Investments (Realized Investment Gains Losses Net) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule Of Gain Loss On Investments [Line Items]
Realized investment gains (losses), net	$ (83,230)	$ 71,783	$ 136,039
Fixed Maturities [Member]
Schedule Of Gain Loss On Investments [Line Items]
Realized investment gains (losses), net	22,684	74,395	126,687
Equity Securities [Member]
Schedule Of Gain Loss On Investments [Line Items]
Realized investment gains (losses), net	703	1,996	(123)
Commercial Mortgage Loans [Member]
Schedule Of Gain Loss On Investments [Line Items]
Realized investment gains (losses), net	1,043	6,866	(84)
Derivative [Member]
Schedule Of Gain Loss On Investments [Line Items]
Realized investment gains (losses), net	(107,663)	(11,366)	9,508
Other [Member]
Schedule Of Gain Loss On Investments [Line Items]
Realized investment gains (losses), net	$ 3	$ (108)	$ 51