Investments (Components Of Realized Gains And Losses) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Gain (Loss) on Investments [Line Items]
Gross realized gains on sale of invested assets	$ 28,773	$ 51,915	$ 146,780	$ 154,387
Gross realized losses on sale of invested assets	(9,955)	(40,770)	(26,228)	(82,812)
Net realized and unrealized gains (losses) on derivatives	2,171	(4,169)	(24,469)	3,392
Net realized investment (losses) gains	(35,136)	27,487	104,286	(8,074)
Fixed maturity investments, trading [Member]
Gain (Loss) on Investments [Line Items]
Mark-to-market (losses) gains	(40,843)	30,383	18,039	(101,205)
Equity securities, trading [Member]
Gain (Loss) on Investments [Line Items]
Mark-to-market (losses) gains	(8,479)	(17,198)	(8,768)	(18,555)
Other invested assets [Member]
Gain (Loss) on Investments [Line Items]
Mark-to-market (losses) gains	$ (6,803)	$ 7,326	$ (1,068)	$ 36,719