Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Operating lease costs	$ 3,400	$ 3,600
Erie Insurance Exchange
Lessee, Lease, Description [Line Items]
Operating lease costs, amount reimbursed from Exchange and its subsidiaries	1,400	$ 1,500
Erie Insurance Exchange | Office Space
Lessee, Lease, Description [Line Items]
Operating lease assets	10,700
Other Noncurrent Assets
Lessee, Lease, Description [Line Items]
Operating lease assets	20,381		$ 22,401
Accounts Payable and Accrued Liabilities
Lessee, Lease, Description [Line Items]
Operating lease liabilities - current	10,929		11,289
Other Noncurrent Liabilities
Lessee, Lease, Description [Line Items]
Operating lease liabilities - long-term	9,021		10,665
Liabilities
Lessee, Lease, Description [Line Items]
Total operating lease liabilities	$ 19,950		$ 21,954