Realized and Unrealized Investment Gains (Losses) (Change in Unrealized Gains (Losses) of Available For Sales Securities) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Realized and Unrealized Investment Gains Losses [Line Items]
Change in unrealized gains (losses) before income taxes and noncontrolling interests	$ 76,390	$ (300,478)	$ 188,680	$ (293,662)
Income tax benefit (expense)	(28,190)	103,418	(67,536)	104,412
Noncontrolling interests	(19)	35	(37)	(5)
Total change in unrealized gains	48,181	(197,025)	121,107	(189,255)
Debt Securities [Member]
Realized and Unrealized Investment Gains Losses [Line Items]
Change in unrealized gains (losses) before income taxes and noncontrolling interests	87,882	(277,791)	179,520	(293,380)
Debt Securities Previously Impaired [Member]
Realized and Unrealized Investment Gains Losses [Line Items]
Change in unrealized gains (losses) before income taxes and noncontrolling interests	194	(590)	753	522
Equity securities available for sale
Realized and Unrealized Investment Gains Losses [Line Items]
Change in unrealized gains (losses) before income taxes and noncontrolling interests	(17,870)	(16,191)	8,333	8,370
Investment funds
Realized and Unrealized Investment Gains Losses [Line Items]
Change in unrealized gains (losses) before income taxes and noncontrolling interests	$ 6,184	$ (5,906)	$ 74	$ (9,174)