Quarterly Results of Operations (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Results of Operations (Unaudited) [Abstract]
Net premiums earned	$ 65,422	$ 64,448	$ 61,775	$ 61,098	$ 61,402	$ 54,853	$ 59,655	$ 61,551	$ 252,743	$ 237,461	$ 244,570
Net investment income	2,183	2,192	1,985	2,410	2,734	2,343	2,431	2,422	8,770	9,930	10,729
Net gains (losses) on investments	7,019	1,430	719	14,347	302	8,781	(5,453)	5,381
Losses and loss expenses incurred	40,858	36,967	38,343	34,533	38,970	30,477	33,739	34,904	150,701	138,088	215,555
Net income (loss)	$ 8,967	$ 7,771	$ 4,907	$ 14,943	$ 4,676	$ 11,687	$ 4,050	$ 11,506	$ 36,588	$ 31,919	$ (28,175)
Net income per share - diluted (in dollars per share)	$ 0.60	$ 0.52	$ 0.33	$ 1.00	$ 0.31	$ 0.78	$ 0.27	$ 0.78