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Cover [Abstract] Cash, cash equivalents and short-term investments Cash and Cash Equivalents, Fair Value Disclosure Component of claims paid covered under QSR Transaction Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid Including Amounts Covered By Insurance, Amount Under QSR Transaction Component of total amount of payments to settle insured claims and pay costs incurred in the claims settlement process, including amount covered by insurance, covered under QSR transaction. 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[Domain] Measurement Frequency [Domain] Beginning balance, net of reinsurance recoverables Reserve at end of period, net of reinsurance recoverables Liability for Unpaid Claims and Claims Adjustment Expense, Net Unrealized (losses) gains in accumulated other comprehensive loss, net of tax (benefit) expense of $(5,959) and $8,186 for the quarters ended March 31, 2026 and 2025, respectively OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax Primary insured portfolio, loan default rate (in percent) Liability For Unpaid Claims And Claims Adjustment Expense, Incurred But Not Reported (IBNR) Claims, Number Of Primary Loans In Default, Percent Of Total Policies In-Force Liability For Unpaid Claims And Claims Adjustment Expense, Incurred But Not Reported (IBNR) Claims, Number Of Primary Loans In Default, Percent Of Total Policies In-Force Stockholders' Equity Equity [Text Block] Due after five through ten years Debt Securities, 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Adjustment Expense Treasury stock, at cost: 12,801,970 and 12,086,223 common shares as of March 31, 2026 and December 31, 2025, respectively Treasury Stock, Common, Value Remaining deferred issuance costs, net of accumulated amortization Debt Issuance Costs, Line of Credit Arrangements, Net Termination Date Trading Arrangement Termination Date Net cash used in financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Measure: Measure [Axis] Investment Income, Net [Abstract] Investment Income, Net [Abstract] Basic (in shares) Basic weighted average shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Remaining authorized repurchase amount Share Repurchase Program, Remaining Authorized, Amount Schedule of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] 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Revolving Credit Facility 2024 Premium receivable, number of days to be written off Premium Receivable, Number of Days to be Written Off Premium Receivable, Number of Days to be Written Off U.S. agency mortgage-backed securities U.S. agency mortgage-backed securities Mortgage-Backed Security, Issued by US Government-Sponsored Enterprise [Member] Reinsurance balances, net Increase (Decrease) in Reinsurance Assets and Liabilities Increase (Decrease) in Reinsurance Assets and Liabilities Interest expense Interest Expense, Nonoperating Trading Arrangement: Trading Arrangement [Axis] Total Shareholder Return Amount Total Shareholder Return Amount Schedule of Fair Value Measurements of Financial Instruments Fair Value Measurements, Recurring and Nonrecurring [Table Text Block] Insider Trading Arrangements [Line Items] Security Exchange Name Security Exchange Name Reinsurance recoverable Increase (Decrease) in Reinsurance Recoverable Investment income Interest revenue Investment Income, Interest and Dividend Total liabilities Liabilities Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Axis] Initial Reinsurance Coverage Initial Reinsurance Coverage Initial Reinsurance Coverage Credit facility borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Net investment income Investment Income, Net Financial Financial, Industry Group [Member] Financial, Industry Group [Member] Ceded Ceded premiums earned Ceded Premiums Earned Common stock - $0.01 par value; 88,951,544 shares issued and 76,149,574 shares outstanding as of March 31, 2026 and 88,371,465 shares issued and 76,285,242 shares outstanding as of December 31, 2025 (250,000,000 shares authorized) Common Stock, Value, Outstanding Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Profit commission Reinsurance Profit Commission Reinsurance Profit Commission Reinsurance Disclosures [Abstract] Reinsurance Disclosures [Abstract] Statement [Line Items] Statement [Line Items] Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] Variable Rate [Axis] Variable Rate [Axis] Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Counterparty Name [Axis] Counterparty Name [Axis] Common Stock Common Stock [Member] Fixed maturities, available-for-sale, at fair value (amortized cost of $3,255,203 and $3,190,174) Fair Value Fair Value Fair value of securities Debt Securities, Available-for-Sale Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Non-NEOs Non-NEOs [Member] Corporate debt securities Corporate debt securities Corporate debt securities Corporate Debt Securities [Member] Net increase in cash, cash equivalents and restricted cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Dilutive effect of issuable shares (in shares) Weighted Average Number of Shares Outstanding, Diluted, Adjustment