Investments - Equity Securities, FV-NI (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Mutual Fund
Debt and Equity Securities, FV-NI
Fair value	$ 63,019	$ 65,453
Percent of Total	48.10%	56.10%
Public Utilities
Debt and Equity Securities, FV-NI
Percent of Total	5.00%	3.10%
Common Stock
Debt and Equity Securities, FV-NI
Fair value	$ 53,647	$ 44,492
Percent of Total	41.00%	38.20%
Nonredeemable Preferred Stocks
Debt and Equity Securities, FV-NI
Fair value	$ 7,759	$ 3,002
Percent of Total	5.90%	2.60%
Equity Securities
Debt and Equity Securities, FV-NI
Fair value	$ 131,003	$ 116,610
Percent of Total	100.00%	100.00%