Statistical Measurement [Domain] Statistical Measurement [Domain] Amortization of prior service costs Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Held-to-maturity securities, Amortized cost Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date [Abstract] Award Timing Predetermined Award Timing Predetermined [Flag] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Investment securities, OCI (loss) OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment, Tax Entity File Number Entity File Number Additional paid-in-capital Additional Paid-in Capital [Member] Amortized cost Debt Securities, Available-for-Sale and Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss Depreciation and amortization expense reimbursed from the Exchange and its insurance subsidiaries (as a percent) Insurance Subsidiaries Reimbursed, Percentage Insurance Subsidiaries Reimbursed, Percentage Included in other comprehensive income (loss) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Limited partnerships Income (Loss) from Equity Method Investments Realized investment (gains) losses Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax Tabular List, Table Tabular List [Table Text Block] Salaries and wages paid Payments to Employees Recently adopted accounting standards and Recently issued accounting standards New Accounting Pronouncements, Policy [Policy Text Block] Maximum potential obligation, guaranteed portion Guarantor Obligations, Maximum Exposure, Undiscounted Total available-for-sale securities Available-for-sale securities Debt Securities [Member] Postretirement annual benefit expense reimbursed from the Exchange and its insurance subsidiaries (as a percent) Defined Benefit Plan, Postretirement Benefit (Income) Expense Reimbursement Percentage Represents the percentage at which postretirement benefit income and expense are reimbursed to and from, respectively, the attorney-in-fact. Gross unrealized losses Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Measurement Basis [Axis] Measurement Basis [Axis] Common stock - basic (in dollars per share) Per-share amount (in dollars per share) Earnings Per Share, Basic Adjustment to Compensation: Adjustment to Compensation [Axis] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Revenue Revenue from Contract with Customer [Text Block] Schedule of Stock by Class [Table] Stock, Class of Stock [Table] Schedule of Segment Reporting Information, by Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Management fee rate as a percent of direct and affiliated assumed written premiums of the Exchange 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. Fair value of financial instruments, transfers between levels Fair Value Transfer, Policy [Policy Text Block] Sales/collections and write-offs Financing Receivable, Allowance for Credit Loss, Sales/Collections and Write-offs Amount of decrease in allowance for credit loss on financing receivable from sale and write-off. Gross unrealized gains Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain Adjustment to Compensation, Amount Adjustment to Compensation Amount Affiliated Entity Affiliated Entity [Member] Employee pension plan Pension Plan [Member] Employee Stock Option Share-Based Payment Arrangement, Option [Member] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Administrative and other Other General and Administrative Expense Carrying value Financing Receivable, after Allowance for Credit Loss Before tax, beginning balance Before tax, ending balance Equity, Attributable To Parent, Before Tax Equity, Attributable To Parent, Before Tax 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. Dividends declared Dividends, Common Stock, Cash Total shareholders’ equity Net of tax, beginning balance Net of tax, ending balance Equity, Attributable to Parent Allowance for Credit Loss [Table] Allowance for Credit Loss [Table] Disclosure of information about allowance for credit loss on investment in available-for-sale and held-to-maturity debt securities, and financing receivables. Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-Sale [Table] Insider Trading Policies and Procedures [Line Items] Common stock, authorized (in shares) Common Stock, Shares Authorized Current assets: Assets, Current [Abstract] Total liabilities and shareholders’ equity Liabilities and Equity Pension and other postretirement plans: Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Liabilities and shareholders' equity Liabilities and Equity [Abstract] Cover [Abstract] Cover [Abstract] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Maximum Maximum [Member] Accounting Policies [Abstract] Accounting Policies [Abstract] Total Debt Securities, Available-for-Sale, Unrealized Loss Position Provision and recoveries Credit impaired Debt Securities, Available-for-Sale, Allowance for Credit Loss, Recovery (Impairment) Change in allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), from recovery (impairment). Due after ten years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 10 Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Concentrations of Credit Risk Concentration Risk Disclosure [Text Block] Treasury stock Treasury Stock, Common [Member] Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Pay vs Performance Disclosure [Line Items] Collateralized debt obligations Collateralized Debt Obligations [Member] Retirement Benefits [Abstract] Retirement Benefits [Abstract] Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount 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. Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Entity Shell Company Entity Shell Company Other long-term liabilities Other Liabilities, Noncurrent Net investment income Net investment income Net Investment Income and Income (Loss) from Equity Method Investments Amount, after investment expense, of income earned from investments in securities, limited partnerships and loan receivables. Includes, but is not limited to, dividends, interest, and amount of income (loss) for proportionate share of equity method investee's income (loss). Roll forward of level 3 fair value measurements on a recurring basis Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Company Selected Measure Amount Company Selected Measure Amount Defined benefit plan, plan assets, contributions by employer Defined Benefit Plan, Plan Assets, Contributions by Employer Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Line of Credit Facility [Table] Line of Credit Facility [Table] Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Total equity securities Equity Securities, FV-NI, Total Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Total investment income Total investment income Investment Income, Nonoperating Name Measure Name Due in one year or less Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, Year One OCI (loss) Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent Available-for-sale securities maturities/calls Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-Sale Common Stock Class of Stock [Line Items] Industry Sector [Domain] Industry Sector [Domain] Deferred income taxes, net Deferred Income Tax Liabilities, Net Document Fiscal Period Focus Document Fiscal Period Focus Performance obligations under subscriber's agreement Revenue, Performance Obligation, Number of Performance Obligations Number of performance obligations recognized by Indemnity acting as attorney-in-fact for the subscribers of the Exchange in accordance with Topic 606. Award Timing Method Award Timing Method [Text Block] Award Type Award Type [Axis] Contract liability Contract with Customer, Liability, Noncurrent Investments Investments and Other Noncurrent Assets [Text Block] Total assets Assets Cash flows from investing activities Cash Provided by (Used in) Investing Activity, Continuing Operation [Abstract] Trading Symbol Trading Symbol Securities lending payable Deposits Received for Securities Loaned, at Carrying Value Management fee received Proceeds from Insurance Agency Management Fees Received Cash received for management fees during the current period. Security Type [Axis] Security Type [Axis] Security Type Financing Receivable, Allowance for Credit Loss [Roll Forward] Financing Receivable, Allowance for Credit Loss [Roll Forward] External Credit Rating by Grouping [Domain] External Credit Rating by Grouping [Domain] Entity Address, City or Town Entity Address, City or Town Technology sector Technology Sector [Member] Consumer sector Consumer Sector [Member] Fixed maturity securities Marketable Securities [Line Items] Class of Financing Receivable [Axis] Class of Financing Receivable [Axis] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Expected credit losses: Expected Credit Losses [Abstract] Expected Credit Losses Entity Emerging Growth Company Entity Emerging Growth Company Fair value Estimated fair value Debt Securities, Held-to-Maturity, Fair Value Dividends declared (in dollars per share) Common Stock, Dividends, Per Share, Declared Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Operating lease assets obtained in exchange for lease liabilities Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Earnings per share - Basic and diluted: Earnings Per Share Basic And Diluted Abstract1 [Abstract] Earnings Per Share Basic And Diluted Abstract1 Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Common stock, outstanding (in shares) Common Stock, Shares, Outstanding Carrying value Amortized cost Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss Schedule of Reconciliation of Cost to Fair Value, Net of Credit Loss Allowance, of Fixed Maturity Securities Marketable Securities [Table Text Block] Gross unrealized losses Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss Document Information [Table] Document Information [Table] PEO PEO [Member] Transfers into Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 Schedule of Disaggregation of Revenue by Performance Obligation Disaggregation of Revenue [Table Text Block] Schedule of Amortized Cost and Estimated Fair Value, Net of Credit Loss Allowance, of Fixed Maturity Securities by Remaining Contractual Term to Maturity Investments Classified by Contractual Maturity Date [Table Text Block] Class of Financing Receivable [Domain] Class of Financing Receivable [Domain] Defined benefit pension plan Assets for Plan Benefits, Defined Benefit Plan Number of incentive compensation deferral plan participants Number of Incentive Compensation Deferral Plan Participants Number of Incentive Compensation Deferral Plan Participants Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [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 participants. The arrangement is based on an agreement between the entity and the participant, and contains a promise by the entity to pay certain amounts or benefits at designated future dates, upon compliance with stipulated requirements. Retained earnings Retained Earnings [Member] Service agreement revenue Service Agreement [Member] Service charges we collect from subscribers/policyholders for providing extended payment terms on policies written and assumed by the Exchange, and late payment and policy reinstatement fees. The service charges are fixed dollar amounts per billed installment. Also included is service agreement revenue from shared office space based on utilization statistics. Prepaid expenses and other current assets, net Prepaid Expense and Other Assets, Current 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 participants, which is part of stockholders' equity. Entity Address, Postal Zip Code Entity Address, Postal Zip Code Restatement Determination Date Restatement Determination Date Deferred compensation Common Stock Issued 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 deferred compensation plan participants. This trust does not allow participants 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. Cash and cash equivalents (includes restricted cash of $39,549 and $30,189, respectively) Cash, cash equivalents and restricted cash, beginning of period Cash, cash equivalents and restricted cash, end of period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Income Statement [Abstract] Income Statement [Abstract] Income tax expense Income Tax Expense (Benefit) 12 months or longer Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer Loans to agents and others Payments to Acquire Loans Receivable Accumulated other comprehensive income (loss), tax AOCI Attributable to Parent, Tax [Roll Forward] AOCI Attributable to Parent, Tax [Abstract] Purchase of investments: Payments to Acquire Investments [Abstract] Class B common stock Common Class B [Member] Beginning balance Ending balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Total Investments, Fair Value Disclosure Document Information [Line Items] Document Information [Line Items] Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Product and Service [Domain] Product and Service [Domain] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Non-cash collateral that is not permitted to be sold or repledged Securities Received as Collateral Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Stock repurchases Equity, Class of Treasury Stock [Line Items] City Area Code City Area Code 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. Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] All Trading Arrangements All Trading Arrangements [Member] Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Class of Treasury Stock [Table] Class of Treasury Stock [Table] Commitments and contingencies Commitments and Contingencies, Policy [Policy Text Block] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Security owned and pledged as collateral, associated liabilities, fair value Security Owned and Pledged as Collateral, Associated Liabilities, Fair Value Fair value of securities lent Securities Loaned, Including Not Subject to Master Netting Arrangement and Assets other than Securities Transferred Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Net cash provided by operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Rabbi trust distribution Distributions From Rabbi Trust Plans Distributions From Rabbi Trust Plans Schedule of Impairments [Table] Schedule of Impairments [Table] Schedule of Impairments Gross unrealized losses Debt Securities, Available-for-Sale and Held-to-Maturity, Cumulative Unrecognized Loss Available-for-sale securities sales Proceeds from Sale of Debt Securities, Available-for-Sale Sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales Net actuarial gain amortization Defined Benefit Plan, Amortization of Gain (Loss) Limited partnerships Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member] Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] PEO Total Compensation Amount PEO Total Compensation Amount Settlement gain Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax Weighted average shares outstanding – Basic Weighted Average Number of Shares Outstanding, Basic [Abstract] Erie Insurance Exchange Erie Insurance Exchange [Member] Represents Erie Insurance Exchange, a Pennsylvania-domiciled reciprocal insurer that writes property and casualty insurance. Equity Components [Axis] Equity Components [Axis] Transfers out of Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 Defined benefit pension plan Liability, Defined Benefit Pension Plan, Noncurrent Amortization of prior service costs Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, Tax Nature of Operations Nature of Operations [Text Block] Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Concentration Risk [Table] Concentration Risk [Table] Realized investment (gains) losses Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax Number of reportable segments Number of Reportable Segments Amortization of net actuarial gain Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax Amortized cost Debt Securities, Available-for-Sale, Amortized Cost Other Performance Measure, Amount Other Performance Measure, Amount Entity Address, State or Province Entity Address, State or Province Available-for-sale, equity securities, cash equivalents, and other Interest and Dividend Income, Operating Investments Marketable Securities, Policy [Policy Text Block] 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. Gross unrealized gains Debt Securities, Available-for-Sale and Held-to-Maturity, Cumulative Unrecognized Gain Fair value Loans Receivable, Fair Value Disclosure Related Party [Domain] Related and Nonrelated Parties [Domain] Income available to stockholders on equivalent shares (Diluted EPS) Net Income (Loss) Attributable to Parent, Diluted [Abstract] Total current liabilities Liabilities, Current Equity securities Net (losses) gains recognized during the period Equity Securities, FV-NI, Gain (Loss) Individual: Individual [Axis] Financial instruments carried at fair value Fair Value of Financial Instruments, Policy [Policy Text Block] Settlement gain Other Comprehensive Income (Loss), Defined Benefit Plan, Adjustment for Settlement or Curtailment Gain (Loss), Tax Dividends paid to shareholders Payments of Ordinary Dividends, Common Stock Additional paid-in-capital Additional Paid in Capital, Common Stock Investments [Abstract] Investments [Abstract] Net cash used in investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Performance obligation, satisfaction period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Document Fiscal Year Focus Document Fiscal Year Focus Basis of presentation Basis of Accounting, Policy [Policy Text Block] Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Schedule of Gain (Loss) on Securities [Table] Schedule of Gain (Loss) on Securities [Table] Effective income tax rate (as a percent) Effective Income Tax Rate Reconciliation, Percent Entity Interactive Data Current Entity Interactive Data Current Cash flows from operating activities Cash Provided by (Used in) Operating Activity, Continuing Operation [Abstract] Carrying value Reported Value Measurement [Member] Revenue Revenue from Contract with Customer [Policy Text Block] Contractual Obligation, Fiscal Year Maturity Schedule [Abstract] Contractual Obligation, Fiscal Year Maturity Schedule [Abstract] Net realized and unrealized investment (losses) gains Net realized and unrealized investment (losses) gains Debt and Equity Securities, Gain (Loss) Segment Information Segment Reporting Disclosure [Text Block] 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] U.S. Treasury US Treasury Securities [Member] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Other Commitments [Line Items] Other Commitments [Line Items] Technology infrastructure costs Information Technology and Data Processing Increase (decrease) in shareholders' equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Unrealized losses Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract] Schedule of Pension Plan Cost Schedule of Net Benefit Costs [Table Text Block] Proceeds from investments: Proceeds from Sale, Maturity and Collection of Investments [Abstract] Other debt securities Other Debt Obligations [Member] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Accumulated Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Income Tax, beginning balance Income Tax, ending balance Equity, Attributable To Parent, Tax Equity, Attributable To Parent, Tax Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Other loans receivable, net Other loans receivable Loans Receivable [Member] Restricted cash Restricted Cash and Cash Equivalent, Current 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 Consolidated Statements of Operations Where Net Income is Presented Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Purchase of fixed assets Payments to Acquire Productive Assets Depreciation and amortization expense Depreciation, Depletion and Amortization Other assets, net Other Assets, Noncurrent Agent loans, net Financing Receivable, after Allowance for Credit Loss, Noncurrent Acquisition and underwriting support costs Acquisition And Underwriting Support Costs Acquisition And Underwriting Support Costs Entity Central Index Key Entity Central Index Key Settlement gain Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement 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. PEO Name PEO Name Accumulated other comprehensive income (loss), before tax AOCI Attributable to Parent [Roll Forward] AOCI Attributable to Parent Amount of loan participation program Amount of Loan Participation Program Amount of Loan Participation Program Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Carrying value and fair value measurements of financial instruments not carried at fair value Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Supplemental disclosure of noncash transactions Supplemental Cash Flow Elements [Abstract] Residential mortgage-backed securities Residential mortgage-backed securities Residential Mortgage-Backed Securities [Member] Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Minimum funding percentage of each loan Financing Receivable, before Allowance for Credit Loss, Participation Percentage Participation percentage, before allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement. Revolving line of credit Revolving Credit Facility [Member] Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plan [Table] Arrangement Duration Trading Arrangement Duration Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Dividends declared per share Dividends, Common Stock [Abstract] Contract liability Contract with Customer, Liability, Current Segments [Axis] Segments [Axis] Exercise Price Award Exercise Price Entity Filer Category Entity Filer Category Local Phone Number Local Phone Number Class of Stock [Domain] Class of Stock [Domain] Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Management fee revenue - policy issuance and renewal services Cost of operations - policy issuance and renewal services Policy Issuance and Renewal Services [Member] Policy issuance and renewal services provided by Indemnity that result in executed insurance policies between the Exchange or one of its insurance subsidiaries and the subscriber (policyholder). Assets Assets [Abstract] Credit Facility [Axis] Credit Facility [Axis] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Participation amount in loan program Financing Receivable, before Allowance for Credit Loss Postretirement Benefits Retirement Benefits [Text Block] Fair Value Fair Value Disclosures [Text Block] Credit Facility [Domain] Credit Facility [Domain] Agent Loans, net Agent loans Agent Loans [Member] Agent Loans Shareholders’ equity Equity, Attributable to Parent [Abstract] Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Class of Stock Disclosures [Abstract] Class of Stock Disclosures [Abstract] Entity Address, Address Line One Entity Address, Address Line One Estimated fair value Estimated fair value Debt Securities, Available-for-Sale and Held-to-Maturity, Fair Value Commissions Insurance Commissions Accumulated other comprehensive (loss) income Total AOCI Attributable to Parent [Member] Ratio for converting shares of Class B common stock into shares of Class A common stock 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). Available-for-sale securities: Debt Securities, Available-for-Sale, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract] Investments [Domain] Investments [Domain] Prior service cost amortization Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Industry Sector [Axis] Industry Sector [Axis] Intent to sell Debt Securities, Available-for-sale, Sell before Recovery Debt Securities, Available-for-sale, Sell before Recovery Fair Value as of Grant Date Award Grant Date Fair Value Entry Registrant Name Entity Registrant Name Impairment losses Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI for Write-down of Securities, Net of Tax Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Pension plan cost Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Deferred executive compensation Deferred Compensation Liability, Classified, Noncurrent Personnel costs Labor and Related Expense Weighted shares (denominator) (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements Allocated net income (numerator) Dilutive Securities, Effect on Basic Earnings Per Share, Dilutive Convertible Securities Document Quarterly Report Document Quarterly Report Less than 12 months Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months No. of holdings Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Schedule of Net Realized and Unrealized Investment Gains (Losses) Realized and Unrealized Gain (Loss) on Investments [Table Text Block] Tabular disclosure of realized and unrealized gains and losses on investments reported in the statement of income. Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Equity securities Payments to Acquire Equity Securities, FV-NI Accrued investment income Accrued Investment Income Receivable Investment securities, OCI (loss) Other Comprehensive Income (Loss), Available-for-Sale Securities Adjustment, before Tax, Portion Attributable to Parent Investment Type [Axis] Investment Type [Axis] Interest cost on benefit obligation Defined Benefit Plan, Interest Cost Related Party [Axis] Related and Nonrelated Parties [Axis] Title Trading Arrangement, Individual Title Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Amortization of net actuarial gain Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax Restatement Determination Date: Restatement Determination Date [Axis] Non-PEO NEO Non-PEO NEO [Member] Outstanding amount of letters of credit sublimit under the bank revolving line of credit Letters of Credit Outstanding, Amount Allowance for credit losses, beginning of period Allowance for credit losses, end of period Debt Securities, Available-for-Sale, Allowance for Credit Loss Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Total available-for-sale securities Available-For-Sale Debt Securities, Impairment (Loss) Recovery Available-For-Sale Debt Securities, Impairment Loss Recognized in Earnings Changes in accumulated other comprehensive income (loss) by component, including amounts reclassified to other comprehensive income (loss) and the related line item in the Consolidated Statements of Operations where net income is presented Accumulated Other Comprehensive Income (Loss) [Line Items] Gross unrealized gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax Name Trading Arrangement, Individual Name Allowance for credit losses, beginning of period Allowance for credit losses, end of period Financing Receivable, Allowance for Credit Loss All Award Types Award Type [Domain] Allocated net income (numerator) Dilutive Securities, Effect on Basic Earnings Per Share, Options and Restrictive Stock Units Equity Awards Adjustments Equity Awards Adjustments [Member] Sales/collections and write-offs Debt Securities, Available-for-Sale, Allowance for Credit Loss, Sales/Collections and Write-offs Amount of decrease in allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) from sale and write-off. Investment income Investment Income, Nonoperating [Abstract] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Disaggregation of revenue by performance obligation Disaggregation of Revenue [Line Items] Postretirement Benefits Defined Benefit Plan Disclosure [Line Items] Compensation Amount Outstanding Recovery Compensation Amount Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Fair value Estimate of Fair Value Measurement [Member] Revenue recognized that was included in the contract liability at beginning of year Contract with Customer, Liability, Revenue Recognized 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. Share Repurchase Program [Axis] Share Repurchase Program [Axis] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Assumed conversion of Class B shares Dilutive Securities Effect on Basic Earnings Per Share Assumed Conversion [Abstract] -- None. No documentation exists for this element. -- Net changes in cash collateral for securities lent Increase (Decrease) in Securities Lending Payable MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Due after one year through five years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year One Through Five Name Awards Close in Time to MNPI Disclosures, Individual Name Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Realized investment (gains) losses Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Equity securities: Equity Securities, FV-NI, Gain (Loss) [Abstract] Professional fees Professional and Contracted Services Expense Amount of expense for professional and contracted services. Operating revenue Revenues [Abstract] Due after five years through ten years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 OCI (loss) before reclassifications OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, Tax Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Financial Instruments [Domain] Financial Instruments [Domain] Held-to-maturity securities - due after ten years Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10 Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Segments [Domain] Segments [Domain] Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] General operating expenses paid Payment for Other Operating Activity Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Commissions paid to agents Payments for Commissions Investment income (loss) from portfolios Net Investment Income [Line Items] Financing Receivable, Allowance for Credit Loss [Line Items] Allowance for Credit Loss [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. Investment securities: AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member] Earnings per share Earnings Per Share, Policy [Policy Text Block] Company Selected Measure Name Company Selected Measure Name Fair Value Measurement [Domain] Fair Value Measurement [Domain] Available-for-sale securities Payments to Acquire Debt Securities, Available-for-Sale Bank Line of Credit Debt Disclosure [Text Block] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Held-to-maturity securities, net Held-to-maturity securities US States and Political Subdivisions Debt Securities [Member] Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Held-to-maturity securities, Estimated fair value Debt Securities, Held-to-Maturity, Maturity, Allocated and Single Maturity Date, Fair Value [Abstract] Held-to-maturity securities - due after ten years Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, after Year 10 All Executive Categories All Executive Categories [Member] Sales/collections and write-offs Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Sales/Collections and Write-Offs Amount of decrease in allowance for credit loss on investment in debt security measured at amortized cost (held-to-maturity) from sale and write-off. Net impairment losses recognized in earnings Debt Securities And Financing Receivables, Impairment (Loss) Recoveries Available-For-Sale Debt and Held-To-Maturity Securities And Financing Receivables, Impairment (Loss) Recoveries Recognized in Earnings Common stock Common Stock, Value, Issued Settlement gain Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), after Tax Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Common stock - Diluted (in shares) Weighted shares (denominator) (in shares) Weighted Average Number of Shares Outstanding, Diluted Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Amortization of net actuarial gain Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax Entity Small Business Entity Small Business Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Supplemental employee retirement plan (SERP) Supplemental Employee Retirement Plan [Member] Document Transition Report Document Transition Report Schedule of Investment Income, Net of Expenses Investment Income [Table Text Block] Due after one year through five years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five Schedule of Financial Instruments Not Carried at Fair Value Fair Value Disclosure of Asset and Liability Not Measured at Fair Value [Table Text Block] Income available to stockholders (Basic EPS) Net Income (Loss) Available to Common Stockholders, Basic [Abstract] Underlying Securities Award Underlying Securities Amount Concentration Risk [Line Items] Concentration Risk [Line Items] Pension and other postretirement plans, OCI (loss) Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax, Attributable to Parent Gross realized gains Debt Securities, Available-for-Sale, Realized Gain Equity Component [Domain] Equity Component [Domain] Document Period End Date Document Period End Date PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Due after ten years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10 Income Taxes Income Tax Disclosure [Text Block] Receivables from Erie Insurance Exchange, allowance for credit loss Accounts Receivable, Allowance for Credit Loss Class A common stock Common Class A [Member] Maximum letter of credit sublimit under the bank revolving line of credit Letters Of Credit Maximum, Amount The maximum letters of credit capacity under the credit facility as of the reporting date. Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Revenue from Contract with Customer [Abstract] Revenue from Contract with Customer [Abstract] Risks and Uncertainties [Abstract] Risks and Uncertainties [Abstract] Allowance for credit losses, beginning of period Allowance for credit losses, end of period Debt Securities, Held-to-Maturity, Allowance for Credit Loss Document Type Document Type Level 3 Level 3 Fair Value Fair Value, Inputs, Level 3 [Member] Earnings Per Share Earnings Per Share [Text Block] Name Outstanding Recovery, Individual Name Fixed Maturity Securities [Table] Marketable Securities [Table] Sales and advertising Marketing and Advertising Expense Product and Service [Axis] Product and Service [Axis] Administrative services reimbursements received Administrative Services Reimbursements Received Administrative Services Reimbursements Received Schedule of Allowances for Credit Losses on Investments Allowance for Credit Loss [Table Text Block] Tabular disclosure of allowance for credit loss on investment in available-for-sale and held-to-maturity debt securities, and allowance for credit loss on financing receivable. Net investment income received Proceeds from Interest and Dividends Received and Equity Method Investment Dividends or Distributions Cash received for dividends and interest on the entity's equity and debt investments during the current period and amount of distribution received from equity method investee for return on investment, classified as operating activities. Excludes distribution for return of investment, classified as investing activities. Total operating revenue Revenue Revenue from Contract with Customer, Excluding Assessed Tax Gross realized losses Debt Securities, Available-for-Sale, Realized Loss All Individuals All Individuals [Member] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Transferred at Point in Time Transferred at Point in Time [Member] Name Forgone Recovery, Individual Name Investment Income [Table] Investment Income [Table] Debt Securities, Available-for-Sale, Allowance for Credit Loss [Roll Forward] Debt Securities, Available-for-Sale, Allowance for Credit Loss [Roll Forward] Total current assets Assets, Current Statistical Measurement [Axis] Statistical Measurement [Axis] Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Amount of authorized stock repurchases approved for continuation under the current program Share Repurchase Program, Authorized, Amount Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Allocated net income (numerator) Net Income (Loss) Available to Common Stockholders, Basic Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Share Repurchase Program [Domain] Share Repurchase Program [Domain] Miscellaneous Gain (Loss) on Sale of Other Investments Current liabilities: Liabilities, Current [Abstract] Total other comprehensive (loss) income, net of tax Other comprehensive (loss) income OCI (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Bank line of credit Line of Credit Facility [Line Items] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Total operating expenses Operating Expenses Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Pension and other postretirement plans Pension and other postretirement plans, OCI (loss) Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent Borrowings outstanding under the bank revolving line of credit Long-Term Line of Credit Level 1 Fair Value, Inputs, Level 1 [Member] Common stock - diluted (in dollars per share) Per-share amount (in dollars per share) Earnings Per Share, Diluted Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Receivables from Erie Insurance Exchange and affiliates, net Accounts Receivable, after Allowance for Credit Loss, Current Title of 12(b) Security Title of 12(b) Security Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Roll Forward] Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Roll Forward] Administrative services expenses paid Administrative Services Expenses Paid Administrative Services Expenses Paid Due after five years through ten years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 Management fee revenue Management Fee Revenue [Member] Policy issuance and renewal services provided by Indemnity that result in executed insurance policies between the Exchange or one of its insurance subsidiaries and the subscriber (policyholder) and administrative services provided by Indemnity acting as attorney-in-fact on behalf of the Exchange, as well as a service provider for its insurance subsidiaries, with respect to all claims handling, life insurance, and investment management services. Accumulated other comprehensive income (loss), net of tax AOCI Attributable to Parent, Net of Tax [Roll Forward] Other comprehensive (loss) income, net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Commissions payable Accrued Sales Commission, Current Treasury stock (in shares) Treasury Stock, Common, Shares Net income per share Earnings Per Share [Abstract] Class B common stock shares converted into Class A common stock shares (in shares) Conversion of Stock, Shares Converted Schedule of Impairments [Line Items] Schedule of Impairments [Line Items] Schedule of Impairments [Line Items] Fair value Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items] Available-for-sale securities Debt Securities, Available-for-Sale, Current Equity securities Equity Securities, FV-NI, Noncurrent Available-for-sale securities lent Restricted Investments, Current Net realized and unrealized investment gains (losses) Gain (Loss) on Securities [Line Items] Equity securities Proceeds from Sale of Equity Securities, FV-NI Shares repurchased under stock repurchase program (in shares) Treasury Stock, Shares, Acquired External Credit Rating by Grouping [Axis] External Credit Rating by Grouping [Axis] Level 3 changes Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Income taxes (paid) recovered Income Taxes Paid, Net Cash equivalents Cash Equivalents [Member] Communications sector Communications Sector [Member] Sector of the economy consisting of companies engaged in communications. Financial services sector Financial Services Sector [Member] Award Timing Disclosures [Line Items] Service cost for benefits earned Defined Benefit Plan, Service Cost OCI (loss) before reclassifications OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items] Allocated net income (numerator) Net Income (Loss) Attributable to Parent, Diluted Available borrowing capacity under the bank revolving line of credit, due to outstanding letters of credit Line of Credit Facility, Current Borrowing Capacity Pension contribution and employee benefits paid Pension Contributions and Payments for Other Labor Related Expenses Payments of cash for payroll tax expense, pension contributions, 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. Net income Net income Net income Net Income (Loss) Attributable to Parent 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. Schedule of Available-For-Sale Securities in a Gross Unrealized Loss Position by Length of Time Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value [Table Text Block] Expiration Date Trading Arrangement Expiration Date Collections on agent and other loans Proceeds from Collection of Loans Receivable Net unrealized (losses) gains recognized on securities held at reporting date Equity Securities, FV-NI, Unrealized Gain (Loss) Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Axis] Change in unrealized holding (losses) gains on available-for-sale securities Investment securities, OCI (loss) Other Comprehensive Income (Loss), Available-for-Sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Adoption Date Trading Arrangement Adoption Date Management fee revenue - administrative services Administrative Services Management Fee [Member] Administrative services provided by Indemnity acting as attorney-in-fact on behalf of the Exchange, as well as a service provider for its insurance subsidiaries, with respect to all claims handling, life insurance, and investment management services. Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Entity Current Reporting Status Entity Current Reporting Status Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Cash flows from financing activities Cash Provided by (Used in) Financing Activity, Continuing Operation [Abstract] Operating income Operating income Operating Income (Loss) Due in one year or less Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, Year One Retained earnings Retained Earnings (Accumulated Deficit) Financial Instrument [Axis] Financial Instrument [Axis] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Executive Category: Executive Category [Axis] 12 months or longer Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Transferred Over Time Transferred over Time [Member] Liability incurred to purchase fixed assets Noncash or Part Noncash Acquisition, Fixed Assets Acquired Schedule of Impairments on Investments Schedule of Impairment Losses Recoveries [Table Text Block] Schedule of impairment (losses) recoveries on available-for-sale and held-to-maturity debt securities and financing receivables recognized in earnings. Current Fiscal Year End Date Current Fiscal Year End Date Class of Stock [Axis] Class of Stock [Axis] Less than 12 months Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Incentive compensation paid to agents Payment For Agent Incentive compensation Payment For Agent Incentive compensation Miscellaneous Miscellaneous Investments [Member] Available-for-sale securities Available-for-Sale Debt Securities [Member] Investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Other income Other Nonoperating Income (Expense) Statement [Table] Statement [Table] Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Amortization of prior service costs Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax Total Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss Available-for-sale securities, Amortized cost Debt Securities, Available-for-Sale, Amortized Cost, Fiscal Year Maturity [Abstract] Impairment losses Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI for Write-down of Securities, before Tax Utilities sector Utilities Sector [Member] Sector of the economy consisting of companies engaged in utilities. Timing of Transfer of Good or Service [Domain] Timing of Transfer of Good or Service [Domain] 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] Weighted average shares outstanding – Diluted Weighted Average Number of Shares Outstanding, Diluted [Abstract] All Adjustments to Compensation All Adjustments to Compensation [Member] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Accounts payable and accrued liabilities Accounts Payable and Accrued Liabilities, Current Amendment Flag Amendment Flag Available-for-sale securities, Estimated fair value Debt Securities, Available-for-Sale, Fair Value, Fiscal Year Maturity [Abstract] Energy sector Energy Sector [Member] Treasury stock, at cost; 22,110,132 shares held Treasury Stock, Common, Value Other Commitments [Table] Other Commitments [Table] Termination Date Trading Arrangement Termination Date Net cash used in financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Investment grade External Credit Rating, Investment Grade [Member] Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Measure: Measure [Axis] Provision and recoveries Agent loans Financing Receivable, Credit Loss, Expense (Reversal) 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. Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table] Significant Accounting Policies Basis of Presentation and Significant Accounting Policies [Text Block] Available-for-sale securities, net Debt Securities, Available-for-Sale, Noncurrent 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] Common stock - Basic (in shares) Weighted shares (denominator) (in shares) Weighted Average Number of Shares Outstanding, Basic Approximate amount of repurchase authority remaining under the current stock repurchase program Share Repurchase Program, Remaining Authorized, Amount 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] Held-to-maturity securities - states & political subdivisions Debt Securities, Held-to-Maturity, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract] Deferred executive compensation Deferred Compensation Liability, Current Total investment income Interest and Dividend Income, Operating and Income (Loss) from Equity Method Investments Interest and Dividend Income, Operating and Income (Loss) from Equity Method Investments Subsequent Events [Abstract] Subsequent Events [Abstract] Segment Reporting [Abstract] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Available-for-sale securities: Debt Securities, Available-for-Sale, Realized Gain (Loss), Excluding Other-than-temporary Impairment [Abstract] Debt Disclosure [Abstract] Debt Disclosure [Abstract] Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Less: investment expenses Investment Income, Investment Expense Entity Tax Identification Number Entity Tax Identification Number Cash equivalents and other Cash Equivalents and Other [Member] Cash Equivalents and Other Provision and recoveries Debt Securities, Held-to-Maturity, Credit Loss Expense (Reversal) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration] Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration] Net realized gains (losses) on available-for-sale securities Debt Securities, Available-for-Sale, Realized Gain (Loss) OCI (loss) before reclassifications OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment and Tax Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Common stock, stated value per share (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, issued (in shares) Common Stock, Shares, Issued Available-for-sale and equity securities lent Restricted Investments, Noncurrent Commercial mortgage-backed securities Commercial Mortgage-Backed Securities [Member] Less: net (losses) gains recognized on securities sold Equity Securities, FV-NI, Realized Gain (Loss) Administrative services reimbursement revenue Administrative Services Reimbursements [Member] Administrative services expenses, which are expenses incurred by Indemnity acting as attorney-in-fact on behalf of the Exchange, as well as a service provider for its insurance subsidiaries, with respect to all claims handling, life insurance, and investment management services. Dilutive effect of stock-based awards Dilutive Securities, Effect on Basic Earnings Per Share [Abstract] Agent incentive compensation Agent Incentive Compensation Payable, Current Agent Incentive Compensation Payable, Current Use of estimates Use of Estimates, Policy [Policy Text Block] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Dividends payable Dividends Payable, Current OCI (loss) Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent Non-investment grade External Credit Rating, Noninvestment Grade [Member] Trading Arrangement: Trading Arrangement [Axis] Total Shareholder Return Amount Total Shareholder Return 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. Management Operations Management Operations [Member] Management Operations Subsequent Events Subsequent Events [Text Block] Insider Trading Arrangements [Line Items] Security Exchange Name Security Exchange Name Impairment losses Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI for Write-down of Securities, Tax Equity securities Equity securities Equity Securities [Member] Total liabilities Liabilities Maximum borrowing capacity under the bank revolving line of credit Line of Credit Facility, Maximum Borrowing Capacity Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Operating expenses Operating Expenses [Abstract] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Service agreement revenue received Proceeds from Fees Received Included in earnings Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Security Type [Domain] Security Type [Domain] Security Type [Domain] Statement [Line Items] Statement [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Common stock Common Stock [Member] Total available-for-sale securities Estimated fair value Estimated fair value Debt Securities, Available-for-Sale Total contributed capital and retained earnings Stockholders' Equity before Treasury Stock Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Non-NEOs Non-NEOs [Member] Fair value of cash collateral Fair Value of Securities Received as Collateral that Can be Resold or Repledged Corporate debt securities Corporate Debt Securities [Member] Total revenue from administrative services Administrative Services [Member] Revenue allocated to administrative services, which includes two components: (1) management fee revenue allocated to the administrative services Indemnity provides acting as attorney-in-fact on behalf of the Exchange and its property and casualty insurance subsidiaries with respect to all claims handling and investment management services, as well as the service provider for all life insurance and investment management services for Erie Family Life Insurance Company; and (2) the revenue recorded for the reimbursement of the administrative services expenses. Payment Guarantee Payment Guarantee [Member] Net decrease in cash, cash equivalents and restricted cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Pension and other postretirement plans, OCI (loss) Other Comprehensive (Income) Loss, Defined Benefit Plan, before Tax, after Reclassification Adjustment, Attributable to Parent