Investments - Equity Securities, FV-NI (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Mutual Fund
Debt and Equity Securities, FV-NI
Fair value	$ 7,945	$ 65,453
Percent of Total	21.80%	56.10%
Public Utilities
Debt and Equity Securities, FV-NI
Fair value	$ 0	$ 3,663
Percent of Total	0.00%	3.10%
Common Stock
Debt and Equity Securities, FV-NI
Fair value	$ 20,343	$ 44,492
Percent of Total	55.80%	38.20%
Nonredeemable Preferred Stocks
Debt and Equity Securities, FV-NI
Fair value	$ 8,182	$ 3,002
Percent of Total	22.40%	2.60%
Equity Securities
Debt and Equity Securities, FV-NI
Fair value	$ 36,470	$ 116,610
Percent of Total	100.00%	100.00%