Reinsurance (Ceded Reinsurance Receivable Assets) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables	$ 681,425	$ 637,859
Reinsurance Recoverables, Percentage of Total	100.00%	100.00%
Other Reinsurers [Member]
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables	$ 113,780	$ 107,077
Reinsurance Recoverables, Percentage of Total	16.70%	16.80%
AM Best, A+ Rating [Member] | Reinsurer A [Member]
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables	$ 233,016	$ 199,479
Reinsurance Recoverables, Percentage of Total	34.20%	31.30%
AM Best, A+ Rating [Member] | Reinsurer B [Member]
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables	$ 190,957	$ 179,522
Reinsurance Recoverables, Percentage of Total	28.00%	28.10%
AM Best, A+ Rating [Member] | Reinsurer C [Member]
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables	$ 68,727	$ 72,836
Reinsurance Recoverables, Percentage of Total	10.10%	11.40%
AM Best, A++ Rating [Member] | Reinsurer D [Member]
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables	$ 38,098	$ 41,807
Reinsurance Recoverables, Percentage of Total	5.60%	6.60%
AM Best, A Rating [Member] | Reinsurer E [Member]
Ceded Credit Risk [Line Items]
Reinsurance ceded receivables	$ 36,847	$ 37,138
Reinsurance Recoverables, Percentage of Total	5.40%	5.80%