Concentrations of Credit Risk (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Jan. 01, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Receivables from Erie Insurance Exchange and its affiliates	$ 501,192,000	$ 501,192,000		$ 468,636,000
Erie Insurance Exchange
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Change in allowance for credit loss	$ 0	$ 0
Erie Insurance Exchange | Cumulative effect adjustment | Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Receivables from Erie Insurance Exchange, allowance for credit loss			$ 600,000