Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012 segments	Jun. 30, 2011	Dec. 31, 2011
Segment Reporting Information [Line Items]
Number of business segments			2
Net premiums earned	$ 170,090	$ 152,210	$ 331,593	$ 266,414
Investment income, net of investment expenses	28,749	27,741	57,895	54,804
Net realized investment gains (losses)	564	1,124	3,358	3,777
Other income	243	729	499	885
Total revenues	199,646	181,804	393,345	325,880
Net income (loss)	14,716	(17,914)	33,900	(12,104)
Assets	3,741,263		3,741,263		3,618,924
Invested assets	3,030,720		3,030,720		2,908,008
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net premiums earned	170,201	152,302	331,815	266,598
Investment income, net of investment expenses	28,791	27,845	57,977	54,955
Net realized investment gains (losses)	611	1,124	3,358	3,777
Other income	243	729	499	885
Total reportable segment	199,846	182,000	393,649	326,215
Intersegment eliminations	(200)	(196)	(304)	(335)
Total revenues	199,646	181,804	393,345	325,880
Net income (loss)	14,716	(17,914)	33,900	(12,104)
Assets	3,741,263	3,621,934	3,741,263	3,621,934
Invested assets	3,030,720	2,867,410	3,030,720	2,867,410
Property and Casualty Insurance [Member]
Segment Reporting Information [Line Items]
Number of business locations	6		6
Net premiums earned	153,914	139,009	300,670	240,773
Investment income, net of investment expenses	11,762	9,495	22,440	18,276
Net realized investment gains (losses)	(582)	393	551	1,601
Other income	96	530	196	538
Total reportable segment	165,190	149,427	323,857	261,188
Intersegment eliminations	(89)	(44)	(82)	(88)
Total revenues	165,101	149,383	323,775	261,100
Net income (loss)	13,355	(19,574)	29,991	(16,224)
Assets	1,947,895	1,902,215	1,947,895	1,902,215
Invested assets	1,323,303	1,284,623	1,323,303	1,284,623
Life Insurance [Member]
Segment Reporting Information [Line Items]
Net premiums earned	16,287	13,293	31,145	25,825
Investment income, net of investment expenses	17,029	18,350	35,537	36,679
Net realized investment gains (losses)	1,193	731	2,807	2,176
Other income	147	199	303	347
Total reportable segment	34,656	32,573	69,792	65,027
Intersegment eliminations	(111)	(152)	(222)	(247)
Total revenues	34,545	32,421	69,570	64,780
Net income (loss)	1,361	1,660	3,909	4,120
Assets	1,793,368	1,719,719	1,793,368	1,719,719
Invested assets	$ 1,707,417	$ 1,582,787	$ 1,707,417	$ 1,582,787