Investments (Details 1) $ in Thousands		6 Months Ended	12 Months Ended
		Jun. 30, 2015 USD ($) Number	Dec. 31, 2014 USD ($) Number
Fixed maturity securities, Fair Value
Fixed maturity securities, Fair Value, 12 Months or Less		$ 1,502,900	$ 746,584
Fixed maturity securities, Fair Value, More than 12 Months		149,916	388,536
Fixed maturity securities, Fair Value, Total		1,652,816	1,135,120
Fixed maturity securities, Gross Unrealized Losses
Fixed maturity securities, Gross Unrealized Losses, 12 Months or Less		39,144	14,482
Fixed maturity securities, Gross Unrealized Losses, More than 12 Months		11,131	14,941
Fixed maturity securities, Gross Unrealized Losses, Total		$ 50,275	$ 29,423
Number of positions with a gross unrealized loss position, 12 Months or Less | Number		514	234
Number of position with a gross unrealized loss position, more than 12 months | Number		59	112
Number of position with a gross unrealized loss position, Total | Number		573	346
Fair value as a percentage of total fixed maturities and equity securities fair value, 12 Months or Less		21.50%	10.70%
Fair value as a percentage of total fixed maturities and equity securities fair value, more than 12 months		2.10%	5.50%
Fair value as a percentage of total fixed maturities and equity securities fair value, Total		23.60%	16.20%
Mortgage-backed securities [Member]
Fixed maturity securities, Fair Value
Fixed maturity securities, Fair Value, 12 Months or Less		$ 56,123	$ 2
Fixed maturity securities, Fair Value, More than 12 Months		1,545	39,809
Fixed maturity securities, Fair Value, Total		57,668	39,811
Fixed maturity securities, Gross Unrealized Losses
Fixed maturity securities, Gross Unrealized Losses, 12 Months or Less		2,287	0
Fixed maturity securities, Gross Unrealized Losses, More than 12 Months		208	1,390
Fixed maturity securities, Gross Unrealized Losses, Total		2,495	1,390
Other [Member]
Fixed maturity securities, Fair Value
Fixed maturity securities, Fair Value, 12 Months or Less		267,749	10,317
Fixed maturity securities, Fair Value, More than 12 Months		1,853	117,615
Fixed maturity securities, Fair Value, Total		269,602	127,932
Fixed maturity securities, Gross Unrealized Losses
Fixed maturity securities, Gross Unrealized Losses, 12 Months or Less		8,888	34
Fixed maturity securities, Gross Unrealized Losses, More than 12 Months		146	3,015
Fixed maturity securities, Gross Unrealized Losses, Total		9,034	3,049
Municipal bonds [Member]
Fixed maturity securities, Fair Value
Fixed maturity securities, Fair Value, 12 Months or Less		219,191	31,821
Fixed maturity securities, Fair Value, More than 12 Months		20,870	59,715
Fixed maturity securities, Fair Value, Total		240,061	91,536
Fixed maturity securities, Gross Unrealized Losses
Fixed maturity securities, Gross Unrealized Losses, 12 Months or Less		7,541	200
Fixed maturity securities, Gross Unrealized Losses, More than 12 Months		5,877	4,228
Fixed maturity securities, Gross Unrealized Losses, Total		13,418	4,428
Foreign government bonds [Member]
Fixed maturity securities, Fair Value
Fixed maturity securities, Fair Value, 12 Months or Less		0	0
Fixed maturity securities, Fair Value, More than 12 Months		0	0
Fixed maturity securities, Fair Value, Total		0	0
Fixed maturity securities, Gross Unrealized Losses
Fixed maturity securities, Gross Unrealized Losses, 12 Months or Less		0	0
Fixed maturity securities, Gross Unrealized Losses, More than 12 Months		0	0
Fixed maturity securities, Gross Unrealized Losses, Total		0	0
Corporate bonds [Member]
Fixed maturity securities, Fair Value
Fixed maturity securities, Fair Value, 12 Months or Less		454,925	213,612
Fixed maturity securities, Fair Value, More than 12 Months		39,875	76,099
Fixed maturity securities, Fair Value, Total		494,800	289,711
Fixed maturity securities, Gross Unrealized Losses
Fixed maturity securities, Gross Unrealized Losses, 12 Months or Less		11,940	6,883
Fixed maturity securities, Gross Unrealized Losses, More than 12 Months		3,531	4,373
Fixed maturity securities, Gross Unrealized Losses, Total		15,471	11,256
Other mortgage-backed securities [Member]
Fixed maturity securities, Fair Value
Fixed maturity securities, Fair Value, 12 Months or Less		471,024	477,877
Fixed maturity securities, Fair Value, More than 12 Months		79,074	88,663
Fixed maturity securities, Fair Value, Total		550,098	566,540
Fixed maturity securities, Gross Unrealized Losses
Fixed maturity securities, Gross Unrealized Losses, 12 Months or Less		5,929	4,797
Fixed maturity securities, Gross Unrealized Losses, More than 12 Months		592	1,095
Fixed maturity securities, Gross Unrealized Losses, Total		6,521	5,892
Total fixed maturity securities [Member]
Fixed maturity securities, Fair Value
Fixed maturity securities, Fair Value, 12 Months or Less		1,469,012	733,629
Fixed maturity securities, Fair Value, More than 12 Months		143,217	381,901
Fixed maturity securities, Fair Value, Total		1,612,229	1,115,530
Fixed maturity securities, Gross Unrealized Losses
Fixed maturity securities, Gross Unrealized Losses, 12 Months or Less		36,585	11,914
Fixed maturity securities, Gross Unrealized Losses, More than 12 Months		10,354	14,101
Fixed maturity securities, Gross Unrealized Losses, Total		46,939	26,015
Equity securities [Member]
Fixed maturity securities, Fair Value
Fixed maturity securities, Fair Value, 12 Months or Less	[1]	33,888	12,955
Fixed maturity securities, Fair Value, More than 12 Months	[1]	6,699	6,635
Fixed maturity securities, Fair Value, Total	[1]	40,587	19,590
Fixed maturity securities, Gross Unrealized Losses
Fixed maturity securities, Gross Unrealized Losses, 12 Months or Less	[1]	2,559	2,568
Fixed maturity securities, Gross Unrealized Losses, More than 12 Months	[1]	777	840
Fixed maturity securities, Gross Unrealized Losses, Total	[1]	$ 3,336	$ 3,408

[1] Includes nonredeemable (perpetual) preferred stocks, common stocks and closed-end funds.