Variable Interest Entity (Details) (Indemnity)	9 Months Ended
	Sep. 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%