Financial Derivatives (Schedule Of Gains And Losses On Derivative Contracts) (Details) - USD ($) $ in Thousands		3 Months Ended				9 Months Ended
		Sep. 30, 2015		Sep. 30, 2014		Sep. 30, 2015		Sep. 30, 2014
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		$ 2,358		$ (9,477)		$ (11,693)	[1]	$ (9,075)
Unrealized Gain (Loss) on Financial Derivatives				12,056				3,845
Foreign currency translation		2,403		(465)	[2]	(701)		(48)	[2]
Unrealized Gain (Loss) on Derivatives, including Foreign Currency Translation Gain (Loss)	[3]	(3,449)				4,953
Reimbursement from third party						1,500
Financial Derivatives - Assets [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		11,950		(975)		50,850		9,043
Unrealized Gain (Loss) on Financial Derivatives		9,119	[3]	4,165		(5,351)	[3]	1,919
Financial Derivatives - Liabilities [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(9,592)		(8,502)		(62,543)	[1]	(18,118)
Unrealized Gain (Loss) on Financial Derivatives		(12,568)	[3]	7,891		10,304	[3]	1,926
Derivative [Member]
Derivative [Line Items]
Foreign currency translation		58				(80)
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		446		(2,860)		(717)		(2,135)
Unrealized Gain (Loss) on Financial Derivatives		(310)	[3]	3,004		392	[3]	2,379
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		(154)		(2,145)		(544)		(4,261)
Unrealized Gain (Loss) on Financial Derivatives		526	[3]	2,327		(138)	[3]	2,367
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		(1,426)		(1,459)		(2,704)		653
Unrealized Gain (Loss) on Financial Derivatives		(763)	[3]	414		(2,208)	[3]	(361)
Credit Risk [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Corporate Bonds [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(4)				(4)
Unrealized Gain (Loss) on Financial Derivatives	[3]	1				1
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		(18)		(20)		(60)		(59)
Unrealized Gain (Loss) on Financial Derivatives		18	[3]	(28)		(23)	[3]	(28)
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		(65)		166		52		2,608
Unrealized Gain (Loss) on Financial Derivatives		(692)	[3]	(55)		(484)	[3]	(1,180)
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		(2,958)		(1,878)		(3,441)		(7,639)
Unrealized Gain (Loss) on Financial Derivatives		5,731	[3]	5,034		7,847	[3]	8,948
Credit Risk [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Corporate Bonds [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		40		369		(899)		510
Unrealized Gain (Loss) on Financial Derivatives		(55)	[3]	(395)		722	[3]	(620)
Equity Market Risk [Member] | Financial Derivatives - Assets [Member] | Total Return Swaps [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives				1,079				8,846
Unrealized Gain (Loss) on Financial Derivatives				4				24
Equity Market Risk [Member] | Financial Derivatives - Liabilities [Member] | Total Return Swaps [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives				(4,067)				(5,041)
Unrealized Gain (Loss) on Financial Derivatives				3				27
Equity Market/Credit Risk [Member] | Financial Derivatives - Assets [Member] | Total Return Swaps [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		536				4,602
Unrealized Gain (Loss) on Financial Derivatives	[3]	(67)				173
Equity Market/Credit Risk [Member] | Financial Derivatives - Liabilities [Member] | Total Return Swaps [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		3,103				(3,527)
Unrealized Gain (Loss) on Financial Derivatives	[3]	(1,137)				(3,035)
Interest Rate Risk [Member] | Financial Derivatives - Assets [Member] | Interest Rate Swaps [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		6,808		1,953		33,789		1,904
Unrealized Gain (Loss) on Financial Derivatives		9,641	[3]	191		(5,302)	[3]	(3,940)
Interest Rate Risk [Member] | Financial Derivatives - Assets [Member] | Futures [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives				299				1,266
Unrealized Gain (Loss) on Financial Derivatives				(2,023)				550
Interest Rate Risk [Member] | Financial Derivatives - Assets [Member] | Mortgage Loan Purchase Commitments [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		0				0
Unrealized Gain (Loss) on Financial Derivatives	[3]	11				11
Interest Rate Risk [Member] | Financial Derivatives - Liabilities [Member] | Interest Rate Swaps [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(6,806)		(2,218)		(42,734)	[1]	(6,075)
Unrealized Gain (Loss) on Financial Derivatives		(17,226)	[3]	174		3,515	[3]	(7,539)
Interest Rate Risk [Member] | Financial Derivatives - Liabilities [Member] | Futures [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives				39				14
Unrealized Gain (Loss) on Financial Derivatives				2,650				2,315
Interest Rates/Equity Market Risk [Member] | Financial Derivatives - Assets [Member] | Futures [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		383				3,635
Unrealized Gain (Loss) on Financial Derivatives	[3]	(3)				40
Interest Rates/Equity Market Risk [Member] | Financial Derivatives - Liabilities [Member] | Futures [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(1,426)				(2,210)
Unrealized Gain (Loss) on Financial Derivatives	[3]	(592)				(1,212)
Currency risk [Member] | Financial Derivatives - Assets [Member] | Forwards [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		646		2,218		8,166		2,722
Unrealized Gain (Loss) on Financial Derivatives		(217)	[3]	345		91	[3]	396
Currency risk [Member] | Financial Derivatives - Liabilities [Member] | Forwards [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(231)		(997)		(6,276)		(1,926)
Unrealized Gain (Loss) on Financial Derivatives		64	[3]	314		(4)	[3]	38
Credit/Interest Rate Risk [Member] | Financial Derivatives - Assets [Member] | Other Derivatives [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		4,715		(60)		4,627		48
Unrealized Gain (Loss) on Financial Derivatives		300	[3]	(97)		1,589	[3]	504
Credit/Interest Rate/Equity Market Risk [Member] | Financial Derivatives - Liabilities [Member] | Other Derivatives [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(1,231)		104		(3,448)		(510)
Unrealized Gain (Loss) on Financial Derivatives		$ 1,321	[3]	$ 194		$ 2,978	[3]	$ (35)

[1] Includes a $1.5 million reimbursement from a third party for the nine month period ended September 30, 2015.

[2] Conformed to current period presentation.

[3] Includes foreign currency translation on derivatives in the amount of $58 thousand and $(80) thousand, for the three and nine month periods ended September 30, 2015, respectively, which is included on the Consolidated Statement of Operations in Change in net unrealized gain (loss) on foreign currency translation.