Investments - Impairments on Available-For-Sale Securities (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Available-for-sale securities:
Intent to sell	$ (58)	$ (45)	$ (1,639)	$ (146)
Credit	(55)	(130)	(278)	(283)
Net impairment losses recognized in earnings	$ (113)	$ (175)	$ (1,917)	$ (429)

Amount of impairment recognized in earnings on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) from intent to sell or more likely than not will be required to sell before recovery of amortized cost basis.

No definition available.

Name:	erie_DebtSecuritiesAvailableforsaleSellbeforeRecovery
Namespace Prefix:	erie_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration