Investments Components of Net Investment Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Components of net investment income
Interest on fixed maturity securities	$ 36,961	$ 38,794	$ 40,717
Dividends on equity securities	3,401	3,362	3,428
Equity in earnings of other invested assets	949	918	685
Interest on other assets	64	74	79
Interest on cash and cash equivalents	43	11	10
Total investment income	41,418	43,159	44,919
Investment expenses	3,005	2,625	2,616
Net investment income	$ 38,413	$ 40,534	$ 42,303