Financial Derivatives (Schedule Of Gains And Losses On Derivative Contracts) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Derivative [Line Items]
Foreign currency transactions		$ (3,073)		$ (1,486)	[1]	$ (4)	[1]
Net Realized Gain/Loss on Financial Derivatives		(10,115)	[2]	(11,211)		(21,479)
Unrealized Gain (Loss) on Financial Derivatives				(8,272)		13,482
Foreign currency translation		(1,706)		(950)	[1]	42	[1]
Unrealized Gain (Loss) on Derivatives, including Foreign Currency Translation Gain (Loss)	[3]	8,780
Reimbursement from third party		1,500
Financial Derivatives - Assets [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		69,666	[2]	26,098		(7,876)
Unrealized Gain (Loss) on Financial Derivatives		(19,901)	[3]	9,338		26,486
Financial Derivatives - Liabilities [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(79,781)	[2]	(37,309)		(13,603)
Unrealized Gain (Loss) on Financial Derivatives		28,681	[3]	(17,610)		(13,004)
Derivative [Member]
Derivative [Line Items]
Foreign currency transactions		200
Foreign currency translation		(1,100)
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		(2,964)	[2]	(4,596)		(2,826)
Unrealized Gain (Loss) on Financial Derivatives		2,098	[3]	4,547		1,070
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		(1,083)	[2]	(4,662)		(5,954)
Unrealized Gain (Loss) on Financial Derivatives		442	[3]	2,059		1,082
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		107	[2]	1,938		626
Unrealized Gain (Loss) on Financial Derivatives		(763)	[3]	(2,589)		1,026
Credit Risk [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Corporate Bonds [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives	[2]	(6)
Unrealized Gain (Loss) on Financial Derivatives	[3]	10
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		(102)	[2]	(78)		(78)
Unrealized Gain (Loss) on Financial Derivatives		35	[3]	111		(349)
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		369	[2]	3,111		1,870
Unrealized Gain (Loss) on Financial Derivatives		(727)	[3]	(1,743)		2,869
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		(8,166)	[2]	(6,242)		(9,573)
Unrealized Gain (Loss) on Financial Derivatives		8,266	[3]	6,926		(9,157)
Credit Risk [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Corporate Bonds [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(999)	[2]	270
Unrealized Gain (Loss) on Financial Derivatives		684	[3]	(782)
Equity Market Risk [Member] | Financial Derivatives - Assets [Member] | Total Return Swaps [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives				12,975		2,992
Unrealized Gain (Loss) on Financial Derivatives				3		4
Equity Market Risk [Member] | Financial Derivatives - Liabilities [Member] | Total Return Swaps [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives				(5,671)		(5,260)
Unrealized Gain (Loss) on Financial Derivatives				46		(3)
Equity Market/Credit Risk [Member] | Financial Derivatives - Assets [Member] | Total Return Swaps [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives	[2]	5,176
Unrealized Gain (Loss) on Financial Derivatives	[3]	77
Equity Market/Credit Risk [Member] | Financial Derivatives - Liabilities [Member] | Total Return Swaps [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives	[2]	(3,338)
Unrealized Gain (Loss) on Financial Derivatives	[3]	(4,641)
Interest Rate Risk [Member] | Financial Derivatives - Assets [Member] | Interest Rate Swaps [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		42,724	[2]	10,610		(2,829)
Unrealized Gain (Loss) on Financial Derivatives		(22,572)	[3]	5,101		23,548
Interest Rate Risk [Member] | Financial Derivatives - Liabilities [Member] | Interest Rate Swaps [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(52,327)	[2],[4]	(23,939)		319
Unrealized Gain (Loss) on Financial Derivatives		24,555	[3],[4]	(24,318)		(3,940)
Interest Rate Risk [Member] | Financial Derivatives - Liabilities [Member] | Futures [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives						(795)
Unrealized Gain (Loss) on Financial Derivatives						(2,302)
Interest Rate Risk [Member] | Financial Derivatives - Liabilities [Member] | Mortgage Loan Purchase Commitments [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives	[2]	0
Unrealized Gain (Loss) on Financial Derivatives	[3]	(8)
Interest Rates/Equity Market Risk [Member] | Financial Derivatives - Assets [Member] | Futures [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		3,430	[2]	4,841
Unrealized Gain (Loss) on Financial Derivatives		(181)	[3]	261
Interest Rates/Equity Market Risk [Member] | Financial Derivatives - Liabilities [Member] | Futures [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(2,722)	[2]	(252)
Unrealized Gain (Loss) on Financial Derivatives		(495)	[3]	2,291
Interest Rates/Equity Market Risk [Member] | Financial Derivatives - Liabilities [Member] | Other Derivatives [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives						(86)
Unrealized Gain (Loss) on Financial Derivatives						(84)
Currency risk [Member] | Financial Derivatives - Assets [Member] | Forwards [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		11,790	[2]	3,845
Unrealized Gain (Loss) on Financial Derivatives		254	[3]	884
Currency risk [Member] | Financial Derivatives - Liabilities [Member] | Forwards [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(7,052)	[2]	(2,215)		0
Unrealized Gain (Loss) on Financial Derivatives		123	[3]	(98)		(38)
Credit/Interest Rate Risk [Member] | Financial Derivatives - Assets [Member] | Other Derivatives [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		10,492	[2]	1,147		115
Unrealized Gain (Loss) on Financial Derivatives		734	[3]	(928)		$ (244)
Credit/Interest Rate/Equity Market Risk [Member] | Financial Derivatives - Liabilities [Member] | Other Derivatives [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(5,444)	[2]	(2,293)
Unrealized Gain (Loss) on Financial Derivatives		$ 889	[3]	$ (43)

[1] Conformed to current period presentation.

[2] Includes foreign currency translation on derivatives in the amount of $0.2 million, for the year ended December 31, 2015, which is included on the Consolidated Statement of Operations in Realized gain (loss) on foreign currency transactions.

[3] Includes foreign currency translation on derivatives in the amount of $(1.1) million, for the year ended December 31, 2015, which is included on the Consolidated Statement of Operations in Change in net unrealized gain (loss) on foreign currency translation.

[4] Includes a $1.5 million reimbursement from a third party for the year ended December 31, 2015.