Quarterly Financial Information Disclosure [Abstract] Quarterly Results of Operations (unaudited) Quarterly Financial Information [Text Block] Compensation and Retirement Disclosure [Abstract] Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] 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] Employee pension plan Pension Plan [Member] Supplemental employee retirement plan (SERP) Supplemental Employee Retirement Plan [Member] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Expected return on assets for 2017 Scenario, Forecast [Member] Postretirement benefits Defined Benefit Plan Disclosure [Line Items] Actuarial assumptions used to determine benefit obligations: Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract] Discount rate (as a percent) Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Pre-retirement discount rate (as a percent) Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation Pre Retirement Discount Rate The pre-retirement interest rate used to adjust for the time value of money for the plan. Post-retirement discount rate (as a percent) Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation Post Retirement, Discount Rate The post-retirement interest rate used to adjust for the time value of money for the plan. Compensation increases (as a percent) Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase Actuarial assumptions used to determine net periodic benefit cost: Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] Discount rate (as a percent) Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate Pre-retirement discount rate (as a percent) Defined Benefit Plan, Assumptions Used Calculating, Net Periodic Benefit Cost, Pre Retirement Discount Rate The pre-retirement interest rate used to adjust for the time value of money. Post-retirement discount rate (as a percent) Defined Benefit Plan, Assumptions Used Calculating, Net Periodic Benefit Cost, Post Retirement Discount Rate The post-retirement interest rate used to adjust for the time value of money. Expected return on assets (as a percent) Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets Rate of compensation increase (as a percent) Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase Accounting Policies [Abstract] Basis of presentation Basis of Accounting, Policy [Policy Text Block] Use of estimates Use of Estimates, Policy [Policy Text Block] Recent accounting standards New Accounting Pronouncements, Policy [Policy Text Block] Cash and cash equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Investments - Available-for-sale securities Marketable Securities, Available-for-sale Securities, Policy [Policy Text Block] Investments - Trading securities Marketable Securities, Trading Securities, Policy [Policy Text Block] Investments - Limited partnerships Equity Method Investments, Policy [Policy Text Block] Deferred taxes Income Tax, Policy [Policy Text Block] Fixed assets Fixed Assets [Policy Text Block] Disclosure of accounting policy for long-lived, physical assets used in the normal conduct of business and not intended for resale, and costs incurred for software when both (1) the software is acquired, internally developed, or modified solely to meet the entity's internal needs, and (2) during the software's development or modification, no substantive plan exists or is being developed to market the software externally. Includes, but is not limited to, basis of assets, depreciation, amortization and depletion methods used, including composite deprecation, estimated useful lives, capitalization policy, accounting treatment for costs incurred for repairs and maintenance, capitalized interest and the method it is calculated, disposals and impairments. Agent bonus estimates Commissions Expense, Policy [Policy Text Block] Recognition of management fee revenue Revenue Recognition, Services, Management Fees [Policy Text Block] Recognition of service agreement revenue Revenue Recognition, Services, Refundable Fees for Services [Policy Text Block] Earnings per share Earnings Per Share, Policy [Policy Text Block] Fair value of financial instruments Fair Value of Financial Instruments, Policy [Policy Text Block] Fair value of financial instruments, transfers between levels Fair Value Transfer, Policy [Policy Text Block] Commitments and contingencies Commitments and Contingencies, Policy [Policy Text Block] Income Tax Disclosure [Abstract] Schedule of provision for income taxes Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Schedule of reconciliation of the provision for income taxes, with amounts determined by applying the statutory federal income tax rate to pre-tax income Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Schedule of temporary differences and carry-forwards, which give rise to deferred tax assets and liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Fair Value Disclosures [Abstract] Fair Value Fair Value Disclosures [Text Block] Property Plant And Equipment and Finite-Lived Intangible Assets, Net By Type [Abstract] Property Plant And Equipment and Finite-Lived Intangible Assets, Net By Type [Abstract] Schedule of Property, Plant and Equipment and Finite-Lived Intangible Assets, Net by Type [Table] Schedule of Property, Plant and Equipment and Finite-Lived Intangible Assets, Net By Type [Table] Schedule of Property, Plant and Equipment and Finite-Lived Intangible Assets, Net By Type [Table] Property, Plant and Equipment and Finite-Lived Intangible Assets, Net By Type [Axis] Property, Plant and Equipment and Finite-Lived Intangible Assets, Net By Type [Axis] Property, Plant and Equipment and Finite-Lived Intangible Assets, Net By Type [Axis] Property, Plant and Equipment and Finite-Lived Intangible Assets, Net By Type [Domain] Property, Plant and Equipment and Finite-Lived Intangible Assets, Net By Type [Domain] Property, Plant and Equipment and Finite-Lived Intangible Assets, Net By Type [Domain] Software Software and Software Development Costs [Member] Equipment Vehicles And Equipment [Member] Vehicles and tangible personal property used in the creation, maintenance and utilization of information systems. Land, buildings, and building improvements Land, Buildings and Improvements [Member] Leasehold improvements Leasehold Improvements [Member] Projects in progress Software Development [Member] Construction in progress Construction in Progress [Member] Fixed assets Schedule of Property, Plant and Equipment and Finite-Lived Intangible Assets, Net by Type [Line Items] [Line Items] for Schedule of Property, Plant and Equipment and Finite-Lived Intangible Assets, Net by Type [Table] Total fixed assets, gross Finite-Lived Intangible Assets, Gross Total fixed assets, gross Property, Plant and Equipment, Gross Total fixed assets, gross Finite-Lived Intangible Assets, Not Yet Subject To Amortization Amount of assets, excluding financial assets and goodwill, lacking physical substance with a finite life, that are not yet subject to amortization. Total fixed assets, gross Finite Lived Intangible Assets And Property Plant And Equipment Gross Amount before amortization, accumulated depreciation and depletion, of assets, excluding financial assets and goodwill, lacking physical substance with a finite life and physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, capitalized internally developed software, land, buildings, machinery and equipment, office equipment, and furniture and fixtures. Less: Accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment and Finite-Lived Intangible Assets Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services and intangible assets, excluding financial assets and goodwill, lacking physical substance with a finite life. Fixed assets, net Finite Lived Intangible Assets And Property Plant And Equipment Net Amount after amortization, accumulated depreciation and depletion, of assets, excluding financial assets and goodwill, lacking physical substance with a finite life and physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, capitalized internally developed software, land, buildings, machinery and equipment, office equipment, and furniture and fixtures. Estimated time to completion of new office building (in years) Construction Period Estimated time to completion of construction project. Depreciation and amortization expense Depreciation, Depletion and Amortization Related Party Transactions [Abstract] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Erie Insurance Exchange (EIE) Erie Insurance Exchange [Member] Represents Erie Insurance Exchange, a Pennsylvania-domiciled reciprocal insurer that writes property and casualty insurance. Erie Family Life Insurance Company (EFL) Erie Family Life Insurance Company [Member] Represents Erie Family Life Insurance Company ("EFL"), an affiliated life insurance company that underwrites and sells individual and group life insurance policies and fixed annuities, wholly owned by the Erie Insurance Exchange. Functional Category [Axis] Functional Category [Axis] Represents the functional category of reimbursements from related parties. Functional Category [Domain] Functional Category [Domain] Represents the functional category of reimbursements from related parties. Operating expenses Operating Expenses [Domain] Represents the operating expense functional category of reimbursements from related parties. Investment expenses Investment Expenses [Domain] Represents the investment expense functional category of reimbursements from related parties. Range [Axis] Range [Axis] Range [Domain] Range [Domain] Maximum Maximum [Member] Related Party Transactions Related Party Transaction [Line Items] Indemnity's management fee rate as a percent of premiums written and assumed by the Exchange (as a percent) Insurance Agency Management Fee, Percent Represents the management fee rate, determined by the board of directors of the entity, calculated as a percentage of the direct and affiliated assumed written premiums. Indemnity's management fee rate effective January 1, 2017 as a percent of premiums written and assumed by the Exchange (as a percent) Insurance Agency Management Fee, Future Percent Represents the management fee rate for the next fiscal year, determined by the board of directors of the entity, calculated as a percentage of the direct and affiliated assumed written premiums. Minimum number of affiliates to be classified as an insurance holding company system Insurance Holding Company System, Minimum Affiliates Minimum number of affiliates to be defined as an insurance holding company system. Minimum number of insurer affiliates to be classified as an insurance holding company system Insurance Holding Company System, Minimum Affiliate Insurers Minimum number of insurer affiliates to be defined as an insurance holding company system. Cash settlements for payments made by Indemnity on the account of related parties Reimbursements Received from Related Party Represents reimbursements received from a related party. Number of field office facilities leased from the Exchange Number Of Field Office Facilities Leased From Related Party Represents the number of field office facilities leases from related parties. Rent expense on office space leased from Exchange Operating Leases, Rent Expense Reimbursements from the Exchange related to rent expense Rent Reimbursed from Related Party Represents rent expense reimbursed from Erie Insurance Exchange and Erie Family Life. Annual rentals paid to EFL Payments for Rent Note receivable from EFL Notes Receivable, Related Parties, Noncurrent Note receivable from EFL, annual interest rate (as a percent) Related Party Transaction, Rate Note receivable from EFL, interest income recognized by Indemnity Interest Income, Related Party Benefits expected to be paid over the next 10 years from pension plans: Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract] 2017 Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months 2018 Defined Benefit Plan, Expected Future Benefit Payments, Year Two 2019 Defined Benefit Plan, Expected Future Benefit Payments, Year Three 2020 Defined Benefit Plan, Expected Future Benefit Payments, Year Four 2021 Defined Benefit Plan, Expected Future Benefit Payments, Year Five 2022-2026 Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Secured debt Secured Debt [Member] Future draw commitments Term loan credit facility Debt Instrument [Line Items] Amount of senior secured draw term loan credit facility Debt Instrument, Face Amount Amount drawn on the credit facility Secured Long-term Debt, Noncurrent Repayment period of credit facility (in years) Debt Instrument, Term Fixed interest rate of credit facility (as a percent) Debt Instrument, Interest Rate, Stated Percentage Quarterly commitment fee on the unused portion of the credit facility (as a percent) Debt Instrument Commitment Fee Percent The fee, expressed as a percentage of the credit facility, for the unused portion of the credit facility. Fair value of bonds pledged as collateral on the credit facility Debt Instrument, Collateral Amount Estimated fair value of the credit facility Long-term Debt, Fair Value Principal payments due in 2019 Long-term Debt, Maturities, Repayments of Principal in Year Three Principal payments due in 2020 Long-term Debt, Maturities, Repayments of Principal in Year Four Principal payments due in 2021 Long-term Debt, Maturities, Repayments of Principal in Year Five Principal payments due in 2022 and thereafter Long-term Debt, Maturities, Repayments of Principal after Year Five Unused portion of the credit facility to be drawn at future dates Debt Instrument, Unused Borrowing Capacity, Amount Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common stock Common Stock [Member] Additional paid-in-capital Additional Paid-in Capital [Member] Accumulated other comprehensive income (loss) AOCI Attributable to Parent [Member] Retained earnings Retained Earnings [Member] Treasury stock Treasury Stock [Member] Deferred compensation Deferred Compensation [Member] Deferred compensation arrangement (such as stock or unit options and share or unit awards) that is equity-based payments with outside directors. The arrangement is based on an agreement between the entity and the director, and contains a promise by the entity to pay certain amounts or benefits at designated future dates, upon compliance with stipulated requirements. Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Class A Common Class A [Member] Class B Common Class B [Member] Statement Statement [Line Items] Increase (decrease) in shareholders' equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Balance, end of year Stockholders' Equity Attributable to Parent Net income Net Income (Loss) Attributable to Parent Other comprehensive (loss) income Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Dividends declared Dividends, Common Stock, Cash Net purchase of treasury stock Net Treasury Stock Value Acquired Held And Reissued Equity impact of the cost of common stock that was repurchased under a publicly announced share repurchase program and equity impact of common stock repurchased, held, or reissued during the period for any equity-based compensation plan, recorded using the cost method. Deferred compensation Deferred Compensation Under Rabbi Trust Plans Deferred compensation under rabbi trust plans that represents the value of common stock issued to the rabbi trust set up specifically to accumulate stock for the sole purpose of distribution to participating directors, which is part of stockholders' equity. Balance, end of year Schedule of payments on behalf of related entities Schedule of Related Party Transactions [Table Text Block] Investments [Abstract] Equity Method Investments and Joint Ventures [Abstract] Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Method Of Accounting [Axis] Method Of Accounting [Axis] Information by method of accounting. Method Of Accounting [Domain] Method Of Accounting [Domain] Various methods of accounting under generally accepted accounting practices. Equity method of accounting Equity Method Of Accounting [Member] An accounting method used by entities to assess the profits earned by investments in other companies. The entity reports the income earned on the investment on its income statement and the reported value is based on the entity's share of the company assets. The reported profit is proportional to the size of the equity investment. This is the standard method used when one company has significant influence over another. Fair value option Fair Value Option [Member] The fair vale option permits entities to choose, at specified election dates, to measure eligible items at fair value (the “fair value option”), the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. A business entity shall report unrealized gains and losses on items for which the fair value option has been elected in earnings (or another performance indicator if the business entity does not report earnings) at each subsequent reporting date. Upfront costs and fees related to items for which the fair value option is elected shall be recognized in earnings as incurred and not deferred. Investment in limited partnerships Schedule of Equity Method Investments [Line Items] Equity in earnings of limited partnerships Income (Loss) from Equity Method Investments Investments Investments in Debt and Equity Instruments, Cash and Cash Equivalents, Unrealized and Realized Gains (Losses) [Text Block] Statement of Cash Flows [Abstract] Cash flows from operating activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Management fee received Proceeds from Insurance Agency Management Fees Received Cash received for management fees during the current period. Service agreement fee received Proceeds from Fees Received Net investment income received Proceeds from Interest and Dividends Received Limited partnership distributions Proceeds from Equity Method Investment, Dividends or Distributions Increase (decrease) in reimbursements collected from affiliates Increase (Decrease) in Due from Related Parties, Current Commissions paid to agents Payments for Commissions Agents bonuses paid Payments For Agent Bonuses The amount of cash paid for agent bonuses during the current period. Salaries and wages paid Payments to Employees Pension contribution and employee benefits paid Pension Contributions and Payments for Other Labor Related Expenses Payments of cash for pension contributions, payroll tax expense, postemployment and benefit-related expenses not elsewhere specified in the taxonomy (such as health plan, profit sharing, incentives, tuition reimbursement, other fringe benefits and perquisites) during the current period. General operating expenses paid Payments for Other Operating Activities Income taxes paid Income Taxes Paid, Net Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities, Continuing Operations Cash flows from investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Purchase of investments: Payments to Acquire Investments [Abstract] Available-for-sale securities Payments to Acquire Available-for-sale Securities Limited partnerships Payments to Acquire Limited Partnership Interests Proceeds from investments: Proceeds from Sale, Maturity and Collection of Investments [Abstract] Available-for-sale securities sales Proceeds from Sale of Available-for-sale Securities Available-for-sale securities maturities/calls Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities Trading securities Proceeds from Sale of Trading Securities Held-for-investment Limited partnerships Proceeds from Limited Partnership Investments Net purchase of fixed assets Payments for (Proceeds from) Productive Assets Net collections on agent loans Payments for (Proceeds from) Loans Receivable Net cash (used in) provided by investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations Cash flows from financing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Purchase of treasury stock Payments for Repurchase of Common Stock Dividends paid to shareholders Payments of Ordinary Dividends, Common Stock Net proceeds from long-term borrowings Proceeds from (Repayments of) Secured Debt Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations Net increase in cash and cash equivalents Net Cash Provided by (Used in) Continuing Operations Cash and cash equivalents, beginning of year Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents, end of year Supplemental disclosure of noncash transactions Noncash Investing and Financing Items [Abstract] Transfer of investments from limited partnerships to trading securities Transfer Between Investment Categories Value of investments transferred between the entity's investments in noncash transactions. Investment Income [Table] Investment Income [Table] Investment Type [Axis] Investment Type [Axis] Investment Type Categorization [Domain] Investments [Domain] Fixed maturities Debt Securities [Member] Equity securities Equity Securities [Member] Cash equivalents and other Cash and Cash Equivalents [Member] Investment income from portfolios Net Investment Income [Line Items] Total investment income Interest and Dividend Income, Operating Less: investment expenses Investment Income, Investment Expense Investment income, net of expenses Net Investment Income Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Related Party Related Party Transactions Disclosure [Text Block] Schedule of fair value measurements on a recurring basis by asset class and level of input Fair Value, Assets Measured on Recurring Basis [Table Text Block] Schedule of roll forward of Level 3 fair value measurements on a recurring basis Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Schedule of fair value measurements on a recurring basis by pricing source Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Table Text Block] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Table] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair value measurements on a recurring basis Fair Value, Measurements, Recurring [Member] Fair value measurements on a nonrecurring basis Fair Value, Measurements, Nonrecurring [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Total Fair Value Hierarchy [Domain] Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Real estate Real Estate Funds [Member] Fair Value Measurements, Fair Value Pricing Sources [Axis] Fair Value Measurements, Fair Value Pricing Sources [Axis] Fair value information by pricing source. Fair Value Measurements, Fair Value Pricing Sources [Domain] Fair Value Measurements, Fair Value Pricing Sources [Domain] Provides the categories of pricing sources used to value financial assets and liabilities measured at fair value. Priced via broker quotes MarketComparablesBrokerQuote [Member] Represents the source of fair value measurement as broker quotes and/or market comparables which are generally used when a price from the pricing service is not available. Priced via pricing services Pricing Services [Member] Represents the source of fair value measurement as a nationally recognized pricing service. Priced via unobservable inputs Unobservable Inputs [Member] Represents the source of fair value measurement as unobservable inputs. Fair value measurements on a recurring basis, valuation techniques Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] Fair value by pricing source Fair Value by Pricing Source [Abstract] -- None. No documentation exists for this element. -- Available-for-sale securities Available-for-sale Securities Other investments Alternative Investments, Fair Value Disclosure Total Investments, Fair Value Disclosure Postretirement annual benefit expense reimbursed to Indemnity from the Exchange (as a percent) Defined Benefit Plan, Postretirement Benefit (Expenses) Reimbursement Percentage Represents the percentage at which postretirement benefit expenses are reimbursed to the attorney-in-fact. Contingent liability for amount of nonparticipating annuity contracts the employee pension plan purchased from EFL Defined Benefit Plan, Estimated Amount of Plan Participants' Future Benefits Covered by Insurance Contracts Issued by Employer or Related Parties Cost of pension plans: Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] Service cost for benefits earned Defined Benefit Plan, Service Cost Interest cost on benefit obligation Defined Benefit Plan, Interest Cost Expected return on plan assets Defined Benefit Plan, Expected Return on Plan Assets Prior service cost amortization Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Net actuarial loss amortization Defined Benefit Plan, Amortization of Gains (Losses) Pension plan cost Defined Benefit Plan, Net Periodic Benefit Cost Statement of Financial Position [Abstract] Assets Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Available-for-sale securities Available-for-sale Securities, Current Receivables from Erie Insurance Exchange and affiliates Accounts Receivable, Related Parties, Current Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Federal income taxes recoverable Income Taxes Receivable, Current Accrued investment income Accrued Investment Income Receivable Total current assets Assets, Current Available-for-sale securities Available-for-sale Securities, Noncurrent Limited partnership investments Equity Method Investments Fixed assets, net Deferred income taxes, net Deferred Tax Assets, Net Note receivable from Erie Family Life Insurance Company Other assets Other Assets, Noncurrent Total assets Assets Liabilities and shareholders' equity Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Commissions payable Accrued Sales Commission, Current Agent bonuses AgentBonusesPayableCurrent Carrying value as of the balance sheet date of obligations incurred and payable for incentive compensation awarded to independent agents or earned by them based on the terms of one or more relevant arrangements. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Accounts payable and accrued liabilities Accounts Payable and Accrued Liabilities, Current Dividends payable Dividends Payable, Current Deferred executive compensation Deferred Compensation Liability, Current Total current liabilities Liabilities, Current Defined benefit pension plans Defined Benefit Pension Plan, Liabilities, Noncurrent Employee benefit obligations Other Postretirement Defined Benefit Plan, Liabilities, Noncurrent Deferred executive compensation Deferred Compensation Liability, Classified, Noncurrent Long-term borrowings Long-term Debt, Excluding Current Maturities Other long-term liabilities Other Liabilities, Noncurrent Total liabilities Liabilities Shareholders’ equity Stockholders' Equity Attributable to Parent [Abstract] Common stock Common Stock, Value, Issued Additional paid-in-capital Additional Paid in Capital, Common Stock Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Retained earnings Retained Earnings (Accumulated Deficit) Total contributed capital and retained earnings Stockholders' Equity before Treasury Stock Treasury stock, at cost; 22,110,132 shares held Treasury Stock, Common, Value Deferred compensation Common Stock Issued Director Stock Trust Value of common stock issued to a trust (for example, a 'rabbi trust') set up specifically to accumulate stock for the sole purpose of distribution to participating directors. This trust does not allow directors to immediately or after a holding period diversify into nonemployer securities. The deferred compensation plan for which this trust is set up must be settled by the delivery of a fixed number of shares of employer stock. Total shareholders’ equity Total liabilities and shareholders’ equity Liabilities and Equity Projected benefit obligation: Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Projected benefit obligation, beginning of year Defined Benefit Plan, Benefit Obligation Plan amendments Defined Benefit Plan, Plan Amendments Actuarial loss (gain) Defined Benefit Plan, Actuarial Gain (Loss) Benefits paid Defined Benefit Plan, Benefits Paid Projected benefit obligation, end of year Accumulated benefit obligation, end of year Defined Benefit Plan, Accumulated Benefit Obligation Accounting Policies [Table] Accounting Policies [Table] Specific details of accounting policies, including the line items affected and the financial effects of those policies. Schedule of Equity Method Investment Equity Method Ownership Percent [Axis] Schedule of Equity Method Investment Equity Method Ownership Percent [Axis] Represents the categorization of equity by ownership percentage. Equity Method Investment Ownership Percent [Domain] Equity Method Investment Ownership Percent [Domain] Represents the categories of percentages of ownership in equity method investees. Less than 10% Equity Method Investment Ownership Percent Less Than 10 Percent [Member] Represents the category of equity method investees in which the entity has less than 10% ownership. Buildings and building improvements Building and Building Improvements [Member] Minimum Minimum [Member] Accounting Policies [Line Items] Accounting Policies [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Revenue recognition Revenue Recognition [Abstract] Number of operating revenue streams Number Of Revenue Streams Represents the Company's number of operating revenue streams based on revenue recognition guidance. Cash and cash equivalents Cash and Cash Equivalents [Abstract] Cash and cash equivalents, maximum maturity at the date of purchase (in months) Cash Equivalents Maximum Maturity Represents the maximum maturity period at date of purchase for an investment to be considered a cash equivalent. Available-for-sale securities Available-for-sale Securities, Current [Abstract] Available-for-sale securities, maximum maturity to be classified as current assets (in months) Available for Sale Securities Maximum Maturity Represents the maximum maturity period at date of purchase for an available-for-sale security to be considered a current asset. Limited partnerships Limited partnerships, general ownership percentage (as a percent) Equity Method Investment, Ownership Percentage Fixed assets Estimated useful life (in years) Finite-Lived Intangible Asset, Useful Life Estimated useful life (in years) Property, Plant and Equipment, Useful Life Agent bonus estimates Selling, General and Administrative Expense [Abstract] Performance period for agent bonuses (in months) Agent Bonus Performance Period Represents the period over which performance is measured for the estimation of agent bonuses. Period of prior year actual underwriting data used to estimate agent bonuses (in years) Agent Bonus Estimate Actual Underwriting Data, Period Represents the period of prior year actual underwriting data used to estimate agent bonuses. Recognition of management fee revenue Insurance Services Revenue [Abstract] Indemnity's maximum management fee rate as a percent of premiums written and assumed by the Exchange (as a percent) Income Statement [Abstract] Operating revenue Revenues [Abstract] Management fee revenue, net Insurance Agency Management Fee Service agreement revenue Contractually Specified Servicing Fees, Late Fees, and Ancillary Fees Earned in Exchange for Servicing Financial Assets Total operating revenue Revenues Operating expenses Operating Expenses [Abstract] Commissions Insurance Commissions Salaries and employee benefits Labor and Related Expense All other operating expenses Other Cost and Expense, Operating Total operating expenses Operating Expenses Net revenue from operations Operating Income (Loss) Investment income Investment Income, Nonoperating [Abstract] Net investment income Net realized investment gains Realized Gain (Loss) on Marketable Securities and Cost Method Investments, Excluding Other than Temporary Impairments, and Other Investments Net impairment losses recognized in earnings Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Available-for-sale Securities Total investment income Investment Income, Nonoperating Interest expense, net Interest Expense Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income tax expense Income Tax Expense (Benefit) Net income Earnings Per Share Earnings Per Share [Abstract] Net income per share Earnings Per Share, Basic and Diluted [Abstract] Common stock - basic (in dollars per share) Earnings Per Share, Basic Common stock - diluted (in dollars per share) Earnings Per Share, Diluted Weighted average shares outstanding – Basic Weighted Average Number of Shares Outstanding, Basic [Abstract] Common stock - basic (in shares) Weighted Average Number of Shares Outstanding, Basic Weighted average shares outstanding – Diluted Weighted Average Number of Shares Outstanding, Diluted [Abstract] Common stock - diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Compensation Related Costs [Abstract] Schedule of Incentive Plans and Deferred Compensation [Table] Schedule of Incentive Plans and Deferred Compensation [Table] Schedule of awards, payments, deferrals and liabilities under the entity's incentive and deferred compensation plans. Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Annual incentive plan Annual Incentive Plan [Member] Represents the entity's annual incentive plan, which is a bonus plan that pays cash to the entity's executive and senior vice presidents annually based upon attainment of corporate and individual performance measures, which can include various financial measures. Long-term incentive plan Long Term Incentive Plan [Member] Represents the entity's long-term incentive plan, which is a performance based incentive plan designed to reward the entity's executive and senior vice presidents who can have a significant impact on the entity's long-term performance and to further align the interests of such employees with those of the entity's shareholders. The long-term incentive plan permits grants of performance shares or units, to be satisfied with shares of the entity's Class A common stock or cash payment as determined by the compensation committee. Deferred compensation plans and stock compensation plan for outside directors Deferred Compensation Plan And Stock Compensation Plan Outside Directors [Member] Represents the entity's combined deferred compensation plans and stock compensation plan for outside directors. The entity's deferred compensation plans, which are arrangements for the entity's executive and senior vice presidents and outside directors that allows participants to elect to defer receipt of a portion of their compensation until a later date. The deferred compensation plan for the entity's outside directors allows participants to defer receipt of a portion of their director and meeting fees until a later date. The entity's stock compensation plan for outside directors, which is a plan to further align the interests of the directors with those of the entity's shareholders that provides for a portion of the directors' annual compensation in shares of the entity's Class A common stock. Upon ending board service, directors are paid shares of our Class A common stock equal to the number of share credits in their deferred stock account. Incentive and deferred compensation plans Incentive Plans and Deferred Compensation [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Awards, employer match, and hypothetical earnings by plan: Incentive Plans And Deferred Compensation [Roll Forward] A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. Annual incentive plan awards Other Labor-related Expenses Long-term incentive plan awards Allocated Share-based Compensation Expense, Gross Represents the gross expense, before forfeitures, recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. Deferred compensation plans, employer match, and hypothetical earnings Deferred Compensation Arrangement with Individual, Compensation Expense Total plan awards and earnings Incentive Plans and Deferred Compensation Total Awards and Earnings The amount of expense recognized in income during the period arising from cash-based incentives, share/equity-based compensation plans, and deferred compensation arrangements, with employees, directors and potentially certain consultants qualifying for treatment as employees. Total plan awards paid Incentive Plan Compensation Total Liabilities Paid The liabilities paid during the accounting period for cash-based incentive and share/equity-based compensation plans, with employees, directors, and potentially certain consultants qualifying for treatment as employees. Compensation deferred under the plans Deferred Compensation Arrangement with Individual Liability Incurred During Period The liability incurred during the period to an individual under a deferred compensation arrangement. This amount may be the result of periodic accruals made over the period of active employment, or reflect termination benefits resulting contractual terms or a death benefit. Distributions from the deferred compensation plans Deferred Compensation Arrangement with Individual, Distributions Paid Forfeitures Compensation Arrangement with Individual, Forfeitures The amount of compensation forfeited by the individual during the period. Funding of rabbi trust for outside directors Deferred Compensation Equity Rabbi Trust Value of stock issued under share-based plans to outside directors which is the unearned portion, accounted for under the fair value method. Gross incentive plan and deferred compensation liabilities at end of period Accrued Bonuses And Deferred Compensation Liability, Current And Noncurrent The carrying amount of the liability as of the balance sheet date of obligations incurred and payable for incentive compensation awarded to employees and directors or earned by them based on the terms of one or more relevant arrangements, and to an individual under a deferred compensation arrangement. This amount may be the result of periodic accruals made over the period of active employment, or reflect termination benefits resulting contractual terms or a death benefit. Risks and Uncertainties [Abstract] Concentrations of credit risk from unsecured receivables Concentration Risks, Types, No Concentration Percentage [Abstract] Schedule Of Earnings Per Share Basic And Diluted [Table] Schedule Of Earnings Per Share Basic And Diluted [Table] Disclosure of an entity's basic and diluted earnings per share calculations, including a reconciliation of numerators and denominators of the basic and diluted per-share computations for income from continuing operations. Reconciliation of the numerators and denominators used in the basic and diluted per-share computations Schedule Of Earnings Per Share Basic And Diluted [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Ratio for converting shares of Class B common stock into shares of Class A common stock (as a percent) Common Stock Conversion Ratio The ratio applied to Class B common stock shares for purposes of determining the number of Class A common stock shares into which the stock will be converted (the number of Class A common stock shares into which one Class B common stock share may be converted). Income available to stockholders (Basic EPS:) Net Income (Loss) Available to Common Stockholders, Basic [Abstract] Allocated net income (numerator) (in dollars) Net Income (Loss) Available to Common Stockholders, Basic Weighted shares (denominator) (in shares) Per-share amount (in dollars per share) Dilutive effect of stock-based awards Dilutive Securities, Effect on Basic Earnings Per Share [Abstract] Allocated net income (numerator) (in dollars) Dilutive Securities, Effect on Basic Earnings Per Share, Options and Restrictive Stock Units Weighted shares (denominator) (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Assumed conversion of Class B shares Dilutive Securities Effect on Basic Earnings Per Share Assumed Conversion [Abstract] -- None. No documentation exists for this element. -- Allocated net income (numerator) (in dollars) Dilutive Securities, Effect on Basic Earnings Per Share, Dilutive Convertible Securities Weighted shares (denominator) (in shares) Incremental Common Shares Attributable to Conversion of Convertible Common Stock Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of convertible common stock using the if-converted method. Income available to stockholders on equivalent shares (Diluted EPS:) Net Income (Loss) Attributable to Parent, Diluted [Abstract] Allocated net income (numerator) (in dollars) Net Income (Loss) Attributable to Parent, Diluted Weighted shares (denominator) (in shares) Per-share amount (in dollars per share) Organization, Consolidation and Presentation of Financial Statements [Abstract] Nature of Operations Nature of Operations [Text Block] Total plan Equity compensation plan Equity Compensation Plan [Member] Represents the entity's equity compensation plan, which is designed to reward key employees, as determined by the entity's compensation committee or the chief executive officer, who can have a significant impact on the entity's long-term performance and to further align the interests of such employees with those of the entity's shareholders. The equity compensation plan permits grants of restricted shares, restricted share units and other share based awards, to be satisfied with shares of the entity's Class A common stock or cash. Incentive compensation deferral plan Incentive Compensation Deferral Plan [Member] Represents the entity's incentive compensation deferral plan, which is a plan where participants can defer up to 100% of their annual or long-term incentive plan award. Deferred awards are credited to deferred stock account as credits denominated in Class A shares of the Company stock. Stock compensation plan for outside directors Stock Compensation Plan Outside Directors [Member] Represents the entity's stock compensation plan for outside directors, which is a plan to further align the interests of the directors with those of the entity's shareholders that provides for a portion of the directors' annual compensation in shares of the entity's Class A common stock. Upon ending board service, directors are paid shares of our Class A common stock equal to the number of share credits in their deferred stock account. Incentive Plan by Performance Period [Axis] Incentive Plan by Performance Period [Axis] Information pertaining to the entity's incentive plans, by the period over which performance is measured to determine the award. Incentive Plan Performance Period [Domain] Incentive Plan Performance Period [Domain] Identification of the period over which performance is measured to determine awards under the entity's incentive plans. 2014-2016 performance period Performance Period Long Term Incentive Plan 2014 To 2016 [Member] Represents the 2014-2016 performance period under the entity's Long-Term Incentive Plan. 2013-2015 performance period Performance Period Long Term Incentive Plan 2013 To 2015 [Member] Represents the 2013-2015 performance period under the entity's Long-Term Incentive Plan. 2012-2014 performance period Performance Period Long Term Incentive Plan 2012 To 2014 [Member] Represents the 2012-2014 performance period under the entity's Long-Term Incentive Plan. Vesting [Axis] Vesting [Axis] Vesting [Domain] Vesting [Domain] Three month vesting period Three Month Vesting Period [Member] For the entity's stock compensation plan for outside directors, each director vests in the grant 25% every three months over the course of a year. Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Performance shares Performance Shares [Member] Vesting period of performance and/or service condition(s) (in years and/or months) Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Maximum number of shares authorized for grant (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Maximum number of shares which may be received by any single participant during any specified period (in shares) Share Based Compensation Arrangement by Share Based Payment Award, Maximum Number of Shares Per Employee Per Specified Period The maximum number of shares that may be earned by any single participant during any specified period, which may be a specified performance period or calendar year, net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. Maximum dollar amount which may be received by any single participant during any specified period Incentive Plan Maximum Compensation Expense Per Employee Per Specified Period The maximum amount of expense that may be earned by any single participant during any specified period, which may be a specified performance period or calendar year, arising from incentive plan compensation arrangements, other than share-based awards, with employees, directors and potentially certain consultants qualifying for treatment as employees. Compensation cost related to share-based compensation plan awards Allocated Share-based Compensation Expense Shares purchased outside of publicly announced stock repurchase program for share-based compensation awards (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Shares Purchased for Award Average price per share for shares delivered (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Per Share Weighted Average Price of Shares Delivered The weighted average share price for shares delivered to participants under the plan. Tax benefits recognized in income related to award expense Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Incentive plan compensation cost reimbursed to Indemnity from the Exchange (as a percent) Incentive Plans, Compensation Cost Reimbursement Percentage Represents the percentage at which incentive plan costs are reimbursed to the parent company. Total unrecognized compensation cost related to share-based compensation plan awards pertaining to open performance periods Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Expected period of recognition related to unrecognized compensation cost (in years) Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Restricted stock units granted Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted Maximum annual incentive plan and/or long-term incentive plan award that can be deferred (as a percent) Incentive Compensation Deferral Plan, Maximum Annual Contributions Per Employee, Percent Maximum percentage of employee annual or long-term incentive plan pay the employee may contribute to the incentive compensation deferral plan. Vesting percent of the grant in Class A common stock (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage Payment period for vested share credits (in years) Payment Period For Vested Share Credits Period over which vested share credits will be paid upon separation from service. Average price per share for shares purchased (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Per Share Weighted Average Price of Shares Purchased Total cost of shares purchased outside of publicly announced stock repurchase program Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Share-based Liabilities Paid Postretirement Benefits Pension and Other Postretirement Benefits Disclosure [Text Block] Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Accumulated Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Quarterly Financial Information [Table] Quarterly Financial Information [Table] Disclosure of the quarterly financial data in the annual financial statements. The disclosure includes financial information for each fiscal quarter for the current and previous year, including revenues, gross profit, income (loss) before extraordinary items and cumulative effect of a change in accounting principle and earnings per share data. Quarterly Results of Operations (unaudited) Quarterly Financial Information [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Operating revenue Operating expenses Investment income, net of interest expense Investment income, Net Of Interest Expense The aggregate amount of income from investments (for example, dividends) not considered a component of the entity's core operations, net of interest expense on borrowing arrangements. Treasury stock (in shares) Treasury Stock, Common, Shares Common stock, stated value per share (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, authorized (in shares) Common Stock, Shares Authorized Common stock, issued (in shares) Common Stock, Shares, Issued Common stock, outstanding (in shares) Common Stock, Shares, Outstanding Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] States & political subdivisions US States and Political Subdivisions Debt Securities [Member] Corporate debt securities Corporate Debt Securities [Member] Residential mortgage-backed securities Residential Mortgage Backed Securities [Member] Commercial mortgage-backed securities Commercial Mortgage Backed Securities [Member] Collateralized debt obligations Collateralized Debt Obligations [Member] Other debt securities Other Debt Obligations [Member] Investment Secondary Categorization [Axis] Investment Secondary Categorization [Axis] Investments by Secondary Categorization [Domain] Investments by Secondary Categorization [Domain] Available-for-sale securities Available-for-sale Securities [Member] Level 3 changes Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Roll forward of Level 3 consolidated fair value measurements on a recurring basis Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Beginning balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Included in 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 Transfers in and (out) of Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net Ending balance Fair value transfers due to changes in available market observable inputs Fair Value Transfers Due to Changes in Available Market Observable Inputs [Abstract] -- None. No documentation exists for this element. -- Transfers from level 1 to level 2 Fair Value, Assets, Level 1 to Level 2 Transfers, Amount During Period Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2 which have taken place during the period. Transfers from level 2 to level 1 Fair Value, Assets Level 2 to Level 1 Transfers, Amount During Period Amount of transfers of assets measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 1 which have taken place during the period. Transfers from level 2 to level 3 FairValueAssetsLevel2ToLevel3TransfersAmountDuringPeriod Amount of transfers of assets measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 3 which have taken place during the period. Transfers from level 3 to level 2 FairValueAssetsLevel3ToLevel2TransfersAmountDuringPeriod Amount of transfers of assets measured on a recurring basis out of Level 3 of the fair value hierarchy into Level 2 which have taken place during the period. No. of securities transferred between Level 2 and Level 3 Number of Securities Transferred, Fair Value Assets, Between Level 2 and Level 3 Represents the number of securities in the entity's investment portfolio that necessitated reclassification between Level 2 and Level 3 due to trading activity levels. No. of securities transferred between Level 3 and Level 2 Number of Securities Transferred, Fair Value Assets, Between Level 3 and Level 2 Represents the number of securities in the entity's investment portfolio that necessitated reclassification between Level 3 and Level 2 due to trading activity levels. Earnings Per Share Earnings Per Share [Text Block] Defined Benefit Plan, Asset Categories [Axis] Defined Benefit Plan, Asset Categories [Axis] Total Plan Asset Categories [Domain] Total equity securities U.S. equity securities Us Equity Securities [Member] Ownership interest or right to acquire or dispose of ownership interest in corporations and other legal entities in the United States for which ownership interest is represented by shares of common or preferred stock, convertible securities, stock rights, or stock warrants. U.S. small capitalization core equity Us Small Capitalization Core Equity [Member] This category includes U.S. equity securities that seek to achieve excess returns relative to the Russell 2000 Index while maintaining portfolio risk characteristics similar to the index. U.S. large capitalization core equity Us Large Capitalization Core Equity [Member] This category includes U.S. equity securities that seek to achieve excess returns relative to the S&P 500 while maintaining portfolio risk characteristics similar to the index. U.S. equity index Us Equity Index [Member] This category comprises U.S. equity index funds not actively managed that track the S&P 500. Non-U.S. equity securities Foreign Equity Securities [Member] Ownership interest or right to acquire or dispose of ownership interest in foreign corporations and other foreign legal entities for which ownership interest is represented by shares of common or preferred stock, convertible securities, stock rights, or stock warrants. International small capitalization risk controlled equity International Small Capitalization Risk Controlled Equity [Member] This category seeks to provide excess returns relative to an international small cap index, while maintaining regional weights similar to the index. International emerging markets equity Emerging Markets Equity [Member] This category seeks long-term capital growth in securities of companies that have their principal business activities in countries in the Morgan Stanley Capital International Emerging Markets Free Index. International risk controlled equity International Risk Controlled Equity [Member] This category seeks long-term capital growth with an emphasis on controlling return volatility relative to an international market index. Debt securities U.S. Treasury Strips US Treasury Securities [Member] U.S. corporate bonds with an emphasis on long duration bonds rated A or better Domestic Corporate Debt Securities [Member] Floating rate high income leverage loans Other Money Market Funds [Member] Target asset allocation for the portfolio: Defined Benefit Plan, Assets, Target Allocations [Abstract] Total plan assets (as a percent) Defined Benefit Plan, Target Plan Asset Allocations Actual asset allocation for the portfolio: Defined Benefit Plan, Information about Plan Assets [Abstract] Total plan assets (as a percent) Defined Benefit Plan, Actual Plan Asset Allocations Supplemental Cash Flow Information [Abstract] Cash flows from operating activities: Adjustments to reconcile net income to net cash provided by operating activities: Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization and Gain (Loss) on Disposition The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets and the amount of gain (loss) on sale or disposal of property, plant and equipment assets, excluding oil and gas property and timber property. Deferred income tax benefit Deferred Income Tax Expense (Benefit) Realized (gains) losses and impairments on investments Realized Investment Gains (Losses) and Impairment of Investments The net realized gains or losses on investments during the period, not including gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity, offset by the amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income. Equity in earnings of limited partnerships Net amortization of bond premium Accretion (Amortization) of Discounts and Premiums, Investments (Decrease) increase in deferred compensation Increase (Decrease) in Deferred Compensation Increase in receivables from affiliates Increase (Decrease) in Accounts Receivable, Related Parties (Increase) decrease in accrued investment income Increase (Decrease) in Accrued Investment Income Receivable Decrease (increase) in federal income taxes recoverable Increase (Decrease) in Income Taxes Receivable Decrease in prepaid pension Increase (Decrease) in Prepaid Pension Costs (Increase) decrease in prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Increase in accounts payable and accrued expenses Increase (Decrease) in Accounts Payable and Accrued Liabilities Increase in commissions payable Increase (Decrease) in Reserve for Commissions, Expense and Taxes Increase in accrued agent bonuses Increase Decrease In Accrued Agent Bonuses The increase (decrease) during the reporting period in the aggregate amount of bonus obligations related to services received from independent agents. Schedule of reconciliation of net income to net cash provided by operating activities as presented in the Statements of Cash Flows Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Expense Classification [Table] Expense Classification [Table] Describes the nature and type of expenses and the percentage that those expenses are to total expenses. Expense Classification [Axis] Expense Classification [Axis] Information by nature and type of expense. Expense Classification [Domain] Expense Classification [Domain] Represents the nature and type of expenses. Agent compensation expense Agent Compensation Expense [Member] Scheduled commissions to agents based upon premiums written as well as additional commissions and bonuses to agents, which are earned by achieving targeted measures. Underwriting and policy processing expense Underwriting Expense [Member] Underwriting and policy processing services provided. Information technology expense Information Technology Expense [Member] Information technology services that support all functions. Nature of expense as a percentage of total expenses Expense Classification [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Nature of expense as a percentage of total expenses (as a percent) Percentage of Total Expenses Represents the nature and type of expense as a percentage of total expenses. Statement of Comprehensive Income [Abstract] Other comprehensive (loss) income, net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Change in unrealized holding gains (losses) on available-for-sale securities Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Pension and other postretirement plans Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent Total other comprehensive (loss) income, net of tax Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Schedule of changes in accumulated other comprehensive income (loss) by component, including amounts reclassified to other comprehensive income (loss) and the related line item in the Statements of Operations where net income is presented Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Schedule of provision for income taxes Components of Income Tax Expense (Benefit), Continuing Operations [Abstract] Current income tax expense Current Income Tax Expense (Benefit) Income tax expense Reconciliation of the provision for income taxes, with amounts determined by applying the statutory federal income tax rates to pre-tax income Effective Income Tax Rate Reconciliation, Amount [Abstract] Income tax at statutory rate Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount Tax-exempt interest Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount Other, net Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Borrowing Arrangements Debt Disclosure [Text Block] Fair value of plan assets: Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Fair value of plan assets, beginning of year Defined Benefit Plan, Fair Value of Plan Assets Actual gain (loss) on plan assets Defined Benefit Plan, Actual Return on Plan Assets Employer contributions Defined Benefit Plan, Contributions by Employer Fair value of plan assets, end of year Fair value measurements of pension plan assets: Total Dividends declared (in dollars per share) Common Stock, Dividends, Per Share, Declared Class of Stock Disclosures [Abstract] Class of Treasury Stock [Table] Class of Treasury Stock [Table] Share Repurchase Program [Axis] Share Repurchase Program [Axis] Share Repurchase Program [Domain] Share Repurchase Program [Domain] Stock repurchase program Share Repurchase Program 1999 [Member] A stock repurchase program was authorized by the company's board of directors for the purchase of its outstanding Class A nonvoting common stock beginning January 1, 1999. These shares are recorded as Treasury shares in the company's statements of financial position at total cost based upon trade date. Other stock based awards Other Stock Based Awards [Member] Represents other compensation for the entity for the issuance of share-based payment awards to executive officers. Stock repurchases Equity, Class of Treasury Stock [Line Items] Shares repurchased under stock repurchase program (in shares) Treasury Stock, Shares, Acquired Amount of authorized stock repurchases approved for continuation under the current program Stock Repurchase Program, Authorized Amount Approximate amount of repurchase authority remaining under the current stock repurchase program Stock Repurchase Program, Remaining Authorized Repurchase Amount Shares purchased outside of stock repurchase program Share-based Compensation [Abstract] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Cumulative-Effect Adjustment, Deconsolidation of Variable Interest Entity Cumulative-Effect Adjustment, Deconsolidation of Variable Interest Entity [Member] ASU 2015-02 cumulative-effect adjustment, deconsolidation of variable interest entity New Accounting Pronouncements or Change in Accounting Principle [Line Items] ASU 2015-02 cumulative-effect adjustment, deconsolidation of variable interest entity New Accounting Pronouncement or Change in Accounting Principle, Retrospective Adjustments [Abstract] Cumulative effect to Indemnity's shareholders' equity due to adoption of ASU 2015-02 New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets Information for the defined benefit pension plans with assets less than accumulated benefit obligation: Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets [Abstract] Projected benefit obligation Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Projected Benefit Obligation Accumulated benefit obligation Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Accumulated Benefit Obligation Plan assets Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Fair Value of Plan Assets Private equity Private Equity Funds [Member] Mezzanine debt Mezzanine Funds [Member] Investments held in mezzanine funds. Asset recorded Deferred tax asset valuation allowance Valuation Allowance [Abstract] Deferred tax asset valuation allowance Deferred Tax Assets, Valuation Allowance Amounts included in accumulated other comprehensive income Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract] Net actuarial loss Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax Prior service cost Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax Net amount not yet recognized Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax Amounts that will be amortized from accumulated other comprehensive income into pension cost during next fiscal year Defined Benefit Plan, Amount to be Amortized from Accumulated Other Comprehensive Income (Loss) Next Fiscal Year [Abstract] Estimated net actuarial loss that will be amortized from accumulated other comprehensive income into pension cost during next fiscal year, before tax Defined Benefit Plan, Future Amortization of Gain (Loss) Estimated net prior service cost that will be amortized from accumulated other comprehensive income into pension cost during next fiscal year, before tax Defined Benefit Plan, Future Amortization of Prior Service Cost (Credit) Capital Stock Stock by Class [Text Block] The entire disclosure of an entity's stock (includes common, convertible, and preferred stocks), including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock including , and, the entire disclosure for an entity's treasury stock, including the average cost per share, carrying basis for each class of treasury stock, description of share repurchase program authorized by an entity's board of directors, the number of shares repurchased, the cost of the shares repurchased, the remaining maximum dollar value of shares available for repurchase under the program, the treatment of the purchase price in excess of the current market value, number of shares held for each class of treasury stock and other information necessary to a fair presentation, and EPS information. Schedule of fixed assets by category Schedule of Property Plant and Equipment and Finite-Lived Intangible Assets, Net [Table Text Block] Schedule of Property Plant and Equipment and Finite-Lived Intangible Assets, Net Income Taxes Income Tax Disclosure [Text Block] Commitments and Contingencies Disclosure [Abstract] Other Commitments [Table] Other Commitments [Table] Contractual commitments to invest in limited partnership investments Other Commitments [Line Items] Represents the entity's maximum contractual commitments to invest in its limited partnership investments Other Commitment Description of commitment: contractual commitment to invest in limited partnership investments Other Commitments, Description Significant Accounting Policies Basis of Presentation and Significant Accounting Policies [Text Block] Schedule of Defined Contribution Plans Disclosures [Table] Schedule of Defined Contribution Plans Disclosures [Table] Schedule of Defined Contribution Plans Disclosures [Table] Defined Contribution Plans [Axis] Defined Contribution Plans [Axis] Defined Contribution Plans [Axis] Defined Contribution Plans [Domain] Defined Contribution Plans [Domain] [Domain] for Defined Contribution Plans [Axis] 100% employer matching contribution One Hundred Percent Match [Member] A 100 percent match of the provided unit. 50% employer matching contribution Fifty Percent Match [Member] A 50 percent match of the provided unit. Employee savings plan Schedule of Defined Contribution Plans Disclosures [Line Items] [Line Items] for Schedule of Defined Contribution Plans Disclosures [Table] Percentage of employer matching contribution of employee contributions (as a percent) Defined Contribution Plan, Employer Matching Contribution, Percent of Match Percentage of eligible employee compensation, matched by employer (as a percent) Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay Employer matching contribution paid to the plan Defined Contribution Plan, Cost Recognized Class A common stock held by plan participants (in shares) Defined Contribution Plan Number of Equity Securities Issued by Employer and Related Parties Included in Plan Assets The number of employer shares or related party shares included in the defined contribution plan assets. Supplementary Data on Cash Flows Cash Flow, Supplemental Disclosures [Text Block] Amounts recognized in other comprehensive income for pension plans: Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract] Net actuarial loss (gain) arising during the year Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax Amortization of net actuarial loss Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax Amortization of prior service cost Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), before Tax Amendments Other Comprehensive Income Defined Benefit Plans Amendments During Period before Tax Pretax change in the value of either the benefit obligation or the plan assets resulting from plan amendments, that has not been recognized in net periodic benefit cost. Total recognized in other comprehensive income Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax Number of new plan participants resulting in charges recognized as amendments Defined Benefit Plan Number of New Plan Participants Related to Amendments The number of new plan participants for which amendment charges were recognized. Deferred tax assets: Deferred Tax Assets, Gross [Abstract] Other employee benefits Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Other Pension and other postretirement benefits Deferred Tax Assets, Tax Deferred Expense Compensation and Benefits Pensions and Postretirement Benefits The tax effect as of the balance sheet date of the amount of estimated future tax deductions arising from pension costs and postretirement benefits, which can only be deducted for tax purposes when actual costs are incurred, and which can only be realized if sufficient tax-basis income is generated in future periods to enable the deduction to be taken. Allowance for management fee returned on cancelled policies Deferred Tax Assets, Net Allowance for Premium Cancellations The amount as of the balance sheet date of the estimated future tax effects attributable to the difference between the methods used to account for the allowance for premium cancellations for tax purposes and under generally accepted accounting principles. The difference in basis of such prepaid expenses will reduce future taxable income when such basis difference reverses. Other Deferred Tax Assets, Other Total deferred tax assets Deferred Tax Assets, Gross, Noncurrent Deferred tax liabilities: Deferred Tax Liabilities, Gross [Abstract] Depreciation Deferred Tax Liabilities, Property, Plant and Equipment Prepaid expenses Deferred Tax Liabilities, Prepaid Expenses Limited partnerships Deferred Tax Liabilities, Equity Method Investments The amount as of the balance sheet date of the estimated future tax effects attributable to the difference between the tax basis and the generally accepted accounting principles basis of a company's equity method investment which will increase future taxable income when such basis difference reverses. Unrealized gains on investments Deferred Tax Liabilities, Investments Other Deferred Tax Liabilities, Other Total deferred tax liabilities Deferred Tax Liabilities, Gross, Noncurrent Net deferred tax asset Document and Entity Information [Abstract] -- None. No documentation exists for this element. -- Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key 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 Current Fiscal Year End Date Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Current Reporting Status Entity Current Reporting Status Entity Voluntary Filers Entity Voluntary Filers Entity Filer Category Entity Filer Category Entity Public Float Entity Public Float Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Investment securities: Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] Pension and other postretirement plans: Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Total Changes in accumulated other comprehensive income (loss) by component, including amounts reclassified to other comprehensive income (loss) and the related line item in the Statements of Operations where net income is presented Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated other comprehensive income (loss), before tax AOCI Attributable to Parent [Abstract] AOCI (loss), beginning of year AOCI before Tax, Attributable to Parent OCI (loss) before reclassifications Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax Realized investment losses (gains) Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Impairment losses Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI for Write-down of Securities, before Tax OCI (loss) Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent OCI (loss) before reclassifications Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments and Tax Amortization of prior service cost Amortization of net actuarial loss OCI (loss) Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax, Portion Attributable to Parent OCI (loss) Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent AOCI (loss), end of year Accumulated other comprehensive income (loss), tax AOCI Attributable to Parent, Tax [Abstract] AOCI Attributable to Parent, Tax [Abstract] AOCI (loss), beginning of year AOCI Tax, Attributable to Parent OCI (loss) before reclassifications Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax Realized investment losses (gains) Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax Impairment losses Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI for Write-down of Securities, Tax OCI (loss) Other Comprehensive Income (Loss), Available-for-sale Securities, Tax OCI (loss) before reclassifications Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, before Reclassification Adjustments, Tax Amortization of prior service cost Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), Tax Amortization of net actuarial loss Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), Tax OCI (loss) Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Tax, Portion Attributable to Parent OCI (loss) Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent AOCI (loss), end of year Accumulated other comprehensive income (loss), net of tax AOCI Attributable to Parent, Net of Tax [Roll Forward] AOCI (loss), beginning of year OCI (loss) before reclassifications Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax Realized investment losses (gains) Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax Impairment losses Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI for Write-down of Securities, Net of Tax OCI (loss) OCI (loss) before reclassifications Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments, Net of Tax Amortization of prior service cost Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), Net of Tax Amortization of net actuarial loss Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), Net of Tax OCI (loss) OCI (loss) AOCI (loss), end of year Schedule of cost of pension plans Schedule of Net Benefit Costs [Table Text Block] Schedule of actuarial assumptions used to measure the year-end obligations and net periodic benefit costs for the subsequent year Schedule of Assumptions Used [Table Text Block] Schedule of funded status of pension plans and amounts recognized in the Statements of Financial Position Schedule of Net Funded Status And Amounts Recognized In Balance Sheet [Table Text Block] Tabular disclosure of net funded status of pension plans and/or other employee benefit plans and tabular disclosure of the amounts that are recognized in the balance sheet (or statement of financial position) for pension plans and/or other employee benefit plans, showing separately the assets and current and noncurrent liabilities (if applicable) recognized. Schedule of reconciliation of beginning and ending balances of the projected benefit obligation, as well as the accumulated benefit obligation Schedule of Accumulated and Projected Benefit Obligations [Table Text Block] Schedule of defined benefit pension plans with assets less than accumulated benefit obligation Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets [Table Text Block] Schedule of reconciliation of beginning and ending balances of the fair value of plan assets Schedule of Changes in Fair Value of Plan Assets [Table Text Block] Schedule of amounts included in accumulated other comprehensive income that were not yet recognized as components of net benefit costs Schedule of Net Periodic Benefit Cost Not yet Recognized [Table Text Block] Schedule of amounts recognized in other comprehensive income for pension plans Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block] Schedule of target and actual asset allocations for the portfolio Schedule of Target and Actual Allocations of Plan Assets [Table Text Block] Tabular disclosure of the target and actual allocations of the major categories of plan assets of pension plans and/or other employee benefit plans. Schedule of fair value measurements of pension plan assets by major category and level of input Schedule of Allocation of Plan Assets [Table Text Block] Schedule of benefits expected to be paid over the next 10 years from pension plans Schedule of Expected Benefit Payments [Table Text Block] Fixed Assets Property, Plant, and Equipment and Intangible Assets [Text Block] Schedule of awards, employer match, and hypothetical earnings by incentive and deferred compensation plans Schedule Of Compensation Cost For Cash Based Incentive And Share Based Payments And Deferred Compensation, Allocation Of Costs By Plan [Table Text Block] Tabular disclosure of the amount of total cash-based incentive plan compensation cost, share/equity-based compensation cost, and deferred compensation arrangements, including the amounts related to awards, payments, deferrals, liabilities, and any tax benefits attributable to each plan. Schedule of quarterly results of operations (unaudited) Quarterly Financial Information [Table Text Block] Concentrations of Credit Risk Concentration Risk Disclosure [Text Block] Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Common stock Class of Stock [Line Items] Minimum multiplier for dividend payable on Class A common stock per dividend declared on Class B common stock (as a percent) Dividends Common Stock Percentage Multiplier Minimum Represents the minimum multiplier applied to a percentage of the dividend declared on Class B common stock to determine the required dividend on Class A common stock. Percentage of dividend declared on Class B common stock used to determine dividend payable on Class A common stock (as a percent) Dividends Common Stock Percentage Represents the percentage of the dividend declared on Class B common stock to which a multiplier is applied to determine the required dividend on Class A common stock. Ratio for converting shares of Class B common stock into shares of Class A common stock (as a percent) Class B common stock shares converted into Class A common stock shares (in shares) Conversion of Stock, Shares Converted Incentive and Deferred Compensation Plans Disclosure Of Compensation Related Costs, Cash Based Incentive And Share Based Payments And Deferred Compensation [Text Block] The entire disclosure for compensation-related costs for cash-based incentive and share/equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of compensation, incentive distributions, compensation arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details, employee stock purchase plan details, and income statement compensation items. Deferred compensation arrangements may include a description of an arrangement with an individual employee, which is generally an employment contract between the entity and a selected officer or key employee containing a promise by the employer to pay certain amounts at designated future dates, usually including a period after retirement, upon compliance with stipulated requirements. This type of arrangement is distinguished from broader based employee benefit plans as it is usually tailored to the employee. Disclosure also typically includes the amount of related compensation expense recognized during the reporting period, the number of shares (units) issued during the period under such arrangements, and the carrying amount as of the balance sheet date of the related liability. Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] 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] U.S. treasury External Credit Rating by Grouping [Axis] External Credit Rating by Grouping [Axis] External Credit Rating by Grouping [Domain] External Credit Rating by Grouping [Domain] Investment grade External Credit Rating, Investment Grade [Member] Non-investment grade External Credit Rating, Non Investment Grade [Member] Available-for-sale securities Schedule of Available-for-sale Securities [Line Items] Fair value Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract] Less than 12 months Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value 12 months or longer Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Total Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Unrealized losses Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss [Abstract] Less than 12 months Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 12 months or longer Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Total Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss No. of holdings Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Line of Credit Facility [Table] Line of Credit Facility [Table] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving line of credit Revolving Credit Facility [Member] Bank line of credit Line of Credit Facility [Line Items] Maximum borrowing capacity under the bank revolving line of credit Line of Credit Facility, Maximum Borrowing Capacity Maximum letter of credit sublimit under the bank revolving line of credit Letters Of Credit Maximum, Amount The maximum letters of credit capcity under the credit facility as of the reporting date. Expiration date of the bank revolving line of credit Line of Credit Facility, Expiration Date Available borrowing capacity under the bank revolving line of credit, due to outstanding letters of credit Line of Credit Facility, Current Borrowing Capacity Outstanding amount of letters of credit sublimit under the bank revolving line of credit Letters of Credit Outstanding, Amount Available amount of letters of credit sublimit under the bank revolving line of credit Letters Of Credit Available, Amount The available amount of letters of credit less the amount of the contingent obligation under letters of credit outstanding under the credit facility as of the reporting date. Borrowings outstanding under the bank revolving line of credit Long-term Line of Credit Fair value of bonds pledged as collateral on the bank revolving line of credit Security Owned and Pledged as Collateral, Fair Value Increase in projected benefit obligations Defined Benefit Plan, Benefit Obligation, Period Increase (Decrease) Number of additional years of updated mortality data that contributed to the increase in projected benefit obligations (in years) Number of Additional Years of Mortality Number of additional years of updated mortality data that contributed to the change in projected benefit obligations. Funding target (as a percentage of the funding target liability) Defined Benefit Plan, Funding Target Percentage Plan assets of a defined benefit plan, as a percentage of the funding target liability as defined by the Pension Protection Act of 2006. Expected employer contribution during next fiscal year Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year Funded status at end of year Defined Benefit Plan, Funded Status of Plan Net amount recognized in the Statements of Financial Position: Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract] Pension liabilities - due within one year Defined Benefit Pension Plan Liabilities, Current Pension liabilities - due after one year Net amount recognized Defined Benefit Plan, Amounts Recognized in Balance Sheet Contractual Obligation, Fiscal Year Maturity Schedule [Abstract] Contractual Obligation, Fiscal Year Maturity Schedule [Abstract] Amortized cost Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract] Due in one year or less Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis Due after one year through five years Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis Due after five years through ten years Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Amortized Cost Basis Due after ten years Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis Amortized cost, fixed maturities Available-for-sale Debt Securities, Amortized Cost Basis Estimated fair value Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract] Due in one year or less Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value Due after one year through five years Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value Due after five years through ten years Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value Due after ten years Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value Estimated fair value, fixed maturities Available-for-sale Securities, Debt Securities Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Government sponsored entities US Government-sponsored Enterprises Debt Securities [Member] Consolidated fair value measurements on a recurring basis by asset class and level of input Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Total Other investments: Other Investments [Abstract] Underlying assets, liquidation period from inception of fund (in years) Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period Contributions made to the funds Distributions received from the funds Unfunded commitments Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments Schedule of Gain (Loss) on Investments [Table] Schedule of Gain (Loss) on Investments [Table] Realized gains (losses) on investments Gain (Loss) on Investments [Line Items] Available-for-sale securities: Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments [Abstract] Gross realized gains Available-for-sale Securities, Gross Realized Gains Gross realized losses Available-for-sale Securities, Realized Losses, Excluding Other than Temporary Impairments Net realized (losses) gains Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments Trading securities: Trading Securities, Realized Gain (Loss) [Abstract] Gross realized gains Trading Securities, Realized Gain Net realized gains Trading Securities, Realized Gain (Loss) Realized investment gains (losses) Realized Investment Gains (Losses) [Abstract] Other-than-temporary impairments on investments Other than Temporary Impairment Losses, Investments, Available-for-sale Securities [Abstract] Other -than-temporary impairments on investments Other than Temporary Impairment Losses, Investments, Available-for-sale Securities Portion recognized 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 Net impairment losses recognized in earnings Schedule of reconciliation of the numerators and denominators used in the basic and diluted per-share computations Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of reconciliation of cost to fair value of available-for-sale securities Schedule of Available-for-sale Securities Reconciliation [Table Text Block] Schedule of amortized cost and estimated fair value of fixed maturities by remaining contractual term to maturity Investments Classified by Contractual Maturity Date [Table Text Block] Schedule of available-for-sale securities in a gross unrealized loss position by length of time Schedule of Unrealized Loss on Investments [Table Text Block] Schedule of investment income, net of expenses, from portfolios Investment Income [Table Text Block] Schedule of realized gains and losses on sales of securities recognized in income based upon the specific identification method Realized Gain (Loss) on Investments [Table Text Block] Schedule of components of other-than-temporary impairments on investments Other than Temporary Impairment, Credit Losses Recognized in Earnings [Table Text Block] Schedule of limited partnership results, generally reported on a one quarter lag Equity Method Investments [Table Text Block] Amortized cost, equity securities Available-for-sale Equity Securities, Amortized Cost Basis Amortized cost Available-for-sale Securities, Amortized Cost Basis Gross unrealized gains, fixed maturities Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax Gross unrealized gains, equity securities Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax Gross unrealized gains Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax Gross unrealized losses, fixed maturities Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax Gross unrealized losses, equity securities Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax Gross unrealized losses Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Estimated fair value, fixed maturities Estimated fair value, equity securities Available-for-sale Securities, Equity Securities Estimated fair value