Nature of Operations (Details 2) (Indemnity, Erie Family Life Insurance Company ("EFL"))	Mar. 31, 2011
Indemnity \| Erie Family Life Insurance Company ("EFL")
Erie Family Life Insurance Company transaction
Indemnity's ownership interest in EFL sold to the Exchange (as a percent)	21.60%

The percentage of ownership of common stock or equity participation in an investee accounted for under the equity method of accounting that was sold.

No definition available.

Name:	erie_EquityMethodInvestmentOwnershipPercentageSold
Namespace Prefix:	erie_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant