Investments (Fair Value Below Amortized Cost of Gross Unrealized Losses for Fixed Maturity and Equity Securities) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Gross unrealized losses with number of securities [Line Items]
Gross Unrealized Losses	$ 393,841	$ 134,919
% of Total	100.00%	100.00%
Less than 20%
Gross unrealized losses with number of securities [Line Items]
Gross Unrealized Losses	$ 373,312	$ 111,965
% of Total	94.80%	83.00%
20% or more for less than six months
Gross unrealized losses with number of securities [Line Items]
Gross Unrealized Losses	$ 10,201	$ 13,698
% of Total	2.60%	10.10%
20% or more for six months or greater
Gross unrealized losses with number of securities [Line Items]
Gross Unrealized Losses	$ 10,328	$ 9,256
% of Total	2.60%	6.90%