Investments - Equity Securities, FV-NI (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Mutual Fund
Debt and Equity Securities, FV-NI
Fair value	$ 52,492	$ 65,453
Percent of Total	46.90%	56.10%
Public Utilities
Debt and Equity Securities, FV-NI
Percent of Total	5.60%	3.10%
Common Stock
Debt and Equity Securities, FV-NI
Fair value	$ 45,801	$ 44,492
Percent of Total	40.90%	38.20%
Nonredeemable Preferred Stocks
Debt and Equity Securities, FV-NI
Fair value	$ 7,367	$ 3,002
Percent of Total	6.60%	2.60%
Equity Securities
Debt and Equity Securities, FV-NI
Fair value	$ 111,915	$ 116,610
Percent of Total	100.00%	100.00%