Assets Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] After five years through ten years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 Short-term investments and other, gross realized gains Short Term Investments And Other Gross Realized Gains Represents the gross profit realized on the sale of short term investment and other. Supplemental information Supplemental Cash Flow Information [Abstract] Bank loan participations: Bank Loan Participations [Abstract] Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Net income (loss) Net income (loss) Net income (loss) to shareholders Net Income (Loss) Attributable to Parent Reserve For Losses And Loss Adjustment Expenses [Table] Reserve For Losses And Loss Adjustment Expenses [Table] A table or schedule providing information pertaining to reserve for losses and Loss adjustment expenses. Entity Emerging Growth Company Entity Emerging Growth Company Short-term investments and other, gross realized losses Short Term Investments And Other Gross Realized Losses Represents the gross loss realized on the sale of short term investment and other. Preferred stock, shares outstanding (in shares) Preferred Stock, Shares Outstanding Entity Address, Address Line Three Entity Address, Address Line Three Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Statistical Measurement [Domain] Statistical Measurement [Domain] Entity Address, Address Line One Entity Address, Address Line One Entity Address, Address Line Two Entity Address, Address Line Two Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Total Amount (thousands) Dividends, Common Stock, Cash Total equity securities Equity securities Equity Securities, FV-NI, Current Forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Issuance of common shares related to outstanding equity plan awards (in shares) Shares Issued, Shares, Share-based Payment Arrangement, before Forfeiture Entity Filer Category Entity Filer Category Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Earnings (loss) per share: Earnings Per Share Reconciliation [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Investment, Name [Axis] Investment, Name [Axis] Segments [Axis] Segments [Axis] Number of shares available for grant (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Change in cash, cash equivalents, and restricted cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Specialty Admitted Insurance Specialty Admitted Insurance [Member] Represents information regarding specialty admitted insurance. Schedule of Gain (Loss) on Securities [Table] Schedule of Gain (Loss) on Securities [Table] Compensation expense under share incentive plans APIC, Share-based Payment Arrangement, Increase for Cost Recognition Schedule of Gross Unrealized Losses and Fair Value for Available-for-Sale Securities Debt Securities, Available-for-sale [Table Text Block] Document Fiscal Year Focus Document Fiscal Year Focus Subsequent Event Type [Domain] Subsequent Event Type [Domain] Amortization of intangible assets Amortization of intangible assets Amortization of Intangible Assets Senior debt issuances Proceeds from Issuance of Senior Long-term Debt Number of securities excluded from the calculations of diluted earnings per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Limited partnerships Partnership Interest [Member] Sale of Stock [Axis] Sale of Stock [Axis] Subsequent Events [Abstract] Subsequent Events [Abstract] Bank Holding Company Bank Holding Company [Member] Represents information about Bank Holding Company. Granted (in dollars 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 Business Acquisition [Axis] Business Acquisition [Axis] Title of Individual [Domain] Title of Individual [Domain] Unrealized gains (losses) arising during the period, net of U.S. income taxes OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax Maturities and calls – fixed maturity securities Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-sale Tax on net unrealized gains (losses) OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment, Tax Total gains or losses (realized/unrealized)-Included in earnings Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Schedule of Gross Carrying Amounts and Accumulated Amortization Schedule of Indefinite-Lived Intangible Assets [Table Text Block] Award Type [Domain] Award Type [Domain] Credit Facility [Domain] Credit Facility [Domain] Assets Assets [Abstract] Schedule of Summary of Available-for-Sale Investments Schedule of Available-for-sale Securities Reconciliation [Table Text Block] Subsegments [Axis] Subsegments [Axis] Non-employee directors Non-employee Directors [Member] Non-employee Directors [Member] Exercisable, end of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number State and municipal US States and Political Subdivisions Debt Securities [Member] Schedule of Summary of Available-for-Sale Investments by Contractual Maturity Investments Classified by Contractual Maturity Date [Table Text Block] Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Goodwill and Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Preferred Shares – 2021 and 2020: $0.00125 par value; 20,000,000 shares authorized; no shares issued and outstanding Preferred Stock, Value, Issued Issuance of common shares under equity incentive plans Proceeds, Issuance of Shares, Share-based Payment Arrangement, Including Option Exercised Liability for Unpaid Claims and Claims Adjustment Expense, Period Increase (Decrease) [Abstract] Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] Beginning of period (in shares) End of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Entity Address, City or Town Entity Address, City or Town Retained (Deficit) Earnings Retained Earnings [Member] Other Operating Expenses [Abstract] Other Operating Expenses and Other Expenses [Abstract] Other Operating Expenses and Other Expenses [Abstract] BBB- or better Standard & Poor's, BBB- or Better Rating [Member] Standard & Poor's, BBB- or Better Rating [Member] Securities available-for-sale: Fixed maturity securities, available-for-sale: Debt Securities, Available-for-sale [Abstract] Contingent Liabilities Commitments and Contingencies Disclosure [Text Block] Fixed maturity securities Debt Securities [Member] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Gross fee income Fee Income Represents amount of fee income . Bank loan participations, at fair value Bank loan participations Fair Value, Option, Loans Held as Assets, Aggregate Fair Value Fair Value, Option, Loans Held as Assets, Aggregate Fair Value Cash distributions from LLCs Proceeds from Equity Method Investment, Distribution Dividend payable, record date Dividends Payable, Date of Record Gain (Loss) on Securities [Line Items] Gain (Loss) on Securities [Line Items] Credit Rating, Standard & Poor's [Axis] Credit Rating, Standard & Poor's [Axis] Purchases Payment To Acquire Bank Loan Participations Represents payment to acquire Bank loan participations. Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Prior years Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Entity Interactive Data Current Entity Interactive Data Current BERMUDA BERMUDA Equity securities, at fair value (cost:  2021 – $84,909; 2020 – $81,698) Equity Securities, FV-NI Development on prior year loss reserves Prior years Prior Year Claims and Claims Adjustment Expense Basic earnings (loss) per share (in dollars per share) Basic (in dollars per share) Earnings Per Share, Basic Indefinite-lived Intangible Assets, Major Class Name [Domain] Indefinite-lived Intangible Assets, Major Class Name [Domain] Equity securities Equity Securities, FV-NI, Realized Gain (Loss) U.S. Treasury securities and obligations guaranteed by the U.S. government US Treasury and Government [Member] Unvested, beginning of period (in shares) Unvested, end of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Document Type Document Type Purchases – equity securities Payments to Acquire Equity Securities, FV-NI After one year through five years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year One Through Five Reduction in bank loan participations Fair Value, Option, Aggregate Differences, Loans and Long-term Receivables Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Acquired Intangible Assets [Line Items] Acquired Intangible Assets [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. Entity Current Reporting Status Entity Current Reporting Status Cumulative Effect, Period of Adoption, Adjustment Cumulative Effect, Period of Adoption, Adjustment [Member] Maximum number of shares available for issuance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Assets deposited for securing letters of credit Assets Deposited For Securing Letters Of Credit Represents amount of assets deposited for securing letters of credit. Reinsurance recoverable on unpaid losses, net Reinsurance Recoverable for Unpaid Claims and Claims Adjustments Liability for Claims and Claims Adjustment Expense [Abstract] Liability for Claims and Claims Adjustment Expense [Abstract] Letter of credit 102.5 Million 2013 Facility 2013 Facility [Member] 2013 Facility Plan Name [Axis] Plan Name [Axis] Quoted Prices in Active Markets for Identical Assets Level 1 Fair Value, Inputs, Level 1 [Member] Other liabilities Other Liabilities Document Transition Report Document Transition Report Underwriting profit (loss) Underwriting Profit (Loss) Represents the amount related to underwriting profit (loss) during the period. Residential mortgage-backed Residential Mortgage Backed Fair Value Represents fair value of residential mortgage backed. Liabilities Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Total liabilities and shareholders’ equity Liabilities and Equity Bank holding companies Bank Holding Companies [Member] Name of the investment category. Premiums receivable and agents’ balances, net Premiums and Other Receivables, Net Exercised (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Additional paid-in capital Additional Paid in Capital Liabilities and Shareholders’ Equity Liabilities and Equity [Abstract] Investment Income [Table] Investment Income [Table] Schedule Of Acquired Intangible Assets [Table] Schedule Of Acquired Intangible Assets [Table] Represents the tabular information related to intangible assets acquired in the acquisition. Assets held in trust Assets Held-in-trust Operating activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Earnings (Loss) Per Share Earnings Per Share [Text Block] Other invested assets: Other Investments [Abstract] Available-for-sale fixed maturity securities and equity securities Securities (Assets) [Member] Expenses Operating Expenses [Abstract] Net realized and unrealized gains (losses) on investments in equity securities Equity Securities, FV-NI, Gain (Loss) Ownership percentage Equity Method Investment, Ownership Percentage Exercise of stock options Stock Issued During Period, Value, Stock Options Exercised Minimum Minimum [Member] Fixed maturity securities, gross realized gains Debt Securities, Available-for-sale, Realized Gain Redemptions Proceeds From Maturities And Repayments Of Other Invested Assets Represents proceeds from maturities and repayments of other invested assets. Number of credit facilities Number of Credit Facilities Number of Credit Facilities Senior debt Drawn balance outstanding Long-term Line of Credit Unearned premiums Unearned Premiums Indefinite-lived Intangible Assets [Axis] Indefinite-lived Intangible Assets [Axis] Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Raiser Raiser [Member] Raiser [Member] Total investments available-for-sale, Gross Unrealized Gains Aggregate net unrealized gain Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Other Operating Expenses and Other Expenses Other Operating Income and Expense [Text Block] After ten years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10 Cumulative Effect, Period of Adoption [Axis] Cumulative Effect, Period of Adoption [Axis] Short-term investments and other Short Term Investments And Other Gross Realized Gains (Losses) Short Term Investments And Other Gross Realized Gains (Losses) Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fixed maturity securities, 12 months or more, fair value Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer Trading Symbol Trading Symbol Amortization of policy acquisition costs Deferred Policy Acquisition Costs, Amortization Expense Percentage of outstanding shares Business Acquisition, Percentage of Voting Interests Acquired Entity Address, Country Entity Address, Country Issuance of common shares Stock Issued During Period, Value, New Issues Senior Debt Debt Disclosure [Text Block] Exercisable, end of period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Line of Credit Line of Credit [Member] Significant Unobservable Inputs Level 3 Fair Value, Inputs, Level 3 [Member] Other income and expenses Other Income And Expenses Represents other income and expenses. Fair Value Measurement Inputs and Valuation Techniques [Line Items] Fair Value Measurement Inputs and Valuation Techniques [Line Items] Equity securities Equity Securities [Member] Contingent Liabilities [Line Items] Contingent Liabilities [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. Accounting Policies [Abstract] Accounting Policies [Abstract] Weighted-average remaining contractual life of options outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Issuance of common shares (in shares) Stock Issued During Period, Shares, New Issues Number of reportable segments Number of Reportable Segments Amount of letters of credit issued Letters of Credit Outstanding, Amount Common Shares – 2021 and 2020: $0.0002 par value; 200,000,000 shares authorized; 37,275,562 and 30,649,261 shares issued and outstanding, respectively Common Stock, Value, Issued Weighted-average period of unrecognized share based compensation expense Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Bank loan participations Bank loan participations Bank Loan Participations, Net Gain (Loss) Bank Loan Participations, realized and unrealized net gains (losses) Unvested, beginning of period (in dollars per share) Unvested, end of period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Commitments and contingent liabilities Commitments and Contingencies Subsequent Event [Table] Subsequent Event [Table] Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax Cash dividend declared (in dollars per share) Dividends Payable, Amount Per Share Schedule of Carrying Value and Fair Value Fair Value, by Balance Sheet Grouping [Table Text Block] Commercial mortgage and asset-backed Commercial Mortgage Backed Securities [Member] Other invested assets Total other invested assets Other Investments Commercial Auto Business Commercial Auto Business [Member] Commercial Auto Business Common share equivalents (in dollars per share) Common Share Equivalents Earnings Per Share Represents amount of earnings per share of common share equivalents. Restricted stock unit dividend equivalents Restricted Stock Unit Dividend Equivalents Represents amount of dividend equivalent of RSU's. Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Document Period End Date Document Period End Date ASU 2016-13 Accounting Standards Update 2016-13 [Member] Schedule of Other Invested Assets Other Invested Asset [Table Text Block] Tabular disclosure of other invested assets consisting of private debt and equity investments. Entity Registrant Name Entity Registrant Name Number of insurance companies Number Of Insurance Companies This element represents number of insurance companies owned by the entity. Add: Reinsurance recoverables on unpaid losses and loss adjustment expenses at end of period Reinsurance Recoverable for Unpaid Claims and Claims Adjustments, Gross Reinsurance Recoverable for Unpaid Claims and Claims Adjustments, Gross Schedule of Other Operating Expenses Schedule of Other Operating Cost and Expense, by Component [Table Text Block] Reserve for losses and loss adjustment expenses net of reinsurance recoverables at beginning of period Reserve for losses and loss adjustment expenses net of reinsurance recoverables at end of period Liability for Unpaid Claims and Claims Adjustment Expense, Net Letters of credit facility, amount Letter Of Credit Facility Amount Represents amount of letter of credit facility. U.S. income taxes OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, Tax Reconciliation of Securities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Financial Instrument [Axis] Financial Instrument [Axis] Dividend declared per share (in dollars per share) Common Stock, Dividends, Per Share, Declared Cash equivalent collateral trust account Cash Equivalent Collateral Held In Trust Account Cash Equivalent Collateral Held In Trust Account Allowance for uncollectible reinsurance balances Reinsurance Recoverable, Allowance for Credit Loss Dividends paid Payments of Dividends Schedule of Dividends Dividends Declared [Table Text Block] Non-qualified stock options Options Share-based Payment Arrangement, Option [Member] Casualty Reinsurance Casualty Reinsurance [Member] Represents information regarding casualty reinsurance. Funds held Funds Held under Reinsurance Agreements, Liability Carrying Value Reported Value Measurement [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Change in restricted cash equivalents Increase (Decrease) in Restricted Cash and Investments Interest income Investment Income, Interest Fixed maturity securities, less than 12 months, fair value Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months Common Shares Common stock Common Stock [Member] Deduct: Loss and loss adjustment expense payments net of reinsurance: Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract] Segment Information Segment Reporting Disclosure [Text Block] Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-sale [Line Items] After one year through five years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five Total investments available-for-sale, Gross Unrealized Losses Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Fixed maturity securities Debt Securities, Available-for-sale, Realized Gain (Loss) Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Purchases Payments to Acquire Other Investments Transfers out of Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 Additional Paid-in Capital Additional Paid-in Capital [Member] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Equity securities: Short-term Investments [Abstract] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Purchases – fixed maturity securities Payments to Acquire Debt Securities, Available-for-sale Amount drawn Proceeds from Lines of Credit Rate of interest Investment Interest Rate Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Outstanding commitments to invest Commitment to Investment In Limited Partnership Commitment to Investment In Limited Partnership Maximum Maximum [Member] U.S. income taxes Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax Sales Proceeds From Bank Loan Participations Represents cash inflow from sales of bank loan participations. Total liabilities Liabilities Contractual life (in years) Share Based Arrangement by Share Based Award Option Contractual Life Share Based Arrangement by Share Based Award Option Contractual Life Securities receivable or payable, net Payments for (Proceeds from) Unsettled Investments, Net Payments for (Proceeds from) Unsettled Investments, Net Legal Entity [Axis] Legal Entity [Axis] Award Type [Axis] Award Type [Axis] Granted (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Total shareholders’ equity Balance Balance Shareholders' equity Stockholders' Equity Attributable to Parent Current year Current Year Claims and Claims Adjustment Expense Common stock, shares issued (in shares) Common Stock, Shares, Issued Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued James River Group, Inc. James River Group Inc [Member] Represents information regarding James River Group, Inc. Number of bank loan participations held Number Of Bank Loan Participations Held Number Of Bank Loan Participations Held Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Disclosure [Abstract] Senior debt repayments Repayments of Senior Debt Fixed maturity securities, gross realized losses Debt Securities, Available-for-sale, Realized Loss Variable Interest Entities Consolidation, Variable Interest Entity, Policy [Policy Text Block] Common share repurchases Payments for Repurchase of Common Stock Shareholders’ equity: Stockholders' Equity Attributable to Parent [Abstract] Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Investment income Investment Income, Net Accounting Standards Update [Axis] Accounting Standards Update [Axis] Measurement Frequency [Domain] Measurement Frequency [Domain] Interest expense Interest expense Interest Expense Insurance licenses and authorities Licensing Agreements [Member] Carrying values of limited partnerships held Carrying Values Of Limited Partnerships Held Represents carrying values of limited partnerships held across segments. Cash provided by operating activities excluding reduction in collateral funds Net Cash Provided by (Used in) Operating Activities Excluding Change in Collateral Funds Net Cash Provided by (Used in) Operating Activities Excluding Change in Collateral Funds U.S. tax benefit on share based compensation expense Share-based Payment Arrangement, Expense, Tax Benefit City Area Code City Area Code Summary of Net Realized Gains and Losses on Investments Realized Gain (Loss) on Investments [Table Text Block] Retained (deficit) earnings Retained Earnings (Accumulated Deficit) Maturities Proceeds From Maturities From Bank Loan Participations Represents cash inflow from maturities of bank loan participations. Fair Value Measurement Inputs and Valuation Techniques [Table] Fair Value Measurement Inputs and Valuation Techniques [Table] RSUs RSUs Restricted Stock Units (RSUs) [Member] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Business Acquisition [Line Items] Business Acquisition [Line Items] Net realized and unrealized gains (losses) on investments Total Gain (Loss) on Investments Unpaid principal balance Fair Value, Option, Loans Held as Assets, Aggregate Unpaid Principal Balance Fair Value, Option, Loans Held as Assets, Aggregate Unpaid Principal Balance Letter of credit 100 Million 2017 Facility 2017 Facility [Member] 2017 Facility Income Statement [Abstract] Income Statement [Abstract] Amendment Flag Amendment Flag Fair Value Estimate of Fair Value Measurement [Member] Asset Class [Domain] Asset Class [Domain] Repaid amount Repayments of Lines of Credit Reserve For Losses And Loss Adjustment Expenses [Line Items] Reserve For Losses And Loss Adjustment Expenses [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. Short-term investments Short-term Investments Identifiable intangibles not subject to amortization Indefinite-lived Intangible Assets (Excluding Goodwill) Accounting Policies Basis of Presentation and Significant Accounting Policies [Text Block] Contingent Liabilities [Table] Contingent Liabilities [Table] Discloses information about contingent liabilities. Forfeited (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Income tax expense (benefit) Income Tax Expense (Benefit) Unsecured Debt Unsecured Debt [Member] Equity Components [Axis] Equity Components [Axis] Below BBB- Standard & Poor's, Below BBB- Rating [Member] Standard & Poor's, Below BBB- Rating [Member] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Investment Type [Axis] Investment Type [Axis] Sale of Stock [Domain] Sale of Stock [Domain] Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales Weighted average common shares outstanding: Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Add: Incurred losses and loss adjustment expenses net of reinsurance: Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract] Schedule of Summary of Company's Segment Results Schedule of Segment Reporting Information, by Segment [Table Text Block] Entity File Number Entity File Number Underwriting (loss) profit of insurance segments Total underwriting profit (loss) of insurance segments Underwriting Profit Loss Of Operating Segments This element represents amount of underwriting Profit (loss) of operating segments. Fair Value Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Maturities, calls and paydowns Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Financing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Small Business Entity Small Business Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Other underwriting expenses of the operating segments Other Underwriting Expense Equity Component [Domain] Equity Component [Domain] 2014 Director Plan Non Employee Director Incentive Plan 2014 [Member] Represents information regarding 2014 Non Employee Director Incentive Plan. Reserve for Losses and Loss Adjustment Expenses Liability For Claims And Claims Adjustment Expense [Text Block] The entire disclosure for the liability for claims and claims adjustment expense. Invested assets: Investments [Abstract] Carrying value of collateralized loan obligation held Carrying Value Of Collateralized Loan Obligation Held Represents carrying value of carrying value of collateralized loan obligation held. Statement [Line Items] Statement [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Other income Other Income Weighted- Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Reinsurance recoverable on paid losses Reinsurance Recoverable for Paid Claims and Claims Adjustments Total invested assets Investments Liabilities: Liabilities [Abstract] Vesting of RSUs Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Cash equivalent collateral trust arrangement Cash Equivalent Collateral Held In Trust Arrangement Cash Equivalent Collateral Held In Trust Arrangement Fixed maturity securities, available-for-sale, at fair value (amortized cost: 2021 – $1,783,267; 2020 – $1,690,890) Fixed maturity securities, available-for-sale Total investments available-for-sale, Fair Value Total fixed maturity securities, available-for-sale Debt Securities, Available-for-sale Counterparty Name [Domain] Counterparty Name [Domain] Total Intangible Assets, Gross Intangible Assets, Gross (Excluding Goodwill) Short-term investments, net Payments for (Proceeds from) Short-term Investments Debt Disclosure [Abstract] Debt Disclosure [Abstract] Broker relationships Broker Relationships [Member] Represents information related to broker relationships. Income (loss) before taxes Pre-tax income (loss) Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Significant Other Observable Inputs Level 2 Fair Value, Inputs, Level 2 [Member] Accounting Standards Update [Domain] Accounting Standards Update [Domain] Fixed maturity securities, fair value Total fair value Debt Securities, Available-for-sale, Unrealized Loss Position Segment Reporting [Abstract] Segment Reporting [Abstract] Entity [Domain] Entity [Domain] Accounting Policies [Table] Accounting Policies [Table] Accounting Policies Fixed maturity securities, available-for-sale, at amortized cost Total fixed maturity securities, Cost or Amortized Cost Debt Securities, Available-for-sale, Amortized Cost Life (Years) Finite-Lived Intangible Asset, Useful Life Estimates and Assumptions Use of Estimates, Policy [Policy Text Block] Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Schedule of Reconciliation of Numerator and Denominator of Basic and Diluted Earnings Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Entity Shell Company Entity Shell Company Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Asset Class [Axis] Asset Class [Axis] Local Phone Number Local Phone Number Net unrealized gains (losses), net of taxes of $2,013 and $(3,635) in 2021 and $6,927 and $5,535 in 2020 Other comprehensive income (loss) Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Schedule of Summary of Share Based Compensation Expense and Related Tax Benefit Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] Issuance of common shares - public offering (Note 12) Proceeds from issuance of stock Proceeds from Issuance of Common Stock Total assets Segment assets Assets Investment, Name [Domain] Investment, Name [Domain] Plan Name [Domain] Plan Name [Domain] Common stock, shares authorized (in shares) Common Stock, Shares Authorized Dividends payable, date to be paid Dividends Payable, Date to be Paid Interest paid Interest Paid, Excluding Capitalized Interest, Operating Activities Geographical [Domain] Geographical [Domain] Title of Individual [Axis] Title of Individual [Axis] Schedule of Summary of RSU Activity Schedule of Nonvested Restricted Stock Units Activity [Table Text Block] Equity securities, gross realized losses Equity Securities, FV-NI, Realized Loss Schedule of Reconciliation of Beginning and Ending Reserve Balances for Losses and Loss Adjustment Expenses Schedule of Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block] Net earned premiums Net earned premiums Premiums Earned, Net Net realized investment gains Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Prepaid reinsurance premiums Prepaid Reinsurance Premiums Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Equity securities, at cost Equity Securities, FV-NI, Cost Cumulative Effect, Period of Adoption [Domain] Cumulative Effect, Period of Adoption [Domain] Measurement Frequency [Axis] Measurement Frequency [Axis] Net cash (used in) operating activities Net Cash Provided by (Used in) Operating Activities Reclassification adjustment for investment gains realized in net income Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Entity Tax Identification Number Entity Tax Identification Number Development on prior year loss reserves Development On Prior Year Loss Reserves [Abstract] Subsequent Event [Line Items] Subsequent Event [Line Items] Cost or Amortized Cost Debt Securities, Available-for-sale, Amortized Cost, Fiscal Year Maturity [Abstract] Third-party Reinsureds Third-party Reinsureds [Member] Third-party Reinsureds [Member] Geographical [Axis] Geographical [Axis] Corporate and Other Corporate and Other [Member] Basic (in shares) Weighted Average Number of Shares Outstanding, Basic Diluted earnings (loss) per share (in dollars per share) Diluted (in dollars per share) Earnings Per Share, Diluted Segments [Domain] Segments [Domain] Shares issued at a public offering price (in dollars per share) Sale of Stock, Price Per Share JRG Reinsurance Company, Ltd. Jrg Reinsurance Company Ltd [Member] Represents reinsurance subsidiary of the entity. Common share equivalents (in shares) Weighted Average Number Diluted Shares Outstanding Adjustment Equity securities, gross realized gain Equity Securities, FV-NI, Realized Gain Residential mortgage-backed Residential Mortgage Backed Amortized Cost Represents Amortized Cost of Residential mortgage-backed securities. Subsequent Events Subsequent Events [Text Block] Total comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Intangible assets, net Intangible Assets, Net (Excluding Goodwill) Bank Loan Participations Loan Participations and Assignments [Member] Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Other Comprehensive Income (Loss), Net of Tax [Abstract] Vesting period (in years) Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Ceded written premiums Ceded Premiums Written Less reclassification adjustment: OCI, Debt Securities, Available-for-Sale, Gain (Loss), before Adjustment, after Tax [Abstract] Schedule of Components of Comprehensive Income (Loss) Comprehensive Income (Loss) [Table Text Block] Investment income (loss) Income (Loss) from Equity Method Investments Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Change in net unearned premiums (Increase) Decrease in Unearned Premiums, Net Amortization of discount Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Amortization of Discount Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Amortization of Discount Other operating expenses Total Other Cost and Expense, Operating Corporate Corporate Debt Securities [Member] Fair Value Measurements Fair Value Disclosures [Text Block] Subsegments [Domain] Subsegments [Domain] Schedule of Assets Measured at Fair Value on a Recurring Basis Fair Value, Assets Measured on Recurring Basis [Table Text Block] Accumulated Other Comprehensive Income AOCI Attributable to Parent [Member] Other assets Other Assets Dividends payable Dividends Payable Common stock, shares outstanding (in shares) Balance (in shares) Balance (in shares) Common Stock, Shares, Outstanding Transfers in to Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 Summary of Net Unrealized Gains and Losses on Investments Unrealized Gain (Loss) on Investments [Table Text Block] Financial Instruments [Domain] Financial Instruments [Domain] After five years through ten years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 Commercial mortgage and asset-backed Commercial Mortgage And Asset Backed Amortized Cost Represents amortized cost of commercial mortgage and asset-backed. Revenues Revenues [Abstract] Vesting of RSUs (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Bank loan participations, gross realized losses Bank Loan Participations, Gross Realized Loss Represents the gross realized losses on bank loan participations. Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Investments Investment [Text Block] Investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Changes in fair values of short-term investments and other Short Term Investments And Other, Changes in Fair Value Short Term Investments And Other, Changes in Fair Value Accrued investment income Accrued Investment Income Receivable Changes in fair values of bank loan participations Bank Loan Participations, Changes in Fair Value Bank Loan Participations, Changes in Fair Value Excess and Surplus Lines Excess And Surplus Lines [Member] Represents information regarding excess and surplus lines segment. Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-sale [Table] One year or less Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, Year One Net investment income Net investment income Net Investment Income Losses due to credit-related impairments Bank Loan Participations, Increase (Decrease) in Fair Value, Credit-Related Impairment Bank Loan Participations, Increase (Decrease) in Fair Value, Credit-Related Impairment Percentage of available for sale securities Percentage Of Available For Sale Debt Securities Represents percentage of available for sale debt securities. Total expenses Operating Expenses Residential mortgage-backed Residential Mortgage Backed Securities [Member] Restricted cash equivalents Restricted cash equivalents at beginning of period Restricted cash equivalents at end of period Amount of collateral held Restricted Cash Equivalents Debt Instrument [Line Items] Debt Instrument [Line Items] Total gains or losses (realized/unrealized)-Included in other comprehensive income Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Earnings Per Share [Abstract] Earnings Per Share [Abstract] Payables to reinsurers Reinsurance Payable Changes in fair values of equity securities Equity Securities, FV-NI, Unrealized Gain (Loss) Document Quarterly Report Document Quarterly Report Fixed maturity securities, gross unrealized losses Gross unrealized losses Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss Total revenues Segment revenues Revenues Trademarks Trademarks [Member] Investment transfer Equity Method Investment, Transfer Equity Method Investment, Transfer Sales – fixed maturity securities Proceeds from Sale of Debt Securities, Available-for-sale Beginning of period (in dollars per share) End of period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Number of issuers Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions Commercial mortgage and asset-backed Commercial Mortgage And Asset Backed Fair Value Represents fair value of commercial mortgage and asset backed. Share based compensation expense Share-based Payment Arrangement, Expense Weighted-average remaining contractual life of options exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Public Stock Offering Public Stock Offering [Member] Public Stock Offering Stock options and restricted share units ("RSU's") Stock Options And Restricted Stock Units Rsu [Member] Stock options and share instrument which is convertible to stock or an equivalent amount of cash, after a specified period of time or when specified performance conditions are met. Per share data: Earnings Per Share, Basic and Diluted [Abstract] Net written premiums Premiums Written, Net 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] Document Fiscal Period Focus Document Fiscal Period Focus Effective U.S. federal income tax benefit rate Effective Income Tax Rate Reconciliation, Percent Accounting Policies [Line Items] Accounting Policies [Line Items] Accounting Policies Investments [Domain] Investments [Domain] Bank Holding Company Investment In Bank Holding Company [Member] Represents information about Investment in bank holding company. Counterparty Name [Axis] Counterparty Name [Axis] Renewable energy LLCs Renewable Energy Llcs [Member] Name of the investment category. Cash, cash equivalents, and restricted cash equivalents at beginning of period Cash, cash equivalents, and restricted cash equivalents at end of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Dividends Dividends Number of common shares issued during period (in shares) Sale of Stock, Number of Shares Issued in Transaction UNITED STATES UNITED STATES Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Gross Carrying Amount Finite-Lived Intangible Assets, Gross Identifiable intangible assets subject to amortization Finite-Lived Intangible Assets, Net [Abstract] Bank loan participations, gross realized gains Bank Loan Participations, Gross Realized Gain Represents the gross realized gains on bank loan participations. Entity Central Index Key Entity Central Index Key Schedule of Gross Carrying Amounts and Accumulated Amortization Schedule of Finite-Lived Intangible Assets [Table Text Block] Income Tax Expense Income Tax, Policy [Policy Text Block] Security Exchange Name Security Exchange Name Unrealized gains (losses) arising during the period, before U.S. income taxes OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment and Tax External Credit Rating, Standard & Poor's [Domain] External Credit Rating, Standard & Poor's [Domain] Reserve for losses and loss adjustment expenses Reserve for losses and loss adjustment expenses gross of reinsurance recoverables on unpaid losses and loss adjustment expenses at end of period Liability for Claims and Claims Adjustment Expense Exercise of stock options (in shares) Exercised (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Diluted (in shares) Diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Beginning balance Ending balance Asset value Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Recurring basis Fair Value, Recurring Fair Value, Recurring [Member] Weighted-average common shares outstanding: Weighted Average Number of Shares Outstanding, Basic [Abstract] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Current Fiscal Year End Date Current Fiscal Year End Date Schedule of Summary of Option Activity Share-based Payment Arrangement, Option, Activity [Table Text Block] Capital Stock and Equity Awards Stockholders' Equity Note Disclosure [Text Block] Measurement Basis [Axis] Measurement Basis [Axis] Losses and loss adjustment expenses Total incurred losses and loss and adjustment expenses Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims Accrued expenses Accrued Liabilities Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Investment in variable interest entities Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount Short-term investments Other Short-term Investments Credit Facility [Axis] Credit Facility [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Renewable energy notes receivable Renewable Energy Bridge Financing Notes [Member] Name of the investment category. Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Schedule of Underwriting Profit of Operating Segments by Individual Segment and Reconciliation to Consolidated Income Before Taxes Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block] Other operating expenses of the Corporate and Other segment Other operating expenses of the Corporate and Other segment Other Operating Expenses Of Corporate And Other Segment Represents Other operating expenses of the Corporate and Other segment. Vested (in dollars 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 Return of capital Proceeds From Other Invested Asset Return Of Capital Represents cash inflow from other invested asset return of capital. Deferred policy acquisition costs Deferred Policy Acquisition Cost Junior subordinated debt Junior subordinated debt Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust Line of credit (up to) Line of Credit Facility, Maximum Borrowing Capacity 2014 LTIP Long Term Incentive Plan 2014 [Member] Represents information regarding Long Term Incentive Plan 2014. Number of equity securities held Number Of Equity Securities Held Number Of Equity Securities Held Gross written premiums Premiums Written, Gross Investment in LLC Investment In Llc [Member] Represents investment in LLC`s. Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Sales – equity securities Proceeds from Sale of Equity Securities, FV-NI Title of 12(b) Security Title of 12(b) Security ASU 2019-05 Accounting Standards Update 2019-05 [Member] Statement [Table] Statement [Table] Total loss and loss adjustment expense payments Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid Unrecognized share based compensation expense Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Letter of credit 75 Million Letter Of Credit 75 Million [Member] Letter Of Credit 75 Million [Member] Statistical Measurement [Axis] Statistical Measurement [Axis] Subsequent Event Subsequent Event [Member] Cover [Abstract] Cover [Abstract] Stockholders' Equity Note [Abstract] Stockholders' Equity Note [Abstract] Preferred Shares Preferred stock Preferred Stock [Member] Goodwill Segment goodwill Goodwill After ten years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 10 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] Fixed maturity securities, less than 12 months, gross unrealized losses Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Subsequent Event Type [Axis] Subsequent Event Type [Axis] One year or less Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, Year One Investment in private subordinated notes Other invested assets – notes receivable Notes Receivable Represents carrying value of notes receivable as on reporting date. Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Other expenses Other Expenses Net Investment Income [Line Items] Net Investment Income [Line Items] Fixed maturity securities, 12 months or more, gross unrealized losses Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Current year Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year