Significant Accounting Policies	9 Months Ended
Significant Accounting Policies	Sep. 30, 2019
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Basis of presentation The accompanying unaudited financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP") for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for the nine months ended September 30, 2019 are not necessarily indicative of the results that may be expected for the year ending December 31, 2019. For further information, refer to the financial statements and footnotes included in our Form 10-K for the year ended December 31, 2018 as filed with the Securities and Exchange Commission on February 21, 2019. Use of estimates The preparation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Recently adopted accounting standards In February 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Codification ("ASC") 842, "Leases", which requires lessees to recognize assets and liabilities arising from operating leases on the Statements of Financial Position and to disclose certain information about leasing arrangements. We adopted ASC 842 on January 1, 2019 using the optional transition method, which permits entities to apply the new guidance prospectively with certain practical expedients available. We elected the package of practical expedients which among other things allowed us to carry forward the historical lease classifications. We did not elect the hindsight practical expedient in determining the lease term for existing leases. The adoption of the new standard resulted in the recognition of operating lease assets of $32.7 million and operating lease liabilities of $32.1 million on the Statement of Financial Position at January 1, 2019. The adoption of this standard did not have a material impact on our Statement of Operations and had no impact on our net cash flows. Recently issued accounting standards In August 2018, the FASB issued Accounting Standards Update ("ASU") 2018-15, "Intangibles-Goodwill and Other Internal-Use Software", which aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. ASU 2018-15 is effective for fiscal years beginning after December 15, 2019 and interim periods within those fiscal years. The amendments under ASU 2018-15 may be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption and early adoption is permitted. We plan to adopt this guidance on a prospective basis and do not expect a material impact on our financial statements or disclosures. In June 2016, the FASB issued ASU 2016-13, "Financial Instruments-Credit Losses", which requires financial assets measured at amortized cost to be presented at the net amount expected to be collected through the use of a new forward-looking expected loss model and credit losses relating to available-for-sale debt securities to be recognized through an allowance for credit losses. ASU 2016-13 is effective for interim and annual reporting periods beginning after December 15, 2019. Early adoption for interim and annual periods beginning after December 15, 2018 is permitted. We have evaluated the impact of this guidance on our financial assets. Our investments are not measured at amortized cost, and therefore do not require the use of a new expected loss model. Our available-for-sale debt securities will continue to be monitored for credit losses, which would be limited to the amount by which the fair value is below amortized cost and reflected as an allowance for credit losses rather than a reduction of the carrying value of the asset. Our receivables from Erie Insurance Exchange and affiliates are unlikely to have a significant credit loss exposure given the financial strength of the Exchange as demonstrated by its strong surplus position, industry ratings, and historical experience of no credit losses. We currently do not record an allowance for credit losses related to our agent loans as historical default amounts have been insignificant and the majority of the loans are senior secured. Accordingly, when we establish an allowance related to agent loans upon adoption of this guidance, we do not expect it to be material. Our cash equivalents include money market mutual funds primarily comprised of U.S. government securities. A corresponding allowance, if any, would be expected to be immaterial. As a result of our evaluation, we do not expect a material impact on our financial statements. Other assets Other assets include agent loans, operating lease assets and other long-term prepaid assets. Agent loans are carried at unpaid principal balance with interest recorded in investment income as earned. It is our policy to charge the loans that are in default directly to expense. We do not record an allowance for credit losses on these loans, as the majority of the loans are senior secured and historically have had insignificant default amounts. The determination of whether an arrangement is a lease, and the related lease classification, is made at inception of a contract. Our leases are classified as operating leases. Operating lease assets and liabilities are recorded at inception based on the present value of the future minimum lease payments over the lease term at commencement date. When an implicit rate for the lease is not available, we use our incremental borrowing rate based on the information available at commencement date to determine the present value of future payments. Lease terms include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Most of our lease contracts contain lease and non-lease components. Non-lease components are expensed as incurred. Operating lease assets are included in other assets, and the current and noncurrent portions of the operating lease liabilities are included in accounts payable and accrued expenses and other long-term liabilities, respectively, in the Statement of Financial Position.