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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.

No definition available.

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Represents the percent of the total permanent tax differences that are related to investment revenues (such as tax exempt interest and dividends received deduction).

No definition available.

Name:	erie_IncomeTaxReconciliationPermanentTaxDifferencesPercentageFromInvestmentRevenues
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Data Type:	num:percentItemType
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Represents the net balance of all deferred tax assets and deferred tax liabilities reported for consolidating disclosure purposes, which could result in a net deferred tax asset or a net deferred tax liability balance as of the balance sheet date, resulting from applying the applicable enacted tax rate to net temporary differences and carryforwards pertaining to assets or liabilities. A temporary difference is a difference between the tax basis of an asset or liability and its carrying amount in the financial statements prepared in accordance with generally accepted accounting principles that will reverse in ensuing periods.

No definition available.

Name:	erie_NetDeferredTaxAssetsOrNetDeferredTaxLiabilitiesConsolidatingPresentation
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Data Type:	xbrli:monetaryItemType
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Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, before jurisdictional netting.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319

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Period Type:	instant

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319

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Data Type:	xbrli:monetaryItemType
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Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences, before jurisdictional netting.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 45

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=37586315&loc=d3e31931-109318

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319