Related Party (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2025 USD ($) insurer affiliate	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($) loan
Related party transactions
Management fee rate as a percent of direct and affiliated assumed written premiums of the Exchange	25.00%
Minimum number of affiliates to be classified as an insurance holding company system | affiliate	2
Minimum number of insurer affiliates to be classified as an insurance holding company system | insurer	1
Total operating revenue	$ 4,067,258	$ 3,795,115	$ 3,268,940
Contribution to charitable foundation	100,000	0	0
Rental Income
Related party transactions
Total operating revenue	$ 24,755	$ 26,350	$ 26,059
Erie Insurance Exchange (EIE)
Related party transactions
Management fee rate as a percent of direct and affiliated assumed written premiums of the Exchange	25.00%	25.00%	25.00%
Erie Insurance Exchange (EIE) | 2021 Lease (Indemnity as Lessor)
Related party transactions
Operating expenses on shared facilities	$ 25,200	$ 21,900	$ 20,000
Reimbursements from the Exchange for shared facilities	6,900	5,900	5,200
Erie Insurance Exchange (EIE) | Rental Income | 2021 Lease (Indemnity as Lessor)
Related party transactions
Total operating revenue	3,000	2,900	$ 2,600
Other Affiliates
Related party transactions
Contribution to charitable foundation	100,000
Other Affiliates | Other loans receivable
Related party transactions
Number of loans issued | loan			2
Loan amount issued			$ 13,600
Allowance for credit loss	8,800	$ 8,000
Other Affiliates | Senior secured first loan
Related party transactions
Loan amount issued	$ 4,600
Fixed interest rate	5.00%
Other Affiliates | Senior secured second loan
Related party transactions
Loan amount issued	$ 9,000
Fixed interest rate	5.00%