Investments Investment, Policy [Policy Text Block] Debt and Equity Securities, FV-NI [Line Items] Debt and Equity Securities, FV-NI [Line Items] Schedule of Prior Year Loss Development for the AmTrust Reinsurance Legacy Operations Schedule of prior year loss development by line of business [Table Text Block] Schedule of prior year loss development by line of business Award Timing Predetermined Award Timing Predetermined [Flag] Entity File Number Entity File Number Commission rate, adjustment criteria, loss ratio floor Related Party Transaction, Commission Rate, Adjustment Criteria, Loss Ratio Floor Related Party Transaction, Commission Rate, Adjustment Criteria, Loss Ratio Floor Additional paid-in capital Additional Paid-in Capital [Member] Quarterly brokerage fee, above portfolio threshold, percent of average holdings Related Party Transaction, Quarterly Brokerage Fee, Above Portfolio Threshold, Percent of Average Holdings Related Party Transaction, Quarterly Brokerage Fee, Above Portfolio Threshold, Percent of Average Holdings Tabular List, Table Tabular List [Table Text Block] Earn Out Liability Earn Out Liability [Policy Text Block] Earn Out Liability Recently Adopted Accounting Standards and Recently Issued Accounting Standards Not Yet Adopted New Accounting Pronouncements, Policy [Policy Text Block] Schedule of Quota Share Arrangements with AmTrust Schedule of Related Party Transactions [Table Text Block] Diversified Legacy Reinsurance Diversified Legacy Segment [Member] Diversified Legacy Segment Schedule of Carrying Value and Fair Value of Senior Notes Fair Value, by Balance Sheet Grouping [Table Text Block] Change in unearned premiums (Increase) Decrease in Unearned Premiums, Net Measurement Basis [Axis] Measurement Basis [Axis] Adjustment to Compensation: Adjustment to Compensation [Axis] Related Party Transactions Related Party Transactions Disclosure [Text Block] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Change in fair value of earn out liability Change in fair value of earn out liability Decrease in fair value of earn out liability Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Earn-Out, Liability Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Earn-Out Liability Percent of premiums written, net of cost of unaffiliated inuring reinsurance from related party Related Party Transaction, Percent of Premium Written, Net of Cost of Unaffiliated Inuring Reinsurance From Related Party Related Party Transaction, Percent of Premium Written, Net of Cost of Unaffiliated Inuring Reinsurance From Related Party Amortized cost Fixed Maturities, Amortized Cost Basis Fixed Maturities, Amortized Cost Basis Schedule of Stock by Class [Table] Stock, Class of Stock [Table] Percent of ceded underwriting risk in exchange for ceding fee Related Party Transaction, Percent of Ceded Underwriting Risk in Exchange for Ceding Fee Related Party Transaction, Percent of Ceded Underwriting Risk in Exchange for Ceding Fee AmTrust Quota Share AmTrust Quota Share [Member] AmTrust Quota Share Related party transaction, loan agreement, obligation threshold Related Party Transaction, Loan Agreement, Obligation Threshold Related Party Transaction, Loan Agreement, Obligation Threshold Assets held for sale Assets held for sale Disposal Group, Including Discontinued Operation, Assets Adjustment to Compensation, Amount Adjustment to Compensation Amount Less: unamortized fair value adjustment Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net Other assets Increase (Decrease) in Other Operating Assets Basis of Reporting and Consolidation Consolidation, Policy [Policy Text Block] Employee Stock Option Share-Based Payment Arrangement, Option [Member] Schedule of Amortized Cost, Gross Unrealized Gains and Losses and Fair Value on Fixed Maturities Schedule of Investments Reconciliation [Table Text Block] Schedule of Investments Reconciliation [Table Text Block] Cash and Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Deposit contracts Deposit Contracts, Liabilities Distribution to shareholders Dividends, Common Stock, Cash Total shareholders’ equity Beginning balance Ending balance Cumulative translation adjustment Equity, Attributable to Parent Accrued investment income Disposal Group, Including Discontinued Operation, Accrued Investment Income Disposal Group, Including Discontinued Operation, Accrued Investment Income Measurement Frequency [Axis] Measurement Frequency [Axis] Schedule of Available-for-sale Securities [Table] Debt Securities, Available-for-Sale [Table] Insider Trading Policies and Procedures [Line Items] Authorized share capital (in shares) Common Stock, Shares Authorized Fair Value, Measurements, Recurring Fair Value, Recurring [Member] Gain Contingencies [Table] Gain Contingencies [Table] Funds withheld receivable (Allowance for expected credit losses: 2025 - $9) Funds withheld receivable Funds Held under Reinsurance Agreements, Asset Reinsurance balances receivable, net (includes $7,712 from related parties in 2025). Allowance for expected credit losses: 2025 - $229) Reinsurance balances receivable, net Premiums Receivable, Net Cover [Abstract] Cover [Abstract] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Assets Held for Sale Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Maximum Maximum [Member] Discount for present value Lessee, Operating Lease, Liability, Fair Value Discount Lessee, Operating Lease, Liability, Fair Value Discount Loss and LAE Policyholder Benefits and Claims Incurred, Net [Abstract] Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Debt Instrument [Line Items] Debt Instrument [Line Items] Cancellation notice period Related Party Transaction, Cancellation Notice Period Related Party Transaction, Cancellation Notice Period Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Direct Direct Premiums Earned External Credit Rating, Standard & Poor's [Domain] External Credit Rating, Standard & Poor's [Domain] Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Gain on bargain purchase Gain on bargain purchase Bargain purchase gain Business Combination, Bargain Purchase, Gain Recognized, Amount Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Entity Shell Company Entity Shell Company Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Kestrel Group Kestrel Group [Member] Kestrel Group Schedule of Composition of Other Investments Summary of Other Investments [Table Text Block] Summary of Other Investments [Table Text Block] Reserve for loss and loss adjustment expenses Increase (Decrease) in Liability for Claims and Claims Adjustment Expense Reserve Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Operating Segments Operating Segments [Member] Shareholder voting power, percentage Common Stock, Shareholder Voting Power, Percentage Common Stock, Shareholder Voting Power, Percentage Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] Net (loss) income from continuing operations Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Business combination, stock conversion ratio Business Combination, Stock Conversion Ratio Business Combination, Stock Conversion Ratio Percent of ceding commission payable, period increase Related Party Transaction, Percent Of Ceding Commission Payable, Period Increase (Decrease) Related Party Transaction, Percent Of Ceding Commission Payable, Period Increase (Decrease) Expenses from related party transactions Management Fee Expense Document Fiscal Period Focus Document Fiscal Period Focus Foreign currency translation adjustment Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax, Portion Attributable to Parent Intangible assets (includes $9,169 from related parties in 2025) Intangible assets Intangible Assets, Net (Including Goodwill) Accrued investment income Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Accrued investment income Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Accrued Investment Income Award Timing Method Award Timing Method [Text Block] Basic (loss) income from continuing operations per share attributable to Kestrel common shareholders (in dollars per share) Basic (loss) earnings from continuing operations per share attributable to Kestrel shareholders (in dollars per share) Income (Loss) from Continuing Operations, Per Basic Share AmTrust Financial Services, Inc. AmTrust Financial Services, Inc. AmTrust Financial Services, Inc. [Member] AmTrust Financial Services, Inc. [Member] Award Type Award Type [Axis] Foreign currency translation Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Silverstone Venture 2 Silverstone Venture 2 [Member] Silverstone Venture 2 Investment, Name [Domain] Investment, Name [Domain] Share-Based Compensation Expense Share-Based Payment Arrangement [Policy Text Block] Trading Symbol Trading Symbol 2029 Lessee, Operating Lease, Liability, to be Paid, Year Four Accounting Treatment for the Combination Business Combination [Policy Text Block] Number of securities in an unrealized loss position Fixed Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions Fixed Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Gross loss and LAE Policyholder Benefits and Claims Incurred, Direct Accrued expenses and other liabilities (includes $68,508 and $0 from related parties in 2025 and 2024, respectively) Accrued expenses and other liabilities Accrued Liabilities and Other Liabilities Fair value of unrealized loss positions Investments, Continuous Unrealized Loss Position, Fair Value Investments, Continuous Unrealized Loss Position, Fair Value Entity Address, City or Town Entity Address, City or Town Effect of exchange rate changes on foreign currency cash, restricted cash and cash equivalents Effect of Exchange Rate on Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Total consideration effectively transferred Total consideration effectively transferred Business Combination, Consideration Transferred Entity Emerging Growth Company Entity Emerging Growth Company Changes in assets – (increase) decrease: Increase (Decrease) in Operating Assets [Abstract] 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] Less: unamortized fair value adjustment Debt Issuance Costs, Net Restricted cash and cash equivalents Restricted cash and cash equivalents, end of period Total restricted cash Restricted Cash and Cash Equivalent Diversified Legacy Reinsurance Diversified Reinsurance legacy business Diversified Reinsurance Segment [Member] Diversified Reinsurance Segment [Member] Common shares, outstanding (in shares) Common Stock, Shares, Outstanding Insurance [Abstract] Insurance [Abstract] Reinsurance, amount retained, per policy Reinsurance, Amount Retained, Per Policy Investments transferred out related to Partial Termination Amendment and Commutation AmTrust Quota Shares Reinsurance Agreement, Partial Termination Amendment [Member] AmTrust Quota Shares Reinsurance Agreement, Partial Termination Amendment [Member] Internal Revenue Service (IRS) Internal Revenue Service (IRS) [Member] 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] Intangible Assets Intangible Assets, Finite-Lived, Policy [Policy Text Block] Fixed maturities, available-for-sale, at fair value Disposal Group Including Discontinued Operation, Debt Securities Disposal Group Including Discontinued Operation, Debt Securities Common shares issued or to be issued (in shares) Business Combination, Contingent Consideration, Shares issued or To Be Issued Business Combination, Contingent Consideration, Shares issued or To Be Issued Effective interest rate Debt Instrument, Interest Rate, Effective Percentage Entity Address, Postal Zip Code Entity Address, Postal Zip Code Restatement Determination Date Restatement Determination Date Less: income tax expense Income tax expense Income tax expense Income Tax Expense (Benefit) Fed funds rate Debt Instrument, Basis Spread on Variable Rate Basic loss from discontinued operations per share attributable to Kestrel common shareholders (in dollars per share) Basic loss from discontinued operations per share attributable to Kestrel shareholders (in dollars per share) Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share Other assets Other Assets Balance - beginning of period Total Level 3 investments - end of period Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Credit Rating, Standard & Poor's [Axis] Credit Rating, Standard & Poor's [Axis] Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Discontinued Operations, Held-for-sale Discontinued Operations, Held-for-Sale [Member] Discontinued Operations and Disposal Groups [Abstract] Discontinued Operations and Disposal Groups [Abstract] Investment Management Fee Investment Management Fees [Member] Investment Management Fees [Member] Treasury Shares Stockholders' Equity, Policy [Policy Text Block] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Solvency ratio Related Party Transaction, Solvency Ratio Related Party Transaction, Solvency Ratio All Trading Arrangements All Trading Arrangements [Member] Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Redemption price, percentage Debt Instrument, Redemption Price, Percentage Collateral held by related party Related Party Transaction, Collateral Held by Related Party Related Party Transaction, Collateral Held by Related Party Number of directors, selected by affiliate Number of Directors, Selected by Affiliate Number of Directors, Selected by Affiliate Senior notes - at fair value Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Long-Term Debt Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Long-Term Debt Collateral on exposure Related Party Transaction, Percentage Of Collateral On Exposure Related Party Transaction, Percentage Of Collateral On Exposure Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Net cash used in operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Proceeds from sales of fixed maturities  Proceeds from Sale of Debt Securities, Available-for-Sale Decrease in allowance for expected credit losses on reinsurance recoverable where credit losses were previously recognized Reinsurance Recoverable, Allowance for Credit Loss, Recovery Sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales Other assets Business Combination, Recognized Asset Acquired, Other Asset, Current Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] PEO Total Compensation Amount PEO Total Compensation Amount Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Discount rates Derivative Liability, Measurement Input Denominator: Weighted Average Number of Shares Outstanding, Basic [Abstract] Schedule of Investments [Abstract] Schedule of Investments [Abstract] Equity Components [Axis] Equity Components [Axis] Net unrealized gains on held for sale fixed maturities OCI, Debt Securities, Held-for-Sale, Unrealized Holding Gain (Loss), before Adjustment and Tax OCI, Debt Securities, Held-for-Sale, Unrealized Holding Gain (Loss), before Adjustment and Tax Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Number of reporting segments Number of Reportable Segments Reinsurance principal amount Loans Payable Net loss and loss adjustment expenses Net loss and LAE Net Net loss and LAE Policyholder Benefits and Claims Incurred, Net Entity Address, Country Entity Address, Country Amount of loss from discontinued operations allocated to participating common shareholders, basic Net Income (Loss) from Discontinued Operations Available to Common Shareholders, Basic Individual: Individual [Axis] Reinsurance Retention Policy [Table] Reinsurance Retention [Table] Income Tax Authority [Domain] Income Tax Jurisdiction [Domain] Equity method investments Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Equity Method Investments Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Equity Method Investments Dividends paid – Kestrel equityholders Payments of Ordinary Dividends, Common Stock Acquisition option term Business Combination, Acquisition Option Term Business Combination, Acquisition Option Term Other investments Other Investment [Member] Other Investment Amortized cost of securities without single maturities Debt Securities, Available-for-Sale, Maturity, without Single Maturity Date, Amortized Cost Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Minority interest Subsidiary, Ownership Percentage, Noncontrolling Owner Equity securities, gross losses Equity Securities, FV-NI, Realized And Unrealized Loss Equity Securities, FV-NI, Realized And Unrealized Loss Entity Interactive Data Current Entity Interactive Data Current Other investments Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Other Investments Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Other Investments Deferred income tax Deferred Tax Assets, Deferred Income Net loan receivable from related party Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Net Loan Receivable From Related Party Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Net Loan Receivable From Related Party Fixed maturities, available-for-sale, at fair value Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Fixed Maturities, Available For Sale Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Fixed Maturities, Available For Sale Related Party Transaction, By Type [Axis] Related Party Transaction, By Type [Axis] Related Party Transaction, By Type [Axis] Ownership [Domain] Ownership [Domain] Portion of the Maiden awards attributable to pre-combination service Business Combination Consideration Transferred Attributable to Pre Combination Service Business Combination Consideration Transferred Attributable to Pre Combination Service Accrued interest Interest Payable, Current Entity Central Index Key Entity Central Index Key PEO Name PEO Name Total revenues Revenues 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] Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Net realized and unrealized gains (losses) on investment, gross gains Realized And Unrealized Gain On Investments Realized And Unrealized Gain On Investments Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Quota Share Reinsurance Agreements Quota Share Reinsurance Agreements [Member] Quota Share Reinsurance Agreements [Member] Net premiums written Net premiums written Net premiums written Net Premiums Written, Net Reinsurance balances receivable, net, allowance for expected credit losses Premium Receivable, Allowance for Credit Loss Exercise Price Award Exercise Price Entity Filer Category Entity Filer Category Less: change in cash and cash equivalents held for sale Increase (Decrease) in Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Held-for-Sale Increase (Decrease) in Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Held-for-Sale Investments in direct lending entities Other investments - Investments in direct lending entities Direct Lending Entities [Member] Direct Lending Entities Cash and cash equivalents Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents 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] Gross premiums written Gross premiums written Premiums Written, Gross Entity Address, Address Line One Entity Address, Address Line One Net unrealized losses on held for sale AFS investments Equity Method Investment, Unrealized Gain (Loss) Equity Method Investment, Unrealized Gain (Loss) Accumulated other comprehensive loss Total AOCI Attributable to Parent [Member] Accrued expenses and other liabilities Increase (Decrease) in Accrued Liabilities and Other Operating Liabilities Investments [Domain] Investments [Domain] Reinsurance recoverable on unpaid losses (Allowance for expected credit losses: 2025 - $1,459) Reinsurance recoverable on unpaid losses Reinsurance Recoverable for Unpaid Claims and Claims Adjustments Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract] Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract] Ownership [Axis] Ownership [Axis] Proceeds from sale and redemption of other investments Proceeds from Sale and Maturity of Other Investments Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Cavello Cavello [Member] Cavello Fair Value as of Grant Date Award Grant Date Fair Value Equity securities, at fair value, cost Cost Equity Securities, FV-NI, Cost Bermuda NewCo shares retained as treasury shares by Maiden Reinsurance at Closing (in shares) Business Combination, Consideration Transferred, Equity Interests Issued and Issuable, Treasury Shares Retained Business Combination, Consideration Transferred, Equity Interests Issued and Issuable, Treasury Shares Retained Operating loss carryforwards Operating Loss Carryforwards Schedule of Issuances of Senior Notes Outstanding Schedule of Long-Term Debt Instruments [Table Text Block] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Expected credit losses on recoverables where credit losses were not previously recognized Decrease in allowance for expected credit losses on reinsurance recoverable where credit losses were previously recognized Reinsurance Recoverable, Credit Loss Expense (Reversal) Document Quarterly Report Document Quarterly Report Silverstone Venture 1 Silverstone Venture 1 [Member] Silverstone Venture 1 Schedule of Significant Unobservable Inputs for Determining Fair Value of Other Investments Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] 2027 Lessee, Operating Lease, Liability, to be Paid, Year Two Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Accrued investment income Accrued Investment Income Receivable Net operating loss carryforwards, with no expiry date, percentage Deferred Tax Assets, Operating Loss Carryforwards, Not Subject to Expiration, Percentage Deferred Tax Assets, Operating Loss Carryforwards, Not Subject to Expiration, Percentage Investment Type [Axis] Investment Type [Axis] Total investments Investments Title Trading Arrangement, Individual Title Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Effect of foreign exchange rate movements Liability for Unpaid Claims and Claims Adjustment Expense, Foreign Currency Transaction and Translation Adjustment Increase (decrease) in liability for unpaid claims and claims adjustment expense due to foreign currency transaction and translation adjustments. Other investments, net Gain (Loss) on Other Securities, Excluding Debt and Equity Securities Gain (Loss) on Other Securities, Excluding Debt and Equity Securities Schedule of the Credit Ratings of Fixed Maturities Schedule of Investment Credit Ratings [Table Text Block] Schedule of Investment Credit Ratings [Table Text Block] Total PPD for Legacy Reinsurance Segment Favorable PPD Total AmTrust Reinsurance PPD Liability for Unpaid Claims and Claims Adjustment Expense, Period Increase (Decrease), Net of Commission Changes Liability for Unpaid Claims and Claims Adjustment Expense, Period Increase (Decrease), Net of Commission Changes Upfront cash Payments to Acquire Businesses, Gross Net unrealized gains on fixed maturity investments Investments, Net Unrealized Gain (Loss) Investments, Net Unrealized Gain (Loss) Non-PEO NEO Non-PEO NEO [Member] Allowance for expected credit losses Debt Securities, Available-for-Sale, Allowance for Credit Loss Net operating loss carryforwards expire Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration Fee revenue Fee revenue Fee Income Genesis Legacy Solutions Genesis Legacy Solutions [Member] Genesis Legacy Solutions Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Gross unrealized gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax ASSETS Disposal Group, Including Discontinued Operation, Assets [Abstract] All Award Types Award Type [Domain] 2026 Lessee, Operating Lease, Liability, to be Paid, Year One Net loan receivable from related party Payments for (Proceeds from) Loans Receivable Additional claims estimated Reinsurance Recoverables, Incurred but Not Reported Claims Equity Awards Adjustments Equity Awards Adjustments [Member] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Restricted Cash and Investments Items [Line Items] Restricted Cash and Investments [Line Items] Restricted Cash and Investments [Line Items] Number of directors Number Of Directors Number Of Directors Compensation Amount Outstanding Recovery Compensation Amount Senior Notes - MHNC – 7.75% 2013 Senior Notes Senior Notes 2013 [Member] Senior Notes 2013 [Member] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Schedule for Reserve for Loss and LAE and Schedule of Prior Period Development Experienced Schedule of Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Estimate of Fair Value Measurement Fair Value Estimate of Fair Value Measurement [Member] % of Total Fair Value, Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments, Percentage Of Total Fair Value, Investments, Entities That Calculate Net Asset Value Per Share, Unfunded Commitments, Percentage Of Total Policy inception, grace period Insurance Contracts, Program Fee Receivables, Premium Receivable, Collection Period Insurance Contracts, Program Fee Receivables, Premium Receivable, Collection Period Schedule of Investments [Line Items] Schedule of Investments [Line Items] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Due after one year through five years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year One Through Five Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward] AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward] Number of reinsurance agreements, open Reinsurance Agreement, Open Reinsurance Agreement, Open Revenues Revenues [Abstract] Non-U.S. government bonds Non-U.S. government bonds Foreign Government Debt [Member] Net realized and unrealized gains (losses) on investment, gross losses Realized And Unrealized Loss On Investments Realized And Unrealized Loss On Investments Due after five years through ten years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 Restricted cash and cash equivalents and investments Total restricted cash and investments Restricted Cash and Investments Schedule of Fair Value of Restricted Assets Schedule of Financial Instruments Owned and Pledged as Collateral [Table Text Block] Accrued investment income Increase (Decrease) in Accrued Investment Income Receivable Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Net Maiden Legacy run-off business acquired Liability for Unpaid Claims and Claims Adjustment Expense, Assumed Business Liability for Unpaid Claims and Claims Adjustment Expense, Assumed Business Financial Instruments [Domain] Financial Instruments [Domain] Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] LIABILITIES Disposal Group, Including Discontinued Operation, Liabilities [Abstract] Minimum Minimum [Member] Other assets Disposal Group, Including Discontinued Operation, Other Assets Net (loss) income available to Kestrel common shareholders before discontinued operations, diluted Net Income (Loss) from Continuing Operations Available to Common Shareholders, Diluted Company Selected Measure Name Company Selected Measure Name Fair Value Measurement [Domain] Fair Value Measurement [Domain] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Gross equity portion of consideration transferred at Closing Business Combination, Consideration Transferred, Equity Interest, Excluding Treasury Stock Business Combination, Consideration Transferred, Equity Interest, Excluding Treasury Stock Net (loss) income attributable to Kestrel common shareholders, diluted Net Income (Loss) Available to Common Stockholders, Diluted Stockholders' Equity Note [Abstract] Stockholders' Equity Note [Abstract] Commitments, Contingencies and Guarantees Commitments and Contingencies Disclosure [Text Block] Weighted average number of common shares - diluted (in shares) Weighted average number of common shares - diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Reconciliation of Assets from Segment to Consolidated [Table] Reconciliation of Assets from Segment to Consolidated [Table] Legacy Reinsurance Legacy Reinsurance Segment Legacy Reinsurance Segment [Member] Legacy Reinsurance Segment Entity Small Business Entity Small Business Income Tax Disclosure [Abstract] Fair value Fixed Maturities, Continuous Unrealized Loss Position, Fair Value [Abstract] Fixed Maturities, Continuous Unrealized Loss Position, Fair Value [Abstract] Shares issued to Maiden Reinsurance Treasury Stock, Shares Issued to Subsidiary Treasury Stock, Shares Issued to Subsidiary Long-Term Debt Long-Term Debt [Text Block] Document Transition Report Document Transition Report Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Commission rate, percent of ceded written premiums Related Party Transaction, Commission Rate, Percent of Ceded Written Premiums Related Party Transaction, Commission Rate, Percent of Ceded Written Premiums Due after one year through five years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five Underlying Securities Award Underlying Securities Amount Fixed maturities, gross gains Debt Securities, Available-for-Sale, Realized Gain Equity Component [Domain] Equity Component [Domain] Document Period End Date Document Period End Date Income Taxes Income Tax Disclosure [Text Block] AEL AEL [Member] AEL [Member] Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Total net unrealized losses Investments, Unrealized Gain (Loss), Gross Of Deferred Income Tax Expense Investments, Unrealized Gain (Loss), Gross Of Deferred Income Tax Expense Schedule of Investments [Table] Schedule of Investments [Table] % of Total fair value Fixed Maturities, Percent of Total Fair Value Fixed Maturities, Percent of Total Fair Value % of Total Equity Method Investments, Percent Of Total Equity Method Investments, Percent Of Total Document Type Document Type Significant Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Schedule of Reconciliation to Consolidated Total Assets Reconciliation of Assets from Segment to Consolidated [Table Text Block] Earnings per Common Share Earnings Per Share [Text Block] Name Outstanding Recovery, Individual Name Percent of losses with respect to current lines of business, excluding those above covered business threshold to related party Related Party Transaction, Percent of Losses With Respect to Current Lines of Business, Excluding Those Above Covered Business Threshold To Related Party Related Party Transaction, Percent of Losses With Respect to Current Lines of Business, Excluding Those Above Covered Business Threshold To Related Party Additional paid-in capital Additional Paid in Capital Product and Service [Axis] Product and Service [Axis] Funds withheld receivable Increase (Decrease) in Funds Held under Reinsurance Agreements Business Combination, Intangible Asset, Acquired, Finite-Lived [Table] Business Combination, Intangible Asset, Acquired, Finite-Lived [Table] Reinsurance recoverables on unpaid losses Reinsurance Recoverables on Unpaid Losses, Gross Reinsurer, Name [Domain] Reinsurer, Name [Domain] Restricted investments – liability for investments purchased for related party agreements Restricted Investment, Liability Restricted Investment, Liability Reserve for loss and loss adjustment expenses Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Reserve For Loss And Loss Adjustment Expenses Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Reserve For Loss And Loss Adjustment Expenses Assumed Assumed Premiums Earned Statistical Measurement [Axis] Statistical Measurement [Axis] Income on funds withheld Funds Withheld Arrangement [Member] Funds Withheld Arrangement [Member] Private credit investments Private Credit Lending [Member] Private Credit Lending Premium Repayment Loan Agreement Premium Repayment Loan Agreement [Member] Premium Repayment Loan Agreement Other investments, gross gains Marketable Securities, Realized Gain Marketable Securities, Realized Gain Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Maximum limit of liability attaching Related Party Transaction, Maximum Limit of Liability Attaching Related Party Transaction, Maximum Limit of Liability Attaching Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Net (loss) income attributable to Kestrel common shareholders, basic Net Income (Loss) Available to Common Stockholders, Basic Investment Ownership, Issued at closing of Combination Investment Ownership, At Merger Closing [Member] Investment Ownership, At Merger Closing Other comprehensive loss, after tax Net current period other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Thereafter Lessee, Operating Lease, Liability, Payments Due After Year Four Lessee, Operating Lease, Liability, Payments Due After Year Four General and administrative expenses Operating Expenses Bermuda NewCo share price (in dollars per share) Bermuda NewCo share price (in dollars per share) Business Combination, Price Per Share Number of reinsurance agreements, completing 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Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Schedule of Variable Interest Entities [Table] Variable Interest Entity [Table] Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Company Selected Measure Amount Company Selected Measure Amount 2028 Lessee, Operating Lease, Liability, to be Paid, Year Three Original fair value adjustment at acquisition date Debt Issuance Costs, Gross Equity securities, gross gains Equity Securities, FV-NI, Realized And Unrealized Gain Equity Securities, FV-NI, Realized And Unrealized Gain Comprehensive (loss) income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Measurement Input Type [Axis] Measurement Input Type [Axis] Name Measure Name Reinsurance recoverable on unpaid losses Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Reinsurance Recoverable on 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