Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Trading Arrangement: Trading Arrangement [Axis] Maximum Maximum [Member] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Title of 12(b) Security Title of 12(b) Security Reported Value Measurement Reported Value Measurement [Member] Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-Sale [Table] Derivative Instruments Gain Loss By Hedging Relationship By Income Statement Location By Derivative Instrument Risk [Table] Derivative Instruments, Gain (Loss) [Table] Additions (reductions) for expected credit losses on loans where credit losses were previously recognized Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff (Recovery) Adjustment to Compensation, Amount Adjustment to Compensation Amount Other Investments [Line Items] Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items] Redemption Restriction Type [Axis] Redemption Restriction Type [Axis] Information by type of redemption restriction. Financial Instrument [Axis] Financial Instrument [Axis] Segment Reporting [Abstract] Segment Reporting [Abstract] Unearned premiums Increase (Decrease) in Unearned Premiums Derivative Instrument Risk [Axis] Derivative Instrument [Axis] Insurance and reinsurance balances payable Reinsurance Payable Unrealized gains (losses) arising during the period Other Comprehensive Income (Loss) before Reclassifications, Tax Insurance and reinsurance balances, net (Increase) Decrease In Premiums Receivable And Reinsurance Payable Net The net change in the premium receivable and the amount due to other insurance companies on the balance sheet. (Increase) decrease in allowance for expected credit losses, fixed maturities, available for sale Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss, Period Increase (Decrease) U.S. government and agency US Treasury and Government [Member] Average price per share (in usd per share) Shares Acquired, Average Cost Per Share Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Other amortization and depreciation Other Depreciation and Amortization Other comprehensive income (loss), net of tax: Other Comprehensive Income (Loss), Net of Tax [Abstract] Net cash inflows Other Significant Noncash Transaction, Value of Consideration Received Related Portfolio [Axis] Related Portfolio [Axis] Information that identifies a derivative or a group of derivatives by related portfolio. Reinsurance recoverable on paid losses and loss expenses Increase (Decrease) In Reinsurance Recoverable On Paid Losses And Loss Expenses The increase (decrease) during the reporting period in the amount of reinsurance recoverable on paid losses and loss expenses. Summary of Fixed Maturities, Held-to-Maturity Debt Securities, Held-to-Maturity [Table Text Block] RELATED PARTY TRANSACTIONS Related Party Transactions Disclosure [Text Block] Allowance for expected credit losses (as a percent) Financing Receivable, Allowance For Credit Loss, Real Estate, Percentage Of Total Financing Receivable, Allowance For Credit Loss, Real Estate, Percentage Of Total Total Unrealized loss position Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss Unrealized losses Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract] Reclassification out of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Member] Catastrophic Event [Domain] Catastrophic Event [Domain] Intangible assets Intangible Asset, Excluding Goodwill, after Accumulated Amortization Nonvested restricted stock units - beginning of period (in shares) Nonvested restricted stock units - end of period (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number Market Condition Share-Based Payment Arrangement, Tranche One [Member] Amortization of fixed maturities Accretion (Amortization) of Discounts and Premiums, Investments Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Uncommitted Bilateral Short-Term Line Of Credit Uncommitted Bilateral Short-Term Line Of Credit [Member] Uncommitted Bilateral Short-Term Line Of Credit Number of reportable segments Number of Reportable Segments Reinsurance recoverable on unpaid losses and loss expenses Reinsurance Recoverable On Unpaid Losses And Loss Expense [Member] Reinsurance Recoverable On Unpaid Losses And Loss Expense Fixed maturities, available for sale, amortized cost Amortized cost Amortized cost, total Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss Monarch Point Re (ISA 2024) Ltd Monarch Point Re (ISA 2024) Ltd [Member] Monarch Point Re (ISA 2024) Ltd Entity Address, City or Town Entity Address, City or Town Liability for Future Policy Benefit, by Product Segment [Line Items] Liability for Future Policy Benefit, by Product Segment [Line Items] Granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period Gross investment income Investment Income For Investments And Cash And Cash Equivalents The net gain or loss (both realized and unrealized) related to investments in certain entities that calculate net asset value per share and the amount after accretion (amortization) of discount (premium), of interest income and dividend income on nonoperating securities. Reconcilation of Beginning and Ending Balance of Nonvested Restricted Stock (including RSUs) [Line Items] Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Percentage of investment composition (as a percent) Percentage Of Investment Composition Percentage Of Investment Composition Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Federal Home Loan Bank Branch [Axis] Federal Home Loan Bank Branch [Axis] Net incurred losses and loss expenses related to: Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract] Advances from FHLB, fair value Federal Home Loan Bank Borrowings, Fair Value Disclosure Significant other observable inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward] Debt Securities, Available-for-Sale, Allowance for Credit Loss [Roll Forward] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Unrealized gains (losses) arising during the period OCI, before Reclassifications, before Tax, Attributable to Parent Class Of Treasury Stock [Table] Class of Treasury Stock [Table] Schedule Of Investment Income Reported Amounts By Category [Table] Investment Income [Table] Summary of Underwriting Results of Reportable Segments Segment Reporting [Table Text Block] Sector Concentration Sector Concentration Risk [Member] Sector Concentration Risk Mortgage loans Gain (Loss) on Sale of Mortgage Loans Related Party [Axis] Related and Nonrelated Parties [Axis] Total other comprehensive income (loss), net of tax Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Net cash outflows Other Significant Noncash Transaction, Value of Consideration Given Loans sold/redeemed/matured Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Loan Sold Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items] Federal Home Loan Bank, Advance, Branch of FHLBank [Line Items] Other investments Alternative Investments [Member] Fair value of investments in certain entities that calculate net asset value per share, including, but not limited to, by unit, membership interest, or other ownership interest. Investments include, but are not limited to, investments in certain hedge funds, venture capital funds, private equity funds, real estate partnerships or funds. Credit Rating [Domain] External Credit Rating by Grouping [Domain] 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 Allowance for expected credit losses Allowance for expected credit losses Balance at beginning of period Balance at end of period Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest Document Period End Date Document Period End Date Dividends paid in period following declaration (in usd per share) Dividends Payable, Amount Per Share Earnings per common share: Earnings per common share Earnings Per Share, Basic [Abstract] Fixed maturities, short-term investments, and cash and cash equivalents Debt Securities, Available-for-Sale, Realized Loss Share Settled Share Settled [Member] Share Settled Treasury shares, at cost (2026: 103,439; 2025: 102,445) Treasury Stock, Common, Value Monarch Point Re Monarch Point Re [Member] Monarch Point Re (ISAC) Ltd. and Monarch Point Re (ISA 2023) Ltd. Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Due after ten years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 10 Number of funds Number Of Investment Funds Number Of Investment Funds Unrealized gains (losses) arising during the period, net of reclassification adjustment Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent Fair value of restricted stock units vested Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Shell Company Entity Shell Company Consolidation Items [Domain] Consolidation Items [Domain] Mortgage Loans Mortgage loans Mortgages [Member] EARNINGS PER COMMON SHARE Earnings Per Share [Text Block] Per share data Earnings Per Share [Abstract] 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 Partner Type [Axis] Partner Type [Axis] Fixed maturities, available for sale, at fair value (Amortized cost 2026: $13,916,563; 2025: $12,937,728 Allowance for expected credit losses 2026: $1,898; 2025: $1,836) Fair value Fair value, total Fixed maturities, available for sale Debt Securities, Available-for-Sale, Excluding Accrued Interest Specialty other Speciality Line, Other [Member] Speciality Line, Other Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward] Net investment income Net investment income Investment Income Net For Investments And Cash And Cash Equivalents The net gain or loss (both realized and unrealized) related to investments in certain entities that calculate net asset value per share and the amount after accretion (amortization) of discount (premium) of interest income and dividend income on nonoperating securities, net of investment expense. Total mortgage loans held-for investment (as a percent) Financing Receivable, After Allowance For Credit Loss, To Total, Percent Financing Receivable, After Allowance For Credit Loss, To Total, Percent Company Selected Measure Name Company Selected Measure Name Included in OCI Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Fixed maturities, available for sale Payments to Acquire Debt Securities, Available-for-Sale Adjustment for reclassification of net realized (gains) losses and impairment losses recognized in net income (loss) Reclassification from AOCI, Current Period, before Tax, Attributable to Parent Repayment of Federal Home Loan Bank advances Repayments Of (Proceeds From) FHLBank Borrowings, Financing Activities Repayments Of (Proceeds From) FHLBank Borrowings, Financing Activities Earnings per diluted common share Earnings Per Share, Diluted [Abstract] Summary of Total Unrealized and Realized Gains (Loss) on Derivatives Not Designated as Hedges Recorded in Earnings Derivatives Not Designated as Hedging Instruments [Table Text Block] Equity securities, cost Cost Equity Securities, FV-NI, Cost Credit Facility [Domain] Credit Facility [Domain] Reserve for losses and loss expenses Gross reserve for losses and loss expenses, beginning of period Gross reserve for losses and loss expenses, end of period Liability for Claims and Claims Adjustment Expense Cash flows from operating activities: Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] FHLB program, investments pledged as security Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged Dividends paid in period of declaration, common shares (in usd per share) Common Stock, Dividends, Per Share, Cash Paid Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Line of Credit Facility [Table] Line of Credit Facility [Table] Transfers out of Level 3 Transfers out of Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 Summary of Net Investment Income Investment Income [Table Text Block] Redemption Frequency [Axis] Redemption Frequency [Axis] Redemption Frequency Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Summary of Changes in Level 3 Financial Instruments Measured at Fair Value on a Recurring Basis, Assets Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Fixed maturities without a single maturity date Debt Securities, Available-for-Sale, Maturity, without Single Maturity Date, Amortized Cost Other items Increase (Decrease) in Other Operating Assets and Liabilities, Net Award Timing Predetermined Award Timing Predetermined [Flag] Summary of Tax Effects Allocated to Each Component of Other Comprehensive Income (Loss) Comprehensive Income (Loss) [Table Text Block] Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Share-based compensation expense APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Quoted prices in active markets for identical assets (Level 1) Fair Value, Inputs, Level 1 [Member] Net reserve for unpaid losses and loss expenses, beginning of period Net reserve for unpaid losses and loss expenses, end of period Liability for Unpaid Claims and Claims Adjustment Expense, Net Share Repurchase Type [Domain] Share Repurchase Type [Domain] Type of share repurchase. Share-based compensation plans (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements Available for sale Debt Securities, Available-for-Sale [Abstract] Schedule of Federal Home Loan Bank Advances, by Branch of FHLB Bank [Table] Federal Home Loan Bank, Advance, Branch of FHLBank [Table] Vesting [Domain] Vesting [Domain] Total fixed maturities with a single maturity date Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Amortized Cost Summary of Prior Year Loss Development Schedule of Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block] Partner Type of Partners' Capital Account, Name [Domain] Partner Type of Partners' Capital Account, Name [Domain] Federal Home Loan Bank Branch [Domain] Federal Home Loan Bank Branch [Domain] Operating lease right-of-use assets Operating Lease, Right-of-Use Asset Concentration Risk Type [Domain] Concentration Risk Type [Domain] Due in one year or less (as a percent) Available For Sale Securities Debt Maturities Within One Year Percentage Of Fair Value Amount of available-for-sale debt securities at fair value maturing in the next fiscal year following the latest fiscal year, expressed as a percentage of the total fair value of debt securities classified as available-for-sale. Net paid losses and loss expenses related to: Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract] Due in one year or less Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, Year One Derivative liability, statement of financial position [Extensible Enumeration] Derivative Liability, Statement of Financial Position [Extensible Enumeration] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Due after one year through five years (as a percent) Available For Sale Securities Debt Maturities After One Through Five Years Percentage Of Fair Value Amount of available-for-sale debt securities at fair value maturing in second through fifth fiscal year following latest fiscal year, expressed as a percentage of the total fair value of debt securities classified as available-for-sale. INVESTMENTS Investment in Debt and Equity Securities and Other Trading Assets [Text Block] Dividends paid - common shares Payments of Ordinary Dividends, Common Stock Expiration Date Trading Arrangement Expiration Date Gross unrealized gains Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain Restricted cash and cash equivalents Restricted Cash and Cash Equivalent Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Cash flows from investing activities: Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Related Party Transaction [Axis] Related Party Transaction [Axis] Unrecognized share-based compensation expense Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Derivative assets Derivative Asset [Abstract] Segments [Domain] Segments [Domain] Underwriting Portfolio Relating to underwriting portfolio: Underwriting Portfolio [Member] Derivative instruments related to the entity's underwriting portfolio. DEBT AND FINANCING ARRANGEMENTS Debt Disclosure [Text Block] Other realized and unrealized investment gains Marketable Security, Gain (Loss) Weighted average loan-to-value ratios (as a percent) Weighted Average Loan-To-Value Ratios Weighted average loan-to-value ratios PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Proceeds from the repayment of mortgage loans Proceeds from Sale and Collection of Mortgage Notes Receivable Annual Redemption Annual Redemption [Member] Annual Redemption Fair value Debt Securities, Available-for-Sale, Fair Value, Fiscal Year Maturity [Abstract] Equity method investments Payments to acquire equity method investments Payments to Acquire Equity Method Investments Liability for Claims and Claims Adjustment Expense [Line Items] Liability for Claims and Claims Adjustment Expense [Line Items] Common share dividends Dividends, Common Stock, Cash Allowance for credit losses on premium balances receivable Premium Receivable, Allowance for Credit Loss Total shareholders’ equity Balance at beginning of period Balance at end of period Equity, Attributable to Parent Held-to-maturity securities with maturity after ten years Debt Securities, Held-To-Maturity, Amortized Cost, After Allowance For Credit Loss, Maturity, Allocated And Single Maturity Date, After 10 Years Amount excluding accrued interest, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity) with single maturity date and allocated without single maturity date, maturing  in the tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). Assets Assets [Abstract] Receivable for investments sold Receivable from Broker-Dealer and Clearing Organization Insider Trading Policies and Procedures [Line Items] Performance Vesting Restricted Stock Units Share-Settled Performance Restricted Stock Units Performance Shares [Member] Net losses and loss expenses Net incurred losses and loss expenses Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims Reorganization expenses Reorganization expenses Restructuring, Settlement and Impairment Provisions Weighted average anti-dilutive shares excluded from the dilutive computation (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Short-term investments Proceeds from Sale of Short-Term Investments FHLB advances, interest rate (as a percent) Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Interest Rate at Period End Entity central index key Entity Central Index Key Additional paid-in capital Additional Paid in Capital, Common Stock Equity [Abstract] 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] Fair Value By Fair Value Hierarchy Level [Axis] Fair Value Hierarchy and NAV [Axis] Liability for Claims and Claims Adjustment Expense [Table] Liability for Claims and Claims Adjustment Expense [Table] Investment, Name [Axis] Investment, Name [Axis] Preferred share dividends Dividends, Preferred Stock, Cash Fixed maturities Fixed maturities, available for sale Fixed Maturities [Member] (Increase) decrease in allowance for expected credit losses Allowance for Credit Loss, Period Increase (Decrease) Amount of increase (decrease) in the total allowance for credit loss of investments. Accumulated other comprehensive income (loss) AOCI Attributable to Parent [Member] All Individuals All Individuals [Member] Non-agency RMBS Mortgage-Backed Securities, Issued by Private Enterprises [Member] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Expected weighted average period associated with the recognition of unrecognized share-based compensation expense Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Statement [Line Items] Statement [Line Items] Total assets Assets Private equity funds Private Equity Funds [Member] Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration] Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration] Before tax amount Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent [Abstract] Operating Segments Operating Segments [Member] Securities sold/redeemed/matured Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss, Sold Gross unrealized gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax SHARE-BASED COMPENSATION Share-Based Payment Arrangement [Text Block] Fixed maturities without a single maturity date Debt Securities, Available-for-Sale, Maturity, without Single Maturity Date, Fair Value Unrealized gains (losses) arising during the period OCI, before Reclassifications, Net of Tax, Attributable to Parent PEO PEO [Member] Settlement Type [Domain] Settlement Type [Domain] Settlement Type [Domain] Commercial (as a percent) Financing Receivable, before Allowance for Credit Loss, to Total, Percent Equity securities Equity Securities, FV-NI, Realized Loss Goodwill Goodwill Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Other Significant Noncash Transaction [Axis] Other Significant Noncash Transaction [Axis] Number of securities in unrealized loss position Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions Total (as a percent) Available For Sale Securities Debt Securities Percentage Of Fair Value Amount of available-for-sale debt securities at fair value, expressed as a percentage of the total fair value of debt securities classified as available-for-sale. FHLB program, admitted assets, actual Federal Home Loan Bank, Admitted Assets, Actual The amount of qualifying assets calculated using statutory rules that are used as a basis for borrowing capacity. Number of investment funds Number Of Funds Redemption Number Of Funds Redemption Accrued interest receivable Increase (Decrease) in Accrued Investment Income Receivable Direct lending funds Direct Lending Funds [Member] Investments in funds that provide financing directly to borrowers. Retained earnings Retained Earnings [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Common shares, outstanding (in shares) Total shares outstanding (in shares) Common Stock, Shares, Outstanding Award Timing Disclosures [Line Items] Cumulative foreign currency translation adjustments, net of tax: Foreign currency translation adjustment Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Corporate debt Corporate Debt Securities [Member] Earnings per diluted common share (in usd per share) Earnings Per Share, Diluted Value of reverse repurchase agreements Securities for Reverse Repurchase Agreements Amortization of intangible assets Amortization of intangible assets Intangible Asset, Finite-Lived, Amortization Expense Stockholders' Equity Note [Abstract] Summary of Reconciliation of Gross Derivative Assets to Net Amounts Presented in Balance Sheets Offsetting Assets [Table Text Block] Net premiums written Premiums Written, Net Share-based Payment Arrangement [Abstract] Share-Based Payment Arrangement [Abstract] Adjustment for reclassification of net realized (gains) losses and impairment losses recognized in net income (loss) Reclassification from AOCI, Current Period, Tax Optional extension of investment term Fair Value Investments Entities That Calculate Net Asset Value Redemption Restriction Period Optional Extension Period by which the General Partner of an investment for which net asset value per share is calculated has the option to extend a redemption restriction related to investments for which net asset value per share is calculated, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Prepaid reinsurance premiums Increase (Decrease) in Prepaid Reinsurance Premiums Summary of Equity Method Investments Equity Method Investments [Table Text Block] Additions (reductions) for expected credit losses on securities where credit losses were previously recognized Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss, Not to Sell before Recovery, Credit Loss, Previously Recorded, Expense (Reversal) Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Short-term investments Payments to Acquire Short-Term Investments Agency RMBS Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member] Expected credit losses on securities where credit losses were not previously recognized Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss, Not Previously Recorded Subsegments [Domain] Subsegments [Domain] Sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales Held to maturity Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss [Abstract] Percentage of total fair value (as a percent) Alternative Investments, Fair Value Disclosure, Percentage Of Total The percentage of the total fair value of investments in certain entities that calculate net asset value per share, including, but not limited to, by unit, membership interest, or other ownership interest. Investments include, but are not limited to, investments in certain hedge funds, venture capital funds, private equity funds, real estate partnerships or funds. Proceeds from the sale of: Proceeds from Sale, Maturity and Collection of Investments [Abstract] Gross realized investment gains DebtAndEquitySecuritiesRealizedGainAbstract [Abstract] Schedule of Equity Method Investments [Table] Equity Method Investment [Table] Change in fair value of investment derivatives Derivative, Gain (Loss) on Derivative, Net Mortgage Loans Mortgage Loans [Member] Mortgage Loans Summary of Dividends Declared and Paid Dividends Declared [Table Text Block] Related Party Transaction [Domain] Related Party Transaction [Domain] Senior notes Notes Payable, Fair Value Disclosure Non-U.S. government Debt Security, Government, Non-US [Member] Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Multi-strategy funds Hedge Funds, Multi-strategy [Member] Equity securities Equity Securities [Member] Gross realized investment losses Debt And Equity Securities, Realized Loss Amount of realized loss on investments, including debt and equity securities and mortgage loans held for investment. Summary of Reconciliation of Allowance for Credit Loss on Mortgage Loans Financing Receivable, Allowance for Credit Loss [Table Text Block] Common shares, issued (in shares) Shares issued, balance at beginning of period (in shares) Total shares issued at end of period (in shares) Common Stock, Shares, Issued Opening balance Closing balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value 12 months or greater Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss OTHER COMPREHENSIVE INCOME (LOSS) Comprehensive Income (Loss) Note [Text Block] Monarch Point Re (ISA 2026) Ltd Monarch Point Re (ISA 2026) Ltd [Member] Monarch Point Re (ISA 2026) Ltd FEDERAL HOME LOAN BANK ADVANCES Federal Home Loan Bank Advances, Disclosure [Text Block] Class of Stock [Line Items] Class of Stock [Line Items] Catastrophe and Weather-related Events Catastrophe [Member] Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Unrealized and realized gains (losses) recognized in earnings for derivatives not designated as hedges Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Limited Partnership Limited Partner [Member] Reclassification out of accumulated comprehensive income into net income available to common shareholders [Line Items] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Termination Date Trading Arrangement Termination Date Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value, Recurring and Nonrecurring [Table] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Current accident year net losses and loss expenses Current year Net loss and loss expenses Current Year Claims and Claims Adjustment Expense Line of Credit Facility, Lender [Domain] Line of Credit Facility, Lender [Domain] Fair Value as of Grant Date Award Grant Date Fair Value Summary of Fixed Maturities and Equities in an Unrealized Loss Position Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value [Table Text Block] Due after ten years (as a percent) Available For Sale Securities Debt Maturities After Year Ten Percentage Of Fair Value Amount of available-for-sale debt securities at fair value maturing in the tenth fiscal year following latest fiscal year, expressed as a percentage of the total fair value of debt securities classified as available-for-sale. Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Remaining amount of stock repurchase plan authorized Share Repurchase Program, Remaining Authorized, Amount Arrangement Duration Trading Arrangement Duration Consolidation Items [Axis] Consolidation Items [Axis] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Less than 12 months Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Allowance for credit losses on reinsurance recoverable for unpaid losses and loss expenses Reinsurance Recoverable, Allowance for Credit Loss Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Interest expense on FHLB borrowings Interest Expense, Federal Home Loan Bank and Federal Reserve Bank Advances, Short-Term Total revenues Revenues Interest in income (loss) of equity method investments Interest in income of equity method investments Income (Loss) from Equity Method Investments Other investments, at fair value Other investments Alternative Investment Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Citibank Citibank [Member] Citibank Europe plc Total fixed maturities with a single maturity date Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Fair Value FHLB program, maximum borrowing capacity Federal Home Loan Bank, Advances, General Debt Obligations, Maximum Amount Available Unrealized gains (losses) arising during the period for which an allowance for expected credit losses has not been recognized AOCI, Gain (Loss), Debt Securities, Available-for-Sale, without Allowance for Credit Loss, Parent [Member] Vesting period Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period Summary of Financial Instruments Measured at Fair Value on a Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Award Type [Domain] Award Type [Domain] Depositary shares, each representing a 1/100th interest in a 5.50% Series E preferred share Series E Preferred Depositary Share [Member] American Depositary Share, each representing a 1/100th interest in a 5.50% Series E preferred share Fair Value Option, Disclosures [Table] Fair Value Option, Disclosures [Table] FAIR VALUE MEASUREMENTS Fair Value Disclosures [Text Block] Significant unobservable inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Expected term (in years) Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Term Shares repurchased (in shares) Total shares (in shares) Treasury Stock, Shares, Acquired Fair value based on NAV practical expedient Fair Value Measured at Net Asset Value Per Share [Member] Fixed maturities, held to maturity, allowance for expected credit losses Allowance for expected credit losses Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Excluding Accrued Interest Other assets Other Assets Legal Entity [Axis] Legal Entity [Axis] Shares repurchased Total cost Treasury Stock, Value, Acquired, Cost Method Loan advances made Loan Advances [Member] Loan Advances Cash, cash equivalents and restricted cash - beginning of period Cash, cash equivalents and restricted cash - end of period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Summary of Reclassifications Out of AOCI Into Net Income (Loss) Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Non-NEOs Non-NEOs [Member] Due after five years through ten years (as a percent) Available For Sale Securities Debt Maturities After Five Through Ten Years Percentage Of Fair Value Amount of available-for-sale debt securities at fair value maturing in sixth through tenth fiscal year following latest fiscal year, expressed as a percentage of the total fair value of debt securities classified as available-for-sale. Wells Fargo Bank National Association Wells Fargo Bank National Association [Member] Wells Fargo Bank National Association Equity method investment, ownership percentage (as a percent) Equity Method Investment, Ownership Percentage Investment, Name [Domain] Investment, Name [Domain] 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 Treasury Shares [Line Items] Equity, Class of Treasury Stock [Line Items] Summary of Additional Information Related to Share-based Compensation Disclosure of Share-Based Compensation Arrangements by Share-Based Payment Award [Table Text Block] Repurchase of common shares Payments for Repurchase of Common Stock Statistical Measurement [Axis] Statistical Measurement [Axis] Award Type [Axis] Award Type [Axis] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Retained earnings Retained Earnings (Accumulated Deficit) Restructuring and Related Activities [Abstract] Restructuring and Related Activities [Abstract] Equity securities, at fair value (Cost 2026: $606,505; 2025: $581,275) Fair value Equity securities Equity Securities, FV-NI Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Common shares Common shares (par value) Common stocks Common Stock [Member] Credit Rating [Axis] External Credit Rating by Grouping [Axis] Reclassifications Out of Accumulated Other Comprehensive Income (Loss) [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] Derivative Contract Type [Domain] Derivative Contract [Domain] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Total liabilities and shareholders’ equity Liabilities and Equity Goodwill and intangible assets Intangible Asset, Including Goodwill, after Accumulated Amortization Gains (loss) on overseas deposits Realized Investment Gains (Losses) Employee Stock Option Share-Based Payment Arrangement, Option [Member] Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Insurance and reinsurance balances payable, net Insurance And Reinsurance [Member] Insurance And Reinsurance Segments [Axis] Segments [Axis] Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Asset Class [Axis] Asset Class [Axis] Related Party [Domain] Related and Nonrelated Parties [Domain] Tabular List, Table Tabular List [Table Text Block] Vesting [Axis] Vesting [Axis] Unrealized gains (losses) arising during the period for which an allowance for expected credit losses has been recognized AOCI, Gain (Loss), Debt Securities, Available-for-Sale, with Allowance for Credit Loss, Parent [Member] Reinsurance recoverable on unpaid losses and loss expenses (Allowance for expected credit losses 2026: $41,354; 2025: $40,340) Less reinsurance recoverable on unpaid losses and loss expenses, beginning of period Reinsurance recoverable on unpaid losses and loss expenses, end of period Reinsurance Recoverable for Unpaid Claims and Claims Adjustments Reinsurance recoverable on unpaid losses and loss expenses Increase (Decrease) in Reinsurance Recoverable Fixed maturities, held to maturity Payments to Acquire Held-to-Maturity Securities Gross unrealized losses Equity Securities, FV-NI, Unrealized Loss Other insurance related income Other insurance related income Other Operating Income (Expense), Net Name Awards Close in Time to MNPI Disclosures, Individual Name 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] Preferred shares Preferred Stock, Value, Issued Adjustment to Compensation: Adjustment to Compensation [Axis] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Interest paid Interest Paid, Excluding Capitalized Interest, Operating Activity Hedging Designation [Axis] Hedging Designation [Axis] Redemption Restriction Type [Domain] Redemption Restriction Type [Domain] Circumstances in which an otherwise redeemable investment, comprising or included in the major category, of those certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments) is not redeemable (for example, investments subject to a lockup or gate). Credit Facility [Axis] Credit Facility [Axis] REORGANIZATION EXPENSES Restructuring and Related Activities Disclosure [Text Block] Total Assets Assets, Fair Value Disclosure Minimum required collateral for reverse repurchase agreements, expressed as a percentage of loan principal (as a percent) Securities Purchased Under Agreements To Resell, Required Collateral, Percentage Of Principal Minimum value of securities received as collateral against securities purchased under agreement to resell, expressed as a percentage of loan principal. Name Measure Name Impairments of securities which the Company intends to sell or more likely than not will be required to sell Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss, Sell before Recovery Pay vs Performance Disclosure [Line Items] Fair Value Measurements Fair Value Hierarchy [Domain] Fair Value Hierarchy and NAV [Domain] Equity securities Proceeds from Sale of Equity Securities, FV-NI Reserve for losses and loss expenses Increase (Decrease) in Liability for Claims and Claims Adjustment Expense Reserve Additional paid-in capital Additional Paid-in Capital [Member] % of Total fair value Available For Sale Securities Percentage Of Fair Value [Abstract] Available For Sale Securities Percentage Of Fair Value [Abstract] Redemption notice period Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Notice Period Accrued interest receivable Interest Receivable Name Trading Arrangement, Individual Name Cash and cash equivalents Cash and Cash Equivalent Purchases of: Payments to Acquire Investments [Abstract] Net investment gains: Realized Investment Gains (Losses) [Abstract] Other privately held investments Other Privately Held Investments [Member] Other Privately Held Investments [Member] Company Selected Measure Amount Company Selected Measure Amount Net unrealized gains (losses) on equity securities Equity Securities, FV-NI, Unrealized Gain (Loss) Summary of Other Significant Noncash Transactions Schedule of Other Significant Noncash Transactions [Table Text Block] Bond mutual funds Non United States Bond Mutual Fund [Member] An investment in a fund that invests in non-U.S. fixed maturities and provides daily liquidity. Non-PEO NEO Non-PEO NEO [Member] Advance from Federal Home Loan Bank Advance from Federal Home Loan Bank [Abstract] Combined ratio (as a percent) Combined Ratio Foreign exchange losses (gains) Foreign exchange (losses) gains Gain (Loss), Foreign Currency Transaction, before Tax Award Timing Method Award Timing Method [Text Block] Decrease 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] Total net investment gains Net investment gains Net Investment Gain (Loss) This item represents the net realized gains and losses on available for sale debt securities, the net realized and unrealized gains and losses on equity securities with FV recorded in net income, together with the change in fair value of investment derivatives, and expected and realized credit losses. Redemption Frequency [Domain] Redemption Frequency [Domain] Redemption Frequency Net income Net income Net income Net Income (Loss) Attributable to Parent Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Restatement Determination Date: Restatement Determination Date [Axis] Acquisition cost ratio (as a percent) Acquisition Cost Ratio Held-to-maturity securities with maturity after one year through three years Debt Securities, Held-to-Maturity, Amortized Cost, After Allowance For Credit Loss, Maturity, Allocated And Single Maturity Date, After Year One Through Three Amount excluding accrued interest, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity) with single maturity date and allocated without single maturity date, maturing in the first through third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). Fixed maturities without a single maturity date (as a percent) Available For Sale Securities Debt Maturities Without Single Maturity Date Percentage Of Fair Value Amount of available-for-sale debt securities at fair value that do not have a single maturity date and which the entity has decided to disclose separately rather than allocating the fair value over several maturity groupings, expressed as a percentage of the total fair value of debt securities classified as available-for-sale. Purchase of other assets Payments for (Proceeds from) Productive Assets Mortgage loans, held for investment, at fair value (Allowance for expected credit losses 2026: $27,957; 2025: $29,742) Total mortgage loans held for investment Mortgage Loans on Real Estate, Commercial and Consumer, Net Revenues Revenues [Abstract] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Statistical Measurement [Domain] Statistical Measurement [Domain] Net realized and unrealized gains on other investments Net Realized And Unrealized Gain Loss On Alternative Investments Net realized and the change in net unrealized (gains) losses related to investments in certain entities that calculate net asset value per share, including, but not limited to, by unit, membership interest, or other ownership interest . Investments include, but are not limited to, investments in certain hedge funds, venture capital funds, private equity funds, real estate partnerships or funds. Document fiscal year focus Document Fiscal Year Focus Gross amounts offset Derivative Liability, Subject to Master Netting Arrangement, Asset Offset Number of restricted stock units Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Liability for Future Policy Benefit, by Product Segment [Table] Liability for Future Policy Benefit, by Product Segment [Table] Common shares (shares issued 2026: 176,580; 2025: 176,580 shares outstanding 2026: 73,141; 2025: 74,135) Common Stock, Value, Issued Summary of Share-Settled Restricted Stock Units Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block] Taxes paid on withholding shares Payment, Tax Withholding, Share-Based Payment Arrangement Interest expense and financing costs Interest expense and financing costs Interest Expense, Operating and Nonoperating Line of Credit Line of Credit [Member] Restatement Determination Date Restatement Determination Date Amendment flag Amendment Flag Equity method investments Proceeds from Sale of Equity Method Investments Debt and Equity Securities, FV-NI [Line Items] Debt and Equity Securities, FV-NI [Line Items] Gross unrealized losses Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax Investments [Domain] Investments [Domain] Investment Portfolio Relating to investment portfolio: Investment Portfolio [Member] Derivative instruments related to the entity's investment portfolio. Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Table] Liability for Unpaid Claim and Claim Adjustment Expense, Change [Table] Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Transfers into Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 LOC Facility Letter of Credit Facility [Member] Letter of Credit Facility Equity securities Payments to Acquire Equity Securities, FV-NI 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 Assets Assets, Fair Value Disclosure [Abstract] Held to maturity securities with no single maturity date Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, without Single Maturity Date Derivative notional amount Derivative, Notional Amount Weighted average common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Deferred acquisition costs Increase (Decrease) in Deferred Policy Acquisition Costs Summary of Reconciliation of Allowance for Credit Loss on Fixed Maturities, Available for Sale Debt Securities, Available-for-Sale, Allowance for Credit Loss [Table Text Block] Uncommitted Unsecured Letter of Credit Uncommitted Unsecured Letter of Credit [Member] Uncommitted Unsecured Letter of Credit Investments: Investments [Abstract] Due after five years through ten years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 Available for sale investments: Other Comprehensive Income (Loss), Available-for-Sale Securities Adjustment, Net of Tax, Portion Attributable to Parent [Abstract] Related Portfolio [Domain] Related Portfolio [Domain] The name that identifies a derivative or a group of derivatives, by related portfolio. Amortized cost Debt Securities, Available-for-Sale, Amortized Cost, Fiscal Year Maturity [Abstract] Document Information [Line Items] Document Information [Line Items] 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] Dividends paid - preferred shares Payments of Ordinary Dividends, Preferred Stock and Preference Stock Class of Stock [Axis] Class of Stock [Axis] Net income available to common shareholders Net income available to common shareholders Net Income (Loss) Available to Common Stockholders, Basic Federal Home Loan Bank of Chicago Federal Home Loan Bank of Chicago [Member] Debt Securities, Held-to-maturity [Table] Debt Securities, Held-to-Maturity [Table] Weighted average debt service coverage ratios Weighted Average Debt Service Coverage Ratios Weighted Average Debt Service Coverage Ratios Line of credit facility Line of Credit Facility, Maximum Borrowing Capacity Loan advances made Financing Receivable, Excluding Accrued Interest, after Allowance for Credit Loss Investment expenses Investment Income, Investment Expense Stated interest rate (as a percent) Related Party Transaction, Rate Changes in: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Net cash provided by (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] SHAREHOLDERS' EQUITY Equity [Text Block] Security Exchange Name Security Exchange Name Amortized cost Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss Gross premiums written Premiums Written, Gross Credit Loss Status [Domain] Credit Loss Status [Domain] Publicly Announced Programs Publicly Announced Programs [Member] Publicly Announced Programs Reinsurance Reinsurance [Member] Reinsurance segment Investment Funds, Term, Period One Investment Funds, Term, Period One [Member] Investment Funds, Term, Period One Total Liabilities Liabilities, Fair Value Disclosure 12 months or greater Debt securities fair value Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer Mortgage loans Payments to Acquire Mortgage Notes Receivable Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Name Outstanding Recovery, Individual Name Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] 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] Private company investment funds Private Company Investment Funds [Member] Private Company Investment Funds Gross realized investment losses DebtandEquitySecuritiesRealizedLossAbstract [Abstract] Adjustment for reclassification of net realized (gains) losses and impairment losses recognized in net income (loss) Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent Preferred shares, dividends paid per share (in usd per share) Preferred Stock, Dividends, Per Share, Cash Paid Number Of Authorized Shares, Not Disclosed NumberOfAuthorizedSharesNotDisclosed NumberOfAuthorizedSharesNotDisclosed Interest receivable on loan advances made Interest Receivable On Loan Advances [Member] Interest Receivable On Loan Advances Other investments Payments to Acquire Other Investments Asset Class [Domain] Asset Class [Domain] Related Party Transactions [Abstract] Ceded reserves related to retroactive transactions Liability for Unpaid Claims and Claims Adjustment Expense, Ceded Reserves, Other Reconciling Item Liability for Unpaid Claims and Claims Adjustment Expense, Ceded Reserves, Other Reconciling Item Compensation Amount Outstanding Recovery Compensation Amount Individual: Individual [Axis] Weighted average diluted common shares outstanding (in shares) Weighted average diluted common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Diluted Entity Emerging Growth Company Entity Emerging Growth Company Commercial Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss Underlying Security Market Price Change Underlying Security Market Price Change, Percent DERIVATIVE INSTRUMENTS Derivative Instruments and Hedging Activities Disclosure [Text Block] Gross unrealized losses Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss Quarterly Redemption Quarterly Redemption [Member] Quarterly Redemption Maximum exposure to loss Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount Gross amounts Derivative Liability, Subject to Master Netting Arrangement, before Offset Settlement Type [Axis] Settlement Type [Axis] Settlement Type (Increase) decrease in allowance for expected credit losses, mortgage loans Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Period Increase (Decrease) Current accident year loss ratio (as a percent) Current Accident Year, Loss Ratio Current Accident Year, Loss Ratio Underwriting income Underwriting Income Loss Net Net premiums earned less: net losses and loss expenses, acquisition costs and general and administrative expenses directly related to underwriting activities. ABS Asset-Backed Securities, Securitized Loans and Receivables [Member] Treasury shares, at cost Treasury Stock, Common [Member] Reinsurance recoverable on paid losses and loss expenses Reinsurance Recoverable for Paid Claims and Claims Adjustments Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-Sale [Line Items] Nonvested restricted stock units - beginning of period (in usd per share) Nonvested restricted stock units - end of period (in 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] Loan advances made Advances to affiliate during the period Payments for Advance to Affiliate Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Net of tax amount Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Settlements/ distributions Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Share Repurchase Type [Axis] Share Repurchase Type [Axis] Information by share repurchase type. Summary of Basic and Diluted Earnings Per Common Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Debt Disclosure [Abstract] Debt Disclosure [Abstract] SEGMENT INFORMATION Segment Reporting [Text Block] Proceeds from redemption of fixed maturities, available for sale Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-Sale Minimum Minimum [Member] Investment Type [Axis] Investment Type [Axis] Unfunded commitments related to other investments Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments Treasury shares reissued Stock Issued During Period, Value, Treasury Stock Reissued Including To Satisfy Equity Based Compensation Obligations Equity impact of the value of treasury stock (units) reissued during the period. Upon reissuance of shares (units) from treasury, either the common or preferred stock (unit) reissued is outstanding. Liabilities Liabilities [Abstract] Effect of exchange rate changes on foreign currency cash, cash equivalents and restricted cash Effect of Exchange Rate on Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Income Statement Location [Axis] Location, Statement of Income, Balance [Axis] Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] 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] Summary of Common Shares Issued and Outstanding Schedule of Common Stock Outstanding Roll Forward [Table Text Block] Other liabilities Other Liabilities Federal Home Loan Bank advances Advances from FHLB, carrying value Advance from Federal Home Loan Bank Reinsurance recoverable on unpaid losses Liability For Unpaid Claims And Claims Adjustment Expense, Foreign Exchange, Loss Portfolio Transfer, And Other Amount of other items that increase (decrease) the cost of settling unpaid claims after deduction of reinsurance recoveries, such as foreign exchange, loss portfolio transfer and other miscellaneous items. Performance adjustment (in shares) Share-Based Compensation Arrangement By Share-Based Payment Award, Equity Instruments Other Than Options, Performance Adjustment In Period Share-Based Compensation Arrangement By Share-Based Payment Award, Equity Instruments Other Than Options, Performance Adjustment In Period Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Fixed maturities, short-term investments, and cash and cash equivalents Debt Securities, Available-for-Sale, Realized Gain Schedule of Held-to-maturity Securities [Line Items] Schedule of Held-to-Maturity Securities [Line Items] Fair value Debt Securities, Available-For-Sale, Unrealized Loss Position, Fair Value [Abstract] Debt Securities, Available-For-Sale, Unrealized Loss Position, Fair Value [Abstract] Due after ten years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10 Exercise Price Award Exercise Price Fixed maturities, held to maturity, at amortized cost (Fair value 2026: $402,105; 2025: $395,942 Allowance for expected credit losses 2026: $nil; 2025: $nil) Net carrying value Fixed maturities, held to maturity, at amortized cost Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Amount of stock repurchase plan authorized Share Repurchase Program, Authorized, Amount Segment Information [Line Items] Segment Reporting [Line Items] 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] Municipals US States and Political Subdivisions Debt Securities [Member] Lender Name [Axis] Lender Name [Axis] Fixed maturities, available for sale Proceeds from Sale of Debt Securities, Available-for-Sale Income before income taxes and interest in income (loss) of equity method investments Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Series E preferred shares Series E Preferred Stock [Member] Prior years Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years Summary of Cost and Fair Value of Equity Securities Marketable Securities [Table Text Block] Derivative liabilities Derivative Liability [Abstract] Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Equity method investments Total equity method investments Equity Method Investments Equity Component [Domain] Equity Component [Domain] Prior year reserve development ratio (as a percent) Prior Year Reserve Development Ratio Prior Year Reserve Development Ratio Deferred acquisition costs Deferred Policy Acquisition Cost Included in net income Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Expenses Benefits, Losses and Expenses [Abstract] Adoption Date Trading Arrangement Adoption Date Counterparty Name [Domain] Counterparty Name [Domain] Payable for investments purchased Broker-Dealer, Payable to Other Broker-Dealer and Clearing Organization Title Trading Arrangement, Individual Title Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Accounting Policies [Abstract] Accounting Policies [Abstract] Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Risk-free interest rate (as a percent) Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Operating lease liabilities Operating Lease, Liability Fixed maturities, held to maturity, fair value Fair value Debt Securities, Held-to-Maturity, Fair Value Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Other investments Proceeds from Sale and Maturity of Other Investments Unrealized and Realized Gains (Losses) Recognized in Earnings for Derivatives Not Designated As Hedges [Line Items] Derivative Instruments, Gain (Loss) [Line Items] General and administrative expenses Underwriting-related general and administrative expenses Selling, General and Administrative Expense Current year Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year Letter of Credit Letter of Credit [Member] COMMITMENTS AND CONTINGENCIES Commitments and Contingencies Disclosure [Text Block] Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Share-Settled Service Restricted Stock Units Restricted Stock Units (RSUs) [Member] All Adjustments to Compensation All Adjustments to Compensation [Member] Corporate expenses Segment Reporting, Reconciling Item, Corporate Nonsegment [Member] Net cash provided by (used in) operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Net favorable prior year reserve development Prior years Prior years - net favorable (adverse) effect Prior Year Claims and Claims Adjustment Expense Other Redemption Restriction Other Redemption Restriction [Member] Redemption restriction on investments for which net asset value per share is calculated (including, but not limited to, by unit, membership interest, or other ownership interest) other than gates and lockups. Income Statement [Abstract] Income Statement [Abstract] Shareholders’ equity Equity, Attributable to Parent [Abstract] Document Transition Report Document Transition Report Fair Value, Option, Quantitative Disclosures [Line Items] Fair Value, Option, Quantitative Disclosures [Line Items] Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Harrington Re Harrington Reinsurance Holdings Limited [Member] Harrington Reinsurance Holdings Limited [Member] Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] City Area Code City Area Code Real estate funds Real Estate Funds [Member] Document Information [Table] Document Information [Table] Name Forgone Recovery, Individual Name 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] Entity [Domain] Entity [Domain] Shares issued (in shares) Stock Issued During Period, Shares, New Issues Share-based compensation expense Share-Based Payment Arrangement, Expense Number of securities in a continuous unrealized loss position Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions Gross amounts offset Derivative Asset, Subject to Master Netting Arrangement, Liability Offset Measurement Basis [Axis] Measurement Basis [Axis] Total investments Investments Granted (in 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 Due in one year or less Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, Year One Forfeited (in usd per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Mortgage loans, held for investment: Financing Receivable, after Allowance for Credit Loss, Current [Abstract] Unrealized gains (losses) on available for sale investments, net of tax: Available for sale investments Unrealized gains (losses) on available for sale investments AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member] Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Unrealized gains (losses) arising during period OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Foreign exchange and other Liability for Unpaid Claims and Claims Adjustment Expense, Foreign Currency Translation Gain (Loss) Entity Current Reporting Status Entity Current Reporting Status Net cash used in financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Total Shareholder Return Amount Total Shareholder Return Amount Shares reissued (in shares) Stock Issued During Period Shares Treasury Stock Reissued Including To Satisfy Equity Based Compensation Obligations Number of treasury shares (units) reissued during the period. Upon reissuance of shares (units) from treasury, either the common or preferred stock (unit) reissued is outstanding. Liabilities Liabilities, Fair Value Disclosure [Abstract] Casualty Casualty Line [Member] Casualty Line Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Adjustments to reconcile net income to net cash provided by (used in) operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Cash flows from financing activities: Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Net Investment Income [Line Items] Net Investment Income [Line Items] Financial Instruments [Domain] Financial Instruments [Domain] Prepaid reinsurance premiums Prepaid Reinsurance Premiums Other liabilities Deferred Credits and Other Liabilities Derivative instruments (refer to Note 5) Derivative asset fair value Net amounts Derivative Asset Underlying Securities Award Underlying Securities Amount Common Shares Issued and Outstanding [Roll Forward] common shares issued and outstanding [Roll Forward] common shares issued and outstanding [Roll Forward] Estimate of Fair Value Measurement Estimate of Fair Value Measurement [Member] Fair Values Derivatives Balance Sheet Location By Derivative Contract Type By Hedging Designation [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Derivative asset, statement of financial position [Extensible Enumeration] Derivative Asset, Statement of Financial Position [Extensible Enumeration] Subsegments [Axis] Subsegments [Axis] Preferred shares Preferred stocks Preferred Stock [Member] Impairment losses Impairment losses Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff Segment Reporting [Table] Segment Reporting [Table] Summary of Amortized Cost and Fair Values of Fixed Maturities Schedule of Available-for-Sale Securities Reconciliation [Table Text Block] Commitments and Contingencies Disclosure [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 Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Expected credit losses on loans where credit losses were not previously recognized Financing Receivable, Excluding Accrued Interest, Credit Loss Expense (Reversal) 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] Dividends declared, common shares (in usd per share) Common Stock, Dividends, Per Share, Declared Entity File Number Entity File Number Summary of Contractual Maturities of Fixed Maturities Investments Classified by Contractual Maturity Date [Table Text Block] Summary of Reconciliation of Beginning and Ending Gross Reserve for Losses and Loss Expenses and Net Reserve for Unpaid Losses and Loss Expenses Schedule of Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Dividends declared, preferred shares (in usd per share) Preferred Stock, Dividends Per Share, Declared Measure: Measure [Axis] Gross unrealized gains Equity Securities, FV-NI, Unrealized Gain Proceeds from redemption of equity securities (preferred stock) Proceeds From Redemption Of Investment In Preferred Stock Proceeds From Redemption Of Investment In Preferred Stock Treasury shares (in shares) Treasury shares, balance at beginning of period (in shares) Total treasury shares at end of period (in shares) Treasury Stock, Common, Shares Net premiums earned Premiums Earned, Net From Employees Employees [Member] Directly from employees of the entity to satisfy withholding tax liabilities upon vesting of restricted stock awards. These repurchases are not part of the entity's Board-authorized share repurchase program. Treasury Shares Issued and Outstanding [Roll Forward] Treasury Shares Issued and Outstanding [Roll Forward] Treasury Shares Issued and Outstanding [Roll Forward] Statement, Equity Components [Axis] Equity Components [Axis] Equity Components [Axis] Related Party Related Party [Member] Income taxes paid Income Tax Paid, after Refund Received Entity Interactive Data Current Entity Interactive Data Current 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 Adjustment for reclassification of net realized (gains) losses and impairment losses recognized in net income Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax Entity Small Business Entity Small Business Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Unearned premiums Unearned Premiums Equity securities Equity Securities, FV-NI, Realized Gain Summary of Portfolio of Other Investments Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Table Text Block] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Document Type Document Type Other Significant Noncash Transaction, Name [Domain] Other Significant Noncash Transaction, Name [Domain] 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] Fixed maturities, available for sale, allowance for credit loss Allowance for expected credit losses Balance at beginning of period Balance at end of period Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest Cash and cash equivalents Cash and Cash Equivalents [Member] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Debt Securities, Trading, and Equity Securities, FV-NI [Table] Debt Securities, Trading, and Equity Securities, FV-NI [Table] Local Phone Number Local Phone Number Short-term investments, at fair value Short-term investments Other Short-Term Investments Unrealized gains (losses) arising during the period, net of reclassification adjustment Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Executive Category: Executive Category [Axis] Counterparty Name [Axis] Counterparty Name [Axis] Gross realized investment gains Debt And Equity Securities, Realized Gain Amount of realized gain on investment in debt and equity securities. Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Supplemental disclosures of cash flow information: Supplemental Cash Flow Information [Abstract] Below Investment Grade or Not Rated External Credit Rating, Noninvestment Grade [Member] PEO Name PEO Name Net paid losses and loss expenses Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Entity Tax Identification Number Entity Tax Identification Number Debt Notes Payable Tax benefits associated with share-based compensation expense Share-Based Payment Arrangement, Expense, Tax Benefit Credit Loss Status [Axis] Credit Loss Status [Axis] Fair value of other investments subject to redemption restrictions Fair Value Investments Entities That Calculate Net Asset Value Redemption Restriction The total value of investments that cannot be redeemed because of a redemption restriction as of the statement of financial position date. Preferred share dividends Less: Preferred share dividends Preferred Stock Dividends, Income Statement Impact Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Proceeds from redemption of short-term investments Proceeds from Maturities, Prepayments and Calls of Short-Term Investments Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Fair Value Investments Entities That Calculate Net Asset Value Per Share [Table] Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Table] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] 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] Lockup Redemption Restriction Lockup Redemption Restriction [Member] Redemption restriction on investments for which net asset value per share is calculated (including, but not limited to, by unit, membership interest, or other ownership interest) due to lockups. Debt Instrument [Axis] Debt Instrument [Axis] Share-based compensation expense Share-Based Payment Arrangement, Noncash Expense Insurance Insurance [Member] Insurance segment Proceeds from redemption of fixed maturities, held to maturity Proceeds from Maturities, Prepayments and Calls of Held-to-Maturity Securities Summary of Location and Amounts of Derivative Fair Values on the Consolidated Balance Sheet Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Earnings per common share (in usd per share) Earnings Per Share, Basic Insider Trading Arrangements [Line Items] Summary of Share Repurchases Class of Treasury Stock [Table Text Block] Unrealized gains (losses) arising during the period, net of reclassification adjustment Other Comprehensive Income (Loss), Available-for-Sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Acquisition costs Acquisition costs Deferred Policy Acquisition Costs, Amortization Expense 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] Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Schedule of information required and determined to be provided for purposes of reconciling beginning and ending balances of fair value measurements of assets and liabilities using significant unobservable inputs (level 3). Such reconciliation, separately presenting changes during the period, at a minimum, may include, but is not limited to: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets) and gains or losses recognized in other comprehensive income, and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issues, and settlements (each type disclosed separately); and (3) transfers in and transfers out of level 3 (for example, transfers due to changes in the observability of significant inputs), by class of asset or liability. Expected volatility (as a percent) Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions, Expected Volatility Rate Fair Value Measurement [Domain] Fair Value Measurement [Domain] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Cover page. Cover [Abstract] Fixed maturities with a single maturity date (as a percent) Available For Sale Securities Debt Maturities Single Maturity Date Percentage Of Fair Value Fair value of investment in available-for-sale debt securities with a single maturity date and expressed as a percentage of the total fair value of debt securities classified as available-for-sale. Insurance [Abstract] Insurance [Abstract] Investment Funds, Term, Period Three Investment Funds, Term, Period Three [Member] Investment Funds, Term, Period Three Run-off Run Off Line [Member] Run Off Line Income tax (expense) benefit Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent, Parenthetical Disclosure [Abstract] General and administrative expense ratio (as a percent) General and Administrative Expense Ratio Representation (as a percent) Concentration Risk, Percentage Number of commercial mortgage loans, past due Number Of Mortgage Loans, Held For Investment, Past Due Number Of Mortgage Loans, Held For Investment, Past Due Equity Awards Adjustments Equity Awards Adjustments [Member] Performance adjustment (in usd per share) Share-Based Compensation Arrangement By Share-Based Payment Award, Equity Instruments Other Than Options, Performance Adjustment In Period, Weighted Average Grant Date Fair Value Share-Based Compensation Arrangement By Share-Based Payment Award, Equity Instruments Other Than Options, Performance Adjustment In Period, Weighted Average Grant Date Fair Value Investment Funds, Term [Axis] Investment Funds, Term [Axis] Investment Funds, Term Summary of Mortgage Loans Net of Valuation Allowance Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Changes in Level 3 Financial Instruments Measured at Fair Value on a Recurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. RESERVE FOR LOSSES AND LOSS EXPENSES Liability for Future Policy Benefits and Unpaid Claims Disclosure [Text Block] Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Short-term investments Short-Term Investments [Member] Entity Address, Country Entity Address, Country Forfeited (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period Derivative Fair Values on Consolidated Balance Sheet [Line Items] Derivatives, Fair Value [Line Items] Held-to-maturity securities with maturity after three years through ten years Debt Securities, Held-To-Maturity, Amortized Cost, After Allowance For Credit Loss, Maturity, Allocated And Single Maturity Date, After Three Years Through 10 Years Amount excluding accrued interest, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity) with single maturity date and allocated without single maturity date, maturing in the third through tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). Axis Corporate Capital UK II Limited Axis Corporate Capital UK II Limited [Member] Axis Corporate Capital UK II Limited CMBS Commercial Mortgage-Backed Securities [Member] Hedging Designation [Domain] Hedging Designation [Domain] Loan With Monarch Point Re Loan Agreement With Monarch Point Re [Member] Loan Agreement With Monarch Point Re Class of Stock [Domain] Class of Stock [Domain] Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Foreign exchange forward contracts Foreign exchange forward contracts Foreign Exchange Forward [Member] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Investment Funds, Term, Period Two Investment Funds, Term, Period Two [Member] Investment Funds, Term, Period Two Entity Filer Category Entity Filer Category Total Debt Securities, Available-for-Sale, Unrealized Loss Position Monarch Point Re (ISAC) Ltd and Monarch Point Re (ISA 2023) Ltd Monarch Point Re (ISAC) Ltd and Monarch Point Re (ISA 2023) Ltd [Member] Monarch Point Re (ISAC) Ltd and Monarch Point Re (ISA 2023) Ltd Investment term Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Redemption Restriction Period Summary of Reconciliation of Gross Derivative Liabilities to Net Amounts Presented in Balance Sheets Offsetting Liabilities [Table Text Block] Vesting as a percentage of target (as a percent) Share-Based Compensation Arrangement By Share-Based Payment, Vesting Percentage Of Target Share-Based Compensation Arrangement By Share-Based Payment, Vesting Percentage Of Target Net losses and loss expenses ratio (as a percent) Loss Ratio Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Not Designated as Hedging Instruments Not Designated as Hedging Instrument [Member] Investments, Debt and Equity Securities [Abstract] Investments, Debt and Equity Securities [Abstract] Investment Funds, Term [Domain] Investment Funds, Term [Domain] Investment Funds, Term [Domain] Property Property Line [Member] Property Line Summary of Net Investment Gains (Losses) Gain (Loss) on Securities [Table Text Block] Change in unrealized gains/(losses) Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss) Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Schedule of Stock by Class [Table] Stock, Class of Stock [Table] Derivative instruments (refer to Note 5) Derivative liability fair value Net amounts Derivative Liability Entity Address, Address Line One Entity Address, Address Line One Total expenses Benefits, Losses and Expenses Vested (in 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 Commercial mortgage loans, past due amount Mortgage Loans, Held for Investment, Amount Past Due This item represents the amortized cost of commercial mortgage loans held for investments that are past due. Income tax expense Income tax benefit Income Tax Expense (Benefit) Insurance and reinsurance premium balances receivable (Allowance for expected credit losses 2026: $14,479; 2025: $15,821) Premiums Receivable, Net Statement [Table] Statement [Table] Performance Condition Share-Based Payment Arrangement, Tranche Two [Member] Catastrophic Event [Axis] Catastrophic Event [Axis] Segment Reconciling Items Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment [Member] Net investment (gains) losses Net Investment Gain (Loss) Cash Flow This item represents the net realized gains and losses recognized on the statement of operations, net of realized gains/losses from overseas deposits. Exchange-traded funds Exchange Traded Funds [Member] Trading days preceding performance period Trading Days Preceding Performance Period Trading Days Preceding Performance Period Gross amounts Derivative Asset, Subject to Master Netting Arrangement, before Offset Monarch Point Re (ISA 2025) Ltd Monarch Point Re (ISA 2025) Ltd [Member] Monarch Point Re (ISA 2025) Ltd BASIS OF PRESENTATION AND ACCOUNTING POLICIES Basis of Presentation and Significant Accounting Policies [Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract]