Senior notes and other debt Senior notes and other debt Senior notes and other debt. Equity securities available for sale Available-for-sale Securities, Equity Securities Total investments Investments Cash and cash equivalents at end of period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents at beginning of year Cash and Cash Equivalents, at Carrying Value, Total Cash and cash equivalents Accrued investment income Accrued Investment Income Receivable, Total Accrued Investment Income Receivable Prepaid reinsurance premiums Prepaid Reinsurance Premiums Deferred policy acquisition costs Deferred Policy Acquisition Costs, Total Deferred Policy Acquisition Costs Real estate, furniture and equipment Property, Plant and Equipment, Net, Total Property, Plant and Equipment, Net, Beginning Balance Property, Plant and Equipment, Net, Ending Balance Property, Plant and Equipment, Net Deferred federal and foreign income taxes Deferred Tax Assets, Net, Total Deferred Tax Assets, Net Goodwill Goodwill, Beginning Balance Goodwill, Ending Balance Goodwill Current federal and foreign income taxes Income Taxes Receivable, Current Other assets Other Assets Total assets Assets Unearned premiums Unearned Premiums, Total Unearned Premiums Due to reinsurers Reinsurance Payable Other liabilities Other Liabilities, Total Other Liabilities Total liabilities Liabilities Preferred stock, par value $.10 per share: Authorized 5,000,000 shares; issued and outstanding - none Preferred Stock, Value, Issued, Total Preferred Stock, Value, Issued, Beginning Balance Preferred Stock, Value, Issued, Ending Balance Preferred Stock, Value, Issued Common stock, par value $.20 per share: Authorized 500,000,000 shares, issued and outstanding, net of treasury shares, 148,421,425 and 156,552,355 shares Common Stock, Value, Issued Common Stock, Value, Issued, Ending Balance Common Stock, Value, Issued, Beginning Balance Common Stock, Value, Issued, Total Retained earnings Retained Earnings (Accumulated Deficit), Total Retained Earnings (Accumulated Deficit), Beginning Balance Retained Earnings (Accumulated Deficit), Ending Balance Retained Earnings (Accumulated Deficit) Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax, Total Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning Balance Accumulated Other Comprehensive Income (Loss), Net of Tax, Ending Balance Accumulated Other Comprehensive Income (Loss), Net of Tax Treasury stock, at cost, 86,696,493 and 78,565,563 shares Treasury stock, at cost, XXX and 78,565,563 shares Treasury Stock, Value, Beginning Balance Treasury Stock, Value, Ending Balance Treasury Stock, Value Stockholders' Equity Attributable to Parent End of period Beginning of period Stockholders' Equity Attributable to Parent, Total Total stockholders' equity Treasury stock, at cost, and 78,565,563 shares Stockholders' Equity Attributable to Noncontrolling Interest End of period Beginning of period Noncontrolling interests Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest End of period Beginning of period Total equity Total liabilities and equity Liabilities and Stockholders' Equity Investment in arbitrage funds Investment in arbitrage funds Investment in arbitrage funds. Net income before noncontrolling interests Net income to common stockholders Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net Income (Loss), Including Portion Attributable to Noncontrolling Interest, Total Unrealized holding gains on investment securities arising during the period, net of taxes Other Comprehensive Income, Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax Comprehensive income to common stockholders Comprehensive Income, Net of Tax, Attributable to Parent Comprehensive income (loss) Comprehensive income to the noncontrolling interests Comprehensive income (loss) to the noncontrolling interest Comprehensive Income, Net of Tax, Attributable to Noncontrolling Interest Comprehensive income Comprehensive Income, Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive income (loss) to common shareholders Increase (Decrease) in Unearned Premiums Change in net unearned premiums Unearned premiums Premiums Earned, Net Net premiums earned Realized Investment Gains (Losses) Net investment (gains) losses Net investment (gains) losses Realized Investment Gains (Losses), Total Net realized gains on investment sales Marketable Securities, Realized Gain (Loss), Other than Temporary Impairments, Amount Other-than-temporary impairments Other-than-temporary impairments Gain (Loss) on Investments Net investment (gains) losses Net investment (gains) losses Net investment gains (losses) Net investment (gains) losses Other Income Revenues Net Investment Income Other Cost and Expense, Operating Interest Expense Operating Costs and Expenses Income tax (expense) benefit Income Tax Expense (Benefit) Income tax expense (benefit) Net income Net Income (Loss) Attributable to Noncontrolling Interest Noncontrolling interests Net income Noncontrolling interests Noncontrolling interests Stock Issued During Period, Value, New Issues Stock issued to directors Dividends Dividends Other Comprehensive Income, Foreign Currency Transaction and Translation Adjustment, Net of Tax Net change in period Change in unrealized foreign exchange gains (losses) Other comprehensive income, net of tax Other comprehensive income Other Comprehensive Income (Loss), Net of Tax Other income Total revenues Net investment income Net Investment Income, Total Other operating costs and expenses Other Cost and Expense, Operating, Total Interest expense Total operating costs and expenses Depreciation, Depletion and Amortization, Nonproduction Depreciation, Depletion and Amortization, Nonproduction, Total Depreciation and amortization Increase (Decrease) in Trading Securities Securities trading account Increase (Decrease) in Trading Securities, Total Securities trading account Increase (Decrease) in Broker-Dealer Related Receivables (Payables), Net Change in balances due to security brokers Change in balances due to security brokers Increase (Decrease) in Reinsurance Recoverable Due from reinsurers Due from reinsurers Increase (Decrease) in Accrued Investment Income Receivable Accrued investment income Accrued investment income Increase (Decrease) in Prepaid Reinsurance Premiums Prepaid reinsurance premiums Prepaid reinsurance premiums Increase (Decrease) in Deferred Policy Acquisition Costs Deferred policy acquisition costs Deferred policy acquisition costs Increase (Decrease) in Deferred Income Taxes Deferred income taxes Deferred income taxes Increase (Decrease) in Other Operating Assets Other assets Other assets Increase (Decrease) in Loss and Loss Adjustment Expense Reserve Reserves for losses and loss expenses Reserves for losses and loss expenses Increase (Decrease) in Reinsurance Payables Due to reinsurers Increase (Decrease) in Other Operating Liabilities Other liabilities Net cash from (used in) operating activities Net Cash Provided by (Used in) Operating Activities Net cash from (used in) investing activities Net Cash Provided by (Used in) Investing Activities Payments for Repurchase of Common Stock Purchase of common treasury shares Purchase of common treasury shares Payments of Dividends, Common Stock Cash dividends to common stockholders Cash dividends to common stockholders Proceeds from Stock Options Exercised Net proceeds from stock options exercised Other, net Proceeds from (Payments for) Other Financing Activities Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Effect of Exchange Rate on Cash and Cash Equivalents Net impact on cash due to change in foreign exchange rates Net increase (decrease) in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and Cash Equivalents, Period Increase (Decrease), Total Proceeds from Sale of Available-for-sale Securities, Equity Equity securities Payments to Acquire Available-for-sale Securities, Equity Equity securities Equity securities Payments for (Proceeds from) Loans Receivable Change in loans receivable Payments for (Proceeds from) Loans Receivable, Total Change in loans receivable Increase (Decrease) in Payables to Broker-Dealers Trading account receivables from brokers and clearing organizations Change in net unearned premiums Change in net unearned premiums Change in net unearned premiums Change in net unearned premiums. Assets [Abstract] Assets Investments [Abstract] Investments: Liabilities and Stockholders' Equity [Abstract] Liabilities and Equity Liabilities [Abstract] Liabilities: Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Equity: Preferred Stock, Par or Stated Value Per Share Preferred stock, par value Preferred Stock, Shares Authorized Preferred stock, authorized Preferred Stock, Shares Issued Preferred Stock, Shares Issued, Total Preferred stock, issued Preferred Stock, Shares Outstanding Preferred Stock, Shares Outstanding, Ending Balance Preferred Stock, Shares Outstanding, Beginning Balance Preferred stock, outstanding Common Stock, Par or Stated Value Per Share Common stock, par value Common Stock, Shares Authorized Common stock, authorized Common Stock, Shares, Outstanding Common Stock, Shares, Outstanding, Ending Balance Common Stock, Shares, Outstanding, Beginning Balance Common stock, shares outstanding Treasury Stock, Shares Treasury Stock, Shares, Ending Balance Treasury Stock, Shares, Beginning Balance Treasury stock, at cost Revenues [Abstract] REVENUES: Gain (Loss) on Investments [Abstract] Net investment gains (losses): Operating Costs and Expenses [Abstract] OPERATING COSTS AND EXPENSES: NET INCOME PER SHARE: Per share data [Abstract] COMMON STOCK: ADDITIONAL PAID-IN CAPITAL: RETAINED EARNINGS: ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS): Unrealized investment gains (losses): Currency translation adjustments: Net pension asset: TREASURY STOCK: NONCONTROLLING INTERESTS: Other comprehensive income: Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] CASH FROM (USED IN) OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income to net cash from (used in) operating activities: Increase (Decrease) in Operating Capital [Abstract] Change in: CASH FLOWS FROM (USED IN) INVESTING ACTIVITIES: Net Cash Provided by (Used in) Investing Activities [Abstract] Proceeds from Sale and Maturity of Marketable Securities [Abstract] Proceeds from sales, excluding trading account: Payments to Acquire Marketable Securities [Abstract] Cost of purchases, excluding trading account: CASH FLOWS USED IN FINANCING ACTIVITIES: Net Cash Provided by (Used in) Financing Activities [Abstract] Earnings Per Share, Basic Earnings Per Share, Basic, Total Basic Earnings Per Share, Diluted Diluted Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] General Earnings Per Share [Text Block] Per share data Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Text Block] Recent Accounting Pronouncements Recent Accounting Pronouncements [Abstract] General [Abstract] Available-for-sale Securities [Text Block] Investments in Equity Securities Available for Sale Investments in Equity Securities Available for Sale [Abstract] Arbitrage Trading Account And Arbitrage Funds Text Block Arbitrage Trading Account and Arbitrage Funds Arbitrage Trading Account And Arbitrage Funds [Abstract] Investment [Text Block] Investment Funds Investment Funds [Abstract] Investment Income [Text Block] Net Investment Income Schedule of Accounts, Notes, Loans and Financing Receivable [Text Block] Loans Receivable Loans Receivable [Abstract] Realized And Unrealized Investment Gains And Losses Text Block Realized and Unrealized Investment Gains and Losses Realized And Unrealized Investment Gains And Losses [Abstract] Reinsurance [Text Block] Reinsurance Reinsurance [Abstract] Fair Value of Financial Instruments [Abstract] Restricted Stock Units Text Block Restricted stock units Restricted Stock Units [Abstract] Segment Reporting Disclosure [Text Block] Industry Segments Industry Segments [Abstract] Entity Registrant Name Entity Central Index Key Document Type Document Period End Date Amendment Flag Document Fiscal Year Focus Document Fiscal Period Focus Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Current Reporting Status Entity Filer Category Entity Public Float Entity Common Stock, Shares Outstanding Consolidated Balance Sheets [Abstract] Consolidated Statements of Operations [Abstract] Consolidated Statements of Stockholders' Equity [Abstract] Statement [Table] Statement, Equity Components [Axis] Equity Component [Domain] Parent [Member] Statement [Line Items] Consolidated Statements of Comprehensive Income [Abstract] Consolidated Statements of Cash Flows [Abstract] Net Investment Income [Abstract] Securities in Unrealized Loss Position Text Block Securities in an Unrealized Loss Position Securities in an Unrealized Loss Position. Document and Entity Information [Abstract] Document and Entity Information [Abstract] Revenues from wholly-owned investees. Revenues from wholly owned investees Revenues from wholly-owned investees Expenses from wholly-owned investees. Expenses from wholly owned investees Expenses from wholly-owned investees Securities in an Unrealized Loss Position. Securities in an Unrealized Loss Position [Abstract] Securities in an Unrealized Loss Position [Abstract] Insurance Commissions and Fees Insurance service fees Premiums Written, Net Premiums Written, Net, Total Net premiums written Net income to common stockholders Net income to common stockholders Net Income (Loss) Attributable to Parent Share-based Compensation Share-based Compensation, Total Stock incentive plans Fixed maturity securities. Proceeds From Fixed Maturity Securities Fixed maturity securities Payments Of Fixed Maturity Securities Fixed maturity securities Fixed maturity securities Fixed maturity securities. Payments to Acquire Property, Plant, and Equipment Net additions to real estate, furniture and equipment Payments to Acquire Property, Plant, and Equipment, Total Other Comprehensive Income, Defined Benefit Plan's Net Unamortized (Gain) Loss Arising During Period, Net of Tax Net change in period Change in unrecognized pension obligation, net of taxes Change in unrecognized pension obligation, net of taxes Net change in period Fair Value, by Balance Sheet Grouping [Text Block] Fair Value of Financial Instruments Fair Value, Measurement Inputs, Disclosure [Text Block] Fair Value Measurements Fair Value Measurements [Abstract] Fair Value Measurements [Abstract] Investments in Fixed Maturity Securities. Investments in Fixed Maturity Securities [Abstract] Investments in Fixed Maturity Securities [Abstract] Investments in Fixed Maturity Securities. Investments In Fixed Maturity Securities Text Block Investments in Fixed Maturity Securities Treasury Stock, Value, Acquired, Cost Method Stock repurchased Stock Issued During Period, Value, Treasury Stock Reissued Stock options exercised/vested Additional Paid in Capital, Common Stock Additional paid-in capital Other Comprehensive Income Unrealized Gain Losses On Other Than Temporarily Impaired Securities Unrealized gain on other-than-temporarily impaired securities Unrealized gain (losses) on other-than-temporarily impaired securities. Unrealized gains on securities not other-than-temporarily impaired Unrealized gain (losses) on securities not other-than-temporarily impaired. Other Comprehensive Income Unrealized Gain Losses On Securities Not Other Than Temporarily Impaired Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures, Total Restricted stock units expensed Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition, Value Stock options exercised and restricted units issued including tax benefit Payments to Acquire Businesses, Net of Cash Acquired Payment for business purchased, net of cash acquired Payment for business purchased, net of cash acquired Statements of Cash Flow [Abstract] Cash Flow, Supplemental Disclosures [Text Block] Statements of Cash Flow Commitments, Litigation and Contingent Liabilities [Abstract] Commitments, Litigation and Contingent Liabilities Commitments, Litigation and Contingent Liabilities Abstract. Commitments and Contingencies Disclosure [Text Block] Commitments, Litigation and Contingent Liabilities Marketable Securities, Fixed Maturities Fixed maturity securities Mortgage Loans on Real Estate, Commercial and Consumer, Net Loans receivable Premiums and Other Receivables, Net Premiums and Other Receivables, Net, Total Premiums and fees receivable Reinsurance Recoverables Reinsurance Recoverables, Ending Balance Reinsurance Recoverables, Beginning Balance Due from reinsurers Trading account receivables from brokers and clearing organizations Trading Assets The carrying amount of assets as of the balance sheet date that pertain to principal and customer trading transactions, or which may be incurred with the objective of generating a profit from short-term fluctuations in price as part of an entity's market-making, hedging and proprietary trading. Liability for Claims and Claims Adjustment Expense Liability for Claims and Claims Adjustment Expense, Total Reserves for losses and loss expenses Trading Liabilities Trading Liabilities, Total Trading account securities sold but not yet purchased Portion Of Impairment Loss Recognized In Other Comprehensive Income Less investment impairments recognized in other comprehensive income Portion of impairment loss recognized in other comprehensive income.