Financial Derivatives (Schedule Of Gains And Losses On Derivative Contracts) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018		Dec. 31, 2017
Derivative [Line Items]
Foreign currency transactions		$ 4,131		$ 3,845
Net Realized Gain/Loss on Financial Derivatives		1,911	[1]	(18,704)	[2]
Unrealized Gain (Loss) on Financial Derivatives		7,807	[3]	(317)	[4]
Foreign currency translation		(7,071)		4,326
Derivative [Member]
Derivative [Line Items]
Foreign currency transactions		100		(100)
Foreign currency translation		100		(200)
Credit Default Swaps On Asset Backed Securities [Member] | Credit Risk [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(687)	[1]	(601)	[2]
Unrealized Gain (Loss) on Financial Derivatives		715	[3]	(263)	[4]
Credit Default Swaps On Asset Backed Indices [Member] | Credit Risk [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(2,293)	[1]	(5,291)	[2]
Unrealized Gain (Loss) on Financial Derivatives		2,013	[3]	(817)	[4]
Credit Default Swaps On Corporate Bond Indices [Member] | Credit Risk [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(1,983)	[1]	(3,336)	[2]
Unrealized Gain (Loss) on Financial Derivatives		3,540	[3]	(459)	[4]
Credit Default Swaps On Corporate Bonds [Member] | Credit Risk [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		2,993	[1]	205	[2]
Unrealized Gain (Loss) on Financial Derivatives		(2,648)	[3]	907	[4]
Total Return Swaps [Member] | Equity Market/Credit Risk [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		3,844	[1]	(1,825)	[2]
Unrealized Gain (Loss) on Financial Derivatives		(5)	[3]	149	[4]
Interest Rate Swaps [Member] | Interest Rate Risk [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		(985)	[1]	(1,171)	[2]
Unrealized Gain (Loss) on Financial Derivatives		3,648	[3]	571	[4]
Futures [Member] | Interest Rate Risk [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives	[2]			(195)
Unrealized Gain (Loss) on Financial Derivatives	[4]			(423)
Futures [Member] | Interest Rate/Currency Risk [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives	[1]	162
Unrealized Gain (Loss) on Financial Derivatives	[3]	108
Forwards [Member] | Currency risk [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives		923	[1]	(6,390)	[2]
Unrealized Gain (Loss) on Financial Derivatives		359	[3]	(18)	[4]
Warrant [Member] | Equity Market Risk [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives	[2]			(100)
Unrealized Gain (Loss) on Financial Derivatives	[4]			(5)
Mortgage Loan Purchase Commitments [Member] | Interest Rate Risk [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives	[2]			0
Unrealized Gain (Loss) on Financial Derivatives	[4]			31
Options [Member] | Equity Market/Credit Risk [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives	[2]			0
Unrealized Gain (Loss) on Financial Derivatives	[4]			$ 10
Options [Member] | Interest Rates/Equity Market Risk [Member]
Derivative [Line Items]
Net Realized Gain/Loss on Financial Derivatives	[1]	(63)
Unrealized Gain (Loss) on Financial Derivatives	[3]	$ 77

[1] Includes gain/(loss) on foreign currency transactions on derivatives in the amount of $0.1 million for the year ended December 31, 2018, which is included on the Consolidated Statement of Operations in Realized gain (loss) on foreign currency transactions.

[2] Includes gain/(loss) on foreign currency transactions on derivatives in the amount of $(0.1) million for the year ended December 31, 2017, 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 $0.1 million for the year ended December 31, 2018, which is included on the Consolidated Statement of Operations in Change in net unrealized gain (loss) on foreign currency translation.

[4] Includes foreign currency translation on derivatives in the amount of $(0.2) million for the year ended December 31, 2017, which is included on the Consolidated Statement of Operations in Change in net unrealized gain (loss) on foreign currency translation.