Investments, Summary of Investments by Type (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Debt securities, at fair value [Abstract]
Debt securities, at fair value	$ 341,915	$ 284,099
Percent of debt securities at fair value to total investments	88.50%	85.90%
Debt securities, at amortized cost [Abstract]
Debt securities, at amortized cost	$ 6,387	$ 7,417
Percent of debt securities at amortized cost to total investments	1.65%	2.24%
Total debt securities	$ 348,302	$ 291,516
Percent of debt securities to total investments	90.15%	88.14%
Equity securities, at fair value	$ 38,086	$ 39,247
Percentage of equity securities to total investments	9.85%	11.86%
Total investments	$ 386,388	$ 330,763
Total investments	100.00%	100.00%
United States Government Obligations and Authorities [Member]
Debt securities, at fair value [Abstract]
Debt securities, at fair value	$ 65,994	$ 62,323
Percent of debt securities at fair value to total investments	17.08%	18.84%
Debt securities, at amortized cost [Abstract]
Debt securities, at amortized cost	$ 4,221	$ 4,490
Percent of debt securities at amortized cost to total investments	1.09%	1.36%
Obligations of States and Political Subdivisions [Member]
Debt securities, at fair value [Abstract]
Debt securities, at fair value	$ 108,597	$ 91,614
Percent of debt securities at fair value to total investments	28.11%	27.70%
Corporate [Member]
Debt securities, at fair value [Abstract]
Debt securities, at fair value	$ 155,324	$ 119,024
Percent of debt securities at fair value to total investments	40.20%	35.99%
Debt securities, at amortized cost [Abstract]
Debt securities, at amortized cost	$ 2,101	$ 2,681
Percent of debt securities at amortized cost to total investments	0.54%	0.81%
International [Member]
Debt securities, at fair value [Abstract]
Debt securities, at fair value	$ 12,000	$ 11,138
Percent of debt securities at fair value to total investments	3.11%	3.37%
Debt securities, at amortized cost [Abstract]
Debt securities, at amortized cost	$ 65	$ 246
Percent of debt securities at amortized cost to total investments	0.02%	0.07%