Financial Derivatives (Schedule Of Gains And Losses On Derivative Contracts) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016		Mar. 31, 2015
Derivative [Line Items]
Foreign currency transactions		$ 420		$ 733
Net Realized Gain/Loss on Financial Derivatives		(10,358)	[1]	(38)
Unrealized Gain (Loss) on Financial Derivatives		(20,310)	[2]	(5,148)	[3]
Foreign currency translation		3,219		(5,063)
Financial Derivatives - Assets [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		16,461	[1]	25,306
Unrealized Gain (Loss) on Financial Derivatives		9,812	[2]	(7,156)	[3]
Financial Derivatives - Liabilities [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(26,819)	[1]	(25,344)
Unrealized Gain (Loss) on Financial Derivatives		(30,122)	[2]	2,008	[3]
Derivative [Member]
Derivative [Line Items]
Foreign currency transactions		28
Foreign currency translation		1,600		1,000
Credit Risk [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Asset Backed Securities [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		91	[1]	401
Unrealized Gain (Loss) on Financial Derivatives		(105)	[2]	(355)	[3]
Credit Risk [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Asset Backed Indices [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		2,745	[1]	226
Unrealized Gain (Loss) on Financial Derivatives		(839)	[2]	(1,252)	[3]
Credit Risk [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Corporate Bond Indices [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(1,957)	[1]	(3,014)
Unrealized Gain (Loss) on Financial Derivatives		3,239	[2]	828	[3]
Credit Risk [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Corporate Bonds [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives	[1]	477
Unrealized Gain (Loss) on Financial Derivatives	[2]	5
Credit Risk [Member] | Financial Derivatives - Assets [Member] | Warrant [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives	[1]	(50)
Unrealized Gain (Loss) on Financial Derivatives	[2]	0
Credit Risk [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Asset Backed Securities [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(16)	[1]	(19)
Unrealized Gain (Loss) on Financial Derivatives		1	[2]	0	[3]
Credit Risk [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Asset Backed Indices [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(159)	[1]	145
Unrealized Gain (Loss) on Financial Derivatives		(92)	[2]	206	[3]
Credit Risk [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Corporate Bond Indices [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(5,143)	[1]	2,124
Unrealized Gain (Loss) on Financial Derivatives		(13,636)	[2]	(2,656)	[3]
Credit Risk [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Corporate Bonds [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(505)	[1]	(668)
Unrealized Gain (Loss) on Financial Derivatives		118	[2]	485	[3]
Equity Market/Credit Risk [Member] | Financial Derivatives - Assets [Member] | Total Return Swaps [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(877)	[1]	1,810
Unrealized Gain (Loss) on Financial Derivatives		989	[2]	110	[3]
Equity Market/Credit Risk [Member] | Financial Derivatives - Liabilities [Member] | Total Return Swaps [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(4,789)	[1]	(458)
Unrealized Gain (Loss) on Financial Derivatives		3,858	[2]	(304)	[3]
Interest Rate Risk [Member] | Financial Derivatives - Assets [Member] | Interest Rate Swaps [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		12,725	[1]	19,460
Unrealized Gain (Loss) on Financial Derivatives		7,169	[2]	(6,987)	[3]
Interest Rate Risk [Member] | Financial Derivatives - Assets [Member] | Futures [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives				2,398
Unrealized Gain (Loss) on Financial Derivatives	[3]			824
Interest Rate Risk [Member] | Financial Derivatives - Assets [Member] | Purchase Commitment [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives	[1]	0
Unrealized Gain (Loss) on Financial Derivatives	[2]	43
Interest Rate Risk [Member] | Financial Derivatives - Liabilities [Member] | Interest Rate Swaps [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(16,509)	[1]	(25,197)
Unrealized Gain (Loss) on Financial Derivatives		(13,112)	[2]	4,321	[3]
Interest Rates/Equity Market Risk [Member] | Financial Derivatives - Assets [Member] | Futures [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives	[1]	(63)
Unrealized Gain (Loss) on Financial Derivatives	[2]	99
Interest Rates/Equity Market Risk [Member] | Financial Derivatives - Liabilities [Member] | Futures [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(471)	[1]	(32)
Unrealized Gain (Loss) on Financial Derivatives		28	[2]	(411)	[3]
Currency risk [Member] | Financial Derivatives - Assets [Member] | Forwards [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(307)	[1]	7,285
Unrealized Gain (Loss) on Financial Derivatives		(1,138)	[2]	(884)	[3]
Currency risk [Member] | Financial Derivatives - Liabilities [Member] | Forwards [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(25)	[1]	(1,489)
Unrealized Gain (Loss) on Financial Derivatives		(1,909)	[2]	(581)	[3]
Credit/Interest Rate Risk [Member] | Financial Derivatives - Assets [Member] | Options [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		3,677	[1]	(3,260)
Unrealized Gain (Loss) on Financial Derivatives		350	[2]	560	[3]
Credit/Interest Rate Risk [Member] | Financial Derivatives - Liabilities [Member] | Options [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives				250
Unrealized Gain (Loss) on Financial Derivatives	[3]			$ 948
Credit/Interest Rate/Equity Market Risk [Member] | Financial Derivatives - Liabilities [Member] | Options [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives	[1]	798
Unrealized Gain (Loss) on Financial Derivatives	[2]	$ (5,378)

[1] Includes gain/(loss) on foreign currency transactions on derivatives in the amount of $28 thousand, for the three month period ended March 31, 2016, which is included on the Consolidated Statement of Operations in Realized gain (loss) on foreign currency transactions.

[2] Includes foreign currency translation on derivatives in the amount of $1.6 million, for the three month period ended March 31, 2016, which is included on the Consolidated Statement of Operations in Change in net unrealized gain (loss) on foreign currency translation.

[3] Includes foreign currency translation on derivatives in the amount of $1.0 million which is shown on the Consolidated Statement of Operations in Change in net unrealized gain (loss) on foreign currency translation.