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Losses and expenses: Benefits, Losses and Expenses [Abstract] Due after 10 years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value Fair Value of Financial Instruments Fair Value of Financial Instruments, Policy [Policy Text Block] Reserve for losses and LAE Reserve for losses and LAE at beginning of year Reserve for losses and LAE at end of year Total gross reserve for losses and LAE Liability for Claims and Claims Adjustment Expense Financial Instruments [Domain] Financial Instruments [Domain] Audit Information [Abstract] Audit Information Weighted average discount rate - operating leases Operating Lease, Weighted Average Discount Rate, Percent Liability for Claims and Claims Adjustment Expense [Table] Liability for Claims and Claims Adjustment Expense [Table] Additional paid-in capital Additional Paid in Capital, Common Stock Dilutive effect of nonvested shares (in shares) Incremental Common Shares Attributable to Dilutive Effect of Nonvested Shares with Forfeitable Dividends Due in 1 year Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value Total accounts receivable Accounts Receivable, before Allowance for Credit Loss 2016 Short-Duration Insurance Contracts, Accident Year 2016 [Member] 2021 Performance based share awards Two Thousand Twenty One Performance-Based Grants [Member] Two Thousand Twenty One Performance-Based Grants Income tax payments Income Taxes Paid Antidilutive nonvested shares (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Year 9 Short-Duration Insurance Contracts, Historical Claims Duration, Year Nine Share Repurchase Program [Domain] Share Repurchase Program [Domain] 2028 and thereafter Lessee, Operating Lease, Liability, to be Paid, after Year Five Number of states in which the entity is licensed to write mortgage insurance Number of States in which Entity Operates Net investment income Net investment income Net Investment Income Equity Component [Domain] Equity Component [Domain] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Term Loan Secured Debt [Member] Investment, Name [Domain] Investment, Name [Domain] % of pretax income Effective Income Tax Rate Reconciliation, Percent [Abstract] Year 7 Short-Duration Insurance Contracts, Historical Claims Duration, Year Seven Related Party [Domain] Related Party [Domain] Total investments available for sale Fair Value Debt Securities, Available-for-Sale Extinguishment of Debt [Axis] Extinguishment of Debt [Axis] Supplemental Disclosure of Cash Flow Information Supplemental Cash Flow Information [Abstract] Total unrecognized compensation expense Share-Based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount Plan Name [Domain] Plan Name [Domain] Net premiums earned: Premiums Earned, Net [Abstract] Credit facility borrowings (at carrying value, less unamortized deferred costs of $4,136 in 2022 and $5,177 in 2021) Credit facility borrowings (at carrying value, less unamortized deferred costs of $4,136 in 2022 and $5,177 in 2021) Long-Term Line of Credit Withholding taxes accrued with respect to un-remitted earnings Deferred Tax Liabilities, Undistributed Foreign Earnings Essent Holdings Essent Us Holdings Inc [Member] Represents Essent US Holdings, Inc. (Essent Holdings), an indirect wholly-owned subsidiary of the reporting entity through which, by way of its wholly-owned subsidiaries, the reporting entity's primary operations are conducted. Due in 1 year Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost Nonvested shares or share units outstanding Nonvested Shares, Share Units [Member] Nonvested Shares, Share Units [Member] Award Type [Axis] Award Type [Axis] Radnor Re 2021-2 Ltd. Radnor Re 2021-2 Ltd. [Member] Radnor Re 2021-2 Ltd. Lease cost: Lease, Cost [Abstract] Due after 5 but within 10 years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Fair Value Essent Guaranty Essent Guaranty Inc [Member] Represents information pertaining to Essent Guaranty, Inc. (Essent Guaranty), a regulated and licensed indirect wholly-owned subsidiary of the reporting entity. 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of Prior Period, Error Correction, Adjustment [Member] Assumed from Other Companies Assumed Premiums Earned Capital Maintenance Agreement Capital Maintenance Agreement Disclosure [Text Block] The entire disclosure for the capital maintenance agreement under which the entity guaranty agreed to contribute funds, under specified conditions. 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Amortized Cost SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Cost Compounded Annual Book Value Per Share Growth 16% 16% Compounded Annual Growth Rate, Three Year Book Value Achieved, 16 Percent [Member] Compounded Annual Book Value Per Share Growth Achieved 16 Percent [Member] Other Reinsurance Other Reinsurance [Member] Other Reinsurance [Member] 15% Compounded Annual Growth Rate, Three Year Book Value Achieved, 15 Percent [Member] Represents information pertaining to 15% compounded annual book value per share growth achieved. Retained earnings Retained Earnings (Accumulated Deficit) Scenario [Domain] Scenario [Domain] Vesting Based On Performance Vesting Based On Performance [Member] Represents a share based compensation award with vesting based on achievement of performance conditions. 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Less: Reclassification adjustment for gains included in net income, before tax Reclassification from AOCI, Current Period, before Tax, Attributable to Parent Due after 10 years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost Insurance Written Period [Domain] Insurance Written Period [Domain] Insurance Written Period Credit Facility Borrowings Subordinated Borrowings [Abstract] Excess tax (benefit) deficit from stock-based compensation Effective Income Tax Rate Reconciliation, Tax Expense (Benefit), Share-Based Payment Arrangement, Percent Earned premiums from mortgage guaranty insurance monthly policies as a percentage of total earned premiums Mortgage Guaranty Insurance Contracts Monthly Policies Earned Premium Percentage of Total Represents the earned premium during the period from mortgage guaranty insurance contracts which provide for monthly payments as a percentage of total earned premium. ILN Radnor Entities [Member] Radnor Entities [Member] Nonvested shares Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-Based Compensation Cost Committed capacity Line of Credit Facility, Current Borrowing Capacity Common shares, outstanding (in shares) Common Stock, Shares, Outstanding Investment in consolidated subsidiaries Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Reinsurance for mortgage insurance coverage in excess of 25% Excess Mortgage Insurance Coverage [Member] Represents an arrangement to assume that portion of the risk retained by an affiliate that is in excess of 25% of the balance of any mortgage loan insured by that affiliate after consideration of other reinsurance agreements at that affiliate, in accordance with certain state law requirements. 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Remaining Risk in Force Reinsurance, Remaining Risk In Force Reinsurance, Remaining Risk In Force Total investments Investments Investments-Other Than Investments in Related Parties SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items] Common shares, $0.015 par value: Authorized - 233,333; issued and outstanding - 107,683 shares in 2022 and 109,377 shares in 2021 Common shares Common Stock, Value, Issued Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Limited Partnership Investment Limited Partnership Investment [Member] Limited Partnership Investment Percentage of award issuable if current period end were end of contingency period Share-based Compensation Arrangement by Share-based Payment Award, Award Period to Date Vesting Rights, Percentage Percentage of vesting of share-based compensation awards if the end of the current reporting period were the end of the vesting period. Ceding commission Reinsurance, Ceded Premiums Earned, Ceding Commission, Percent Reinsurance, Ceded Premiums Earned, Ceding Commission, Percent 13% Compounded Annual Growth Rate, Three Year Book Value Achieved, 13 Percent [Member] Represents information pertaining to 13% compounded annual book value per share growth achieved. Earnings per share: Earnings Per Share, Basic and Diluted EPS [Abstract] Earnings Per Share, Basic and Diluted EPS Time-Based Share Awards Vesting Based On Service [Member] Represents a share based compensation award with vesting based on length of service. Employee Employee [Member] Employee [Member] Other income Other Income Property, Plant and Equipment, Net Property, Plant and Equipment, Net [Abstract] Ceded premiums earned related to percent of risk on eligible single premium policies Reinsurance, Ceded Premiums Earned, Percent Of Risk On Eligible Single Premium Policies Reinsurance, Ceded Premiums Earned, Percent Of Risk On Eligible Single Premium Policies Profit commission, maximum Reinsurance, Profit Commissions, Maximum Reinsurance, Profit Commissions, Maximum Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Assets on deposit under reinsurance agreement Assets on Deposit Under Reinsurance Agreements Assets on Deposit Under Reinsurance Agreements Tax allocation bonds Tax Allocation Municipal Bonds [Member] Bonds issued in conjunction with a redevelopment project. The taxes pledged to their repayment come from the increase of assessed value over and above a pre-established base. 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Interest Stock-Based Compensation Share-Based Payment Arrangement [Text Block] Less: Allowance for doubtful accounts Accounts Receivable, Allowance for Credit Loss Fixed maturities Fixed Maturities [Member] Schedule of Compensation Expense, Net of Forfeitures, and Related Tax Effects Recognized in Connection with Nonvested shares Share-Based Payment Arrangement, Cost by Plan [Table Text Block] Net premiums written Net premiums written Premiums Written, Net Award Date [Axis] Award Date [Axis] Due after 5 but within 10 years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Amortized Cost Percent of defaults cured Risk In Force, Percent Of Defaults Cured Risk In Force, Percent Of Defaults Cured Schedule of Net Deferred Tax (Liability) Asset and Components Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Related Party [Axis] Related Party [Axis] Before Tax AOCI Attributable To Parent, Before Tax [Roll 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Net of Tax AOCI Attributable to Parent, Net of Tax [Roll Forward] Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Current Fiscal Year End Date Current Fiscal Year End Date All other corporate bonds Other Corporate Bonds [Member] Second Vesting Date Share-Based Payment Arrangement, Tranche Two [Member] Stock-based compensation expense APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Concentration Risk Type [Axis] Concentration Risk Type [Axis] Schedule of Accounts Receivable Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Net reserve for losses and LAE at beginning of year Net reserve for losses and LAE at end of year Reserve for losses and LAE, net of reinsurance Liability for Unpaid Claims and Claims Adjustment Expense, Net Amortization period Amortization Period Excess of Loss Portfolio Amortization Period Excess of Loss Portfolio Utilities Utilities Sector [Member] Utilities Sector [Member] Non-U.S. government securities Foreign government and agency securities Debt Security, Government, Non-US [Member] Net change in short-term investments Payments for (Proceeds from) Short-Term Investments Reinsurance Reinsurance [Text Block] Income Tax Authority [Domain] Income Tax Authority [Domain] Prepaid federal income tax Mortgage Guaranty Insurer United States Mortgage Guaranty Tax and Loss Bonds Represents, for a mortgage guaranty insurer, the amount of investment in United States Mortgage Guaranty Tax and Loss Bonds issued by the Treasury Department for eligibility for certain tax deductions under enacted tax laws. Financial Assets: Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Deferred Policy Acquisition Costs Deferred Policy Acquisition Costs Disclosures [Abstract] (Benefit) provision for losses and LAE Net incurred losses and LAE during the current year Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims Credit Facility [Axis] Credit Facility [Axis] Unassigned surplus Dividend Payments Restrictions Schedule, Statutory Capital and Surplus Equity [Abstract] Vested (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period Shares authorized (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized Reserve for Losses and Loss Adjustment Expenses Liability for Future Policy Benefits and Unpaid Claims Disclosure [Text Block] Quota share reinsurance Quota Share Reinsurance Transaction [Member] Represents an agreement between an insurer and a reinsurer whereby the reinsurer pays an agreed-upon percentage of all losses the insurer sustains. Reinsurance Disclosures [Abstract] Reinsurance Disclosures [Abstract] Relative Total Shareholder Return [Domain] Relative Total Shareholder Return [Domain] Relative Total Shareholder Return 11% Compounded Annual Growth Rate, Three Year Book Value Achieved, 11 Percent [Member] Represents information pertaining to 11% compounded annual book value per share growth achieved. Consolidated Entities [Domain] Consolidated Entities [Domain] Shares tendered by employees to pay employee withholding taxes (in shares) Share-Based Payment Arrangement, Shares Withheld for Tax Withholding Obligation Premiums Receivable Premiums Receivable [Member] Reinsurance Policy, Type [Axis] Reinsurance Contract [Axis] Share Repurchase Plan 2022 Share Repurchase Plan 2022 [Member] Share Repurchase Plan 2022 Schedule of Reconciliation of Difference between Income Tax Expense and Expected Tax Provision at Weighted Average Tax Rate Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Net (decrease) increase in cash Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Year 1 Short-Duration Insurance Contracts, Historical Claims Duration, Year One Fair value of investments deposited with insurance regulatory authorities to meet statutory requirements Debt Securities, Available-for-Sale, Restricted Fixed assets Deferred Tax Assets, Property, Plant and Equipment Entity Central Index Key Entity Central Index Key Short-duration Insurance Contracts, Accident Year [Axis] Short-Duration Insurance Contracts, Accident Year [Axis] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] QSR-2022 QSR 2022 [Member] QSR 2022 50th percentile "Target" Share-based Payment Arrangement, 50th Percentile [Member] Share-based Payment Arrangement, 50th Percentile Entity [Domain] Entity [Domain] City Area Code City Area Code Assets Assets [Abstract] Statutory Accounting Statutory Accounting Disclosure [Text Block] Represents the entire disclosure pertaining to the statutory accounting. U.S. agency mortgage-backed securities Collateralized Mortgage-Backed Securities [Member] Earnings per Share Earnings Per Share, Policy [Policy Text Block] 8% Compounded Annual Growth Rate, Three Year Book Value Achieved, 8 Percent [Member] Compounded Annual Growth Rate, Three Year Book Value Achieved, 8 Percent Stock-based compensation expense Share-Based Payment Arrangement, Noncash Expense Purchase of other invested assets Investments in subsidiaries Payments to Acquire Equity Method Investments Income (loss) from other invested assets (Income) loss from other invested assets Income from other invested assets Income (Loss) from Equity Method Investments Purchase of property and equipment Payments to Acquire Property, Plant, and Equipment General obligation bonds General Obligation Municipal Bonds [Member] A bond secured by a pledge of the issuer's taxing powers (limited or unlimited). More commonly the general obligation bonds of local governments are paid from ad valorem property taxes and other general revenues. Considered the most secure of all municipal debt. Schedule of Reconciliation of Net Income and Weighted Average Common Shares Outstanding used in Computations of Basic and Diluted Earnings per Common Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Amounts outstanding Notes Receivable, Related Parties Realized gross losses Debt Securities, Available-for-Sale, Realized Loss Operating lease liabilities arising from obtaining right-of-use assets Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Unearned premium reserve Unearned Premiums Effective Income Tax Rate Reconciliation, Amount Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract] Statutory Accounting Practices, Statutory Amount Available for Dividend Payments [Abstract] Statutory Accounting Practices, Statutory Amount Available for Dividend Payments [Abstract] Due after 1 but within 5 years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost Changes in Stockholders' Equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Total lease payments to be paid Lessee, Operating Lease, Liability, to be Paid Statutory net income Statutory Accounting Practices, Statutory Net Income Amount Maximum Exposure to Loss, Off - Balance Sheet Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount Off The Balance Sheet Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount Off The Balance Sheet Entity Address, Postal Zip Code Entity Address, Postal Zip Code Reserve rate Risk In Force, Reserve Percentage Risk In Force, Reserve Percentage Equity-Based Arrangements, Individual Contracts, Type of Deferred Compensation [Axis] Equity-Based Arrangements, Individual Contracts, Type of Deferred Compensation [Axis] 2017 Short-Duration Insurance Contracts, Accident Year 2017 [Member] Credit facility, maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Receivable [Domain] Receivable [Domain] Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Investing Activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Statistical Measurement [Domain] Statistical Measurement [Domain] Year 6 Short-Duration Insurance Contracts, Historical Claims Duration, Year Six Fair Value Debt Securities, Available-for-Sale, Realized Gain (Loss) [Abstract] Share-based Payment Arrangement [Abstract] Share-Based Payment Arrangement [Abstract] Mortgage Insurance Linked Notes Mortgage Insurance Linked Notes [Member] Mortgage Insurance Linked Notes [Member] U.S. Domestic Tax Authority [Member] Maximum number of votes per share for certain shareholders under 9.5% shareholder provision Maximum Number Of Votes Certain Shareholders Under 9.5 Percent Shareholder Provision Maximum Number Of Votes Certain Shareholders Under 9.5 Percent Shareholder Provision Treasury stock acquired Shares acquired and cancelled Treasury Stock, Value, Acquired, Cost Method Net income Net income Net income Net income Net Income (Loss) Attributable to Parent Consumer, non-cyclical Consumer, Non-cyclical Sector [Member] Consumer, Non-cyclical Sector [Member] Maximum Exposure to Loss, On - Balance Sheet Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount On The Balance Sheet Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount On The Balance Sheet Subsequent Event Type [Axis] Subsequent Event Type [Axis] Written From October 1 Through December 31, 2022 Coverage Period One [Member] Coverage Period One Other underwriting and operating expenses Other Underwriting and Operating Expenses Represents the aggregate amount of costs incurred during the period, such as those relating to general administration and policy maintenance that do not vary with, and are not primarily related to the acquisition or renewal of insurance contracts and other operating costs, that are associated with the entity's normal revenue producing operation. Scenario [Axis] Scenario [Axis] Total assets at fair value Assets, Fair Value Disclosure Reconciliation of the beginning and ending reserve balances for losses and loss adjustment expenses (LAE) Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] Incentive Program Bonus Award Fiscal Year Performance Incentive Program Bonus Award Fiscal Year Performance [Member] Represents an incentive program covering bonus awards based on performance for previous fiscal year. Vesting percentage Nonvested Common Shares Earned Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage States, municipalities and political subdivisions US States and Political Subdivisions Debt Securities [Member] Share-based payment arrangement, plan modification, incremental cost Share-Based Payment Arrangement, Plan Modification, Incremental Cost Plan Name [Axis] Plan Name [Axis] Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Quoted Prices in Active  Markets for Identical Instruments (Level 1) Fair Value, Inputs, Level 1 [Member] Essent Irish Intermediate Essent Irish Intermediate Holdings Limited [Member] Represents Essent Irish Intermediate Holdings Limited (Essent Irish Intermediate), a wholly-owned subsidiary of the reporting entity and direct parent of Essent Holdings, Inc. (Essent Holdings). 2014 Short-Duration Insurance Contracts, Accident Year 2014 [Member] Investments by Secondary Categorization [Domain] Investments by Secondary Categorization [Domain] Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Accounts receivable Accounts, Notes, Loans and Financing Receivable [Line Items] Schedule of Nonvested Common Share and Nonvested Common Share unit activity Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block] Organizational expenditures Deferred Tax Assets, Organizational Expenses Represents the amount before the allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from organizational expenditures. Related Party Transaction [Domain] Related Party Transaction [Domain] Increase in contingency reserve Statutory Accounting Practices, Increase (Decrease) in Contingency Reserve Represents the amount of increase (decrease) in contingency reserve. Government Government Investment Sector [Member] Government Investment Sector Due after 1 but within 5 years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value Accounts Receivable Accounts Receivable, after Allowance for Credit Loss [Abstract] Receivables [Abstract] Receivables [Abstract] Document Annual Report Document Annual Report Legal Entity [Axis] Legal Entity [Axis] Premiums receivable Premiums Receivable, Gross Basic Materials Basic Materials Sector [Member] Basic Materials Sector [Member] Accounts Receivable Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Geographical [Axis] Geographical [Axis] Issuance of common shares Stock Issued During Period, Value, New Issues Prior years Incurred claims and claim adjustment expenses Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years Due from affiliates Due from Affiliates Reinsurance debt issued to cover insurance term Reinsurance, Debt Issued To Cover Insurance, Term Reinsurance, Debt Issued To Cover Insurance, Term Schedule of Balances by Type of Long-Lived Assets Property, Plant and Equipment [Table Text Block] Number of Shares Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Taxes provided on un-remitted earnings Deferred Tax Liabilities, Undistributed Domestic Earnings Amount of deferred tax liability attributable to taxable temporary differences from undistributed earnings of subsidiaries and other recognized entities within the country of domicile of the entity. Return of investment from other invested assets Proceeds from Equity Method Investment, Distribution, Return of Capital Debt Obligations Debt Disclosure [Text Block] Product and Service [Domain] Product and Service [Domain] Operating Activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Entity Shell Company Entity Shell Company Schedule of Coverages and Retentions Reinsurance Retention [Table Text Block] Other accrued liabilities Increase (Decrease) in Accrued Liabilities Direct Gross Amount Direct Premiums Earned Schedule of Net Investment Income Investment Income [Table Text Block] Other Invested Assets Other Invested Assets [Member] Other Invested Assets Average Annual Percentage Payout of Incurred Losses and Allocated LAE by Year Liability for Unpaid Claims and Claims Adjustment Expense, Activity in Liability [Abstract] 2023 Lessee, Operating Lease, Liability, to be Paid, Year One Withholding tax rate on dividends paid Foreign Earnings Repatriated, Withholding Tax Rate, Percent This element represents the withholding tax percentage applied to the amount of foreign earnings repatriated from subsidiaries outside the country of domicile. Financial Instrument [Axis] Financial Instrument [Axis] Affiliated Entity Affiliated Entity [Member] Subsequent Event Subsequent Event [Member] Change in unrealized appreciation (depreciation) of investments, tax (benefit) expense Other Comprehensive Income (Loss), Available-for-Sale Securities, Tax, Portion Attributable to Parent Document Period End Date Document Period End Date Unearned single premium recognized as earned upon notice of policy cancellation due to repayment of insured loan by borrower Non-refundable, Single Premium Primary Mortgage Insurance, Unearned Premium Recognized as Earned upon Cancellation due to Loan Repayment Represents, for single premium primary mortgage insurance policies with a nonrefundable premium, the total amount of unearned premium recognized as earned premium upon notification of cancellation due to repayment of the insured loan by the borrower. Unusual or Infrequent Item, or Both [Axis] Unusual or Infrequent Item, or Both [Axis] Tax exempt interest, net of proration Income Tax Reconciliation at Weighted Average Income Tax Rate Tax Exempt Income Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the weighted average income tax rate to pretax income (loss) from continuing operations attributable to income (loss) exempt from income taxes. Schedule of Rollforward of Accumulated Other Comprehensive Income (loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Total assets Total VIE Assets Assets Certain Senior Management Certain Senior Management [Member] Represents some, but not all, of a team of individuals at the highest level of organizational management who have the day-to-day responsibilities of managing the entity. Year 4 Short-Duration Insurance Contracts, Historical Claims Duration, Year Four Tax Effect AOCI Attributable To Parent, Tax [Roll Forward] AOCI Attributable To Parent, Tax Earnings Per Share [Abstract] Earnings Per Share [Abstract] Performance-based share awards Performance Shares [Member] Credit Concentration Risk Credit Concentration Risk [Member] 2027 Lessee, Operating Lease, Liability, to be Paid, Year Five Share repurchase approved amount Stock Repurchase Program, Authorized Amount Less: Reclassification adjustment for gains included in net income, net of tax Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent Asset-backed securities Asset-Backed Securities [Member] Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Earnings per Share (EPS) Earnings Per Share [Text Block] Less: Reinsurance recoverables Plus: Reinsurance recoverables Reinsurance recoverables Reinsurance Recoverable for Unpaid Claims and Claims Adjustments Short-term investments Short-Term Investments [Member] 2022 Performance-Based Grants Two Thousand Twenty Two Performance-Based Grants [Member] Two Thousand Twenty Two Performance-Based Grants Award Type [Domain] Award Type [Domain] Computer hardware Computer Equipment [Member] Financing Activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Other comprehensive income (loss): Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent, Parenthetical Disclosure [Abstract] Residential mortgage down payment percentage for which mortgage insurance is generally required (less than) Financing Receivable Consumer Mortgage Insured Down Payment Percentage Financing Receivable Consumer Mortgage Insured Down Payment Percentage Absent Benefits Of United States Ireland Tax Treaty Absent Benefits Of United States Ireland Tax Treaty [Member] Represents information absent benefits under the U.S./Ireland tax treaty. United States Ireland Tax Treaty Benefits Availed United States Ireland Tax Treaty Benefits Availed [Member] Represents information assuming benefits under the U.S./Ireland tax treaty are availed. Insurance [Abstract] Insurance [Abstract] Costs of internal-use software Software Development [Member] Insurance Premium Revenue Recognition Insurance Premiums Revenue Recognition, Policy [Policy Text Block] 2022 Short-Duration Insurance Contract, Accident Year 2022 [Member] Entity Address, City or Town Entity Address, City or Town Equity-Based Arrangements, Individual Contracts, Type of Deferred Compensation [Domain] Equity-Based Arrangements, Individual Contracts, Type of Deferred Compensation [Domain] Condensed Statements of Comprehensive Income (Loss) Condensed Income Statements, Captions [Line Items] Expenses: Operating Expenses [Abstract] Policy acquisition costs deferred Deferred Policy Acquisition Cost, Capitalization Total of IBNR plus Expected Development on Reported Defaults Short-Duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Deferred policy acquisition costs Deferred Policy Acquisition Cost Auditor Name Auditor Name Extinguishment of Debt, Type [Domain] Extinguishment of Debt, Type [Domain] Other Income Tax Reconciliation at Weighted Average Income Tax Rate Other Adjustments Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the weighted average income tax rate to pretax income (loss) from continuing operations attributable to other adjustments. Reinsurance percentage Reinsurance, Reinsured Risk, Percentage Less: Reclassification adjustment for gains included in net income, tax effect Reclassification from AOCI, Current Period, Tax Threshold period unpaid for write-off of mortgage insurance premiums (more than) Threshold Period Past Due for Write-off of Trade Accounts Receivable 2020 Performance-Based Grants Two Thousand Twenty Performance Based Grants [Member] Two Thousand Twenty Performance Based Grants Maximum Exposure to Loss, Total Variable Interest Entity, Reporting Entity Involvement, Maximum Loss (Gain) Exposure, Amount Variable Interest Entity, Reporting Entity Involvement, Maximum Loss (Gain) Exposure, Amount Nonvested Share Units Share Units Restricted Stock Units (RSUs) [Member] Essent Re Essent Reinsurance Ltd [Member] Represents information pertaining to Essent Reinsurance Ltd. (Essent Re), a wholly-owned Bermuda-domiciled Class 3A Insurer licensed pursuant to Section 4 of the Bermuda Insurance Act 1978, which offers mortgage-related insurance and reinsurance. Other comprehensive (loss) income: Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Parent Company Parent Company [Member] Shareholder ownership threshold for voting rights Shareholder Voting Rights Ownership Percentage Threshold Shareholder Voting Rights Ownership Percentage Threshold Total revenues Revenues Investments Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] 12 months or more Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer Subtotal Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Fair Value Interest payments Interest Paid, Excluding Capitalized Interest, Operating Activities 2025 Lessee, Operating Lease, Liability, to be Paid, Year Three Contingency reserve liability Statutory Accounting Practices, Statutory Contingency Reserve Liability Represents the amount of contingency reserve liability, as of the balance sheet date, using prescribed or permitted statutory accounting practices (rather than GAAP, if different) of the state or country. Radnor Re 2018-1 Ltd. Radnor Re 2018-1 Ltd. [Member] Radnor Re 2018-1 Ltd. SEC Schedule, 12-17, Insurance Companies, Reinsurance [Abstract] SEC Schedule, 12-17, Insurance Companies, Reinsurance [Abstract] Property Insurance Product Line Property Insurance [Member] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Counterparty Name [Domain] Counterparty Name [Domain] Treasury Stock Treasury Stock [Member] Total stockholders' equity Stockholders equity, beginning of year Stockholders equity, end of year Total equity Stockholders' Equity Attributable to Parent Director Director [Member] Number of votes per share Common Stock Number of Votes Represents the number of votes for each share of common stock held. Condensed Balance Sheet Statement [Table] Condensed Balance Sheet Statement [Table] Unearned ceding commissions Deferred Tax Assets, Deferred Expense, Unearned Ceding Commissions Deferred Tax Assets, Deferred Expense, Unearned Ceding Commissions 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 Vesting [Domain] Vesting [Domain] Credit Facility [Line Items] Line of Credit Facility [Line Items] Accounts receivable Financing Receivable, after Allowance for Credit Loss Dividends Restrictions Statutory Accounting Practices [Line Items] Award Date [Domain] Award Date [Domain] 2021 Short-Duration Insurance Contract, Accident Year 2021 [Member] Deferred Policy Acquisition Costs [Line Items] Deferred Policy Acquisition Costs [Line Items] [Line Items] for Deferred Policy Acquisition Costs [Table] Proceeds from sales of investments available for sale Proceeds from Sale of Debt Securities, Available-for-Sale Retained Earnings Retained Earnings [Member] Schedule IV - Reinsurance SEC Schedule, 12-17, Insurance Companies, Reinsurance [Text Block] Condensed Statements of Cash Flows Condensed Cash Flow Statements, Captions [Line Items] Lease cost Total lease cost Lease, Cost Common Shares Common Stock [Member] Associated withholding tax liability on cumulative amount of earnings that would be subject to withholding tax, if distributed outside of the U.S. Deferred Tax Liability Not Recognized, Amount of Unrecognized Deferred Tax Liability, Undistributed Earnings of Domestic Subsidiaries Schedule of Lease Cost and Other Information Lease, Cost [Table Text Block] Number of share available for future grant (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant Tax provision at weighted average statutory rates Effective Income Tax Rate Reconciliation at Weighted Average Statutory Income Tax Rate Percentage of weighted average statutory tax rate applicable to pretax income (loss). Statement [Table] Statement [Table] Vesting Criteria [Domain] Vesting Criteria [Domain] The types of vesting specified for share-based compensation awards. 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 Radnor Re Radnor Re [Member] Radnor Re [Member] Investments in limited partnerships Deferred Tax Liabilities, Investments Furniture and fixtures Furniture and Fixtures [Member] Statistical Measurement [Axis] Statistical Measurement [Axis] Leasehold improvements Leasehold Improvements [Member] Related Party Transaction [Axis] Related Party Transaction [Axis] United States Government and government agencies and authorities US Treasury and Government [Member] Threshold coverage period for single premium primary mortgage insurance policies (more than) Primary Mortgage Guaranty Insurance Contracts, Single Premium Polices, Minimum Period Equity Components [Axis] Equity Components [Axis] Investment company, committed capital Investment Company, Committed Capital Dividends Payable [Table] Dividends Payable [Table] Short-duration Insurance Contracts, Accident Year [Domain] Short-Duration Insurance Contracts, Accident Year [Domain] Liability for Future Policy Benefits and Unpaid Claims and Claims Adjustment Expense [Abstract] Liability for Future Policy Benefits and Unpaid Claims and Claims Adjustment Expense [Abstract] Revision of Prior Period [Domain] Revision of Prior Period [Domain] Statement Statement [Line Items] Outstanding at beginning of year (in shares) Outstanding at end of period (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Effects of Reinsurance [Line Items] Effects of Reinsurance [Line Items] 2019 Short-Duration Insurance Contract, Accident Year 2019 [Member] Net premiums written: Premiums Written, Net [Abstract] Operating lease right-of-use asset Operating Lease, Right-of-Use Asset Unrealized Losses Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Accumulated Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Decrease in unearned premiums (Increase) Decrease in Unearned Premiums, Net Auditor Firm ID Auditor Firm ID Document Transition Report Document Transition Report Other comprehensive (losses) gain, before tax Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent Bermuda Foreign Tax Authority [Member] Local Phone Number Local Phone Number Assets on deposit for the benefit of the sponsor Assets On Deposit For The Benefit Of The Sponsor Assets On Deposit For The Benefit Of The Sponsor Other operating expenses Other Cost and Expense, Operating Recently Issued Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Assumed Premiums as a Percentage of Net Premiums SEC Schedule, 12-17, Insurance Companies, Reinsurance, Premium, Percentage Assumed to Net Contingently issuable awards Weighted Average Number of Shares Outstanding, Diluted, Adjustment [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Collaborative Arrangement and Arrangement Other than Collaborative [Table] Collaborative Arrangement and Arrangement Other than Collaborative [Table] Long-Lived Assets Property, Plant and Equipment, Policy [Policy Text Block] 2026 Lessee, Operating Lease, Liability, to be Paid, Year Four Additional Paid-In Capital Additional Paid-in Capital [Member] Document Fiscal Period Focus Document Fiscal Period Focus Prepaid expenses Deferred Tax Liabilities, Prepaid Expenses Special revenue bonds Special Revenue Municipal Bonds [Member] A municipal bond whose debt service is payable solely from the revenues derived from operating the facilities acquired or constructed with the proceeds of the bonds. Diluted (in shares) Diluted weighted average shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Diluted Capital maintenance agreement Capital Maintenance Agreement [Member] Represents an agreement between two wholly-owned insurance subsidiaries of a common parent for one subsidiary to contribute funds, under specified conditions, to maintain the other subsidiary's risk to capital ratio at or below a level, as specified in the agreement, in return for a surplus note. RIF ceded Risk In Force, Ceded Risk In Force, Ceded Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Equity in undistributed net income of subsidiaries Equity in net income of subsidiaries Income (Loss) from Subsidiaries, Net of Tax Components of income tax expense Components of Income Tax Expense (Benefit), Continuing Operations [Abstract] Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-Sale [Line Items] Schedule of Investments Available for Sale Schedule of Available-for-Sale Securities Reconciliation [Table Text Block] Quarterly cash dividends paid (in dollars per share) Common Stock, Dividends, Per Share, Cash Paid Year 3 Short-Duration Insurance Contracts, Historical Claims Duration, Year Three Premium Deficiency Reserve Insurance Loss Reserves [Abstract] Prepaid federal income tax Net purchases of T&L Bonds Increase (Decrease) in Mortgage Guaranty Insurer United States Mortgage Guaranty Tax and Loss Bonds Represents, for a mortgage guaranty insurer, the increase (decrease) during the reporting period in the amount of investment in United States Mortgage Guaranty Tax and Loss Bonds issued by the Treasury Department for eligibility for certain tax deductions under enacted tax laws. ICFR Auditor Attestation Flag ICFR Auditor Attestation Flag Unamortized deferred costs Debt Issuance Costs, Gross 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 14% Compounded Annual Growth Rate, Three Year Book Value Achieved, 14 Percent [Member] Represents information pertaining to 14% compounded annual book value per share growth achieved. Realized investment (losses) gains, net Realized investment losses (gains), net Realized investment losses, net Loss on the sale of investments, net Realized Investment Gains (Losses) Schedule of Assets and Liabilities Measured at Fair Vale on a Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Short-term lease cost Short-Term Lease, Cost Communications Communications Sector [Member] Communications Sector [Member] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Net income Net income Net Income (Loss) Available to Common Stockholders, Basic Common shares, issued (in shares) Common shares, issued (in shares) Common Stock, Shares, Issued Nonvested shares, share units or DEU Nonvested Shares, Share Units Or DEU [Member] Nonvested Shares, Share Units Or DEU [Member] Other invested assets Equity Method Investments Reinsurance for mortgage insurance coverage threshold (in excess of) Reinsurance Retention Policy, Reinsured Risk, Percentage Threshold Threshold percentage of risk reinsured on insurance products per entity policy. 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] Reserve for losses and LAE, for prior years Liability for Unpaid Claims and Claims Adjustment Expense Prior Years Liability, as of the balance sheet date, for amounts representing estimated cost of settling unpaid claims for prior years under the terms of the underlying insurance policies, less estimated reinsurance recoveries on such claims. This includes an estimate for claims which have been incurred but not reported. Claim adjustment expenses represent the costs estimated to be incurred in the settlement of unpaid claims. Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities US Internal Revenue Service (IRS) [Member] Radnor Re 2020-1 Ltd. Radnor Re 2020-1 Ltd. [Member] Radnor Re 2020-1 Ltd. Credit facility borrowings Proceeds from Long-Term Lines of Credit Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent 2020 Short-Duration Insurance Contract, Accident Year 2020 [Member] Deferred policy acquisition costs Deferred Tax Liabilities, Deferred Expense, Deferred Policy Acquisition Cost Schedule I - Summary of Investments-Other Than Investments in Related Parties SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Text Block] 9% Compounded Annual Growth Rate Three Year Book Value Achieved 9 Percent [Member] Compounded Annual Growth Rate Three Year Book Value Achieved 9 Percent Entity Current Reporting Status Entity Current Reporting Status Condensed Financial Information Disclosure [Abstract] Condensed Financial Information Disclosure [Abstract] Unrealized (gain) loss on investments Deferred Tax Liabilities, Unrealized Gains on Trading Securities Reduction of reserves on hurricane-related defaults Liability for Unpaid Claims and Claims Adjustment Expense, Period Increase (Decrease) Existing term loans Existing Term Loans [Member] Existing Term Loans Insurance Ratios [Abstract] Insurance Ratios [Abstract] ≥75th percentile Share-based Payment Arrangement, Greater than or Equal to 75th Percentile [Member] Share-based Payment Arrangement, Greater than or Equal to 75th Percentile Remaining First Layer Retention Reinsurance, Amount Retained, Per Life Components of the net deferred tax asset Components of Deferred Tax Assets and Liabilities [Abstract] Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Liabilities Liabilities [Abstract] Property and equipment (at cost, less accumulated depreciation of $67,352 in 2022 and $64,340 in 2021) Property, Plant and Equipment, Net Premium Deficiency Reserve Anticipated Investment Income as Component of Premium Deficiency on Short-Duration Contracts, Policy [Policy Text Block] Office equipment Office Equipment [Member] Cumulative amount of earnings that would be subject to withholding tax, if distributed outside of the U.S. Undistributed Earnings of Domestic Subsidiaries Title of Individual [Domain] Title of Individual [Domain] Dividends and dividend equivalents declared Dividends Released contingency reserves Statutory Accounting Practices, Contingency Reserves Released Statutory Accounting Practices, Contingency Reserves Released Tax provision at weighted average statutory rates Income Tax Reconciliation Income Tax Expense Benefit at Weighted Average Income Tax Rate The amount of income tax expense or benefit for the period computed by applying the weighted average income tax rate to pretax income from continuing operations. Forfeited (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period Share price (in dollars per share) Sale of Stock, Price Per Share 2018 Short-Duration Insurance Contracts, Accident Year 2018 [Member] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Accumulated other comprehensive (loss) income Accumulated Other Comprehensive Income (Loss), Net of Tax Time and Performance- Based Share Awards Vesting Based On Service And Performance [Member] Represents a share based compensation award with vesting based on a combination of length of service and achievement of performance conditions. Entity Small Business Entity Small Business Quarterly cash dividends declared (in dollars per share) Common Stock, Dividends, Per Share, Declared Revenues: Revenues [Abstract] Performance Based Grants 2015, 2016, 2017 & 2018 Two Thousand Fifteen, Sixteen, Seventeen and Eighteen Performance Based Grants [Member] Two Thousand Fifteen, Sixteen, Seventeen and Eighteen Performance Based Grants Reserve for Losses and Loss Adjustment Expenses Unpaid Policy Claims and Claims Adjustment Expense, Policy [Policy Text Block] Residential and commercial mortgage securities Residential And Commercial Mortgage Securities [Member] Residential And Commercial Mortgage Securities [Member] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Net premiums earned Premiums Earned, Net Fair value of the required investments on deposit in trusts Assets Held-in-trust All outstanding liabilities before 2013, net of reinsurance Short-Duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented 10% Compounded Annual Growth Rate, Three Year Book Value Achieved, 10 Percent [Member] Compounded Annual Growth Rate, Three Year Book Value Achieved, 10 Percent Property, Plant and Equipment, Type [Domain] Long-Lived Tangible Asset [Domain] Radnor Re 2019-1 Ltd. Radnor Re 2019-1 Ltd. [Member] Radnor Re 2019-1 Ltd. [Member] Other assets, fair value Other Assets, Fair Value Disclosure Consolidated Entities [Axis] Consolidated Entities [Axis] Other information: Lessee, Operating Lease, Description [Abstract] Distribution of income from other invested assets Proceeds from Equity Method Investment, Distribution Other accrued liabilities Other Accrued Liabilities Payment of issuance costs for credit facility Payments of Debt Issuance Costs Operating lease liabilities Present value of lease liabilities Operating Lease, Liability U.S. agency securities US Government Agencies Debt Securities [Member] Impairment loss Debt Securities, Held-to-Maturity, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff Stock-Based Compensation Share-Based Payment Arrangement [Policy Text Block] Investments, Debt and Equity Securities [Abstract] Investments, Debt and Equity Securities [Abstract] Internal Credit Assessment [Axis] Internal Credit Assessment [Axis] Performance period Share Based Compensation Arrangement by Share Based Payment Award Performance Period Represents the period over which a performance condition to the award is measured, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Internal Investment Grade Internal Investment Grade [Member] Amortized Cost Amortized Cost Amortized cost Debt Securities, Available-for-Sale, Amortized Cost Unrealized holding (losses) gains arising during the year, before tax OCI, before Reclassifications, before Tax, Attributable to Parent Schedule of Portion of Nonvested Common Shares Earned based upon Achievement of Compounded Annual Book Value per share Growth Schedule of Shares Earned Unvested Performance Shares [Table Text Block] Tabular disclosure of shares earned for unvested performance shares. Net deferred tax asset Deferred Tax Assets, Net [Abstract] SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Abstract] SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Abstract] Other assets Increase (Decrease) in Other Operating Assets Schedule of Amortized Cost and Fair Value of Investments Available for Sale by Contractual Maturity Investments Classified by Contractual Maturity Date [Table Text Block] Auditor Location Auditor Location Income Tax Authority, Name [Axis] Income Tax Authority, Name [Axis] Entity Filer Category Entity Filer Category U.S. UNITED STATES State taxes, net of federal benefit Effective Income Tax Rate Reconciliation, State And Local Taxes, Net Of Federal Benefit, Percent Effective Income Tax Rate Reconciliation, State And Local Taxes, Net Of Federal Benefit, Percent Compensation expense Share-Based Payment Arrangement, Expense Noncash Transactions Noncash Investing and Financing Items [Abstract] Commitments and contingencies (see Note 8) Commitments and contingencies Commitments and Contingencies Security Exchange Name Security Exchange Name Amortization of deferred policy acquisition costs Deferred Policy Acquisition Costs, Amortization Expense Accrued investment income Increase (Decrease) in Accrued Investment Income Receivable Radnor Re 2019-2 Ltd. Radnor Re 2019-2 [Member] Radnor Re 2019-2 [Member] Cover [Abstract] Cover [Abstract] Entity Voluntary Filers Entity Voluntary Filers Other assets Other Assets Add provision for losses and LAE, net of reinsurance, occurring in: Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract] Year 2 Short-Duration Insurance Contracts, Historical Claims Duration, Year Two Investments [Domain] Investments [Domain] Forecast Forecast [Member] AOCI tax effect, beginning of year AOCI tax effect, end of year AOCI Tax, Attributable to Parent Documents Incorporated by Reference Documents Incorporated by Reference [Text Block] Total liabilities and stockholders' equity Liabilities and Equity Current year Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year Relative Total Shareholder Return [Axis] Relative Total Shareholder Return [Axis] Relative Total Shareholder Return Remaining authorized repurchase amount Stock Repurchase Program, Remaining Authorized Repurchase Amount Cash Cash SEC Schedule, 12-17, Insurance Companies, Reinsurance [Table] SEC Schedule, 12-17, Insurance Companies, Reinsurance [Table] Deferred tax assets Deferred Tax Assets, Gross Other invested assets Equity Method Investments [Member] QSR-2019 QSR 2019 [Member] QSR 2019 Certificate of participation bonds Certification Of Participation Bonds [Member] Represents a type of financing where an investor purchases a share of the lease revenues of a program rather than the bond being secured by those revenues. Realized gross gains Debt Securities, Available-for-Sale, Realized Gain Less: Future interest expense Lessee, Operating Lease, Liability, Undiscounted Excess Amount EPS calculation Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items] Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items] Vesting [Axis] Vesting [Axis] Diluted (in dollars per share) Diluted earnings per share (in dollars per share) Earnings Per Share, Diluted 7% Compounded Annual Growth Rate Three Year Book Value Achieved 7 Percent [Member] Compounded Annual Growth Rate Three Year Book Value Achieved 7 Percent SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items] SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items] Vesting period Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period 2019 Performance-Based Grants Two Thousand Nineteen Performance Based Grants [Member] Two Thousand Nineteen Performance Based Grants [Member] 2024 Lessee, Operating Lease, Liability, to be Paid, Year Two Fair Value Fair Value Debt Securities, Trading and Available-for-Sale Line of credit facility, accordion feature Line of Credit Facility, Accordion Feature Line of Credit Facility, Accordion Feature Unrecognized tax benefits Unrecognized Tax Benefits Bermuda Office of the Tax Commissioner, Bermuda [Member] DEU Dividend Equivalent Unit [Member] Dividend Equivalent Unit [Member] Share Repurchase Program [Axis] Share Repurchase Program [Axis] Corporate debt securities Corporate Debt Securities [Member] Credit facility, commitment fee rate Line of Credit Facility, Commitment Fee Percentage Investment expenses Investment Income, Investment Expense Schedule of Lease Liability Maturity Lessee, Operating Lease, Liability, Maturity [Table Text Block] Entity Address, Address Line Two Entity Address, Address Line Two Entity Address, Address Line One Entity Address, Address Line One Total losses and expenses Benefits, Losses and Expenses Radnor Re 2022-1 Ltd. Radnor Re 2022-1 Ltd. [Member] Radnor Re 2022-1 Ltd. SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Table] SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Table] Product and Service [Axis] Product and Service [Axis] Ceded Ceded Premiums Written Interest expense Interest Expense Investments, Other Invested Assets Equity Method Investments [Policy Text Block] Investments Fair Value Debt Securities, Available-for-Sale [Abstract] Technology Technology Debt Sector [Member] Technology Debt Sector [Member] Gross investment income Gross Investment Income, Operating 19% Compounded Annual Growth Rate, Three Year Book Value Achieved, 19 Percent [Member] Compounded Annual Book Value Per Share Growth Achieved 19 Percent [Member] Energy Energy Sector [Member] Energy Sector Income Tax Authority, Name [Domain] Income Tax Authority, Name [Domain] Deferred tax liabilities Deferred Tax Liabilities, Gross Other comprehensive income (loss): Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent [Abstract] Panel of Reinsurers Panel Of Reinsurers [Member] Panel Of Reinsurers [Member] 12% Compounded Annual Growth Rate, Three Year Book Value Achieved, 12 Percent [Member] Represents information pertaining to 12% compounded annual book value per share growth achieved. Consumer, cyclical Consumer, Cyclical Sector [Member] Consumer, Cyclical Sector [Member] Year 8 Short-Duration Insurance Contracts, Historical Claims Duration, Year Eight Subtotal Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Amortized Cost Equipment, computer hardware and purchased software Equipment, Computer Hardware And Purchased Software [Member] Equipment, Computer Hardware And Purchased Software [Member] Accrued investment income Accrued Investment Income Receivable Measurement Frequency [Axis] Measurement Frequency [Axis] 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] Financial Financial Sector [Member] Financial Sector [Member] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Amount available for dividend distribution Amount Available for Dividend Distribution without Affecting Capital Adequacy Requirements Direct Direct Premiums Written Proceeds from maturities and paydowns of investments available for sale Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-Sale Fair Value SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Fair Value Radnor Re 2021-1 Ltd. Radnor Re 2021-1 Ltd. [Member] Radnor Re 2021-1 Ltd. Cancellation of treasury stock Treasury Stock, Retired, Cost Method, Amount Amount paid for remedies (less than) Loss Contingency Accrual, Payments Impairments on available-for-sale investment securities Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Impairment Losses