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Disclosure - Note 11 - Credit Agreements (Details Textual) link:presentationLink link:calculationLink link:definitionLink 995905 - Disclosure - Note 13 - Subsequent Event - Additional Information (Details) link:presentationLink link:calculationLink link:definitionLink Equity securities Equity securities, at fair value (cost: $38,482 in 2025; $32,987 in 2024) Equity securities, at fair value (cost: $38,482 in 2025; $32,987 in 2024) Released, weighted average grant date fair value (in dollars per share) Proceeds from Sale of Property, Plant, and Equipment Proceeds from Sale of Property, Plant, and Equipment, Total Proceeds from sale of property and equipment Reinsurance recoverable on unpaid losses and loss adjustment expenses Add: Reinsurance recoverables on unpaid losses and LAE at end of period Schedule of Nonvested Performance-Based Units Activity [Table Text Block] Entity Incorporation, State or Country Code Preferred Stock, Shares Issued (in shares) Preferred Stock, Shares Issued (in shares) us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1 Current year Due within one year, Fair Value Due within one year, Fair Value Average price per share Shares Acquired, Average Cost Per Share Plan Name [Axis] 12 Months or Longer, fair value 12 Months or Longer, fair value Equity [Abstract] Entity Current Reporting Status US Government Agencies Debt Securities [Member] US Government Agencies Debt Securities [Member] Acquisition expenses, net of ceding commissions and fronting fees Other comprehensive income (loss) before reclassification Fair Value, Inputs, Level 2 [Member] Common Stock, Shares Authorized (in shares) Common Stock, Shares Authorized (in shares) Chris Uchida [Member] Chris Uchida. us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1 Total incurred Amount of increase (decrease) in additional paid in capital (APIC) resulting from policyholder contribution to surplus. Policyholder contribution to surplus Policyholder contribution to surplus Product and Service [Axis] Document Fiscal Period Focus Amount of maximum advances or credit lines available from the Federal Home Loan Bank (FHLB) as percentage of statutory admitted assets, plmr_FederalHomeLoanBankAdvancesGeneralDebtObligationsMaximumAmountAvailableAsPercentageOfStatutoryAdmittedAssets Federal Home Loan Bank, Advances, General Debt Obligations, Maximum Amount Available as Percentage of Statutory Admitted Assets Entity Shell Company Segment Reporting, Policy [Policy Text Block] Segment Reporting Cash and cash equivalents Cash and cash equivalents Number Of Additional Stock Price Milestones Achieved Number Of Additional Stock Price Milestones Achieved Represents number of additional stock price milestones achieved. Duration of award service period under share-based compensation arrangement. plmr_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardServicePeriod Share-based Compensation Arrangement by Share-based Payment Award, Award Service Period (Year) Common Stock, Shares, Issued (in shares) Common Stock, Shares, Issued (in shares) TEXAS Statement [Table] Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased (in shares) Share Repurchase Program, Remaining Authorized, Number of Shares Statement [Line Items] Treasury Stock, Value, Acquired, Cost Method Treasury Stock, Value, Acquired, Cost Method Business Combination [Domain] Payments on Line of Credit Payments on line of credit. Payments on line of credit Put Option [Member] livestock put options [Member] Entity Filer Category us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent Amounts reclassified from AOCI, net of tax us-gaap_LiabilitiesAndStockholdersEquity Total liabilities and stockholders' equity Equity [Table] Equity. us-gaap_PaymentsToAcquireMarketableSecurities Purchases of equity securities Business Combination, Voting Equity Interest Acquired, Percentage Business Acquisition, Percentage of Voting Interests Acquired Issuance of common stock via equity incentive plan (in shares) Issuance of common stock via equity incentive plan (in shares) Change in allowance for credit losses us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Subsequent Event [Line Items] Reinsurance Disclosures [Abstract] HAWAII us-gaap_EffectiveIncomeTaxRateContinuingOperations Effective Income Tax Rate Reconciliation, Percent Interest income Geographical [Domain] Identification of the acquiree in a material business combination (or series of individually immaterial business combinations), which may include the name or other type of identification of the acquiree. First Indemnity of America Insurance Company [Member] Asset-Backed Securities [Member] Asset-Backed Securities [Member] Due after ten years, Amortized Cost Due after ten years, Amortized Cost Represents percentage of gross written premiums. Percentage of Gross Written Premiums Additional paid-in capital Additional paid-in capital Vesting [Domain] Disaggregation of Revenue [Table] Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Reinsurance [Text Block] Investments Classified by Contractual Maturity Date [Table Text Block] Basic earnings per share (in dollars per share) Basic (in dollars per share) Disaggregation of Revenue [Table Text Block] Options, Outstanding, Number (in shares) Outstanding, options (in shares) Outstanding, options (in shares) Schedule of Available-for-Sale Securities Reconciliation [Table Text Block] Revolving Credit Facility [Member] us-gaap_ProceedsFromSaleOfEquitySecuritiesFvNi Proceeds from Sale of Equity Securities, FV-NI Add: Balance acquired from FIA(1) Sales and maturities of fixed maturity securities Stockholders' equity: Stockholders' equity: Entity Small Business Retained earnings Retained earnings us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod Options cancelled (in shares) Represents Palomar Specialty Insurance Company. Palomar Specialty Insurance Company [Member] us-gaap_ReinsuranceRetentionAmountRetainedPerEvent Reinsurance, Amount Retained, Per Event Fair value amount of catastrophe bond. plmr_CatastropheBondFaceValue Catastrophe Bond, Face Value Common Share equivalents (in shares) Catastrophic Event [Axis] Amendment Flag Net realized investment losses Net realized investment gains (losses) Product and Service [Domain] Non-Rule 10b5-1 Arrangement Modified Non Rule 10b 51 Arr Modified Flag Non Rule 10b 51 Arr Modified Flag. Entity Address, Postal Zip Code Net cash provided by operating activities Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description Common Stock [Member] Common Stock [Member] Losses and loss adjustment expenses Debt Securities, Available-for-Sale [Line Items] Entity Address, Address Line One Fair Value Hierarchy and NAV [Axis] Earnings Per Share [Abstract] Supplementary cash flow information: Fair value Debt Securities, Available-for-Sale, Unrealized Loss Position Fair value us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt Purchases of fixed maturity securities Earthquake [Member] Document Type Change in unearned premiums Cash paid for income taxes Entity Central Index Key Line of Credit Facility [Table] Investments, Debt and Equity Securities [Abstract] us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect Net increase in cash, cash equivalents and restricted cash Subsequent Event Type [Domain] Goodwill and intangible assets, net Goodwill and intangible assets, net Accrued investment income Accrued investment income Repurchases of common stock (in shares) Stock Repurchased and Retired During Period, Shares Repurchases of common stock (in shares) Option Indexed to Issuer's Equity [Axis] Common Stock, Par Value (in dollars per share) Common Stock, Par or Stated Value Per Share (in dollars per share) Common Stock, Par Value (in dollars per share) Other comprehensive income (loss), net of tax Other comprehensive income (loss) Other comprehensive income/loss net of tax Share-Based Payment Arrangement, Tranche One [Member] Liabilities: Liabilities: Outstanding, options, weighted average remaining contractual term (Year) Available-for-Sale, Amortized Cost Amortized Cost Available-for-Sale, Amortized Cost Total, Fair Value Fixed maturity securities available for sale, at fair value (amortized cost: $1,015,892 in 2025; $973,330 in 2024) Debt Securities, Available-for-sale Fixed maturity securities available for sale, at fair value (amortized cost: $1,146,855 in 2025; $973,330 in 2024) us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised Options exercised, options (in shares) Debt Disclosure [Abstract] Represents number of dates for achievement of milestone stock price. plmr_NumberOfDaysAchievementOfMilestoneStockPrice Number of Days, Achievement of Milestone Stock Price Current Fiscal Year End Date Amount of cash inflow from policyholders contribution to surplus. plmr_ProceedsFromPolicyholdersContributionToSurplus Policy holder contribution to surplus Document Quarterly Report CALIFORNIA Entity Address, State or Province Equity Instruments Other than Options, Nonvested, Number (in shares) Non-vested, shares (in shares) Non-vested, shares (in shares) Purchase of policy renewal rights Payment To Acquire Policy Renewal Rights Payment to acquire policy renewal rights. Preferred Stock, Shares Outstanding (in shares) Preferred Stock, Shares Outstanding (in shares) us-gaap_ComprehensiveIncomeNetOfTax Net comprehensive income Available-for-sale, Accumulated Gross Unrealized Gain Available-for-sale, Accumulated Gross Unrealized Gain us-gaap_CommonStockCapitalSharesReservedForFutureIssuance Total (in shares) Geographical [Axis] Represents special revenue excluding asset backed securities. Special Revenue Excluding Asset Backed Securities [Member] Special Revenue Excluding Asset Backed Securities [Member] Schedule of Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block] Performance Shares [Member] Deferred tax assets, net Deferred tax assets, net Sales of equity securities Subsequent Event [Member] Subsequent Event Equity [Line Items] Equity. Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Amount reclassified to earnings Other underwriting expenses WASHINGTON us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage Basis of Presentation and Significant Accounting Policies [Text Block] Represents corporate debt securities and other debt obligations. Corporate Debt Securities and Other Debt Obligations [Member] Corporate Debt Securities and Other Debt Obligations [Member] us-gaap_InterestExpenseDebt Interest Expense, Debt Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract] us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt Proceeds from Sale of Debt Securities, Available-for-Sale Share-Based Payment Arrangement, Cost by Plan [Table Text Block] AOCI Attributable to Parent [Member] AOCI Attributable to Parent [Member] us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments Represents other states. Other States [Member] Business Combination, Consideration Transferred Business Combination, Consideration Transferred Business Combination, Consideration Transferred, Total Preferred stock, $0.0001 par value, 5,000,000 shares authorized, 0 shares issued and outstanding as of June 30, 2025 and December 31, 2024 Preferred stock, $0.0001 par value, 5,000,000 shares authorized, 0 shares issued and outstanding as of September 30, 2025 and December 31, 2024 Mortgage and asset-backed securities, Amortized Cost Mortgage and asset-backed securities, Amortized Cost Minimum [Member] Granted, weighted average grant date fair value (in dollars per share) Financial Instrument [Axis] Reinsurance recoverables Increase (Decrease) in Reinsurance Recoverable Represents the increase in the number of shares available for grant under the plan as a percentage of common stock issued and outstanding as of the immediately preceding fiscal year end date. plmr_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageNumberOfAdditionalSharesAvailableForGrant Share Based Compensation Arrangement By Share Based Payment Award Percentage, Number of Additional Shares Available for Grant Fair Value, Inputs, Level 3 [Member] Ceded unearned premiums Ceded unearned premiums Segment Reporting [Abstract] Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Represents inland marine and other properties. Inland Marine and Other Property [Member] Stock Repurchased and Retired During Period, Value Repurchases of common stock Repurchases of common stock Note 2 - Investments - Summary of Available for Sale Investments (Details) us-gaap_SharesOutstanding Balance (in shares) Balance (in shares) Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value [Table Text Block] us-gaap_PaymentsForLossesAndLossAdjustmentExpense Total payments us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue Non-vested outstanding, weighted average grant date fair value (in dollars per share) Non-vested outstanding, weighted average grant date fair value (in dollars per share) Excess of loss protection amount of reinsurance policy. plmr_ReinsurancePolicyExcessOfLossProtectionAmount Reinsurance Policy, Excess of Loss Protection Amount Ceded premium payable Ceded premium payable us-gaap_DebtInstrumentBasisSpreadOnVariableRate1 Debt Instrument, Basis Spread on Variable Rate Equity Securities, Cost Equity Securities, Cost Amount of unrealized gain (loss) on investment in equity method security measured at fair value with change in fair value recognized in net income (FV-NI). Net unrealized gains (losses) on equity method investment Reserve for losses and loss adjustment expenses Reserve for losses and LAE gross of reinsurance recoverables on unpaid losses and LAE at end of period Basic (in shares) Gain (Loss) on Securities [Table Text Block] Represents vesting on first anniversary. Share Based Payment Arrangement Tranche One First Anniversary [Member] Document Information [Line Items] Segment Reporting, Expense Information Used by CODM, Description Options [Member] Options Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss 12 Months or Longer, Accumulated Loss Funds held under reinsurance treaty Funds held under reinsurance treaty Subsequent Events Subsequent Events [Text Block] Variable Rate [Domain] Angela Grant [Member] Angela Grant [Member] us-gaap_StockholdersEquity Balance Balance Total stockholders' equity Preferred Stock, Par Value (in dollars per share) Preferred Stock, Par or Stated Value Per Share (in dollars per share) Preferred Stock, Par Value (in dollars per share) Basis of Accounting, Policy [Policy Text Block] Basis of Presentation Statement of Stockholders' Equity [Abstract] Share-Based Payment Arrangement, Tranche Two [Member] Equity method investment Equity method investment us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsTax Federal income tax (benefit) expense Use of Estimates, Policy [Policy Text Block] Use of Estimates us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent Other comprehensive income (loss) before reclassification, net of tax Fair Value Disclosures [Text Block] Prepaid expenses and other assets Prepaid expenses and other assets Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration] Plan Name [Domain] Interest expense Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Entity [Domain] Gains on sales of equity securities Due after ten years, Fair Value Due after ten years, Fair Value Credit Facility [Axis] Vested and Exercisable, options, weighted average exercise price (in dollars per share) Accrued Income Taxes Accrued Income Taxes, Total Income taxes payable Income taxes payable Entity Address, City or Town Treasury Stock, Shares, Acquired (in shares) Stock Repurchased During Period, Shares Liability for Unpaid Claims and Claims Adjustment Expense, Activity in Liability [Abstract] Security Exchange Name Credit Facility [Domain] us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet Reserve for losses and LAE net of reinsurance recoverables at end of period Reserve for losses and LAE net of reinsurance recoverables at beginning of period us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest Income before income taxes Reinsurance recoverable on paid losses and loss adjustment expenses Reinsurance recoverable on paid losses and loss adjustment expenses Amount of realized loss on investment in debt and equity securities. plmr_DebtAndEquitySecuritiesRealizedLoss Total realized losses Liability for Claims and Claims Adjustment Expense [Table] Reinsurance Retention [Line Items] Cash paid for interest Statistical Measurement [Domain] Amount of realized gain on investment in debt and equity securities. plmr_DebtAndEquitySecuritiesRealizedGain Total realized gains Stock-Based Compensation Document Period End Date Fair Value Hierarchy and NAV [Domain] Represents fronting premium. Fronting Premium [Member] Statement of Financial Position [Abstract] Restricted Stock Units (RSUs) [Member] us-gaap_DebtSecuritiesAvailableForSaleRealizedLoss Losses on sales of fixed maturity securities Vesting [Axis] Other comprehensive income, net: Represents the amount of loss and loss adjustment expense reserve redundancy. plmr_LossAndLossAdjustmentExpenseReserveRedundancy Loss and Loss Adjustment Expense Reserve Redundancy us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions Expenses: us-gaap_Liabilities Total liabilities Financial Instruments [Domain] us-gaap_ReclassificationFromAociCurrentPeriodBeforeTaxAttributableToParent Amounts reclassified from AOCI Gross written premiums Restricted cash Restricted cash NEW YORK Variable Rate [Axis] ILLINOIS us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss Less than 12 Months, Accumulated Loss Diluted (in shares) Diluted (in shares) Entity File Number us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod Forfeited, shares (in shares) Federal income tax (benefit) expense Number of Shares Authorized (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares) Number of Operating Segments Number of operating segment Segment Reporting Disclosure [Text Block] Subsequent Event [Table] Derivative assets -- livestock put options Derivative Assets (Liabilities), at Fair Value, Net Derivative Assets (Liabilities), at Fair Value, Net, Total Dividend income Share Repurchase Program, Expiration Date Share repurchase program, expiration date Continental hurricane [Member] Continental hurricane [Member] Continental Hurricane [Member] Represents employee stock purchase plan 2019. Employee Stock Purchase Plan 2019 [Member] New Accounting Pronouncements, Policy [Policy Text Block] Recent Accounting Pronouncements us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1 Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year) Comprehensive Income (Loss) Note [Text Block] us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions Share-Based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount Common Stock, Shares, Outstanding (in shares) Common Stock, Shares, Outstanding (in shares) Document Transition Report Payments for Repurchase of Common Stock Repurchases of common stock Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid (Refunded), Prior Years. plmr_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidRefundedPriorYears Prior years Statement of Cash Flows [Abstract] Issuance of common stock in stock offering, net of offering costs Stock Issued During Period, Value, New Issues us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired Acquisitions, net of cash acquired Equity [Text Block] Earnings Per Share [Text Block] us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Net income Net income Outstanding, options, aggregate intrinsic value us-gaap_DebtAndEquitySecuritiesGainLoss Net realized and unrealized gains on investments Net unrealized gains on equity securities Line of Credit Facility [Line Items] Hurricane [Member] Schedule Of Capital Reserved For Future Issuance [Line Items] Schedule of capital reserved for future issuance. Vested and Exercisable, options, aggregate intrinsic value Document Fiscal Year Focus The net cash outflow or inflow from securities during the period, which are classified as investing activities. Change in securities receivable or payable, net Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Represents the Laulima Insurance Company. Laulima Insurance Company [Member] Investing activities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Fair value portion of cash, cash equivalents and restricted cash. plmr_CashCashEquivalentsAndRestrictedCashFairValueDisclosure Cash, cash equivalents, and restricted cash us-gaap_InterestExpenseLoansFromOtherFederalHomeLoanBanks Interest Expense, Loans from Other Federal Home Loan Banks Net investment income Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items] Proceeds from common stock issued via stock option exercises Fair Value Disclosures [Abstract] FLORIDA Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value [Table] us-gaap_LineOfCredit Long-Term Line of Credit us-gaap_AssetsFairValueDisclosure Total assets Proceeds from common stock issued via employee stock purchase plan Schedule of Nonvested Restricted Stock Units Activity [Table Text Block] The amount of commission and other revenue earned during period. Commission and other income us-gaap_Revenues Total revenues us-gaap_NetCashProvidedByUsedInInvestingActivities Net cash used in investing activities Title of 12(b) Security us-gaap_InvestmentIncomeNet Net investment income Share Repurchase Program, Remaining Authorized, Amount Authorized amount available for future repurchases Options cancelled (in dollars per share) Forfeited, weighted average grant date fair value (in dollars per share) Due after one year through five years, Amortized Cost Due after one year through five years, Amortized Cost Weighted-average common shares outstanding: Income Tax Disclosure [Text Block] us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss Available-for-Sale, Allowance for Credit Loss us-gaap_PaymentsForSoftware Capitalized software costs Document Information [Table] Consolidated Entities [Axis] Legal Entity [Axis] Due after one year through five years, Fair Value Due after one year through five years, Fair Value us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice Outstanding, options, weighted average exercise price (in dollars per share) Outstanding, options, weighted average exercise price (in dollars per share) Income Tax Disclosure [Abstract] Fair Value, Recurring and Nonrecurring [Table] Business Combination [Text Block] Additional Paid-in Capital [Member] Additional Paid-in Capital [Member] Represents predetermined performance achievement as a percentage. plmr_PredeterminedPerformanceAchievementPercentage Predetermined Performance Achievement, Percentage Measurement Frequency [Domain] Share Repurchase Program, Authorized, Amount Share repurchase program, authorized, amount Trading Symbol Schedule Of Capital Reserved For Future Issuance [Table] Schedule of capital reserved for future issuance. Due within one year, Amortized Cost Due within one year, Amortized Cost Subsequent Event Type [Axis] Financing activities us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Fair Value, Recurring [Member] Represents earthquake premiums. Earthquake Premiums [Member] Represents Equity Incentive Plan 2019. Equity Incentive Plan 2019 [Member] us-gaap_CededPremiumsWritten Ceded written premiums Equity Components [Axis] Vested and Exercisable, options, weighted average remaining contractual term (Year) Equity Component [Domain] Share-Based Payment Arrangement, Activity [Table Text Block] NORTH DAKOTA NORTH DAKOTA Represents alternate base rate. Alternate Base Rate [Member] Deferred policy acquisition costs, net of ceding commissions and fronting fees Deferred policy acquisition costs, net of ceding commissions and fronting fees Total investments us-gaap_Investments Business Combination [Axis] Rule 10b5-1 Arrangement Modified Rule 10b 51 Arr Modified Flag Rule 10b 51 Arr Modified Flag. Due after five years through ten years, Amortized Cost Due after five years through ten years, Amortized Cost Derivative, Fair Value, Net Derivative, Fair Value, Net, Total Fair value of derivative instrument Issuance of common stock via equity incentive plan Issuance of common stock via equity incentive plan Issuance of common stock via employee stock purchase plan (in shares) Issuance of common stock via employee stock purchase plan (in shares) us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year) us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch Federal Home Loan Bank, Advance, Branch of FHLBank, Amount The entire disclosure of reserve for losses and loss adjustment expenses. Reserve for Losses and Loss Adjustment Expenses [Text Block] Represents the amount of unrealized gain (loss) on other investments during the period. Net unrealized gains on other investments Represents Hawaii Hurricane. Hawaii Hurricane [Member] Maximum [Member] Statistical Measurement [Axis] Options exercised, options, weighted average exercise price (in dollars per share) us-gaap_PremiumsWrittenNet Net written premiums Common stock, $0.0001 par value, 500,000,000 shares authorized, 26,735,132 and 26,529,402 shares issued and outstanding as of June 30, 2025 and December 31, 2024, respectively Common stock, $0.0001 par value, 500,000,000 shares authorized, 26,494,524 and 26,529,402 shares issued and outstanding as of September 30, 2025 and December 31, 2024, respectively Represents securities on deposit with state regulatory authorities. Securities on Deposit With State Regulatory Authorities [Member] Secured Overnight Financing Rate (SOFR) [Member] Gains on sales of fixed maturity securities Net unrealized gains on securities available for sale Premiums receivable Premiums receivable us-gaap_BenefitsLossesAndExpenses Total expenses Current year Preferred Stock, Shares Authorized (in shares) Preferred Stock, Shares Authorized (in shares) us-gaap_PremiumsEarnedNet Net earned premiums us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss Accumulated Loss Accounts payable and other accrued liabilities Accounts payable and other accrued liabilities Employee Stock [Member] Entity Registrant Name Debt Disclosure [Text Block] us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax Available-for-sale, Accumulated Gross Unrealized Loss us-gaap_TreasuryStockSharesAcquired Treasury Stock, Shares, Acquired (in shares) us-gaap_AdditionalPaidInCapital Additional Paid in Capital Accumulated Other Comprehensive Income (Loss) [Table] us-gaap_EquitySecuritiesFvNiRealizedLoss Losses on sales of equity securities Subsequent Events [Abstract] The tabular disclosure of common stock reserved for future issuance. Schedule of Capital Reserved for Future Issuance [Table Text Block] Consolidated Entities [Domain] Income tax expense Measurement Frequency [Axis] Other investments Other investments Stock Repurchased During Period, Value Treasury Stock, Value, Acquired, Cost Method Proceeds from Issuance of Common Stock Proceeds from stock offering, net of offering costs Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Investment Income [Table Text Block] Entity Common Stock, Shares Outstanding US States and Political Subdivisions Debt Securities [Member] US States and Political Subdivisions Debt Securities [Member] Accumulated other comprehensive loss Accumulated other comprehensive income (loss) Represents casualty. Casualty [Member] us-gaap_PaymentsToAcquirePropertyPlantAndEquipment Purchases of property and equipment Net realized and unrealized gains on investments Granted, shares (in shares) us-gaap_Assets Total assets Income Statement [Abstract] Jon Christianson [Member] Jon Christianson. Issuance of common stock in stock offering, net of offering costs (in shares) Stock Issued During Period, Shares, New Issues Unearned premiums Unearned premiums us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod Released, shares (in shares) Per Share Data: Business Combination [Abstract] Diluted earnings per share (in dollars per share) Diluted (in dollars per share) Disaggregation of Revenue [Abstract] Mortgage and asset-backed securities, Fair Value Mortgage and asset-backed securities, Fair Value City Area Code Proceeds from Lines of Credit Proceeds from Lines of Credit, Total Proceeds from line of credit Represents number of stock price milestones achieved. plmr_NumberOfStockPriceMilestonesAchieved Number of Stock Price Milestones Achieved us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity Line of Credit Facility, Maximum Borrowing Capacity Insurance [Abstract] Issuance of common stock via employee stock purchase plan Issuance of common stock via employee stock purchase plan Investments: Stock-based compensation Stock-based compensation Property and equipment, net Property and equipment, net Gray Casualty & Surety Company Gray Casualty And Surety Company [Member] Gray Casualty And Surety Company. Vested and Exercisable, options (in shares) Prior years us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations Cash, cash equivalents and restricted cash at end of period Cash, cash equivalents and restricted cash at beginning of period Cash and cash equivalents and restricted cash Represents maximum authorized annual increase of shares under share-based compensation arrangement for shares available for grant. plmr_SharebasedCompensationArrangementBySharebasedPaymentAwardSharesAvailableForIssuanceAuthorizedAnnualIncreaseMaximum Share-based Compensation Arrangement by Share-based Payment Award, Shares Available for Issuance, Authorized Annual Increase, Maximum (in shares) Retained Earnings [Member] Retained Earnings [Member] Less than 12 Months, fair value Less than 12 Months, fair value Fair Value, Inputs, Level 1 [Member] us-gaap_NetCashProvidedByUsedInFinancingActivities Net cash (used in) provided by financing activities Notes Payable Notes Payable, Total Borrowings from credit agreements Due after five years through ten years, Fair Value Due after five years through ten years, Fair Value Debt Securities, Available-for-Sale [Table] Entity Interactive Data Current Represents U.S. hurricane. U.S. Hurricane [Member] us-gaap_PaymentsForAdvanceToAffiliate Investments in limited partnerships and other assets Operating activities Catastrophic Event [Domain] Represents crops. Crop [Member] Option Indexed to Issuer's Equity, Type [Domain] Note 3 - Fair Value Measurements Entity Tax Identification Number Local Phone Number Accumulated Other Comprehensive Income (Loss) [Line Items] us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts Offering Costs (related to prior year offering) Accounting Policies [Abstract] Significant Accounting Policies Amount of income (expenses) related to the generation of investment income. plmr_InvestmentIncomeInvestmentIncomeExpense Investment income (expense) Disaggregation of Revenue [Line Items] us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1 Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year) Represents Palomar Excess And Surplus Insurance Company. Palomar Excess And Surplus Insurance Company [Member] Entity Emerging Growth Company Note 7 - Underwriting Information