Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Trading Arrangement: Trading Arrangement [Axis] Maximum Maximum [Member] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Statistical Measurement [Domain] Statistical Measurement [Domain] Ceded Ceded Premiums Earned Title of each class Title of 12(b) Security Subsequent Event Subsequent Event [Member] Carrying Value Reported Value Measurement [Member] Schedule of Available-for-sale Securities [Table] Debt Securities, Available-for-Sale [Table] Net income - diluted Net Income (Loss) Available to Common Stockholders, Diluted Document Fiscal Year Focus Document Fiscal Year Focus Adjustment to Compensation, Amount Adjustment to Compensation Amount Financial Instrument [Axis] Financial Instrument [Axis] Cash equivalents Other Assets, Fair Value Disclosure Segment Reporting [Abstract] 2020 QSR and 2021 QSR Quota Share Reinsurance Transaction, 2020 and 2021 - 2021 NIW [Member] Quota Share Reinsurance Transaction, 2020 and 2021 - 2021 NIW Fair value measurements for items measured at fair value Fair Value, Assets Measured on Recurring Basis [Table Text Block] Common stock Common Stock, Value, Issued Payment of withholding taxes related to share-based compensation net share settlement Payment, Tax Withholding, Share-Based Payment Arrangement Depreciation and amortization Depreciation, Amortization and Accretion, Net Unearned premiums Increase (Decrease) in Unearned Premiums Benefit Plans Retirement Benefits [Text Block] Remaining First Layer Retention Reinsurance, Amount Retained, Per Policy Ceding commission on quota share reinsurance Reinsurance Ceding Commission Earned Reinsurance Ceding Commission Earned Restatement Determination Date Restatement Determination Date Proceeds from sales of investments Proceeds from Sale, Maturity and Collection of Investments Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Percentage of statutory policyholders surplus used to determine maximum allowable dividends (as a percent) Percentage of statutory policyholders surplus used to determine maximum allowable dividends The percentage of statutory policyholders' surplus, as defined, as of the preceding calendar year end which is used in the determination of the maximum allowable dividends that the insurance subsidiaries may pay in any twelve-month period without regulatory approval by the Office of the Commissioner of Insurance of the State of Wisconsin. Measurement Frequency [Axis] Measurement Frequency [Axis] U.S. Treasury securities and obligations of U.S. government corporations and agencies US Treasury and Government [Member] Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding One Percentage Point Increase/Decrease In Average Claim Rate Reserve Factor One Percentage Point Increase/Decrease In Average Claim Rate Reserve Factor [Member] One Percentage Point Increase/Decrease In Average Claim Rate Reserve Factor Losses incurred: Policyholder Benefits and Claims Incurred, Net [Abstract] Investment income, net of expenses Net Investment Income Total interest payments Interest Paid, Including Capitalized Interest, Operating and Investing Activities Gross Unrealized Losses Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax ABS Asset-Backed Securities [Member] 2020 Traditional XOL 2020 Traditional XOL [Member] 2020 Traditional XOL Amortized cost, gross unrealized gains and losses and fair value of fixed income securities Debt Securities, Available-for-Sale [Table Text Block] Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Table] Liability for Unpaid Claim and Claim Adjustment Expense, Change [Table] Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Premium refund liability, expected claim payments Premium refund liability, expected claim payments The carrying amount for the estimate of premiums to be refunded on expected claim payments. Other invested assets Other Invested Assets, Fair Value Disclosure Fair value portion of other invested assets. Entity Address, State or Province Entity Address, State or Province Total - Unrealized Losses Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss PEO Total Compensation Amount PEO Total Compensation Amount Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Reclassification from Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Member] Home Re 2023-1, Ltd. Home Re 2023-1 [Member] Home Re 2023-1 Weighted average common shares outstanding - basic (in shares) Weighted average common shares outstanding - basic (in shares) Weighted Average Number of Shares Outstanding, Basic Retirement Benefits [Abstract] Retirement Benefits [Abstract] Schedule of stock-based compensation, activity Share-Based Payment Arrangement, Activity [Table Text Block] Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount 2024 QSR Quota Share Reinsurance Transaction, 2024 - 2024 NIW [Member] Quota Share Reinsurance Transaction, 2024 - 2024 NIW Direct Direct Premiums Earned Number of reportable segments Number of Reportable Segments Deferred insurance policy acquisition costs Increase (Decrease) in Deferred Policy Acquisition Costs Investments [Abstract] Investments [Abstract] Due after five years through ten years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 Total debt securities with single maturity date, amortized cost Available For Sale Securities, Debt Maturities, With Single Maturity Date, Amortized Cost This item represents the total debt securities, categorized neither as held-to-maturity nor trading securities, which have a single maturity date, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments, as defined), and fair value hedge accounting adjustments, if any. Net gains (losses) on investments and other financial instruments Net (gains) losses on investments and other financial instruments Net Gains (Losses) on Investments and Other Financial Instruments Amount of realized and unrealized gain (loss) on investments and other financial instruments, including the changes in fair value of embedded derivatives related to Home Re Transactions. Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Entity Address, City or Town Entity Address, City or Town Granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period Amortized cost Debt Securities, Available-for-Sale, Amortized Cost, Fiscal Year Maturity [Abstract] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] 2025 QSR Quota Share Reinsurance Transaction, 2025 - 2025 NIW [Member] Quota Share Reinsurance Transaction, 2025 - 2025 NIW Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Losses and LAE incurred in respect of delinquency notices received in: Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract] Net income - basic Net Income (Loss) Available to Common Stockholders, Basic Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Insurance Loss Reserves [Abstract] Insurance Loss Reserves [Abstract] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Prospective Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Disaggregation of Significant Segment Expenses Segment Reporting [Table Text Block] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] Banking Regulation, Regulatory Capital Requirement, Compliance [Table] Other comprehensive income (loss), net of tax Other comprehensive income (loss), net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Statutory Capital [Abstract] Statutory Capital [Abstract] Long-term debt Long-Term Debt Due after one year through five years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five Document Period End Date Document Period End Date Change in certain assets and liabilities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Other underwriting and operating expenses, net Total other underwriting and operating expenses net Other Underwriting Expense Net cash provided by (used in) investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Employee costs Compensation Expense, Excluding Cost of Good and Service Sold Debt instrument, face amount Debt Instrument, Face Amount Earnings Per Share, Basic Earnings Per Share, Basic [Abstract] Shareholders' Equity Equity [Text Block] Security Exchange Name Security Exchange Name Gross realized losses on sales of fixed income securities Debt Securities, Available-for-Sale, Realized Loss Statutory Information Insurance Disclosure [Text Block] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Due after ten years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 10 Income tax benefit (expense) Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent Eligible New Insurance Written In 2027 Eligible New Insurance Written In 2027 [Member] Eligible New Insurance Written In 2027 Accumulated other comprehensive income (loss), net of tax Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Shell Company Entity Shell Company 12 Months or Greater - Fair Value Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Earnings per Share Earnings Per Share [Text Block] Name Outstanding Recovery, Individual Name Reinsurance, quote share reinsurance agreement, annual loss ratio cap (as a percent) Reinsurance, Quota Share Reinsurance Agreement, Terms, Annual Loss Ratio Cap Reinsurance, Quota Share Reinsurance Agreement, Terms, Annual Loss Ratio Cap Earnings per share: Earnings Per Share [Abstract] Earnings Per Share [Abstract] Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Document Fiscal Period Focus Document Fiscal Period Focus Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Total Liabilities Liabilities Trading Symbol Trading Symbol Additions to property and equipment Payments to Acquire Property, Plant, and Equipment Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Quota Share Reinsurance Transactions Quota Share Reinsurance Transactions [Member] Quota Share Reinsurance Transactions Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Schedule of coverages and retention Reinsurance Retention [Table Text Block] Loss Reserve [Roll Forward] Movement in Liability for Future Policy Benefits [Roll Forward] Company Selected Measure Name Company Selected Measure Name Less: Amounts reclassified from AOCI Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent Schedule of Investments [Table] Schedule of Investments [Table] Timothy J. Mattke [Member] Timothy J. Mattke Excess of Loss Reinsurance Transactions, Home Re Transactions Excess of Loss Reinsurance Transactions, Home Re Transactions [Member] Excess of Loss Reinsurance Transactions, Home Re Transactions Earnings Per Share, Diluted Earnings Per Share, Diluted [Abstract] Reinsurance, quota share reinsurance agreement, terms, quota share, percent Quota Share % Reinsurance, Quota Share Reinsurance Agreement, Terms, Quota Share, Percent Reinsurance, Quota Share Reinsurance Agreement, Terms, Quota Share, Percent Net benefit plan assets and (obligations) recognized in shareholders' equity Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Cost Equity Securities, FV-NI, Cost Asset Class [Domain] Asset Class [Domain] Loss reserves Reserve at beginning of period Reserve at end of period Liability for Claims and Claims Adjustment Expense Compensation Amount Outstanding Recovery Compensation Amount Home Re 2021-2, Ltd. Home Re 2021-2 [Member] Home Re 2021-2 Individual: Individual [Axis] Weighted average common shares outstanding - diluted (in shares) Weighted average common shares outstanding - diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Quarterly cash dividend paid (per share) Common Stock, Dividends, Per Share, Cash Paid Entity Emerging Growth Company Entity Emerging Growth Company Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items] Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Commercial paper Commercial Paper [Member] Percent of shares that may vest (as a percent) Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] 2026 QSR Quota Share Reinsurance Transaction, 2026 - 2026 NIW [Member] Quota Share Reinsurance Transaction, 2026 - 2026 NIW Accrued investment income Accrued Investment Income Receivable 2022 QSR and 2023 QSR Quota Share Reinsurance Transaction, 2022 and 2023 - 2023 NIW [Member] Quota Share Reinsurance Transaction, 2022 and 2023 - 2023 NIW Total debt securities without single maturity date, amortized cost Debt Securities, Available-for-Sale, Maturity, without Single Maturity Date, Amortized Cost Other, net Increase (Decrease) in Other Operating Assets and Liabilities, Net Award Timing Predetermined Award Timing Predetermined [Flag] Other comprehensive income Comprehensive Income (Loss) [Table Text Block] Reinsurance recoverable on paid losses Reinsurance Recoverable for Paid Claims and Claims Adjustments Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-Sale [Line Items] Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Equity compensation APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Losses incurred, net Losses incurred, net Policyholder Benefits and Claims Incurred, Net Quoted Prices in Active Markets for Identical Assets (Level 1) Fair Value, Inputs, Level 1 [Member] Net reserve at beginning of period Net reserve at end of period Liability for Unpaid Claims and Claims Adjustment Expense, Net Federal tax credits payable Transferable Federal Tax Credit Payable Transferable Federal Tax Credit Payable Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] 2021 Traditional XOL 2021 Traditional XOL [Member] 2021 Traditional XOL Non Catastrophic Event [Domain] Noncatastrophic Event [Domain] Unvested RSUs (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements Investment portfolio: Debt Securities, Available-for-Sale [Abstract] Real Estate Acquired Real Estate Acquired [Member] This category includes information about real estate acquired by the entity through claim settlement. All Executive Categories All Executive Categories [Member] Purchases of common stock Common stock repurchased and retired during period Stock Repurchased and Retired During Period, Value Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] RMBS Residential Mortgage-Backed Securities [Member] Other comprehensive income (loss), net of tax: Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] 2023 QSR Quota Share Reinsurance Transaction, 2023 - 2023 NIW [Member] Quota Share Reinsurance Transaction, 2023 - 2023 NIW Ceded Policyholder Benefits and Claims Incurred, Ceded Components of net periodic benefit cost Schedule of Net Benefit Costs [Table Text Block] Depreciation expense Depreciation Prior year development of the reserves Schedule of Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block] Losses and LAE paid in respect of delinquency notices received in: Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract] Due in one year or less Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, Year One Calculation of earnings (loss) per share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] 2023 Traditional XOL 2023 Traditional XOL [Member] 2023 Traditional XOL Debt Disclosure [Abstract] Debt Disclosure [Abstract] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Segment Reporting Segment Reporting [Text Block] Investments Investment in Debt and Equity Securities and Other Trading Assets [Text Block] Minimum Minimum [Member] Non-employee director RSUs Non-employee director RSUs [Member] Non-employee director RSUs Dividends paid Payments of Ordinary Dividends, Common Stock Expiration Date Trading Arrangement Expiration Date Net increase (decrease) in cash and cash equivalents and restricted cash and cash equivalents Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Excluding Exchange Rate Effect, Including Discontinued Operation Liabilities: Liabilities [Abstract] Home Re 2022-1, Ltd. Home Re 2022-1 [Member] Home Re 2022-1 Restricted cash and cash equivalents Restricted Cash and Cash Equivalent Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Other liabilities Other Liabilities Net periodic benefit cost (benefit) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Losses paid: Losses paid [Abstract] Common stock, shares authorized (in shares) Common Stock, Shares Authorized Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Gross realized gains on sales of fixed income securities Debt Securities, Available-for-Sale, Realized Gain Due after ten years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10 2021 QSR and 2022 QSR Quota Share Reinsurance Transaction, 2021 and 2022 - 2021 NIW [Member] Quota Share Reinsurance Agreement, 2021 [Member] Exercise Price Award Exercise Price Fair Value, Recurring Fair Value, Recurring [Member] Segment Reporting [Line Items] Segment Reporting [Line Items] Document Quarterly Report Document Quarterly Report Outside services Outside Services Expense Outside Services Expense Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Segments [Domain] Segments [Domain] Obligations of U.S. states and political subdivisions US States and Political Subdivisions Debt Securities [Member] Current income taxes Increase (Decrease) in Income Taxes Payable, Net of Income Taxes Receivable Proceeds from sales of fixed income securities Proceeds from Sale of Debt Securities, Available-for-Sale Ceding commission, percentage (as a percent) Reinsurance, Quota Share Reinsurance Agreement, Terms, Ceding Commission, Percent Reinsurance, Quota Share Reinsurance Agreement, Terms, Ceding Commission, Percent Debt Debt Disclosure [Text Block] Prior years Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Legal Maturity Amortization Period Excess of Loss Reinsurance Coverage Amortization Period Excess of Loss Reinsurance Coverage Equity Component [Domain] Equity Component [Domain] Total debt securities with single maturity date, fair value Available For Sale Securities, Debt Maturities, With Single Maturity Date, Fair Value This item represents the total fair value of debt securities, categorized neither as held-to-maturity nor trading securities, which have a single maturity date. Deferred insurance policy acquisition costs Deferred Policy Acquisition Cost PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Losses and Expenses: Benefits, Losses and Expenses [Abstract] Fair Value Debt Securities, Available-for-Sale, Fair Value, Fiscal Year Maturity [Abstract] Change in embedded derivative on Home Re Transactions(1) Embedded Derivative, Gain (Loss) on Embedded Derivative, Net Adoption Date Trading Arrangement Adoption Date Stated interest rate Debt Instrument, Interest Rate, Stated Percentage Total Shareholders’ Equity Balance, beginning of period Balance, end of period Equity, Attributable to Parent Equity securities, at fair value (cost 2026 - $16,360; 2025 - $16,286) Equity securities Equity Securities, FV-NI, Current Assets Assets [Abstract] Title Trading Arrangement, Individual Title Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Other invested assets, at cost Other Investments Direct Direct Premiums Written Fixed maturities, amortized cost Amortized Cost Amortized Cost Debt Securities, Available-for-Sale, Amortized Cost Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Adjusted statutory net income measurement period (in years) Statutory Accounting Practices, Statutory Amount Available For Dividend Payments Without Regulatory Approval, Measurement, Measurement Period Statutory Accounting Practices, Statutory Amount Available For Dividend Payments Without Regulatory Approval, Measurement, Measurement Period Optional Reduced Quota Shares %, option 2 Reinsurance, Quota Share Reinsurance Agreement, Terms, Ceding Rate, Percent, Option Two Reinsurance, Quota Share Reinsurance Agreement, Terms, Ceding Rate, Percent, Option Two Insider Trading Policies and Procedures [Line Items] Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] RSUs subject to performance conditions Performance Shares [Member] Deferred tax expense (benefit) Deferred Income Tax Expense (Benefit) Current year Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year Total losses incurred Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims $1,000 Increase/Decrease In Average Severity Reserve Factor $1,000 Increase/Decrease In Average Severity Reserve Factor [Member] $1,000 Increase/Decrease In Average Severity Reserve Factor Excess of Loss Reinsurance Transactions Excess of Loss Reinsurance Transactions [Member] Excess of Loss Reinsurance Transactions Embedded derivative related to Home Re transactions Embedded Derivative, Fair Value of Embedded Derivative, Net Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] RSUs subject only to service conditions Restricted Stock Units (RSUs) [Member] Entity Central Index Key Entity Central Index Key 2025 Traditional XOL 2025 Traditional XOL [Member] 2025 Traditional XOL Components of Net Periodic Benefit Cost [Abstract] Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] Paid-in capital Additional Paid in Capital, Common Stock All Adjustments to Compensation All Adjustments to Compensation [Member] Proceeds from maturity of fixed income securities Proceeds From Maturity of Fixed Income Securities Proceeds from the maturity of fixed income securities for the period. Equity [Abstract] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Net cash provided by (used in) operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Litigation and Contingencies Legal Matters and Contingencies [Text Block] Losses incurred related to prior year notices Prior years Prior Year Claims and Claims Adjustment Expense Income Statement [Abstract] Income Statement [Abstract] Shareholders’ equity: Equity, Attributable to Parent [Abstract] Document Transition Report Document Transition Report Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Schedule of Investments [Line Items] Schedule of Investments [Line Items] Premium taxes Insurance Premium, Tax Expense Insurance Premium, Tax Expense Deferred income taxes, net Deferred Income Tax Assets, Net Fixed income Fixed Maturities [Member] Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Effect of reinsurance transactions Effects of Reinsurance [Table Text Block] New Insurance Written In 2026 through 2030 New Insurance Written In 2026 through 2030 [Member] New Insurance Written In 2026 through 2030 Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] Optional Reduced Quota Shares %, option 1 Reinsurance, Quota Share Reinsurance Agreement, Terms, Ceding Rate, Percent, Option One Reinsurance, Quota Share Reinsurance Agreement, Terms, Ceding Rate, Percent, Option One City Area Code City Area Code Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] All Individuals All Individuals [Member] Schedule of quota share reinsurance transactions Schedule Of Quota Share Reinsurance Agreements [Table Text Block] Schedule Of Quota Share Reinsurance Agreements Name Forgone Recovery, Individual Name Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Increase (decrease) in estimated claim rate on primary defaults Increase Decrease in Expected Claim Rate [Member] The increase (decrease) in the expected claim rate on primary and/or pool defaults that occurred in prior periods. Statement [Line Items] Statement [Line Items] Fixed income securities: Fixed Income Securities [Abstract] Fixed Income Securities Total Assets Total VIE Assets Assets Entity [Domain] Entity [Domain] Credit Union QSR Credit Union Quota Share Reinsurance Transaction [Member] Credit Union Quota Share Reinsurance Transaction New Accounting Pronouncements and Changes in Accounting Principles [Abstract] Accounting Standards Update and Change in Accounting Principle [Abstract] Initial excess of loss reinsurance coverage Initial Excess of Loss Reinsurance Coverage Reinsurance Retention Policy, Excess Of Loss Reinsurance Coverages Reinsurance Retention Policy, Excess of Loss Reinsurance Coverages Prior service cost (credit) Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Benefit plan adjustments Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent Gross Unrealized Gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax Share-Based Compensation Share-Based Payment Arrangement [Text Block] Total debt securities without single maturity date, fair value Debt Securities, Available-for-Sale, Maturity, without Single Maturity Date, Fair Value Other comprehensive income (loss) before reclassifications OCI, before Reclassifications, Net of Tax, Attributable to Parent PEO PEO [Member] Shares repurchased and retired in period (in shares) Stock Repurchased and Retired During Period, Shares Measurement Basis [Axis] Measurement Basis [Axis] Reinsurer Name [Domain] Reinsurer, Name [Domain] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Number of securities in unrealized loss position (in securities) Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions Total investment portfolio Investments Weighted Average Fair Value per Share (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 Accrued investment income Increase (Decrease) in Accrued Investment Income Receivable Due in one year or less Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, Year One Adjusted statutory net income dividend payment measurement period (in years) Statutory Accounting Practices, Statutory Amount Available for Dividend Payments without Regulatory Approval, Measurement, Dividend Payment Period Statutory Accounting Practices, Statutory Amount Available for Dividend Payments without Regulatory Approval, Measurement, Dividend Payment Period Subsequent Event Type [Domain] Subsequent Event Type [Domain] Assumed Policyholder Benefits And Claims Incurred, Assumed, Net Of Adjustments Policyholder Benefits And Claims Incurred, Assumed, Net Of Adjustments Retained Earnings Retained Earnings [Member] Net unrealized gains and (losses) on available-for-sale securities AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member] Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Assets held in trust for the benefit of contractual counterparties Asset, Held-in-Trust Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Award Timing Disclosures [Line Items] Carrying value and fair value of financial assets and liabilities Fair Value, by Balance Sheet Grouping [Table Text Block] Corporate debt securities Corporate Debt Securities [Member] Diluted (in dollars per share) Diluted earnings per share (in dollars per share) Earnings Per Share, Diluted Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Entity Current Reporting Status Entity Current Reporting Status Net cash provided by (used in) financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Total Shareholder Return Amount Total Shareholder Return Amount Stockholders' Equity Note [Abstract] Stockholders' Equity Note [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Reinsurer, Name [Axis] Reinsurer, Name [Axis] Change in estimates related to severity on primary defaults, pool reserves, LAE reserves, reinsurance, and other Increase Decrease Related To Severity, Pool Reserves, LAE Reserves, Reinsurance and Other [Member] Increase Decrease Related To Severity, Pool Reserves, LAE Reserves, Reinsurance and Other Net premiums written Premiums Written, Net New Insurance Written In 2020 through 2025 New Insurance Written In 2020 through 2025 [Member] New Insurance Written In 2020 through 2025 Share-based Payment Arrangement [Abstract] Share-Based Payment Arrangement [Abstract] Home office and equipment, net Property, Plant, and Equipment, after Accumulated Depreciation, Depletion, and Amortization Mortgage Insurance Segment Mortgage Insurance Segment [Member] Mortgage Insurance Segment Interest cost Defined Benefit Plan, Interest Cost Financial Instruments [Domain] Financial Instruments [Domain] 2022 Traditional XOL 2022 Traditional XOL [Member] 2022 Traditional XOL Other revenue Other Income Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Underlying Securities Award Underlying Securities Amount Fair Value Estimate of Fair Value Measurement [Member] Sales of real estate assets acquired Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales Assumed Assumed Premiums Written Percent of reinsurance coverage threshold, option to terminate (as a percent) Reinsurance Agreement, Optional Call Feature, Right To Terminate, Percent Of Reinsurance Coverage Threshold Reinsurance Agreement, Optional Call Feature, Right To Terminate, Percent Of Reinsurance Coverage Threshold Segment Reporting [Table] Segment Reporting [Table] Statutory net income Statutory Accounting Practices, Statutory Net Income Amount Cash flows from investing activities: Cash Provided by (Used in) Investing Activity, Continuing Operation [Abstract] 2022 QSR and 2023 QSR Quota Share Reinsurance Transaction, 2022 and 2023 - 2022 NIW [Member] Quota Share Reinsurance Transaction, 2022 and 2023 - 2022 NIW Cash flows from operating activities: Cash Provided by (Used in) Operating Activity, Continuing Operation [Abstract] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] All Trading Arrangements All Trading Arrangements [Member] Less Than 12 Months - Fair Value Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months Other Performance Measure, Amount Other Performance Measure, Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Current Fiscal Year End Date Current Fiscal Year End Date Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Senior Notes Payable Notes Payable, Fair Value Disclosure Foreign government debt Debt Security, Government, Non-US [Member] Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Quarterly cash dividend declared (per share) Common Stock, Dividends, Per Share, Declared Entity File Number Entity File Number Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Company service cost (1) Defined Benefit Plan, Service Cost Issuance of common stock, net under share-based compensation plans Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture Amortized cost and fair values of fixed income securities by contractual maturity Investments Classified by Contractual Maturity Date [Table Text Block] Reconciliation of beginning and ending loss reserves Schedule of Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Senior notes Senior Notes Common stock, shares issued (in shares) Common Stock, Shares, Issued Measure: Measure [Axis] Schedule of total assets of Home Re Schedule of Variable Interest Entities [Table Text Block] Fair Value Gains Equity Securities, FV-NI, Unrealized Gain Net premiums earned Premiums Earned, Net Profit commission on quota share reinsurance Reinsurance, Profit Commission Reinsurance, Profit Commission 12 Months or Greater - Unrealized Losses Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Other Comprehensive Income Comprehensive Income (Loss) Note [Text Block] Decrease in unearned premiums, net (Increase) Decrease in Unearned Premiums, Net Statutory capital requirements [Abstract] Statutory capital requirements [Abstract] Equity Components [Axis] Equity Components [Axis] Product and Service [Domain] Product and Service [Domain] Class of Stock [Line Items] Class of Stock [Line Items] Entity Interactive Data Current Entity Interactive Data Current Effects of Reinsurance [Line Items] Effects of Reinsurance [Line Items] Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Due after one year through five years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year One Through Five Entity Small Business Entity Small Business Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Comprehensive Income (Loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Unearned premiums Unearned Premiums Termination Date Trading Arrangement Termination Date Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Current year Current Year Claims and Claims Adjustment Expense Cash flows from financing activities: Cash Provided by (Used in) Financing Activity, Continuing Operation [Abstract] Document Type Document Type 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] Fair Value as of Grant Date Award Grant Date Fair Value Aging of the fair value of securities in an unrealized loss position Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value [Table Text Block] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Remaining authorized repurchase amount Share Repurchase Program, Remaining Authorized, Amount Arrangement Duration Trading Arrangement Duration Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Local Phone Number Local Phone Number Other Postretirement Benefit Plans Other Postretirement Benefits Plan [Member] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Less Than 12 Months - Unrealized Losses Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Total other comprehensive income (loss) Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent Income before tax Total reclassifications Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Contingencies Commitments and Contingencies Total Revenues Revenues Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Executive Category: Executive Category [Axis] Funding Percentage Reinsurance Retention Policy, Funding Percentage Reinsurance Retention Policy, Funding Percentage Initial First Layer Retention Reinsurance Retention Policy, Initial Amount Retained Reinsurance Retention Policy, Initial Amount Retained Award vesting period (in years) Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period Liabilities and Shareholders’ Equity Liabilities and Equity [Abstract] Reinsurance Reinsurance [Text Block] Award Type [Domain] Award Type [Domain] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Fair Value Measurements Fair Value Disclosures [Text Block] Significant Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] PEO Name PEO Name Total losses paid Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid All other underwriting and operating Segment Reporting, Other Segment Item, Amount Other assets Other Assets Reinsurance recoverable on paid losses Increase Decrease In Reinsurance Recoverable On Paid Losses The net change during the reporting period in the amount of receivables currently due from reinsurers for ceded claims paid. Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Entity Tax Identification Number Entity Tax Identification Number Legal Entity [Axis] Legal Entity [Axis] Interest expense Interest Expense, Debt Premiums written: Premiums Written, Gross [Abstract] Cash and cash equivalents and restricted cash and cash equivalents at beginning of period Cash and cash equivalents and restricted cash and cash equivalents at end of period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Direct Policyholder Benefits and Claims Incurred, Direct Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Effects of Reinsurance [Table] Effects of Reinsurance [Table] Reclassification out of accumulated other comprehensive income Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Non-NEOs Non-NEOs [Member] Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Nature of Business and Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Measurement Frequency [Domain] Measurement Frequency [Domain] Equity Securities, FV-NI, Gain (Loss) [Abstract] Equity Securities, FV-NI, Gain (Loss) [Abstract] Debt Instrument [Axis] Debt Instrument [Axis] Equity compensation Share-Based Payment Arrangement, Noncash Expense Number of jurisdictions with risk-to-capital requirements (in jurisdictions) Number of jurisdictions with risk to capital requirements The number of jurisdictions that require a mortgage insurer to maintain a minimum amount of statutory capital relative to the risk in force (or a similar measure) in order for the mortgage insurer to continue to write new business. This is generally referred to as a risk-to-capital requirement. Cash dividends Dividends, Cash Long-term debt Schedule of Debt [Table Text Block] Due after five years through ten years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Basic (in dollars per share) Basic earnings per share (in dollars per share) Earnings Per Share, Basic Non Catastrophic Event [Axis] Noncatastrophic Event [Axis] Repurchase of common stock Payments for Repurchase of Common Stock Statistical Measurement [Axis] Statistical Measurement [Axis] Insider Trading Arrangements [Line Items] Remaining Excess of Loss Reinsurance Coverage Reinsurance, Excess Retention, Amount Reinsured, Per Policy Award Type [Axis] Award Type [Axis] Equity securities gains (losses): Debt and Equity Securities, Gain (Loss) [Abstract] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Change in unrealized investment gains and losses Other Comprehensive Income (Loss), Available-for-Sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Retained earnings Retained Earnings (Accumulated Deficit) Home Re special purpose insurers Home Re special purpose insurers [Member] Home Re special purpose insurers [Member] Product and Service [Axis] Product and Service [Axis] Amortization of deferred insurance policy acquisition costs Deferred Policy Acquisition Costs, Amortization Expense Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Common Stock Common Stock [Member] Home Re 2026-1, Ltd. Home Re 2026-1 [Member] Home Re 2026-1 Fixed income available-for-sale Fair Value Total at end of period Debt Securities, Available-for-Sale Legal Maturity Reinsurance Retention Policy, Debt Issued To Cover Insurance, Term Reinsurance Retention Policy, Debt Issued To Cover Insurance, Term Fair Value Measurement [Domain] Fair Value Measurement [Domain] Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] Dividend paid to MGIC Investment Corp Statutory Accounting Practices, Dividends Paid with Approval of Regulatory Agency Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Cover [Abstract] Cover [Abstract] Equity Awards Adjustments Equity Awards Adjustments [Member] Assumed Assumed Premiums Earned Total Liabilities and Shareholders’ Equity Liabilities and Equity Percent of total trust assets invested in cash or direct U.S. federal government obligations Reinsurance Retention Policy, Percent Of Total Trust Assets Invested In Cash Or Direct U.S. Federal Government Obligations Reinsurance Retention Policy, Percent Of Total Trust Assets Invested In Cash Or Direct U.S. Federal Government Obligations Reinsurance, quota reinsurance agreement, lifetime loss ratio cap (as a percent) Reinsurance, Quota Share Reinsurance Agreement, Terms, Lifetime Loss Ratio Cap Reinsurance, Quota Share Reinsurance Agreement, Terms, Lifetime Loss Ratio Cap Employee Stock Option Share-Based Payment Arrangement, Option [Member] Purchases of real estate assets acquired Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Segments [Axis] Segments [Axis] Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Asset Class [Axis] Asset Class [Axis] Premiums receivable Increase (Decrease) in Premiums Receivable Tabular List, Table Tabular List [Table Text Block] Reinsurance recoverable on loss reserves Reinsurance recoverable on loss reserves Less reinsurance recoverable Plus reinsurance recoverable Reinsurance Recoverable for Unpaid Claims and Claims Adjustments Reinsurance recoverable on loss reserves Increase (Decrease) in Reinsurance Recoverable Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Loss Reserves Liability for Future Policy Benefits and Unpaid Claims Disclosure [Text Block] Short-Term Investments Short-Term Investments [Member] Fair Value Losses Equity Securities, FV-NI, Unrealized Loss Name Awards Close in Time to MNPI Disclosures, Individual Name Contingency loss reserves Contingency Reserve An amount of money established from retained earnings to allow for unforeseen losses in business. Amount of reserves for future policy claims payable and loss expenses to be incurred. Purchases of investments Payments to Acquire Investments Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Cost and fair value of investments in equity securities Debt Securities, Trading, and Equity Securities, FV-NI [Table Text Block] Ceded Ceded Premiums Written Schedule of realized gains (losses) and proceeds from sale of securities Schedule of Realized Gain (Loss) [Table Text Block] Adjustment to Compensation: Adjustment to Compensation [Axis] CMBS Commercial Mortgage-Backed Securities [Member] Mortgage Guaranty Insurance Corporation Mortgage Guaranty Insurance Corporation [Member] Another company which is controlled, directly or indirectly, by its parent. The usual condition for control is ownership of a majority (over 50%) of the outstanding voting stock. The power to control may also exist with a lesser percentage of ownership, for example, by contract, lease, agreement with other stockholders or by court decree. Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Cost of settlements and curtailments Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment 2021 QSR and 2022 QSR Quota Share Reinsurance Transaction, 2021 and 2022 - 2022 NIW [Member] Quota Share Reinsurance Transaction, 2021 and 2022 - 2022 NIW 2026 Traditional XOL 2026 Traditional XOL [Member] 2026 Traditional XOL Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Total assets Assets, Fair Value Disclosure Name Measure Name Pay vs Performance Disclosure [Line Items] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] 5.25% Senior Notes Due 2028 Five Point Two Five Percent Senior Notes [Member] Five Point Two Five Percent Senior Notes Debt Instrument [Line Items] Debt Instrument [Line Items] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] 2024 Traditional XOL 2024 Traditional XOL [Member] 2024 Traditional XOL Loss reserves Increase (decrease) in loss reserves Increase (Decrease) in Liability for Claims and Claims Adjustment Expense Reserve Retirement Plan Type [Domain] Retirement Plan Type [Domain] Paid-in Capital Additional Paid-in Capital [Member] Entity Filer Category Entity Filer Category Total - Fair Value Debt Securities, Available-for-Sale, Unrealized Loss Position Pension and Supplemental Executive Retirement Plans Pension And Supplemental Plans [Member] Pension And Supplemental Plans [Member] Name Trading Arrangement, Individual Name Cash and cash equivalents Cash and Cash Equivalent Annual Loss Ratio to Exhaust Profit Commission (as a percent) Loss Ratio Threshold for private mortgage insurer eligibility requirements for termination election (less than) (as a percent) Reinsurance, Quota Share Reinsurance Agreement, Terms, Threshold For Private Mortgage Insurer Eligibility Requirements For Termination Election Reinsurance, Quota Share Reinsurance Agreement, Terms, Threshold For Private Mortgage Insurer Eligibility Requirements For Termination Election Company Selected Measure Amount Company Selected Measure Amount Summary of amounts disclosed under statutory accounting practices Statutory Accounting Practices Disclosure [Table Text Block] Losses incurred: Losses incurred: [Abstract] Equity securities, gains (losses), market adjustment Equity Securities, FV-NI, Unrealized Gain (Loss) Premiums earned: Premiums Earned, Net [Abstract] Post-vesting holding period for grants to executive officers and non-employee directors Share-Based Compensation Arrangement by Share-Based Payment Award, Post Vesting Holding Period The holding period after the vesting of RSUs that were granted to executive officers and non-employee directors after which the vested awards will be convertible into shares. Schedule of Stock by Class [Table] Stock, Class of Stock [Table] Non-PEO NEO Non-PEO NEO [Member] Senior Notes Senior Notes [Member] Entity Address, Address Line One Entity Address, Address Line One Total Losses and Expenses Benefits, Losses and Expenses Provision for income tax Income tax benefit (expense) Income Tax Expense (Benefit) CLOs Collateralized Loan Obligations [Member] Dilutive Securities, Effect on Basic Earnings Per Share [Abstract] Dilutive Securities, Effect on Basic Earnings Per Share [Abstract] Statutory policyholders' surplus Statutory Accounting Practices, Statutory Capital and Surplus, Balance Assets held by insurance regulatory requirements Assets Held by Insurance Regulators Award Timing Method Award Timing Method [Text Block] Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Premiums receivable Premiums Receivable, Net Net actuarial losses (gains) Defined Benefit Plan, Amortization of Gain (Loss) Significant Accounting Policies Accounting Standards Update and Change in Accounting Principle [Text Block] AOCI Attributable to Parent, Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Net Income Net Income Net Income (Loss) Attributable to Parent Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Statement [Table] Statement [Table] Restatement Determination Date: Restatement Determination Date [Axis] Accumulated other comprehensive income (loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Reinsurance Disclosures [Abstract] Reinsurance Disclosures [Abstract] Revenues: Revenues [Abstract] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block]