Accounting Policies [Abstract] Schedule of Property, Plant and Equipment Property, Plant and Equipment [Table Text Block] Statement of Cash Flows [Abstract] Operating Activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net earnings Net Income (Loss) Attributable to Parent Adjustments: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation Depreciation Amortization Accretion (Amortization) of Discounts and Premiums, Investments Net realized gains on investments Realized Investment Gains (Losses) (Gain) loss on disposal of property and equipment Assets Disposed of by Method Other than Sale, in Period of Disposition, Gain (Loss) on Disposition Gain on sale of subsidiaries Gain (Loss) on Disposition of Stock in Subsidiary or Equity Method Investee Loss on redemption of long-term debt Gains (Losses) on Extinguishment of Debt Share-based compensation expense Share-based Compensation Excess tax benefits from share-based payment arrangements Excess Tax Benefit from Share-based Compensation, Operating Activities Activity related to rabbi trust Non-Cash Activity Related to Rabbi Trust Non-cash activity related to rabbi trust Change in accrued investment income Increase (Decrease) in Accrued Investment Income Receivable Change in agents’ balances and premium receivable Increase (Decrease) in Premiums Receivable Change in reinsurance receivables Increase (Decrease) in Reinsurance Recoverable Change in deferred policy acquisition costs Increase (Decrease) in Deferred Policy Acquisition Costs Change in other assets Increase (Decrease) in Other Operating Assets Change in unpaid losses and loss adjustment expenses Increase (Decrease) in Liability for Claims and Claims Adjustment Expense Reserve Change in unearned premium Increase (Decrease) in Unearned Premiums Change in other liabilities Increase (Decrease) in Other Operating Liabilities Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Investing Activities: Payments to Acquire Investments [Abstract] Purchases of fixed maturities Payments to Acquire Available-for-sale Securities, Debt Purchases of equity securities Payments to Acquire Available-for-sale Securities, Equity Purchases of short-term investments Payments to Acquire Short-term Investments Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Maturities and redemptions of fixed maturities Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities Maturities and redemptions of short-term investments Proceeds from Maturities, Prepayments and Calls of Short-term Investments Proceeds from sale of subsidiary companies Proceeds from Divestiture of Businesses Proceeds from sale of fixed maturities Proceeds from Sale of Available-for-sale Securities, Debt Proceeds from sale of equity securities Proceeds from Sale of Available-for-sale Securities, Equity Proceeds from sale of short-term investments Proceeds from Sale of Short-term Investments Proceeds from sale of property and equipment Proceeds from Sale of Property, Plant, and Equipment Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Financing Activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds from stock options exercised and employee stock purchases Proceeds from Stock Options Exercised Excess tax benefits from share-based payment arrangements Excess Tax Benefit from Share-based Compensation, Financing Activities Redemption of long-term debt Proceeds from (Repayments of) Debt Principal payments under capital lease obligations Repayments of Long-term Capital Lease Obligations Acquisition of treasury stock Payments for Repurchase of Common Stock Dividends paid to shareholders Payments of Ordinary Dividends, Common Stock Net cash (used in) provided by financing activities Net Cash Provided by (Used in) Financing Activities Net (decrease) increase in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents at end of period Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] ESPP Employee Stock Purchase Plan (ESPP) [Member] Employee Stock Purchase Plan (ESPP) [Member] Award Type [Axis] Award Type [Axis] Award Type [Domain] Equity Award [Domain] Common Stock Common Stock [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Discount from market price on purchase date Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Purchase Date Maximum percentage of employee base salary Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate Maximum annual purchase amount per employee Share-based Compensation Arrangement by Share-based Payment Award, Maximum Annual Purchase Amount Per Employee Share-based Compensation Arrangement by Share-based Payment Award, Maximum Annual Purchase Amount Per Employee Shares reserved for issuance Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Outstanding (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Additional Information [Abstract] Additional Financial Information Disclosure [Abstract] Allowance for Doubtful Accounts Receivable [Roll Forward] Allowance for Doubtful Accounts Receivable [Roll Forward] Beginning balance Allowance for Doubtful Accounts Receivable Provision for losses Provision for Doubtful Accounts Uncollectible amounts written off Allowance for Doubtful Accounts Receivable, Write-offs Ending balance Supplemental Cash Flow Elements [Abstract] Negative cash book balances Outstanding Checks Outstanding Checks Restricted Stock Plan Restricted Stock Plan [Member] Restricted Stock Plan [Member] Directors Plan Directors Plan [Member] Directors Plan [Member] PSP Performance Share Plan (PSP) [Member] Performance Share Plan (PSP) [Member] Expense Recognized in Earnings Allocated Share-based Compensation Expense Tax Benefit Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Statement of Comprehensive Income [Abstract] Other comprehensive (loss) income before tax: Other Comprehensive Income (Loss), before Tax [Abstract] Net change in postretirement benefit liability Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax Unrealized gains (losses) on investments: Unrealized Gain (Loss) on Investments [Abstract] Unrealized holding gains (losses) arising during the period Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax Less: Reclassification adjustments for gains included in net earnings Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Unrealized gains (losses) on investments, net Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax Other comprehensive income (loss), before tax Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent Income tax benefit (expense) related to components of other comprehensive income Other Comprehensive Income (Loss), Tax Other comprehensive income (loss), net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Quarterly Financial Information Disclosure [Abstract] Total revenues Revenues Net earnings Basic earnings per share (usd per share) Earnings Per Share, Basic Diluted earnings per share (usd per share) Earnings Per Share, Diluted Realized gains (losses) on investments Additional Information Additional Financial Information Disclosure [Text Block] Debt Disclosure [Abstract] Long-term Debt Long-term Debt [Text Block] Stockholders' Equity Note [Abstract] Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Accumulated Change Postretirement Benefite Liability [Member] Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Accumulated Unrealized Gains on Investments, net [Member] Accumulated Net Unrealized Gain (Loss) and Other-than-Temporary Impairment [Member] Accumulated Net Unrealized Gain (Loss) and Other-than-Temporary Impairment [Member] Reclassification Adjustment for Other-than-Temporary Impairment [Member] Accumulated Other-than-Temporary Impairment Attributable to Parent [Member] Accumulated Unrealized Gains on Investments, Net [Member] Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Before Tax [Abstract] Accumulated other comprehensive income, beginning of period AOCI Including Portion Attributable to Noncontrolling Interest, before Tax Effect on other comprehensive income Other Comprehensive Income (Loss), before Tax Other comprehensive income before reclassification Other Comprehensive Income (Loss), before Reclassifications, before Tax Reclassicification adjustment Reclassicification from Accumulated Other Comprehensive Income, Current Period, Before Tax Reclassicification from Accumulated Other Comprehensive Income, Current Period, Before Tax Accumulated other comprehensive income, end of period Income Tax [Abstract] Other Comprehensive Income (Loss), Tax [Abstract] Accumulated other comprehensive income, beginning of period Accumulated Other Comprehensive Income (Loss), Tax Accumulated Other Comprehensive Income (Loss), Tax Other comprehensive income before reclassification Other Comprehensive Income (Loss) before Reclassifications, Tax Reclassicification adjustment Reclassicification from Accumulated Other Comprehensive Income, Current Period, Tax Reclassicification from Accumulated Other Comprehensive Income, Current Period, Tax Effect on other comprehensive income Accumulated other comprehensive income, end of period Net [Abstract] Other Comprehensive Income (Loss), Net of Tax [Abstract] Accumulated other comprehensive income, beginning of period Accumulated Other Comprehensive Income (Loss), Net of Tax Reclassicification adjustment Reclassicification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Reclassicification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Other comprehensive income before reclassification Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Other Comprehensive Income (Loss), Net of Tax Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive income, end of period Compensation and Retirement Disclosure [Abstract] Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract] Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract] Discount rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Health care cost trend rate assumed for next fiscal year Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year Ultimate health care cost trend rate Defined Benefit Plan, Ultimate Health Care Cost Trend Rate Year that rate reaches ultimate trend rate Defined Benefit Plan, Year that Rate Reaches Ultimate Trend Rate Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract] Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract] Next twelve months Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months Year two Defined Benefit Plan, Expected Future Benefit Payments, Year Two Year three Defined Benefit Plan, Expected Future Benefit Payments, Year Three Year four Defined Benefit Plan, Expected Future Benefit Payments, Year Four Year five Defined Benefit Plan, Expected Future Benefit Payments, Year Five Years five through ten Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter Total expected future benefit payments Defined Benefit Plan, Expected Future Benefit Payments, Total Defined Benefit Plan, Expected Future Benefit Payments, Total Estimated future employer contributions in next fiscal year Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year Schedule of Error Corrections and Prior Period Adjustment Restatement [Table] Schedule of Error Corrections and Prior Period Adjustment Restatement [Table] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Error Corrections and Prior Period Adjustments Restatement [Line Items] Error Corrections and Prior Period Adjustments Restatement [Line Items] Installment and other fee income ipcc_InstallmentandOtherFeeIncome Installment and other fees collected from policyholders. Schedule of allowances for uncollectible accounts Allowance for Credit Losses on Financing Receivables [Table Text Block] Investments, Debt and Equity Securities [Abstract] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Severity of Unrealized Loss [Axis] Severity of Unrealized Loss [Axis] Severity of Unrealized Loss [Axis] Severity of Unrealized Loss [Domain] Severity of Unrealized Loss [Domain] Severity of Unrealized Loss [Domain] Less Than 5% as a Percentage of Amortized Cost or Cost Less Than Five Percent as a Percentage of Amortized Cost or Cost [Member] Less Than Five Percent as a Percentage of Amortized Cost or Cost [Member] 5% - 10% as a Percentage of Amortized Cost or Cost Between Five Percent and Ten Percent as a Percentage of Amortized Cost or Cost [Member] Between Five Percent and Ten Percent as a Percentage of Amortized Cost or Cost [Member] Greater Than 10% as a Percentage of Amortized Cost or Cost Greater Than Ten Percent as a Percentage of Amortized Cost or Cost [Member] Greater Than Ten Percent as a Percentage of Amortized Cost or Cost [Member] Age of Unrealized Loss [Axis] Age of Unrealized Loss [Axis] Age of Unrealized Loss [Axis] Age of Unrealized Loss [Domain] Age of Unrealized Loss [Domain] Age of Unrealized Loss [Domain] 0-3 months Zero To Three Months [Member] Zero To Three Months [Member] 3-6 months Three To Six Months [Member] Three To Six Months [Member] 6-9 months Six To Nine Months [Member] Six To Nine Months [Member] 9-12 months Nine To Twelve Months [Member] Nine To Twelve Months [Member] Greater than twelve months Greater Than Twelve Months [Member] Greater Than Twelve Months [Member] Schedule of Available-for-sale Securities [Line Items] Schedule of Available-for-sale Securities [Line Items] Fair Value of Securities with Unrealized Losses, 0-12 Months Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Fair Value of Securities with Unrealized Losses, Greater Than 12 Months Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Fair Value of Securities with Unrealized Losses Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Total Gross Unrealized Losses, 0-12 Months Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Total Gross Unrealized Losses, Greater Than 12 Months Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Total Gross Unrealized Losses Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss Document Information [Abstract] Document Information [Abstract] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Public Float Entity Public Float Consolidated Statements of Earnings [Abstract] Consolidated Statements of Earnings [Abstract] Revenues: Revenues [Abstract] Earned premium Premiums Earned, Net Earned premium, percent change Increase Decrease in Premiums Earned, Net, Property And Casualty Increase Decrease in Premiums Earned, Net, Property And Casualty Installment and other fee income, percent change Increase Decrease Installment and Other Fee Income Increase Decrease Installment and Other Fee Income Net investment income Net Investment Income Net investment income, percent change Increase Decrease in Net Investment Income Increase Decrease in Net Investment Income Net realized gains on investments Net realized gains on investments, percent change Increase Decrease Realized Investment Gains Losses Increase Decrease Realized Investment Gains Losses Gain on sale of subsidiaries Gain (Loss) on Disposition of Stock in Subsidiary Gain on sale of subsidiaries, percent change Increase Decrease in Gain or Loss On Sale of Stock In Subsidiary Increase Decrease in Gain or Loss On Sale of Stock In Subsidiary Other income Other Income Other income, percent change Increase Decrease in Other Income Increase Decrease in Other Income Total revenues Total revenues, percent change Increase Decrease in Revenues Increase Decrease in Revenues Costs and Expenses: Costs and Expenses [Abstract] Losses and loss adjustment expenses Policyholder Benefits and Claims Incurred, Net, Property, Casualty and Liability Losses and loss adjustment expense, percent change Increase Decrease in Incurred Claims Property Casualty And Liability Increase Decrease in Incurred Claims Property Casualty And Liability Commissions and other underwriting expenses Commissions and Other Underwriting Expenses Commission expense incurred to persons or entities for generating or placing insurance policies with the company, determined as percentage of policy premiums, as well as costs incurred during the period, such as those relating to general administration and policy maintenance, that do not vary with and are not primarily related to the acquisition or renewal of insurance contracts. Commissions and other underwriting expenses, percent change Increase Decrease in Commissions And Other Underwriting Expenses Increase Decrease in Commissions And Other Underwritting Expenses Interest expense Interest Expense Interest expense, percent change Increase Decrease in Interest Expense Increase Decrease in Interest Expense Corporate general and administrative expenses General and Administrative Expense Corporate general and administrative expenses, percent change Increase Decrease in General and Administrative Expense Increase Decrease in General and Administrative Expense Loss on redemption of long-term debt Other expenses Other Cost and Expense, Operating Other expenses, percent change Increase Decrease in Other Cost and Expense Operating Increase Decrease in Other Cost and Expense Operating Total costs and expenses Benefits, Losses and Expenses Total costs and expenses, percent change Increase Decrease in Benefits Losses and Expenses Increase Decrease in Benefits Losses and Expenses Earnings before income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest Earnings before income taxes, percent change Increase Decrease in Income Loss from Continuing Operations Before Income Taxes Minority Interest and Inome Loss from Equity Method Investments Increase Decrease in Income Loss from Continuing Operations Before Income Taxes Minority Interest and Inome Loss from Equity Method Investments Income Taxes Provision for income taxes Income Tax Expense (Benefit) Provision for income taxes, percent change Increase Decrease in Income Tax Expense Benefit Increase Decrease in Income Tax Expense Benefit Net Earnings Net Earnings, percent change Increase Decrease in Net Income Loss Increase Decrease in Net Income Loss Net Earnings per Common Share: Earnings Per Share [Abstract] Basic earnings per share, percent change Increase Decrease in Earnings Per Share Basic Increase Decrease in Earnings Per Share Basic Diluted earnings per share, percent change Increase Decrease in Earnings Per Share Diluted Increase Decrease in Earnings Per Share Diluted Average Number of Common Shares: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Basic average number of common shares Weighted Average Number of Shares Outstanding, Basic Basic average number of common shares, percent change Increase Decrease in Weighted Average Number of Shares Outstanding Basic Increase Decrease in Weighted Average Number of Shares Outstanding Basic Diluted average number of common shares Weighted Average Number of Shares Outstanding, Diluted Diluted average number of common shares, percent change Increase Decrease in Weighted Average Number of Diluted Shares Outstanding Increase Decrease in Weighted Average Number of Diluted Shares Outstanding Cash Dividends per Common Share (usd per share) Common Stock, Dividends, Per Share, Cash Paid Cash Dividends per Common Share, percent change Increase Decrease in Common Stock Dividends Per Share Cash Paid Increase Decrease in Common Stock Dividends Per Share Cash Paid Net realized gains before impairment losses Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments Net realized gains before impairment losses, percent change Increase Decrease in Avaiable for Sale Securities Gross Realized Gain Loss Excluding Other than Temporary Impairments Increase Decrease in Avaiable for Sale Securities Gross Realized Gain Loss Excluding Other than Temporary Impairments Total other-than-temporary impairment (OTTI) losses Other than Temporary Impairment Losses, Investments, Available-for-sale Securities Total other-than-temporary impairment (OTTI) losses, percent change Increase Decrease in Impairment Losses Investment Available for Sale Securities Increase Decrease in Impairment Losses Investment Available for Sale Securities Non-credit portion in other comprehensive income Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Loss, before Tax, Including Portion Attributable to Noncontrolling Interest, Available-for-sale Securities Non-credit portion in other comprehensive income, percent change Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Loss, before Tax, Including Portion Attributable to Noncontrolling Interest, Securities, Percent Change Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Loss, before Tax, Including Portion Attributable to Noncontrolling Interest, Securities, Percent Change OTTI losses reclassified from other comprehensive income Impairment Loss Reclassified From Other Comprehensive Income To Earnings Other-than-temporary impairment losses reclassed from other comprehensive income to earnings. OTTI losses reclassified from other comprehensive income, percent change Increase Decrease in Impairment Loss Reclassified from Other Comprehensive Income To Earnings Increase Decrease in Impairment Loss Reclassified from Other Comprehensive Income To Earnings Net impairment losses recognized in earnings Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities Net impairment losses recognized in earnings, percent change Increase Decrease in Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net Available for Sale Securities Increase Decrease in Other Than Temporary Impairment Losses Investments Portion Recognized In Earnings Net Available for Sale Securities Loss Contingency [Abstract] Legal and Regulatory Proceedings Legal Matters and Contingencies [Text Block] Benefit Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Fair Value Disclosures [Abstract] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping, Disclosure Item Amounts [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Carrying Value Reported Value Measurement [Member] Fair Value Estimate of Fair Value Measurement [Member] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] Fixed maturities Debt Securities [Member] Equity securities Equity Securities [Member] Short-term investments Short-term Investments [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Available-for-sale securities Available-for-sale Securities Total cash and investments Available-for-sale Securities and Cash and Cash Equivalents, Fair Value Disclosure Available-for-sale Securities and Cash and Cash Equivalents, Fair Value Disclosure Long-term debt Notes Payable, Fair Value Disclosure Insurance [Abstract] Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] Balance at Beginning of Period [Abstract] Balance at Beginning of Period [Abstract] Balance at Beginning of Period [Abstract] Unpaid losses on known claims Liability for Unpaid Claims, Reported Claims, Property and Casualty, Amount Liability for Unpaid Claims, Reported Claims, Property and Casualty, Amount IBNR losses Liability for Unpaid Claims, Incurred but Not Reported Claims (IBNR), Property and Casualty, Amount Liability for Unpaid Claims, Incurred but Not Reported Claims (IBNR), Property and Casualty, Amount LAE Liability for Claims Adjustment Expense, Property and Casualty, Amount Liability for Claims Adjustment Expense, Property and Casualty, Amount Total unpaid losses and LAE Liability for Claims and Claims Adjustment Expense Reinsurance recoverables Reinsurance Recoverables, Incurred but Not Reported Claims Unpaid losses and LAE, net of reinsurance recoverables Liability for Unpaid Claims and Claims Adjustment Expense, Net Current Activity [Abstract] Current Activity [Abstract] Current Activity [Abstract] Loss and LAE incurred, current accident year Current Year Claims and Claims Adjustment Expense Loss and LAE incurred, prior accident years Prior Year Claims and Claims Adjustment Expense Total loss and LAE incurred Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims Loss and LAE payments, current accident year Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year Loss and LAE payments, prior accident years Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years Total loss and LAE payments Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid Balance at End of Period [Abstract] Balance at End of Period [Abstract] Balance at End of Period [Abstract] Unpaid losses and LAE, net of reinsurance recoverables Add back reinsurance recoverables Reinsurance Recoverables, Excluding Paid Losses Recoverables Reinsurance Recoverables, Excluding Paid Losses Recoverable Total unpaid losses and LAE Unpaid losses on known claims IBNR losses LAE Total unpaid losses and LAE Income Tax Disclosure [Abstract] Reconciliation of provision for income taxes Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Components of income tax expense Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Schedule of deferred tax assets and liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Schedule of Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Table] Schedule of Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Table] Restricted stock Restricted Stock [Member] Stock options Employee Stock Option [Member] Performance Shares Performance Shares [Member] Computation of net earnings per share Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items] Average basic shares outstanding (shares) Dilutive shares Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Average diluted shares outstanding (shares) Schedule of Deferred Compensation Arrangement with Individual, Postretirement Benefits [Table] Schedule of Deferred Compensation Arrangement with Individual, Postretirement Benefits [Table] Defined Contribution Plan, Employer Match Threshold [Axis] Defined Contribution Plan, Employer Match Threshold [Axis] Defined Contribution Plan, Employer Match Threshold [Axis] Defined Contribution Plan, Employer Match Threshold [Domain] Defined Contribution Plan, Employer Match Threshold [Domain] [Domain] for Defined Contribution Plan, Employer Match Threshold [Axis] Threshold One [Member] Threshold One [Member] Threshold One [Member] Threshold Two [Member] Threshold Two [Member] Threshold Two [Member] Investment [Axis] Investment [Axis] Investment [Domain] Investment [Domain] Rabbi Trust [Member] Rabbi Trust [Member] Rabbi Trust [Member] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Domain] Defined Benefit Plan and Other Postretirement Benefit Plan [Domain] Supplemental Employee Retirement Plan, Defined Benefit [Member] Supplemental Employee Retirement Plan [Member] Deferred Bonus and Profit Sharing Arrangements, Individual Contracts, Type of Deferred Compensation [Axis] Deferred Bonus and Profit Sharing Arrangements, Individual Contracts, Type of Deferred Compensation [Axis] Type of Deferred Compensation, All Types [Domain] Deferred Bonus and Profit Sharing Arrangement, Individual Contract, Type of Deferred Compensation [Domain] Deferred compensation, excluding share-based payments and retirement benefits [Member] Deferred Compensation, Excluding Share-based Payments and Retirement Benefits [Member] Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items] Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items] Maximum employee annual contribution Defined Contribution Plan, Maximum Employee Annual Contribution Per Employee, Amount Defined Contribution Plan, Maximum Employee Annual Contribution Per Employee, Amount Maximum employee annual contribution, percent Defined Contribution Plan, Maximum Employee Annual Contribution Per Employee, Percent Defined Contribution Plan, Maximum Employee Annual Contribution Per Employee, Percent Minimum age eligible for catch-up contributions Defined Contribution Plan, Catch-up Contributions, Minimum Age of Employees Defined Contribution Plan, Catch-up Contributions, Minimum Age of Employees Maximum employee annual catch-up contribution Defined Contribution Plan, Catch-up Contributions, Maximum Employee Annual Contribution Per Employee, Amount Defined Contribution Plan, Catch-up Contributions, Maximum Employee Annual Contribution Per Employee, Amount Maximum employer annual contribution per employee, (percent) Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent Employer match after initial threshold, percent Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay Maximum annual contribution per employee, amount Defined Contribution Plan, Maximum Annual Contributions Per Employee, Amount Employer contribution Deferred Compensation Arrangement with Individual, Employer Contribution Statutory annual compensaiton limit Deferred Compensation Arrangement with Individual, Statutory Annual Compensaiton Limit Deferred Compensation Arrangement with Individual, Statutory Annual Compensaiton Limit Investments in the rabbi trust Assets Held-in-trust Recorded liability Deferred Compensation Arrangement with Individual, Recorded Liability Interest expense Deferred Compensation Arrangement with Individual, Increase to Liability From Interest Earned During Period Deferred Compensation Arrangement with Individual, Increase to Liability From Interest Earned During Period Unrecognized actuarial gain, gross Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax Unrecognized actuarial gain, net Defined Benefit Plan, Accumulated Other Comprehensive Income Net Gains (Losses), after Tax Plan amendment Defined Benefit Plan, Plan Amendments Net prior service cost, before tax Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax Net prior service cost, after tax Defined Benefit Plan, Accumulated Other Comprehensive Income Net Prior Service Cost (Credit), after Tax Amortization of net gains (losses) Defined Benefit Plan, Future Amortization of Gain (Loss) Amortization of prior service cost Defined Benefit Plan, Estimated Amortization of Prior Service Cost (Credit) in Next Fiscal Year Defined Benefit Plan, Estimated Amortization of Prior Service Cost (Credit) in Next Fiscal Year Funded status at end of year Defined Benefit Plan, Funded Status of Plan Cost recognized Defined Contribution Plan, Cost Recognized Benefit obligation Defined Benefit Plan, Benefit Obligation Range [Axis] Range [Axis] Range [Domain] Range [Domain] Maximum [Member] Maximum [Member] Minimum [Member] Minimum [Member] Less than 12 Months Less Than Twelve Months [Member] Less Than 12 Months [Member] 12 Months or More 12 Months or more [Member] 12 Months or more [Member] 12 Months or more [Member] U.S. government US Government Debt Securities [Member] State and municipal US States and Political Subdivisions Debt Securities [Member] Mortgage-backed securities: Collateralized Mortgage Backed Securities [Member] Residential Residential Mortgage Backed Securities [Member] Commercial Commercial Mortgage Backed Securities [Member] Asset-backed securities Asset-backed Securities, Securitized Loans and Receivables [Member] Corporates Corporate Debt Securities [Member] Less than 12 Months., Number of Securities with Unrealized Losses Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year Less than 12 Months, Fair Value Less than 12 months, Gross Unrealized Losses Unrealized Losses as Percentage of Cost Unrealized Losses as Percentage of Cost Unrealized Losses as Percentage of Cost Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions 12 Months or More, Number of Securities with Unrealized Losses Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year 12 Months or More, Fair Value 12 Months or More, Gross Unrealized Losses Threshold for impairment evaluation, percentage of book value Threshold for Impairment Evaluation, Percentage of Book Value Threshold for Impairment Evaluation, Percentage of Book Value Threshold for impairment evaluation, unrealized loss amount Threshold for Impairment Evaluation, Unrealized Loss Amount Threshold for Impairment Evaluation, Unrealized Loss Amount Investments by Unrealized Gain or Loss Position [Axis] Investments by Unrealized Gain or Loss Position [Axis] Investments by Unrealized Gain or Loss Position [Axis] Investments by Unrealized Gain or Loss Position [Domain] Investments by Unrealized Gain or Loss Position [Domain] Investments by Unrealized Gain or Loss Position [Domain] Securities with Unrealized Gains Securities with Unrealized Gains [Member] Securities with Unrealized Gains [Member] Securities with Unrealized Losses Securities with Unrealized Losses [Member] Securities with Unrealized Losses [Member] Securities with No Unrealized Gains or Losses Securities with No Unrealized Gains or Losses [Member] Securities with No Unrealized Gains or Losses [Member] One year or less, fair value Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value One year or less, amortized cost Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis After one year through five years, fair value Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value After one year through five years, amortized cost Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis After five years through ten years, fair value Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value After five years through ten years, amortized cost Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Amortized Cost Basis After ten years, fair value Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value After ten years, amortized cost basis Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis Mortgage-backed, asset-backed and collateralized mortgage obligations, fair value Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value Mortgage-backed, asset-backed and collateralized mortgage obligations, amortized cost Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis Fixed maturities Available-for-sale Securities, Debt Securities Fixed maturities, amortized costs Available-for-sale Debt Securities, Amortized Cost Basis Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] Operating Loss Carryforwards [Line Items] Operating Loss Carryforwards [Line Items] Current Current Income Tax Expense (Benefit) Deferred Deferred Income Tax Expense (Benefit) Provision for income taxes Commitments and Contingencies Disclosure [Abstract] Schedule of Operating Leased Assets [Table] Schedule of Operating Leased Assets [Table] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Automobiles [Member] Automobiles [Member] Entity by Location [Axis] Entity by Location [Axis] Location [Domain] Location [Domain] Birmingham, Alabama [Member] Miami, Florida [Member] Miami, Florida [Member] Los Angeles, California [Member] Los Angeles, California [Member] Los Angeles, California [Member] Operating Leased Assets [Line Items] Operating Leased Assets [Line Items] Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] 2013 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2014 Operating Leases, Future Minimum Payments, Due in Two Years 2015 Operating Leases, Future Minimum Payments, Due in Three Years 2016 Operating Leases, Future Minimum Payments, Due in Four Years 2017 Operating Leases, Future Minimum Payments, Due in Five Years Thereafter Operating Leases, Future Minimum Payments, Due Thereafter Total Operating Leases, Future Minimum Payments Due Operating leases, lease expiration period Operating Leases, Lease Expiration, Term Operating Leases, Lease Expiration, Term Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] 2013 Capital Leases, Future Minimum Payments Due, Next Twelve Months 2014 Capital Leases, Future Minimum Payments Due in Two Years 2015 Capital Leases, Future Minimum Payments Due in Three Years 2016 Capital Leases, Future Minimum Payments Due in Four Years 2017 Capital Leases, Future Minimum Payments Due in Five Years Thereafter Capital Leases, Future Minimum Payments Due Thereafter Total Capital Leases, Future Minimum Payments Due Lease expense Operating Leases, Rent Expense Sublease income Operating Leases, Income Statement, Sublease Revenue Total Operating Leases, Rent Expense, Net Guarantor Obligations, Maximum Exposure, Undiscounted Guarantor Obligations, Maximum Exposure, Undiscounted Schedule of quarterly financial information Schedule of Quarterly Financial Information [Table Text Block] Schedule of Prior Period Adjustments Schedule of Error Corrections and Prior Period Adjustments [Table Text Block] Income Taxes Income Tax Disclosure [Text Block] Statutory accounting practices disclosure Statutory Accounting Practices Disclosure [Table Text Block] Reinsurance Disclosures [Abstract] Reinsurance Reinsurance [Text Block] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Senior Notes Due 2022 Senior Notes Due 2022 [Member] Senior Notes Due 2022 [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving Credit Facility Revolving Credit Facility [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Senior Notes Senior Notes [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Principal amount Debt Instrument, Face Amount Coupon rate Debt Instrument, Interest Rate, Stated Percentage Capitalized debt issuance costs Debt Issuance Cost Fair value spread to U.S. Treasury Note rate Fair Value, Debt Instrument, Valuation Basis Spread Fair Value, Debt Instrument, Valuation Basis Spread Treasury note rate used for debt fair value calculation Fair Value, Debt Instrument, Valuation Basis, US Treasury Note Rate Fair Value, Debt Instrument, Valuation Basis, US Treasury Note Rate Interest payments on debt Interest Paid Credit facility capacity Line of Credit Facility, Current Borrowing Capacity Term of revolving credit facility Debt Instrument, Term Unrealized holding gains (losses) on securities arising during the period, pre-tax Realized (gains) losses on securities sold, pre-tax Impairment losses recognized in net earnings, pre-tax Unrealized gains (losses) on investments, net, pre-tax Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss) before Taxes Unrealized holding gains (losses) on securities arising during the period, tax effects Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax Realized (gains) losses on securities sold, tax effects Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments, Tax Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments, Tax Impairment losses recognized in net earnings, tax effect Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities, Tax Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities, Tax Change in unrealized gains (losses) on marketable securities, net, tax effects Available-for-sale Securities, Income Tax Expense on Change in Unrealized Holding Gain (Loss) Unrealized holding gains (losses) on securities arising during period, net of tax Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax Realized (gains) losses on securities sold, net of tax Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments, Net of Tax Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments, Net of Tax Impairment loss recognized in earnings, net of tax Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities, Net of Tax Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities, Net of Tax Change in unrealized gains (losses) on marketable securities, net, net of tax Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax Deferred tax asset valuation allowance Deferred Tax Assets, Valuation Allowance Direct written premium, gross amount Reinsurance Premiums for Insurance Companies, Direct Written Premium, Gross Amount Reinsurance Premiums for Insurance Companies, Direct Written Premium, Gross Amount Direct written premium, amount assumed from other companies Reinsurance Premiums for Insurance Companies, Direct Written Premium, Amount Assumed From Other Companies Reinsurance Premiums for Insurance Companies, Direct Written Premium, Amount Assumed From Other Companies Direct written premium, amount ceded to other companies Reinsurance Premiums for Insurance Companies, Direct Written Premium, Amount Ceded to Other Companies Reinsurance Premiums for Insurance Companies, Direct Written Premium, Amount Ceded to Other Companies Direct written premium, net amount Reinsurance Premiums for Insurance Companies, Direct Written Premium, Net Amount Reinsurance Premiums for Insurance Companies, Direct Written Premium, Net Amount Direct written premium, percentage of amount assumed to net Reinsurance Premiums for Insurance Companies, Direct Written Premium, Percentage of Amount Assumed to Net Reinsurance Premiums for Insurance Companies, Direct Written Premium, Percentage of Amount Assumed to Net Direct earned premium, gross amount Reinsurance Premiums for Insurance Companies, Direct Earned Premium, Gross Amount Reinsurance Premiums for Insurance Companies, Direct Earned Premium, Gross Amount Direct earned premium, amount assumed from other companies Reinsurance Premiums for Insurance Companies, Direct Earned Premium, Amount Assumed From Other Companies Reinsurance Premiums for Insurance Companies, Direct Earned Premium, Amount Assumed From Other Companies Direct earned premium, amount ceded to other companies Reinsurance Premiums for Insurance Companies, Direct Earned Premium, Amount Ceded to Other Companies Reinsurance Premiums for Insurance Companies, Direct Earned Premium, Amount Ceded to Other Companies Direct earned premium, net amount Reinsurance Premiums for Insurance Companies, Direct Earned Premium, Net Amount Reinsurance Premiums for Insurance Companies, Direct Earned Premium, Net Amount Direct earned premium, percentage of amount assumed to net Reinsurance Premiums for Insurance Companies, Direct Earned Premium, Percentage of Amount Assumed to Net Reinsurance Premiums for Insurance Companies, Direct Earned Premium, Percentage of Amount Assumed to Net Share-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Quarterly Operating Results Quarterly Financial Information [Text Block] Deferred tax assets: Deferred Tax Assets, Net [Abstract] Discount on loss reserves Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Provision for Loan Losses Unearned premium reserve Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Unearned Premiums Reserve Bad debts Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts Accrued bonuses Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Bonuses Deferred compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Compensation Long-term incentive compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost Other Deferred Tax Assets, Other Gross deferred tax assets Deferred Tax Assets, Gross Valuation allowance for deferred tax assets Deferred Tax Assets, Valuation Allowance, Other Deferred Tax Assets, Valuation Allowance, Other Deferred tax assets, net of valuation allowance Deferred Tax Assets, Net of Valuation Allowance Deferred tax liabilities: Deferred Tax Liabilities, Gross [Abstract] Deferred policy acquisition costs Deferred Tax Liabilities, Deferred Expense Investment securities – unrealized gains Deferred Tax Liabilities, Other Comprehensive Income Other Deferred Tax Liabilities, Other Net deferred tax assets Deferred Tax Liabilities, Gross Net deferred tax assets Deferred Tax Assets, Net Current income taxes Income Taxes Receivable (Payable), Current Income Taxes Receivable (Payable), Current Current and deferred income taxes Deferred Tax Assets, Net and Income Taxes Receivable, Current Deferred Tax Assets, Net and Income Taxes Receivable, Current Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Additional Paid-in Capital Additional Paid-in Capital [Member] Retained Earnings Retained Earnings [Member] Accumulated Other Comprehensive Income, Net of Tax AOCI Attributable to Parent [Member] Treasury Stock Treasury Stock [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning Balance Stockholders' Equity Attributable to Parent Net change in postretirement benefit liability Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax Change in unrealized gain on investments Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax, Excluding Other Than Temporary Impairment Portion Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax, Excluding Other Than Temporary Impairment Portion Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax, Excluding Other Than Temporary Impairment Portion Change in non-credit component of impairment losses on fixed maturities Non Credit Portion Of Other Than Temporary Impairments Recognized In Other Comprehensive Income Non-Credit Portion of Other-Than-Temporary Impairments Recognized in Other Comprehensive Income Dividends paid to common shareholders Dividends, Common Stock, Cash Shares issued and share-based compensation expense, including tax benefit Stock Issued During Period Value Value of stock issued during the period as a result of any share-based compensation plan. Acquisition of treasury stock Treasury Stock, Value, Acquired, Par Value Method Ending Balance Accumulated Other Comprehensive Income Comprehensive Income (Loss) Note [Text Block] Fair value of plan assets Defined Benefit Plan, Fair Value of Plan Assets Funded status at end of year Contributions made after the measurement date Defined Benefit Plan, Contributions After the Measurement Date Defined Benefit Plan, Contributions After the Measurement Date Unrecognized actuarial net (gain) loss Defined Benefit Plan, Unrecognized Actuarial Gain (Loss), Net Defined Benefit Plan, Unrecognized Actuarial Gain (Loss), Net Unrecognized prior service cost Defined Benefit Plan, Unrecognized Prior Service Cost (Credit) Defined Benefit Plan, Unrecognized Prior Service Cost (Credit) Number of positions held with unrealized gains Available-for-sale, Securities in Unrealized Gain Positions, Qualitative Disclosure, Number of Positions Available-for-sale, Securities in Unrealized Gain Positions, Qualitative Disclosure, Number of Positions Number of positions held with unrealized losses Number of positions held that individually exceed unrealized gains of $500,000 Available-for-sale, Securities in Unrealized Gain Positions, Qualitative Disclosure, Number of Positions With Unrealized Gains Over Five Hundred Thousand Dollars Available-for-sale, Securities in Unrealized Gain Positions, Qualitative Disclosure, Number of Positions With Unrealized Gains Over Five Hundred Thousand Dollars Individual unrealized gain threshold Available-for-sale, Securities In Unrealized Loss Positions, Qualitative Disclosure, Individual Unrealized Gain Threshold Available-for-sale, Securities In Unrealized Loss Positions, Qualitative Disclosure, Individual Unrealized Gain Threshold Number of positions held that individually exceed unrealized losses of $500,000 Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions With Unrealized Losses Over Five Hundred Thousand Dollars Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions With Unrealized Losses Over Five Hundred Thousand Dollars Individual unrealized loss threshold Available-for-sale, Securities In Unrealized Loss Positions, Qualitative Disclosure, Individual Unrealized Loss Threshold Available-for-sale, Securities In Unrealized Loss Positions, Qualitative Disclosure, Individual Unrealized Loss Threshold Percentage of positions held with unrealized gains that were investment grade Available-for-sale, Securities in Unrealized Gain Positions, Qualitative Disclosure, Percentage of Positions That Were Investment Grade Available-for-sale, Securities in Unrealized Gain Positions, Qualitative Disclosure, Percentage of Positions That Were Investment Grade Percentage of positions held with unrealized losses that were investment grade Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Percentage of Positions That Were Investment Grade Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Percentage of Positions That Were Investment Grade Percentage of fair value held with unrealized gains that were investment grade Available-for-sale, Securities in Unrealized Gain Positions, Qualitative Disclosure, Percentage of Fair Value Held That Were Investment Grade Positions Available-for-sale, Securities in Unrealized Gain Positions, Qualitative Disclosure, Percentage of Fair Value Held That Were Investment Grade Positions Percentage of fair value held with unrealized losses that were investment grade Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Percentage of Fair Value Held That Were Investment Grade Positions Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Percentage of Fair Value Held That Were Investment Grade Positions Statutory Information Statutory Accounting Disclosure [Text Block] Statutory Accounting Disclosure [Text Block] Schedule of reinsurance assumed and ceded Schedule of Reinsurance Assumed and Ceded [Table Text Block] Schedule of Reinsurance Assumed and Ceded [Table Text Block] Subsequent Events [Abstract] Schedule of Earnings per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Statutory net earnings Statutory Accounting Practices, Statutory Net Income Amount Statutory policyholders' surplus Statutory Accounting Practices, Statutory Capital and Surplus, Balance Statutory capital and surplus required Statutory Accounting Practices, Statutory Capital and Surplus Required Amount available for dividend distribution without prior approval from regulatory agency Statutory Accounting Practices, Statutory Amount Available for Dividend Payments without Regulatory Approval Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Fair value of plan assets at beginning of year Employer contributions Defined Benefit Plan, Contributions by Employer Participant contributions Defined Benefit Plan, Contributions by Plan Participants Gross benefits paid Defined Benefit Plan, Benefits Paid Fair value of plan assets at end of year Significant Reporting and Accounting Policies Significant Accounting Policies [Text Block] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Real Estate Related [Member] Land, Buildings and Improvements [Member] Computer Equipment & Software [Member] Computer Equipment and Software [Member] Computer Equipment and Software [Member] Furniture & Fixtures [Member] Furniture and Fixtures [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Gross Asset Property, Plant and Equipment, Gross Accumulated Depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Net Asset Property, Plant and Equipment, Net Capital Leases [Abstract] Leases, Capital [Abstract] Capital leases net of depreciation Capital Leases, Balance Sheet, Assets by Major Class, Net Capital lease accumulated depreciation Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation 2013 Plan 2013 Plan [Member] 2013 Plan [Member] Common stock Title of Individual [Axis] Title of Individual [Axis] Relationship to Entity [Domain] Relationship to Entity [Domain] Officers Officer [Member] Shares reserved for future issuance (shares) Common Stock, Capital Shares Reserved for Future Issuance Collateralized mortgage obligations Collateralized Debt Obligations [Member] Amortized Cost or Cost Available-for-sale Securities, Amortized Cost Basis Gross Unrealized Gains Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax Gross Unrealized Losses Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax Fair Value OTTI Recognized in Accumulated OCI Accumulated Other Comprehensive Income (Loss), Other than Temporary Impairment, Not Credit Loss, Net of Tax, Available-for-sale, Debt Securities Outstanding Investments Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Interest income on fixed maturities, cash and cash equivalents Investment Income, Interest Dividends on equity securities Investment Income, Dividend Gross investment income Investment Income, Interest and Dividend Investment expenses Investment Income, Investment Expense Net investment income Investment Income, Net Prior Plan Prior Plan [Member] Prior Plan [Member] Non-employee Directors' Stock Non-employee Directors' Stock [Member] Non-employee Directors' Stock [Member] Shares issued, net of forfeitures (shares) Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Proceeds from sale of securities Proceeds from Sale of Available-for-sale Securities Receivable for securities sold Receivable for Investments Sold Receivable For Investments Sold Gross realized gains on sale of securities Available-for-sale Securities, Gross Realized Gains Gross realized losses on sale of securities Available-for-sale Securities, Gross Realized Losses Schedule of Shares Issued by Plan Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block] Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block] Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block] Schedule of Nonvested Restricted Stock Shares Activity Nonvested Restricted Stock Shares Activity [Table Text Block] Valuation assumptions of stock options granted Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Stock option activity Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] Statement of Financial Position [Abstract] Assets Assets [Abstract] Investments: Investments [Abstract] Fixed maturities – at fair value (amortized cost $1,404,698 and $1,412,417) Equity securities – at fair value (cost $81,797 and $77,862) Available-for-sale Securities, Equity Securities Short-term investments - at fair value (amortized cost $5,214 and $803) Short-term Investments Total investments Investments Cash and cash equivalents Accrued investment income Accrued Investment Income Receivable Agents’ balances and premium receivable, net of allowances for doubtful accounts of $15,554 and $15,510 Premiums and Other Receivables, Net Property and equipment, net of accumulated depreciation of $71,445 and $63,929 Prepaid reinsurance premium Prepaid Reinsurance Premiums Recoverables from reinsurers (includes $775 and $161 on paid losses and LAE) Reinsurance Recoverables Deferred policy acquisition costs Deferred Policy Acquisition Costs Current and deferred income taxes Other assets Other Assets Goodwill Goodwill Total assets Assets Liabilities: Liabilities [Abstract] Unpaid losses and loss adjustment expenses Liability for Claims and Claims Adjustment Expense, Property Casualty Liability Unearned premium Unearned Premiums Long-term debt (fair value $286,223 and $291,044) Long-term Debt Commissions payable Accrued Sales Commission Payable for securities purchased Payable For Investments Purchased The fair value of purchase transactions of fixed maturity investments available for sale pending settlement. Other liabilities Other Liabilities Total liabilities Liabilities Commitments and contingencies (See Note 14) Commitments and Contingencies Shareholders’ equity: Stockholders' Equity Attributable to Parent [Abstract] Common stock, no par value (50,000,000 shares authorized; 21,766,073 and 21,728,032 shares issued) Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital, Common Stock Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive income, net of tax Treasury stock, at cost (10,468,867 and 10,244,672 shares) Treasury Stock, Value Total shareholders’ equity Total liabilities and shareholders’ equity Liabilities and Equity Liability for unpaid losses and LAE Schedule of Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Recurring basis Fair Value, Measurements, Recurring [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Level 3 Fair Value, Inputs, Level 3 [Member] Asset Class [Axis] Asset Class [Axis] Fair Value by Asset Class [Domain] Asset Class [Domain] U.S. Government Asset-Backed Securities Asset-backed Securities [Member] Fair value level 3 category Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Level 3 reconciliation Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Balance at beginning of period Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Included in net earnings Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Included in other comprehensive income Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Transfers in Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 Transfers out Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 Balance at end of period Number of securities Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Number of Securities Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Number of Securities Number of non-binding securities Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Number of Non-binding Securities Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Number of Non-binding Securities Number of unaffiliated securities Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Number of Unaffiliated Securities Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Number of Unaffiliated Securities Number of nationally recognized securities Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Number of Nationally Recognized Security Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Number of Nationally Recognized Security Income tax payments Income Taxes Paid Federal statutory income tax rate (percent) Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Income tax reconciliation Effective Income Tax Rate Reconciliation, Amount [Abstract] Earnings before income taxes Income taxes at statutory rates Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount Dividends-received deduction Effective Income Tax Rate Reconciliation, Deduction, Dividends, Amount Tax-exempt interest Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount Adjustment to valuation allowance Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount Other Effective Income Tax Rate Reconciliation, Other Adjustments, Amount GAAP effective tax rate (percent) Effective Income Tax Rate Reconciliation, Percent Summarized information of investment portfolio Unrealized Gain (Loss) on Investments [Table Text Block] Unrealized loss by investment category and length of time Schedule of Unrealized Loss on Investments [Table Text Block] Summary of unrealized gains or losses Summary of Unrealized Gains and Losses on Investments [Table Text Block] Summary of Unrealized Gains and Losses on Investments [Table Text Block] Unrealized loss by age and severity Unrealized Loss on Investments by Age and Severity [Table Text Block] Unrealized Loss on Investments by Age and Severity [Table Text Block] Change in unrealized gains (losses) on marketable securities Schedule of Changes in Unrealized Gains (Losses) on Investments [Table Text Block] Schedule of Changes in Unrealized Gains (Losses) on Investments [Table Text Block] Progression of credit losses on fixed maturity securities Other than Temporary Impairment, Credit Losses Recognized in Earnings [Table Text Block] Scheduled maturities of fixed maturity securities Investments Classified by Contractual Maturity Date [Table Text Block] Investment income Investment Income [Table Text Block] Concentration Risk [Table] Concentration Risk [Table] Products and Services [Axis] Products and Services [Axis] Products and Services [Domain] Products and Services [Domain] Personal auto insurance [Member] Personal Auto Insurance [Member] Personal Auto Insurance [Member] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Sales Revenue, Product Line [Member] Sales Revenue, Product Line [Member] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Product Concentration Risk [Member] Product Concentration Risk [Member] Geographic Concentration Risk [Member] Geographic Concentration Risk [Member] Geographical [Axis] Geographical [Axis] Segment, Geographical [Domain] Geographical [Domain] California CALIFORNIA Concentration Risk [Line Items] Concentration Risk [Line Items] Portion of total gross written premiums (percent) Concentration Risk, Percentage Number of states primarilay writes insurance Number of States in Which Entity Primarily Operates Number of States in Which Entity Primarily Operates Available-for-sale securities Assets Held by Insurance Regulators Advertising costs Advertising Expense Deferred policy acquisition cost, amortization expense Deferred Policy Acquisition Cost, Amortization Expense Off premium charges Premiums Receivable, Allowance for Doubtful Accounts, Period to Charge Off Uncollected Amounts Premiums Receivable, Allowance for Doubtful Accounts, Period to Charge Off Uncollected Amounts Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Fair Value, Assets and Liabilities Measured on Recurring Basis Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Total cash and investments Percentage of total cash and investments Fair Value Disclosure, Percentage Fair Value Disclosure, Percentage of Total Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract] Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract] Post-retirement benefit obligations 1% increase Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation Post-retirement benefit obligations 1% decrease Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation Service and interest cost components 1% increase Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components Service and interest cost components 1% decrease Defined Benefit Plan, Effect of One Percentage Point Decrease on Service and Interest Cost Components Fair Value Fair Value Disclosures [Text Block] Schedule of net benefit obligation Schedule of Changes in Projected Benefit Obligations [Table Text Block] Schedule of weighted-average assumptions used Schedule of Assumptions Used [Table Text Block] Schedule of net benefit costs Schedule of Net Benefit Costs [Table Text Block] Schedule of health care cost trend rates Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates [Table Text Block] Schedule of changes in fair value of plan assets Schedule of Changes in Fair Value of Plan Assets [Table Text Block] Schedule of amounts recognized in balance sheet Schedule of Amounts Recognized in Balance Sheet [Table Text Block] Schedule of expected benefit payments Schedule of Expected Benefit Payments [Table Text Block] Insurance Reserves Liability for Future Policy Benefits and Unpaid Claims Disclosure [Text Block] Credit losses on fixed maturity securities Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward] Balance at beginning of year Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held Additions for previously impaired securities Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, Additional Credit Losses Additions for newly impaired securities Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, No Previous Impairment Securities sold and paydowns Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Securities Sold Balance at end of year Equity securities, cost Available-for-sale Equity Securities, Amortized Cost Basis Short-term investments, cost Available-for-sale Securities, Short-term Investments, Amortized Cost Agents' balances and premium receivable, allowance for doubtful accounts Property and equipment, accumulated depreciation Recoverable from reinsurers, paid losses and loss adjustement expenses Reinsurance Receivables Common stock, shares authorized Common Stock, Shares Authorized Common stock, shares issued Common Stock, Shares, Issued Treasury stock, shares Treasury Stock, Shares Computation of Earnings per Share Earnings Per Share [Text Block] Subsequent Event [Table] Subsequent Event [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Line Items] Subsequent Event [Line Items] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Net benefit obligation at end of year Service cost Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Participant contributions Assumption change Defined Benefit Plan, Changes in Assumptions Used Calculating Benefit Obligation Defined Benefit Plan, Changes in Assumptions Used Calculating Benefit Obligation Actuarial (gain) loss Defined Benefit Plan, Actuarial Gain (Loss) Gross benefits paid Net benefit obligation at end of year Nature of Operations Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Basis of Consolidation and Reporting Basis of Accounting, Policy [Policy Text Block] Estimates Use of Estimates, Policy [Policy Text Block] Investments Investment, Policy [Policy Text Block] Cash and Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Reinsurance Reinsurance Accounting Policy [Policy Text Block] Deferred Policy Acquisition Costs (DPAC) Deferred Policy Acquisition Costs, Policy [Policy Text Block] Goodwill Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block] Unpaid Losses and Loss Adjustment Expense (LAE) Unpaid Policy Claims and Claims Adjustment Expense, Policy [Policy Text Block] Premium and Receivables Insurance Premiums Revenue Recognition, Policy [Policy Text Block] Income Taxes Income Tax, Policy [Policy Text Block] Property and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Benefit Plans Pension and Other Postretirement Plans, Policy [Policy Text Block] Recently Issued Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Stock option activity Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Outstanding (in shares) Outstanding (in shares) Stock option activity, weighted-average exercise price Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract] Forecast Scenario, Forecast [Member] Awards granted (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Shares expected to vest (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Non-vested as of January 1, 2014 (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted (shares) Forfeited (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Non-vested as of December 31, 2014 (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Non-vested as of January 1, 2014 (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Non-vested as of December 31, 2014 (in dollars per share) Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] Service cost Interest cost Amortization of prior service cost Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Amortization of net cumulative (gain) loss Defined Benefit Plan, Amortization of Gains (Losses) Net periodic post-retirement benefit cost Defined Benefit Plan, Net Periodic Benefit Cost Fair value by hierarchy Fair Value, Assets Measured on Recurring Basis [Table Text Block] Fair value level 3 reconciliation Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Carrying value and estimated fair value Fair Value, by Balance Sheet Grouping [Table Text Block] Reinsurance Premiums for Insurance Companies, by Product Segment [Table] Reinsurance Premiums for Insurance Companies, by Product Segment [Table] Insurance Policy [Axis] Insurance Product Line [Axis] Reinsurance Premiums for Insurance Companies, by Product Segment [Domain] Insurance Product Line [Domain] Extra-Contractual Loss Reinsurance [Member] Extra-Contractual Loss Reinsurance [Member] Extra-Contractual Loss Reinsurance [Member] GAI [Member] Great American Insurance [Member] Great American Insurance [Member] Involuntary Pools and Associations [Member] Involuntary Pools and Associations [Member] Involuntary Pools and Associations [Member] Commercial Auto Insurance [Member] Commercial Auto Insurance [Member] Commercial Auto Insurance [Member] Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items] Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items] Liability for unpaid losses and LAE Assumed Liability for Unpaid Claims and Claims Adjustment Expense Amount assumed from other companies Assumed Premiums Earned Catastrophe Reinsurance, Additional Coverage, Third Party Recovery, Percentage Catastrophe Reinsurance, Additional Coverage, Third Party Recovery, Percentage Catastrophe Reinsurance, Additional Coverage, Third Party Recovery, Percentage Maximum third party recovery Catastrophe Reinsurance, Maximum Third Party Recovery Catastrophe Reinsurance, Maximum Third Party Recovery Minimum loss threshold per event Catastrophe Reinsurance, Minimum Loss Threshold Per Event Catastrophe Reinsurance, Minimum Loss Threshold Per Event Additional coverage, loss coverage base per event Catastrophe Reinsurance, Additional Coverage, Loss Coverage Base Per Event Catastrophe Reinsurance, Additional Coverage, Loss Coverage Base Per Event Additional coverage, minimum loss threshold per event Catastrophe Reinsurance, Additional Coverage, Minimum Loss Threshold Per Event Catastrophe Reinsurance, Additional Coverage, Minimum Loss Threshold Per Event PropertyCatastropheReinsuranceFirstLayer Property Catastrophe Reinsurance First Layer Property Catastrophe Reinsurance, First Layer First layer percentage reinsured Property Catastrophe Reinsurance, First Layer Percentage Property Catastrophe Reinsurance, First Layer Percentage Remaining layers percentage reinsured Property Catastrophe Reinsurance, Remaining Layers Percentage Property Catastrophe Reinsurance, Remaining Layers Percentage Reduction in losses due to amount ceded to other companies Policyholder Benefits and Claims Incurred, Ceded Schedule of future minimum rental payments for operating leases Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Schedule of Guarantor Obligations Schedule of Guarantor Obligations [Table Text Block] Schedule of Rent Expense Schedule of Rent Expense [Table Text Block]