Related Party (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Related Party Transactions
Minimum number of affiliates to be classified as an insurance holding company system	2
Minimum number of insurer affiliates to be classified as an insurance holding company system	1
Cash settlements for payments made by Indemnity on the account of related parties	$ 442,007	$ 415,655
Note receivable from EFL	$ 25,000	$ 25,000
Erie Insurance Exchange (EIE)
Related Party Transactions
Indemnity's management fee rate as a percent of premiums written and assumed by the Exchange (as a percent)	25.00%	25.00%	25.00%
Indemnity's management fee rate effective January 1, 2016 as a percent of premiums written and assumed by the Exchange (as a percent)	25.00%
Cash settlements for payments made by Indemnity on the account of related parties	$ 406,246	$ 378,496
Number of field office facilities leased from the Exchange	3
Rent expense on office space leased from Exchange	$ 6,500	7,800	$ 5,900
Erie Insurance Exchange (EIE) | Maximum
Related Party Transactions
Indemnity's management fee rate as a percent of premiums written and assumed by the Exchange (as a percent)	25.00%
Erie Family Life Insurance Company (EFL)
Related Party Transactions
Cash settlements for payments made by Indemnity on the account of related parties	$ 35,761	37,159
Annual rentals paid to EFL	400	400	400
Note receivable from EFL	$ 25,000
Note receivable from EFL, annual interest rate (as a percent)	6.70%
Note receivable from EFL, interest income recognized by Indemnity	$ 1,700	$ 1,700	$ 1,700