Investments Components of Net Investment Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Components of net investment income
Interest on fixed maturity securities	$ 42,892	$ 40,988	$ 37,246
Dividends on equity securities	5,268	4,500	3,093
Equity in earnings of other invested assets	1,552	1,182	1,016
Interest on other assets	32	62	89
Total investment income	49,744	46,732	41,444
Investment expenses	3,079	2,944	2,686
Net investment income	$ 46,665	$ 43,788	$ 38,758