Variable Interest Entity (Details) (Indemnity)	6 Months Ended
Jun. 30, 2011	Mar. 31, 2011 Erie Family Life Insurance Company ("EFL")
Variable Interest Entity disclosures
Indemnity's maximum management fee rate as a percent of premiums written and assumed by the Exchange (as a percent)	25.00%
Indemnity's ownership interest in EFL sold to the Exchange (as a percent)		21.60%

Name:

erie_EquityMethodInvestmentOwnershipPercentageSold

Namespace Prefix:

erie

Data Type:

num:percentItemType

Balance Type:

na

Period Type:

instant