Derivative Instruments (Location and Amounts of Unrealized And Realized Gains (Losses) On Derivatives Recorded In The Condensed Consolidated Income Statements) (Details) (Not Designated as Hedging Instrument, USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Realized and unrealized gains (losses) on derivatives	$ 4,057	$ (6,505)	$ (25,048)	$ 2,301
Foreign exchange gain (loss)
Derivative Instruments, Gain (Loss) [Line Items]
Realized and unrealized gains (losses) on derivatives	1,886	(2,336)	(580)	(1,091)
Foreign exchange gain (loss) | Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Realized and unrealized gains (losses) on derivatives	1,886	(2,336)	(580)	(1,091)
Net realized investment gains (losses)
Derivative Instruments, Gain (Loss) [Line Items]
Realized and unrealized gains (losses) on derivatives	2,171	(4,169)	(24,468)	3,392
Net realized investment gains (losses) | Put options
Derivative Instruments, Gain (Loss) [Line Items]
Realized and unrealized gains (losses) on derivatives	0	0	0	(3,822)
Net realized investment gains (losses) | Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Realized and unrealized gains (losses) on derivatives	1,701	(4,164)	857	1,925
Net realized investment gains (losses) | Interest rate futures and swaps
Derivative Instruments, Gain (Loss) [Line Items]
Realized and unrealized gains (losses) on derivatives	$ 470	$ (5)	$ (25,325)	$ 5,289