Valuation (Schedule Of Financial Instruments) (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-	[1]	$ 30,038	$ 28,165
Fair value repurchase agreements	[1]	132,538	155,949
Investments sold short, at fair value-		(691,962)	(642,240)
Financial derivatives–liabilities, at fair value-	[1]	(34,925)	(36,273)
Other secured borrowings, at fair value		(113,775)	(125,105)
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments, financial derivatives–assets, and repurchase agreements, at fair value		2,506,314	2,255,821
Total investments sold short, financial derivatives–liabilities, and other secured borrowings, at fair value		(840,662)	(803,618)
Fair Value, Measurements, Recurring [Member] | Other secured borrowings [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other secured borrowings, at fair value		(113,775)	(125,105)
Fair Value, Measurements, Recurring [Member] | Investments Sold Short [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		(691,962)	(642,240)
Fair Value, Measurements, Recurring [Member] | Investments Sold Short [Member] | Agency residential mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		(499,620)	(460,189)
Fair Value, Measurements, Recurring [Member] | Investments Sold Short [Member] | Government debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		(107,156)	(90,149)
Fair Value, Measurements, Recurring [Member] | Investments Sold Short [Member] | Corporate Debt Sold Short [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		(46,944)	(55,211)
Fair Value, Measurements, Recurring [Member] | Investments Sold Short [Member] | Common Stock Sold Short [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		(38,242)	(36,691)
Fair Value, Measurements, Recurring [Member] | Financial Derivatives - Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		(34,925)	(36,273)
Fair Value, Measurements, Recurring [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Corporate Bond Indices [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		(9,679)	(12,367)
Fair Value, Measurements, Recurring [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		(14,772)	(15,930)
Fair Value, Measurements, Recurring [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Asset Backed Indices [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		(2,200)	(980)
Fair Value, Measurements, Recurring [Member] | Financial Derivatives - Liabilities [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		(7,153)	(6,015)
Fair Value, Measurements, Recurring [Member] | Financial Derivatives - Liabilities [Member] | Total Return Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		(1)
Fair Value, Measurements, Recurring [Member] | Financial Derivatives - Liabilities [Member] | Futures [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		(1,023)	(508)
Fair Value, Measurements, Recurring [Member] | Financial Derivatives - Liabilities [Member] | Forwards [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		(97)	(473)
Fair Value, Measurements, Recurring [Member] | Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents		1,348	26,500
Fair Value, Measurements, Recurring [Member] | Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		2,343,738	2,071,707
Fair Value, Measurements, Recurring [Member] | Investments [Member] | Agency residential mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		1,121,566	995,514
Fair Value, Measurements, Recurring [Member] | Investments [Member] | US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		2,200
Fair Value, Measurements, Recurring [Member] | Investments [Member] | Private Label Residential Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		288,976	259,666
Fair Value, Measurements, Recurring [Member] | Investments [Member] | Private Label Commercial Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		33,166	40,745
Fair Value, Measurements, Recurring [Member] | Investments [Member] | Commercial Mortgage Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		109,294	108,301
Fair Value, Measurements, Recurring [Member] | Investments [Member] | Residential Mortgage Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		240,781	182,472
Fair Value, Measurements, Recurring [Member] | Investments [Member] | Collateralized Loan Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		227,156	210,816
Fair Value, Measurements, Recurring [Member] | Investments [Member] | Consumer loans and asset-backed securities backed by consumer loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		148,422	135,258
Fair Value, Measurements, Recurring [Member] | Investments [Member] | Corporate Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		92,198	75,193
Fair Value, Measurements, Recurring [Member] | Investments [Member] | Real Estate Owned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		29,110	26,277
Fair Value, Measurements, Recurring [Member] | Investments [Member] | Corporate Equity Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		50,869	37,465
Fair Value, Measurements, Recurring [Member] | Financial Derivatives - Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		30,038	28,165
Fair Value, Measurements, Recurring [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Asset Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		3,069	3,140
Fair Value, Measurements, Recurring [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Corporate Bond Indices [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		1,143	1,429
Fair Value, Measurements, Recurring [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		5,999	8,888
Fair Value, Measurements, Recurring [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Asset Backed Indices [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		4,269	5,393
Fair Value, Measurements, Recurring [Member] | Financial Derivatives - Assets [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		15,532	9,266
Fair Value, Measurements, Recurring [Member] | Financial Derivatives - Assets [Member] | Total Return Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		18
Fair Value, Measurements, Recurring [Member] | Financial Derivatives - Assets [Member] | Options [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-			4
Fair Value, Measurements, Recurring [Member] | Financial Derivatives - Assets [Member] | Futures [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-			45
Fair Value, Measurements, Recurring [Member] | Financial Derivatives - Assets [Member] | Forwards [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		8
Fair Value, Measurements, Recurring [Member] | Repurchase Agreements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value repurchase agreements		132,538	155,949
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments, financial derivatives–assets, and repurchase agreements, at fair value		0	48
Total investments sold short, financial derivatives–liabilities, and other secured borrowings, at fair value		(39,265)	(37,199)
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Other secured borrowings [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other secured borrowings, at fair value		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Investments Sold Short [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		(38,242)	(36,691)
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Investments Sold Short [Member] | Agency residential mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Investments Sold Short [Member] | Government debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Investments Sold Short [Member] | Corporate Debt Sold Short [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Investments Sold Short [Member] | Common Stock Sold Short [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		(38,242)	(36,691)
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Financial Derivatives - Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		(1,023)	(508)
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Corporate Bond Indices [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Asset Backed Indices [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Financial Derivatives - Liabilities [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Financial Derivatives - Liabilities [Member] | Total Return Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Financial Derivatives - Liabilities [Member] | Futures [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		(1,023)	(508)
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Financial Derivatives - Liabilities [Member] | Forwards [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents		1,348	26,500
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Investments [Member] | Agency residential mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Investments [Member] | US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Investments [Member] | Private Label Residential Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Investments [Member] | Private Label Commercial Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Investments [Member] | Commercial Mortgage Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Investments [Member] | Residential Mortgage Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Investments [Member] | Collateralized Loan Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Investments [Member] | Consumer loans and asset-backed securities backed by consumer loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Investments [Member] | Corporate Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Investments [Member] | Real Estate Owned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Investments [Member] | Corporate Equity Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Financial Derivatives - Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		0	48
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Asset Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Corporate Bond Indices [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Asset Backed Indices [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Financial Derivatives - Assets [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Financial Derivatives - Assets [Member] | Total Return Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Financial Derivatives - Assets [Member] | Options [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-			3
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Financial Derivatives - Assets [Member] | Futures [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-			45
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Financial Derivatives - Assets [Member] | Forwards [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Repurchase Agreements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value repurchase agreements		0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments, financial derivatives–assets, and repurchase agreements, at fair value		1,747,591	1,594,185
Total investments sold short, financial derivatives–liabilities, and other secured borrowings, at fair value		(687,622)	(641,314)
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Other secured borrowings [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other secured borrowings, at fair value		0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Investments Sold Short [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		(653,720)	(605,549)
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Investments Sold Short [Member] | Agency residential mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		(499,620)	(460,189)
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Investments Sold Short [Member] | Government debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		(107,156)	(90,149)
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Investments Sold Short [Member] | Corporate Debt Sold Short [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		(46,944)	(55,211)
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Investments Sold Short [Member] | Common Stock Sold Short [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Financial Derivatives - Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		(33,902)	(35,765)
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Corporate Bond Indices [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		(9,679)	(12,367)
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		(14,772)	(15,930)
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Asset Backed Indices [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		(2,200)	(980)
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Financial Derivatives - Liabilities [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		(7,153)	(6,015)
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Financial Derivatives - Liabilities [Member] | Total Return Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		(1)
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Financial Derivatives - Liabilities [Member] | Futures [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Financial Derivatives - Liabilities [Member] | Forwards [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		(97)	(473)
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents		0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		1,588,084	1,413,259
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Investments [Member] | Agency residential mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		1,115,438	989,341
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Investments [Member] | US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		2,200
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Investments [Member] | Private Label Residential Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		177,114	158,369
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Investments [Member] | Private Label Commercial Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		19,457	28,398
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Investments [Member] | Commercial Mortgage Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Investments [Member] | Residential Mortgage Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Investments [Member] | Collateralized Loan Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		199,677	185,905
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Investments [Member] | Consumer loans and asset-backed securities backed by consumer loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Investments [Member] | Corporate Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		74,198	51,246
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Investments [Member] | Real Estate Owned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Investments [Member] | Corporate Equity Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Financial Derivatives - Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		26,969	24,977
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Asset Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Corporate Bond Indices [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		1,143	1,429
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		5,999	8,888
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Asset Backed Indices [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		4,269	5,393
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Financial Derivatives - Assets [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		15,532	9,266
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Financial Derivatives - Assets [Member] | Total Return Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		18
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Financial Derivatives - Assets [Member] | Options [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-			1
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Financial Derivatives - Assets [Member] | Futures [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-			0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Financial Derivatives - Assets [Member] | Forwards [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		8
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Repurchase Agreements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value repurchase agreements		132,538	155,949
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investments, financial derivatives–assets, and repurchase agreements, at fair value		758,723	661,588
Total investments sold short, financial derivatives–liabilities, and other secured borrowings, at fair value		(113,775)	(125,105)
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Other secured borrowings [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other secured borrowings, at fair value		(113,775)	(125,105)
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Investments Sold Short [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Investments Sold Short [Member] | Agency residential mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Investments Sold Short [Member] | Government debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Investments Sold Short [Member] | Corporate Debt Sold Short [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Investments Sold Short [Member] | Common Stock Sold Short [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Financial Derivatives - Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Corporate Bond Indices [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Asset Backed Indices [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Financial Derivatives - Liabilities [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Financial Derivatives - Liabilities [Member] | Total Return Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Financial Derivatives - Liabilities [Member] | Futures [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Financial Derivatives - Liabilities [Member] | Forwards [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents		0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		755,654	658,448
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Investments [Member] | Agency residential mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		6,128	6,173
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Investments [Member] | US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Investments [Member] | Private Label Residential Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		111,862	101,297
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Investments [Member] | Private Label Commercial Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		13,709	12,347
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Investments [Member] | Commercial Mortgage Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		109,294	108,301
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Investments [Member] | Residential Mortgage Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		240,781	182,472
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Investments [Member] | Collateralized Loan Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		27,479	24,911
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Investments [Member] | Consumer loans and asset-backed securities backed by consumer loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		148,422	135,258
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Investments [Member] | Corporate Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		18,000	23,947
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Investments [Member] | Real Estate Owned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		29,110	26,277
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Investments [Member] | Corporate Equity Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-		50,869	37,465
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Financial Derivatives - Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		3,069	3,140
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Asset Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		3,069	3,140
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Corporate Bond Indices [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Financial Derivatives - Assets [Member] | Credit Default Swaps On Asset Backed Indices [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Financial Derivatives - Assets [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Financial Derivatives - Assets [Member] | Total Return Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Financial Derivatives - Assets [Member] | Options [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-			0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Financial Derivatives - Assets [Member] | Futures [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-			0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Financial Derivatives - Assets [Member] | Forwards [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-		0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Repurchase Agreements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value repurchase agreements		$ 0	$ 0

[1] In the Company's Consolidated Statement of Assets, Liabilities, and Equity, all balances associated with repurchase agreements, reverse repurchase agreements, and financial derivatives are presented on a gross basis.