Investments - Net Investment Income (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Investment income from portfolios
Total investment income	$ 34,460	$ 31,234	$ 26,155
Less: investment expenses	1,061	1,025	1,516
Investment income, net of expenses	33,399	30,209	24,639
Available-for-sale securities
Investment income from portfolios
Total investment income	22,496	24,978
Available-for-sale securities
Investment income from portfolios
Total investment income			23,669
Equity securities
Investment income from portfolios
Total investment income	1,418	628
Cash equivalents and other
Investment income from portfolios
Total investment income	$ 10,546	5,628	2,486
Erie Family Life Insurance Company (EFL)
Investment income from portfolios
Note receivable from EFL, interest income recognized by Indemnity		$ 1,600	$ 1,700

Represents the total of interest and dividend income, including any amortization and accretion (as applicable) of discounts and premiums, earned from (1) loans and leases whether held-for-sale or held-in-portfolio; (2) investment securities; (3) federal funds sold; (4) securities purchased under agreements to resell; (5) investments in banker's acceptances, commercial paper, or certificates of deposit; (6) dividend income; or (7) other investments not otherwise specified herein.

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