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period Document Type Document Type Unrecognized tax benefits, income tax penalties and interest accrued Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued 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] Fair Value as of Grant Date Award Grant Date Fair Value Debt Instrument, Funding Period [Axis] Debt Instrument, Funding Period [Axis] Debt Instrument, Funding Period Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Debt Instrument, Funding Period [Domain] Debt Instrument, Funding Period [Domain] Debt Instrument, Funding Period [Domain] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Interest on cash and cash equivalents Cash and Cash Equivalents [Member] Arrangement Duration Trading Arrangement Duration Statement of Stockholders' Equity [Abstract] Local Phone Number Local Phone Number Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name All other All Other States [Member] All Other States Less than 12 Months Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Loss before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Unvested, aggregate intrinsic value Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Commitments and Contingencies (Note 15) Commitments and Contingencies Total revenue Total revenue Revenues Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Executive Category: Executive Category [Axis] Sub-total Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Fair Value Vesting period Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period Counterparty Name [Axis] Counterparty Name [Axis] Liabilities and Stockholders' Equity Liabilities and Equity [Abstract] Exercisable, weighted-average remaining contractual, term Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted-Average Remaining Contractual Term Percent of contracts subject to participation through reinsurance Contracts in Force Subject to Participation through Reinsurance, Ratio Award Type [Domain] Award Type [Domain] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Payable to carriers Payable To Carriers Payable To Carriers New Business Financing Agreement New Business Financing Agreement [Member] New Business Financing Agreement Fair Value Measurements Fair Value Disclosures [Text Block] Level 3 Fair Value, Inputs, Level 3 [Member] U.S. Government obligations U.S. Government obligations U.S. Government obligations US Government Agencies Debt Securities [Member] Supplemental disclosure of cash flow information: Supplemental Cash Flow Information [Abstract] Weighted average expected term (years) Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Term Remaining unvested warrant shares (in shares) Class Of Warrant Or Right, Number Of Warrants Cancelled Class Of Warrant Or Right, Number Of Warrants Cancelled PEO Name PEO Name Geographical [Axis] Geographical [Axis] Total paid Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid Other liabilities and accrued expenses Total Accrued Liabilities and Other Liabilities Restricted cash Restricted Cash Cash paid for income taxes Income Tax Paid, before Refund Received Other expenses Segment Reporting, Other Segment Item, Amount Other assets Other Assets Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Entity Tax Identification Number Entity Tax Identification Number Debt Instrument, Funding Period Two Debt Instrument, Funding Period Two [Member] Debt Instrument, Funding Period Two RSUs with market condition Restricted Stock Units, With Market Conditions [Member] Restricted Stock Units, With Market Conditions Legal Entity [Axis] Legal Entity [Axis] Interest expense Interest Expense, Debt Exercised (usd per share) Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Cash, cash equivalents and restricted cash Cash, cash equivalents and restricted cash at beginning of period Cash, cash equivalents and restricted cash at end of period Total cash, cash equivalents and restricted cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Trade payables Increase (Decrease) in Accounts Payable Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Effects of Reinsurance [Table] Effects of Reinsurance [Table] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Non-NEOs Non-NEOs [Member] Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Exercise of stock options and distribution of restricted stock units (in shares) Share Based Compensation Arrangement By Share-Based Payment Award, Options And Restricted Stock Units, Exercises In Period Share Based Compensation Arrangement By Share-Based Payment Award, Options And Restricted Stock Units, Exercises In Period Debt Instrument [Axis] Debt Instrument [Axis] Stock-based compensation Share-Based Payment Arrangement, Noncash Expense Assessment charge Assessment Charge Assessment Charge GC Customer Value Arranger, LLC GC Customer Value Arranger, LLC [Member] GC Customer Value Arranger, LLC Due after ten years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost Investment, Name [Domain] Investment, Name [Domain] Long-Term Debt, Type [Domain] Long-Term Debt, Type [Domain] Net loss per share attributable to common stockholders—basic (usd per share) Earnings Per Share, Basic Statistical Measurement [Axis] Statistical Measurement [Axis] Insider Trading Arrangements [Line Items] Reinsurance, excess retention, amount reinsured, per policy Reinsurance, Excess Retention, Amount Reinsured, Per Policy 2020 ESPP Employee Stock Purchase Plan 2020 [Member] Employee Stock Purchase Plan 2020 Award Type [Axis] Award Type [Axis] Gross written premium Premiums Written, Gross Benchmark [Member] Premiums Written, Gross Benchmark Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Number of shared directors Number Of Shared Directors Number Of Shared Directors Other payables Other Sundry Liabilities Unrealized (loss) gain on investments in fixed maturities Other Comprehensive Income (Loss), Available-for-Sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Accumulated deficit Retained Earnings (Accumulated Deficit) RSUs with service condition Restricted Stock Units, With Service Conditions [Member] Restricted Stock Units, With Service Conditions Florida FLORIDA Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Common Stock Common Stock [Member] Volatility Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Volatility Rate Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Share based compensation arrangement by share based payment award, shares issued in period (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Shares Issued in Period Reference Premium Reference Premium [Member] Reference Premium Cover [Abstract] Insurance [Abstract] Expected dividend yield Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Dividend Rate 2020 Plan Incentive Compensation Plan 2020 [Member] Incentive Compensation Plan 2020 % of GWP Concentration Risk, Percentage Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Colorado COLORADO Equity Awards Adjustments Equity Awards Adjustments [Member] Total liabilities and stockholders' equity Liabilities and Equity Number of shares of common stock per exercised option (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Shares Called By Each Option Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Shares Called By Each Option Pre-tax net realized capital gains (losses) Realized Investment Gains (Losses) Stock options Stock options Options to purchase common stock Share-Based Payment Arrangement, Option [Member] Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Table] Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Table] Segments [Axis] Segments [Axis] Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Plan Name [Axis] Plan Name [Axis] Related Party [Domain] Related and Nonrelated Parties [Domain] Income Tax Jurisdiction [Domain] Income Tax Jurisdiction [Domain] Premium receivable Increase (Decrease) in Premiums Receivable Tabular List, Table Tabular List [Table Text Block] Additional paid-in capital Additional Paid in Capital Less: Reinsurance recoverable at beginning of period Reinsurance recoverable at end of period Reinsurance Recoverable for Unpaid Claims and Claims Adjustments Schedule of Aging of Gross Unrealized losses Unrealized Gain (Loss) on Investments [Table Text Block] Reinsurance recoverable Increase (Decrease) in Reinsurance Recoverable Schedule of Stock-Based Compensation Expense Share-Based Payment Arrangement, Cost by Plan [Table Text Block] Short-term investments Short-Term Investments [Member] Maya Prosor [Member] Maya Prosor Name Awards Close in Time to MNPI Disclosures, Individual Name Fair value of warrant liability (less than) Warrants And Rights Outstanding, Fair Value Disclosure Warrants And Rights Outstanding, Fair Value Disclosure Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Outstanding, aggregate intrinsic value, outstanding Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value Cancelled/Forfeited (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period General and administrative General and Administrative Expense Due after one year through five years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value Preferred stock, authorized (in shares) Preferred Stock, Shares Authorized Adjustment to Compensation: Adjustment to Compensation [Axis] California Wildfires California Wildfires [Member] California Wildfires Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Cash paid for interest expense on borrowings under financing agreement Interest Paid, Excluding Capitalized Interest, Operating Activity Statement of Cash Flows [Abstract] Incentive Stock Plan 2021 Incentive Stock Plan 2021 [Member] Incentive Stock Plan 2021 Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Total Assets, Fair Value Disclosure Income Tax Jurisdiction [Axis] Income Tax Jurisdiction [Axis] Unvested (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Name Measure Name Illinois ILLINOIS Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] Income Taxes Income Tax Disclosure [Text Block] Pay vs Performance Disclosure [Line Items] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Debt Instrument [Line Items] Debt Instrument [Line Items] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Unpaid loss and loss adjustment expense Increase (Decrease) in Liability for Claims and Claims Adjustment Expense Reserve Additional Paid-In Capital Additional Paid-in Capital [Member] Entity Filer Category Entity Filer Category Fair Value Debt Securities, Available-for-Sale, Unrealized Loss Position Short-term investments, cost Short Term Investments, Cost Short Term Investments, Cost Short-term investments (cost: $9.2 million and $14.1 million as of June 30, 2026 and December 31, 2025, respectively) Short term investments Short-Term Investments Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Due in one year or less Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost Use of Estimates Use Of Estimates [Text Block] Use Of Estimates Name Trading Arrangement, Individual Name Advertising expenses Advertising Expense Unrecognized expense, RSUs Share-Based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount Cash and cash equivalents Cash and Cash Equivalent Common stock reserved for issuance, annual increase, percentage of outstanding shares Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized, Annual Increase, Percent Of Shares Outstanding Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized, Annual Increase, Percent Of Shares Outstanding Basis of Presentation Basis of Accounting [Text Block] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Company Selected Measure Amount Company Selected Measure Amount Investments, Debt and Equity Securities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Unvested, weighted-average remaining contractual, term Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term Amended and Restated Customer Investment Agreement Amended And Restated Customer Investment Agreement [Member] Amended And Restated Customer Investment Agreement Total Gross Investment Income, Operating Non-PEO NEO Non-PEO NEO [Member] Entity Address, Address Line One Entity Address, Address Line One Total expense Benefits, Losses and Expenses Vested (usd per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Sale of Stock [Line Items] Subsidiary, Sale of Stock [Line Items] Income tax expense Income tax expense Income Tax Expense (Benefit) Award Timing Method Award Timing Method [Text Block] Net (decrease) increase in cash, cash equivalents and restricted cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Premium receivable, net of allowance for credit losses of $5.0 million and $4.1 million as of June 30, 2026 and December 31, 2025, respectively Premiums Receivable, Net Net loss Net loss Net loss Net Income (Loss) Attributable to Parent Lemonade, Inc. Lemonade, Inc. [Member] Lemonade, Inc. Long-Term Debt, Type [Axis] Long-Term Debt, Type [Axis] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Statement [Table] Statement [Table] Restatement Determination Date: Restatement Determination Date [Axis] Proceeds from stock exercises Proceeds from Stock Options Exercised Exercisable, weighted-average exercise price (usd per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Exercise Price Income taxes payable Accrued Income Taxes Other insurance expense Other insurance expense Other Insurance Expense Other Insurance Expense Revenue Revenues [Abstract] Exercise of stock options and distribution of restricted stock units Stock Issued During Period, Value, Stock Options And Restricted Stock Exercised Stock Issued During Period, Value, Stock Options And Restricted Stock Exercised Metromile Metromile [Member] Metromile Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block]