Investments (Fair Value Below Amortized Cost of Gross Unrealized Losses for Fixed Maturity and Equity Securities) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Gross unrealized losses with number of securities [Line Items]
Gross Unrealized Losses	$ 179,307	$ 324,600
% of Total	100.00%	100.00%
Less than 20%
Gross unrealized losses with number of securities [Line Items]
Gross Unrealized Losses	161,371	296,731
% of Total	90.00%	91.40%
20% or more for less than six months
Gross unrealized losses with number of securities [Line Items]
Gross Unrealized Losses	163	6,444
% of Total	0.10%	2.00%
20% or more for six months or greater
Gross unrealized losses with number of securities [Line Items]
Gross Unrealized Losses	$ 17,773	$ 21,425
% of Total	9.90%	6.60%