Valuation (Schedule Of Financial Instruments) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-	$ 59,664	[1]	$ 48,504	[1]
Fair value repurchase agreements	27,962	[1]	13,650	[1]
Investments sold short, at fair value-	(845,614)		(622,301)
Financial derivatives–liabilities, at fair value-	(44,791)	[1]	(15,212)	[1]
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	183,489		59,084
Total investments and financial derivatives–assets, at fair value and repurchase agreements	0		0
Total investments sold short, financial derivatives–liabilities, and securitized debt, at fair value	(8,742)		(70)
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-	(6,369)
Level 1 [Member] | Investments Sold Short [Member] | US Treasury and Government [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-			0
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
Level 1 [Member] | Investments Sold Short [Member] | Government debt sold short [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-	0
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-	(6,369)
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-	(2,373)		(70)
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
Level 1 [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Asset Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-	0		0
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
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
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		0
Level 1 [Member] | Financial Derivatives - Liabilities [Member] | Put Option [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-	0
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-	(2,373)		(70)
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
Level 1 [Member] | Securitized Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securitized debt	0		0
Level 1 [Member] | Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-	0		0
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
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
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
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
Level 1 [Member] | Investments [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-	0
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
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		0
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
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
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
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
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
Level 1 [Member] | Financial Derivatives - Assets [Member] | Put Option [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-	0
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
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0		0
Total investments and financial derivatives–assets, at fair value and repurchase agreements	1,060,822		837,356
Total investments sold short, financial derivatives–liabilities, and securitized debt, at fair value	(881,313)		(637,442)
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-	(839,245)
Level 2 [Member] | Investments Sold Short [Member] | US Treasury and Government [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-			(622,301)
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-	(811,957)
Level 2 [Member] | Investments Sold Short [Member] | Government debt sold short [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-	(27,288)
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
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-	(42,068)		(15,141)
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-	(11,866)		(13,468)
Level 2 [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Asset Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-	0		0
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-	(24,949)		(484)
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-	(5,064)		(1,124)
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-	(67)		(65)
Level 2 [Member] | Financial Derivatives - Liabilities [Member] | Put Option [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-	(84)
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
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-	(38)
Level 2 [Member] | Securitized Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securitized debt	0		0
Level 2 [Member] | Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-	989,842		811,233
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-	0		0
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-	0		0
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
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
Level 2 [Member] | Investments [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-	0
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-	989,842		811,233
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-	43,018		12,473
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-	4,937		12,468
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
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-	14,273
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-	23,553		5
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-	4
Level 2 [Member] | Financial Derivatives - Assets [Member] | Put Option [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-	251
Level 2 [Member] | Repurchase Agreements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value repurchase agreements	27,962		13,650
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0		0
Total investments and financial derivatives–assets, at fair value and repurchase agreements	756,934		599,914
Total investments sold short, financial derivatives–liabilities, and securitized debt, at fair value	(1,333)		(1,336)
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
Level 3 [Member] | Investments Sold Short [Member] | US Treasury and Government [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-			0
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
Level 3 [Member] | Investments Sold Short [Member] | Government debt sold short [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-	0
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
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-	(350)		(1)
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
Level 3 [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Asset Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-	(350)		(1)
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
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
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		0
Level 3 [Member] | Financial Derivatives - Liabilities [Member] | Put Option [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-	0
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
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
Level 3 [Member] | Securitized Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securitized debt	(983)		(1,335)
Level 3 [Member] | Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-	740,288		563,883
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-	580,772		528,366
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-	32,994		19,327
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-	23,887		9,546
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-	24,062
Level 3 [Member] | Investments [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-	38,069
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-	40,504		6,644
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-	16,646		36,031
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
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-	16,646		36,031
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
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
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
Level 3 [Member] | Financial Derivatives - Assets [Member] | Put Option [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-	0
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
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	183,489		59,084
Total investments and financial derivatives–assets, at fair value and repurchase agreements	1,817,756		1,437,270
Total investments sold short, financial derivatives–liabilities, and securitized debt, at fair value	(891,388)		(638,848)
Estimate of Fair Value, Fair Value Disclosure [Member] | Investments Sold Short [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-	(845,614)
Estimate of Fair Value, Fair Value Disclosure [Member] | Investments Sold Short [Member] | US Treasury and Government [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-			(622,301)
Estimate of Fair Value, Fair Value Disclosure [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-	(811,957)
Estimate of Fair Value, Fair Value Disclosure [Member] | Investments Sold Short [Member] | Government debt sold short [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments sold short, at fair value-	(27,288)
Estimate of Fair Value, Fair Value Disclosure [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-	(6,369)
Estimate of Fair Value, Fair Value Disclosure [Member] | Financial Derivatives - Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-	(44,791)		(15,212)
Estimate of Fair Value, Fair Value Disclosure [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-	(11,866)		(13,468)
Estimate of Fair Value, Fair Value Disclosure [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Asset Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-	(350)		(1)
Estimate of Fair Value, Fair Value Disclosure [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-	(24,949)		(484)
Estimate of Fair Value, Fair Value Disclosure [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-	(5,064)		(1,124)
Estimate of Fair Value, Fair Value Disclosure [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-	(67)		(65)
Estimate of Fair Value, Fair Value Disclosure [Member] | Financial Derivatives - Liabilities [Member] | Put Option [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–liabilities, at fair value-	(84)
Estimate of Fair Value, Fair Value Disclosure [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-	(2,373)		(70)
Estimate of Fair Value, Fair Value Disclosure [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-	(38)
Estimate of Fair Value, Fair Value Disclosure [Member] | Securitized Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securitized debt	(983)		(1,335)
Estimate of Fair Value, Fair Value Disclosure [Member] | Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-	1,730,130		1,375,116
Estimate of Fair Value, Fair Value Disclosure [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-	580,772		528,366
Estimate of Fair Value, Fair Value Disclosure [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-	32,994		19,327
Estimate of Fair Value, Fair Value Disclosure [Member] | Investments [Member] | Commercial Mortgage Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-	23,887		9,546
Estimate of Fair Value, Fair Value Disclosure [Member] | Investments [Member] | Residential Mortgage Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-	24,062
Estimate of Fair Value, Fair Value Disclosure [Member] | Investments [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, at fair value-	38,069
Estimate of Fair Value, Fair Value Disclosure [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-	1,030,346		817,877
Estimate of Fair Value, Fair Value Disclosure [Member] | Financial Derivatives - Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-	59,664		48,504
Estimate of Fair Value, Fair Value Disclosure [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-	4,937		12,468
Estimate of Fair Value, Fair Value Disclosure [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-	16,646		36,031
Estimate of Fair Value, Fair Value Disclosure [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-	14,273
Estimate of Fair Value, Fair Value Disclosure [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-	23,553		5
Estimate of Fair Value, Fair Value Disclosure [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-	4
Estimate of Fair Value, Fair Value Disclosure [Member] | Financial Derivatives - Assets [Member] | Put Option [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives–assets, at fair value-	251
Estimate of Fair Value, Fair Value Disclosure [Member] | Repurchase Agreements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value repurchase agreements	27,962		13,650
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers of financial instruments between Level 1, Level 2, or Level 3	$ 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.