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 [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Total realized and unrealized losses on derivatives	$ 10,759	$ (4,357)	$ (76,095)
Foreign Currency Gain (Loss) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total realized and unrealized losses on derivatives	1,274	(749)	(6,005)
Foreign Currency Gain (Loss) [Member] | Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Total realized and unrealized losses on derivatives	1,274	(749)	(6,005)
Realized Gain (Loss) on Sale of Investments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total realized and unrealized losses on derivatives	9,485	(3,608)	(70,090)
Realized Gain (Loss) on Sale of Investments [Member] | Put options
Derivative Instruments, Gain (Loss) [Line Items]
Total realized and unrealized losses on derivatives	(3,822)	(2,222)	(4,125)
Realized Gain (Loss) on Sale of Investments [Member] | Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Total realized and unrealized losses on derivatives	3,054	(1,024)	(6,242)
Realized Gain (Loss) on Sale of Investments [Member] | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Total realized and unrealized losses on derivatives	5,591	0	0
Realized Gain (Loss) on Sale of Investments [Member] | Interest rate futures
Derivative Instruments, Gain (Loss) [Line Items]
Total realized and unrealized losses on derivatives	$ 4,662	$ (362)	$ (59,723)