Cover [Abstract] Document Type Document Type Document Quarterly Report Document Quarterly Report Document Transition Report Document Transition Report Document Period End Date Document Period End Date Securities Act File Number Entity File Number Entity Registrant Name Entity Registrant Name Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address, Address Line One Entity Address, City or Town Entity Address, City or Town Entity Address, State or Province Entity Address, State or Province Entity Address, Postal Zip Code Entity Address, Postal Zip Code City Area Code City Area Code Local Phone Number Local Phone Number Title of 12(b) Security Title of 12(b) Security Trading Symbol Trading Symbol Security Exchange Name Security Exchange Name Entity Current Reporting Status Entity Current Reporting Status Entity Interactive Data Current Entity Interactive Data Current Entity Filer Category Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Shell Company Entity Shell Company Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Current Fiscal Year End Date Current Fiscal Year End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Entity Central Index Key Entity Central Index Key Amendment Flag Amendment Flag Income Statement [Abstract] Premiums Earned, Net Net premiums earned Net Investment Income Net investment income Realized Investment Gains (Losses) Net realized gains Equity Securities, FV-NI, Unrealized Gain (Loss) Net unrealized gains on equity securities Net unrealized gains (losses) on equity securities Revenues Consolidated revenue Policyholder Benefits and Claims Incurred, Net Losses and settlement expenses Amount of deferred policy acquisition costs charged to expense in the period, generally in proportion to related revenue earned, estimated gross profits, or over the customer relationship or some other period, as well as direct period costs related to acquisition of insurance policies. Policy Acquisition Cost Amortization Expense And Direct Period Costs Policy acquisition costs Operating Expenses Insurance operating expenses Interest Expense, Debt Interest expense on debt Interest expense on debt General corporate expenses. General Corporate Expenses General corporate expense General corporate expenses Benefits, Losses and Expenses Total expenses Income (Loss) from Equity Method Investments Equity in earnings of unconsolidated investees Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Earnings before income taxes Income Tax Expense (Benefit) Income tax (expense) benefit Income tax expense Total tax expense Net earnings Net earnings Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Other comprehensive earnings (loss), net of tax Net current-period other comprehensive earnings (loss) Other comprehensive earnings (loss), net of tax Comprehensive Income (Loss), Net of Tax, Attributable to Parent Comprehensive earnings Earnings Per Share, Basic Basic net earnings per share (in dollars per share) Basic net earnings per share (in dollars per share) Earnings Per Share, Diluted Diluted net earnings per share (in dollars per share) Diluted earnings per share (in dollars per share) Weighted Average Number of Shares Outstanding, Diluted [Abstract] Weighted average number of common shares outstanding: Diluted EPS, Weighted Average Shares (Denominator) Weighted Average Number of Shares Outstanding, Basic Basic weighted average number of common shares outstanding (in shares) Number of shares outstanding Weighted Average Number of Shares Outstanding, Diluted Diluted weighted average number of common shares outstanding (in shares) Number of shares outstanding Statement of Financial Position [Abstract] Assets [Abstract] ASSETS Debt Securities, Available-for-Sale, Excluding Accrued Interest Fair Value Available-for-sale, at fair value (amortized cost of $3,760,876 and allowance for credit losses of $463 at 6/30/26) (amortized cost of $3,642,362 and allowance for credit losses of $828 at 12/31/25) Total available-for-sale Available-for-sale fixed income Equity Securities, FV-NI, Current Equity securities Equity securities, at fair value (cost - $530,730 at 6/30/26 and $534,311 at 12/31/25) Money Market Funds, at Carrying Value Short-term investments, at cost which approximates fair value Short-term investments Other Investments Other invested assets Other investments Cash Cash Investments and Cash Total investments and cash Accrued Investment Income Receivable Accrued investment income The carrying amount as of the balance sheet date due to the entity from (a) agents and insureds, (b) uncollected premiums and (c) others, net of the allowance for doubtful accounts. Also includes receivables currently due from reinsurers for ceded claims paid. Premiums And Reinsurance Balances Receivable Premiums and reinsurance balances receivable, net of allowances for uncollectible amounts of $21,044 at 6/30/26 and $23,673 at 12/31/25 Prepaid Reinsurance Premiums Ceded unearned premium Reinsurance Recoverable for Unpaid Claims and Claims Adjustments Ceded Ceded Reinsurance balances recoverable on unpaid losses and settlement expenses, net of allowances for uncollectible amounts of $10,953 at 6/30/26 and $11,107 at 12/31/25 Deferred Policy Acquisition Cost Deferred policy acquisition costs Property, Plant and Equipment, Net Property and equipment, at cost, net of accumulated depreciation of $88,555 at 6/30/26 and $84,459 at 12/31/25 Equity Method Investments Investment in unconsolidated investees Intangible Assets, Net (Including Goodwill) Goodwill and intangibles Total goodwill and intangibles Other Assets Other assets Assets TOTAL ASSETS Liabilities and Equity [Abstract] LIABILITIES AND SHAREHOLDERS' EQUITY Liabilities [Abstract] Liabilities Liability for Claims and Claims Adjustment Expense Gross Gross Unpaid losses and settlement expenses Unearned Premiums Unearned premiums Reinsurance Payable Reinsurance balances payable The carrying amount, as of the balance sheet date, of funds held, including cash deposits that were received in lieu of a letter of credit. Funds Held Funds held Accrued Income Taxes, Current Income taxes-current Deferred Income Tax Liabilities, Net Income taxes-deferred Short-Term Debt Short-term debt Long-Term Debt Long-term debt Accrued Liabilities Accrued expenses Other Liabilities Other liabilities Liabilities TOTAL LIABILITIES Equity, Attributable to Parent [Abstract] Shareholders' Equity Common Stock, Value, Issued Common stock ($0.01 par value) (Shares authorized - 400,000,000) (137,868,035 shares issued, 91,772,634 shares outstanding at 6/30/26) (137,739,079 shares issued, 91,878,651 shares outstanding at 12/31/25) Additional Paid in Capital, Common Stock Paid-in capital Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive earnings (loss) Retained Earnings (Accumulated Deficit) Retained earnings Compensation and Benefits Trust Deferred compensation Treasury Stock, Common, Value Less: Treasury shares, at cost (46,095,401 shares at 6/30/26 and 45,860,428 shares at 12/31/25) Equity, Attributable to Parent Ending balance Beginning balance TOTAL SHAREHOLDERS' EQUITY Liabilities and Equity TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss Available-for-sale, amortized cost Total available-for-sale Cost or Amortized Cost Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest Allowance for Credit Losses Ending balance Beginning balance Available-for-sale, allowance for credit losses Equity Securities, FV-NI, Cost Equity securities, cost A valuation allowance for the amount deemed uncollectible of an insurance receivable related to a policy by which an insurer indemnifies itself of some or all of the risk associated with another insurance policy. Includes the carrying value as of the balance sheet date of the estimated valuation allowance to reduce gross premiums receivable to net realizable value. Premiums And Reinsurance Balances Receivable Allowances Premiums and reinsurance balances receivable, allowances for uncollectible amounts Reinsurance Recoverables on Unpaid Losses, Allowance Reinsurance balances recoverable on unpaid losses and settlement expenses, allowances for uncollectible amounts Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property and equipment, accumulated depreciation Common Stock, Par or Stated Value Per Share Common stock, par value (in dollars per share) Common Stock, Shares Authorized Common stock, shares authorized (in shares) Common Stock, Shares, Issued Common stock, shares issued (in shares) Common Stock, Shares, Outstanding Common stock, shares outstanding (in shares) Treasury Stock, Common, Shares Treasury stock, shares (in shares) Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components Equity Component [Domain] Equity Component Common Stock [Member] Common Stock Additional Paid-in Capital [Member] Paid-in Capital AOCI Attributable to Parent [Member] Accumulated Other Comprehensive Earnings (Loss) Retained Earnings [Member] Retained Earnings Deferred Compensation, Share-Based Payments [Member] Deferred Compensation Treasury Stock, Common [Member] Treasury Stock at Cost Statement [Line Items] Statement [Line Items] Shares, Outstanding Ending balance (in shares) Beginning balance (in shares) Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase Decrease In Shareholders Equity Roll Forward Deferred compensation that is received or paid out under rabbi trust plans, which offsets treasury stock and is included in shareholders' equity. Transfers Between Deferred Compensation Plan And Treasury Stock Deferred compensation Treasury Stock, Shares, Acquired Purchase of treasury shares (in shares) Treasury Stock, Value, Acquired, Cost Method Purchases of treasury shares Stock Issued During Period, Value, Stock Options Exercised Share-based compensation Number of share options (or share units) exercised during the current period, net of exercises via stock swaps and shares withheld for taxes. Stock Issued During Period Shares Stock Options Exercised Net Share-based compensation (in shares) Dividends, Common Stock Dividends and dividend equivalents Common Stock, Dividends, Per Share, Cash Paid Cash dividends paid per common share Statement of Cash Flows [Abstract] Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Net cash provided by operating activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Cash Flows from Investing Activities Payments to Acquire Investments and Productive Assets [Abstract] Payments To Acquire Investments And Productive Assets [Abstract] Purchase of: Payments to Acquire Debt Securities, Available-for-Sale Fixed income securities, available-for-sale Payments to Acquire Marketable Securities Equity securities Payments to Acquire Property, Plant, and Equipment Property and equipment Represents the amount of net cash outflow from other investing activities. Payments For Other Investing Activities Other Proceeds from Sale of Investments and Productive Assets [Abstract] Proceeds From Sale Of Investments And Productive Assets [Abstract] Proceeds from sale of: Proceeds from Sale of Debt Securities, Available-for-Sale Fixed income securities, available-for-sale Proceeds from Sale and Maturity of Marketable Securities Equity securities Represents the amount of net cash inflow (outflow) from other investing activities. This element is used when there is not a more specific and appropriate element in the taxonomy. Proceeds From Other Investing Activities Other Proceeds from Sale, Maturity and Collection of Investments [Abstract] Proceeds from call or maturity of: Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-Sale Fixed income securities, available-for-sale Payments for (Proceeds from) Short-Term Investments Net proceeds from purchase of short-term investments Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Net cash used in investing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Cash Flows from Financing Activities Proceeds from Issuance of Debt Proceeds from issuance of debt Repayments of Debt Payment of debt Payments of Ordinary Dividends, Common Stock Cash dividends paid Cash inflow (outflow) from stock option exercises. Cash Flow From Stock Option Exercises Proceeds from stock option exercises Payments for Repurchase of Common Stock Purchases of treasury shares Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Net cash used in financing activities Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Net increase in cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Cash at June 30, Cash at the beginning of the period Accounting Policies [Abstract] Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Basis of Presentation and Summary of Significant Accounting Policies Investments, Debt and Equity Securities [Abstract] Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Investments Debt Disclosure [Abstract] Debt Disclosure [Text Block] Debt Historical loss and LAE development disclosure. Historical Loss And L A E Development Disclosure [Abstract] Liability for Future Policy Benefits and Unpaid Claims Disclosure [Text Block] Historical Loss And LAE Development Income Tax Disclosure [Abstract] Income Tax Disclosure [Text Block] Income Taxes Share-Based Payment Arrangement [Abstract] Share-Based Payment Arrangement [Text Block] Stock Based Compensation Segment Reporting [Abstract] Segment Reporting Disclosure [Text Block] Operating Segment Information Leases [Abstract] Lessee, Operating Leases [Text Block] Leases Basis of Accounting, Policy [Policy Text Block] Basis of Presentation New Accounting Pronouncements, Policy [Policy Text Block] Adopted Accounting Standards Disclosure of accounting policy pertaining to prospective accounting standards that have not been early-adopted and may or may not have a material effect on the Company's financial statements. Prospective Accounting Standards Policy Policy [Text Block] Prospective Accounting Standards Reinsurance Accounting Policy [Policy Text Block] Reinsurance Goodwill and Intangible Assets, Policy [Policy Text Block] Intangible Assets Earnings Per Share, Policy [Policy Text Block] Earnings Per Share Stockholders' Equity, Policy [Policy Text Block] Comprehensive Earnings Fair Value of Financial Instruments, Policy [Policy Text Block] Fair Value Measurements Schedule of Intangible Assets and Goodwill [Table Text Block] Schedule of Goodwill and Intangible Assets Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Reconciliation of Numerator and Denominator of the Basic and Diluted Earnings Per Share Computations Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Schedule of Changes in the Balance of Each Component of Accumulated Other Comprehensive Earnings (Loss) Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Schedule of Effects of Reclassifications out of Accumulated Other Comprehensive Earnings (Loss) Schedule of Realized Gain (Loss) [Table Text Block] Schedule of Disposition of Fixed Income and Equity Securities Fair Value, Assets Measured on Recurring Basis [Table Text Block] Fair Value, Assets Measured on Recurring Basis Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Summary of Changes in Balance of Level 3 Securities Investments Classified by Contractual Maturity Date [Table Text Block] Schedule of Contractual Maturity of Securities Schedule of Available-for-Sale Securities Reconciliation [Table Text Block] Schedule of Amortized Cost and Fair Value of Available-for-sale Securities Debt Securities, Available-for-Sale, Allowance for Credit Loss [Table Text Block] Schedule of Debt Securities Available-for-sale Allowance for Credit Loss Unrealized Gain (Loss) on Investments [Table Text Block] Schedule of Securities in an Unrealized Loss Position Segregated by Type and Length of Time in an Unrealized Loss Position For all fixed income securities in an unrealized loss position, a tabular disclosure of the aggregate related fair value of investments with unrealized losses and the aggregate amount of the unrealized losses (that is, the amount by which the book value exceeds the fair value) organized by credit rating. Schedule Of Fixed Income Securities Unrealized Loss On Investments By Credit Quality Indicator Table [Text Block] Schedule of Credit Quality Indicators for Investments in Unrealized Loss Positions Schedule of Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block] Schedule of Reconciliation of Unpaid Losses and Settlement Expenses (LAE) Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Schedule of Reconciliation of Income Tax Expense Attributable to Income from Operations with Amounts Computed by Applying U.S. Federal Tax Rate to Pretax Income from Continuing Operations Share-Based Payment Arrangement, Option, Activity [Table Text Block] Summary of Option Activity Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Summary of Weighted Average Grant-date Assumptions and Weighted Average Fair Values Schedule of Nonvested Restricted Stock Units Activity [Table Text Block] Schedule of Restricted Stock Units Activity Revenue from External Customers by Products and Services [Table Text Block] Summary of Revenue by Major Product Type Schedule of Segment Reporting Information, by Segment [Table Text Block] Summary of Selected Information by Operating Segment Lease, Cost [Table Text Block] Schedule of Components of Lease Expense and Other lease Information Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block] Schedule of Future Minimum Lease Payments under Non-cancellable Leases Ceded Credit Risk [Table] Ceded Credit Risk [Table] Statistical Measurement [Axis] Statistical Measurement