XML 51 R40.htm IDEA: XBRL DOCUMENT
v3.25.3

Fair Value - Fair Value Measurements on a Recurring Basis by Asset Class and Level of Input (Details) - USD ($) $ in Thousands | Sep. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | $ 1,065,833 |
Fair value of securities lent | 56,200 |
Total available-for-sale securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 1,065,833 | $ 1,043,615
Fair value of securities lent | 35,900 |
Corporate debt securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 673,086 | 643,943
Fair value of securities lent |  | 7,300
Collateralized debt obligations |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 90,551 | 114,127
Commercial mortgage-backed securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 122,211 | 124,982
Residential mortgage-backed securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 141,166 | 133,812
Other debt securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 31,449 | 26,751
U.S. Treasury |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 7,370 |
Equity securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Fair value of securities lent | 20,300 |
Fair Value, Measurements, Recurring Basis |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total | 1,140,525 | 1,129,506
Fair Value, Measurements, Recurring Basis | Total available-for-sale securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 1,065,833 | 1,043,615
Fair Value, Measurements, Recurring Basis | Corporate debt securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 673,086 | 643,943
Fair Value, Measurements, Recurring Basis | Collateralized debt obligations |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 90,551 | 114,127
Fair Value, Measurements, Recurring Basis | Commercial mortgage-backed securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 122,211 | 124,982
Fair Value, Measurements, Recurring Basis | Residential mortgage-backed securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 141,166 | 133,812
Fair Value, Measurements, Recurring Basis | Other debt securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 31,449 | 26,751
Fair Value, Measurements, Recurring Basis | U.S. Treasury |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 7,370 |
Fair Value, Measurements, Recurring Basis | Equity securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 74,692 | 85,891
Fair Value, Measurements, Recurring Basis | Equity securities | Financial services sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 60,425 | 69,930
Fair Value, Measurements, Recurring Basis | Equity securities | Utilities sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 3,534 | 5,629
Fair Value, Measurements, Recurring Basis | Equity securities | Energy sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 1,988 | 4,117
Fair Value, Measurements, Recurring Basis | Equity securities | Consumer sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 4,558 | 3,341
Fair Value, Measurements, Recurring Basis | Equity securities | Technology sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 3,224 | 1,974
Fair Value, Measurements, Recurring Basis | Equity securities | Communications sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 963 | 900
Fair Value, Measurements, Recurring Basis | Level 1 |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total | 2,122 | 1,106
Fair Value, Measurements, Recurring Basis | Level 1 | Total available-for-sale securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Corporate debt securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Collateralized debt obligations |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Commercial mortgage-backed securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Residential mortgage-backed securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Other debt securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | U.S. Treasury |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 0 |
Fair Value, Measurements, Recurring Basis | Level 1 | Equity securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 2,122 | 1,106
Fair Value, Measurements, Recurring Basis | Level 1 | Equity securities | Financial services sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 2,122 | 1,052
Fair Value, Measurements, Recurring Basis | Level 1 | Equity securities | Utilities sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Equity securities | Energy sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Equity securities | Consumer sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 0 | 54
Fair Value, Measurements, Recurring Basis | Level 1 | Equity securities | Technology sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 1 | Equity securities | Communications sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 2 |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total | 1,104,408 | 1,091,069
Fair Value, Measurements, Recurring Basis | Level 2 | Total available-for-sale securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 1,043,728 | 1,013,258
Fair Value, Measurements, Recurring Basis | Level 2 | Corporate debt securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 670,031 | 637,675
Fair Value, Measurements, Recurring Basis | Level 2 | Collateralized debt obligations |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 90,551 | 114,127
Fair Value, Measurements, Recurring Basis | Level 2 | Commercial mortgage-backed securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 104,445 | 100,893
Fair Value, Measurements, Recurring Basis | Level 2 | Residential mortgage-backed securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 139,882 | 133,812
Fair Value, Measurements, Recurring Basis | Level 2 | Other debt securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 31,449 | 26,751
Fair Value, Measurements, Recurring Basis | Level 2 | U.S. Treasury |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 7,370 |
Fair Value, Measurements, Recurring Basis | Level 2 | Equity securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 60,680 | 77,811
Fair Value, Measurements, Recurring Basis | Level 2 | Equity securities | Financial services sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 52,798 | 65,378
Fair Value, Measurements, Recurring Basis | Level 2 | Equity securities | Utilities sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 3,534 | 5,629
Fair Value, Measurements, Recurring Basis | Level 2 | Equity securities | Energy sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 1,988 | 4,117
Fair Value, Measurements, Recurring Basis | Level 2 | Equity securities | Consumer sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 1,397 | 1,787
Fair Value, Measurements, Recurring Basis | Level 2 | Equity securities | Technology sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 2 | Equity securities | Communications sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 963 | 900
Fair Value, Measurements, Recurring Basis | Level 3 |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total | 33,995 | 37,331
Fair Value, Measurements, Recurring Basis | Level 3 | Total available-for-sale securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 22,105 | 30,357
Fair Value, Measurements, Recurring Basis | Level 3 | Corporate debt securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 3,055 | 6,268
Fair Value, Measurements, Recurring Basis | Level 3 | Collateralized debt obligations |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | Commercial mortgage-backed securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 17,766 | 24,089
Fair Value, Measurements, Recurring Basis | Level 3 | Residential mortgage-backed securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 1,284 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | Other debt securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | U.S. Treasury |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total available-for-sale securities | 0 |
Fair Value, Measurements, Recurring Basis | Level 3 | Equity securities |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 11,890 | 6,974
Fair Value, Measurements, Recurring Basis | Level 3 | Equity securities | Financial services sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 5,505 | 3,500
Fair Value, Measurements, Recurring Basis | Level 3 | Equity securities | Utilities sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | Equity securities | Energy sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 0 | 0
Fair Value, Measurements, Recurring Basis | Level 3 | Equity securities | Consumer sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 3,161 | 1,500
Fair Value, Measurements, Recurring Basis | Level 3 | Equity securities | Technology sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | 3,224 | 1,974
Fair Value, Measurements, Recurring Basis | Level 3 | Equity securities | Communications sector |  |
Fair value measurements on a recurring basis by asset class and level of input |  |
Total equity securities | $ 0 | $ 0

X
- Definition Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References No definition available. + Details
Name: | erie_EquitySecuritiesFVNITotal
Namespace Prefix: | erie_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Name Accounting Standards Codification -Section 55 -Paragraph 10 -SubTopic 10 -Topic 825 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482881/825-10-55-10 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1A -Publisher FASB -URI https://asc.fasb.org/1943274/2147482736/825-10-45-1A Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-10 Reference 9: http://www.xbrl.org/2003/role/exampleRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 12 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482881/825-10-55-12 Reference 10: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 103 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-103 Reference 11: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 100 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-100 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (aa) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-2 Reference 14: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481830/320-10-45-1 Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(6)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479130/326-30-45-1 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 100 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482078/820-10-55-100 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 + Details
Name: | us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 28 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-28 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-11 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-10 Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2E -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2E + Details
Name: | us-gaap_InvestmentsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, before effects of master netting arrangements, of financial assets loaned to entities in exchange for collateral. Includes liabilities not subject to a master netting arrangement and financial assets transferred other than securities that qualify as secured borrowings. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 860 -SubTopic 30 -Name Accounting Standards Codification -Section 55 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481395/860-30-55-4 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 7 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481420/860-30-50-7 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 7 -Subparagraph (a)(1) -SubTopic 30 -Topic 860 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481420/860-30-50-7 + Details
Name: | us-gaap_SecuritiesLoanedIncludingNotSubjectToMasterNettingArrangementAndAssetsOtherThanSecuritiesTransferred
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_DebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CollateralizedDebtObligationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CommercialMortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_ResidentialMortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_OtherDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EquitySecuritiesByIndustryAxis=us-gaap_FinancialServicesSectorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EquitySecuritiesByIndustryAxis=erie_UtilitiesSectorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EquitySecuritiesByIndustryAxis=us-gaap_EnergySectorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EquitySecuritiesByIndustryAxis=us-gaap_ConsumerSectorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EquitySecuritiesByIndustryAxis=us-gaap_TechnologySectorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EquitySecuritiesByIndustryAxis=erie_CommunicationsSectorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |