Valuation (Schedule Of Financial Instruments) (Details) (USD $)

12 Months Ended

Dec. 31, 2014

Dec. 31, 2013

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial derivatives–assets, at fair value-

$ 80,029,000

^[1]

$ 59,664,000

^[1]

Fair value repurchase agreements

172,001,000

^[1]

27,962,000

^[1]

Investments sold short, at fair value-

(1,291,370,000)

(845,614,000)

Financial derivatives–liabilities, at fair value-

(66,116,000)

^[1]

(44,791,000)

^[1]

Securitized Debt [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Security Owned and Pledged as Collateral, Fair Value

2,200,000

2,300,000

Level 1 [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Cash and cash equivalents

114,140,000

183,489,000

Total investments and financial derivatives–assets, at fair value and repurchase agreements

261,000

0

Total investments sold short, financial derivatives–liabilities, and securitized debt, at fair value

(26,597,000)

(8,742,000)

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-

(26,516,000)

(6,369,000)

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

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

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-

(26,516,000)

(6,369,000)

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-

(81,000)

(2,373,000)

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] | 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

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] | Swaption [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] | Options [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] | Futures [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial derivatives–liabilities, at fair value-

(81,000)

(2,373,000)

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

Level 1 [Member] | Securitized Debt [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Securitized debt(1)

0

^[2]

0

^[3]

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] | 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] | Investments [Member] | US Treasury 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] | 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

0

Level 1 [Member] | Investments [Member] | Other 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] | Other asset-backed securities and 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] | Corporate Debt [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Investments, at fair value-

0

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

Level 1 [Member] | Investments [Member] | Private Corporate Investments [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Investments, at fair value-

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-

261,000

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

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

0

Level 1 [Member] | Financial Derivatives - Assets [Member] | Swaption [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] | Options [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] | Futures [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial derivatives–assets, at fair value-

261,000

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

Level 1 [Member] | Financial Derivatives - Assets [Member] | Warrant [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

1,785,365,000

1,060,822,000

Total investments sold short, financial derivatives–liabilities, and securitized debt, at fair value

(1,330,650,000)

(881,313,000)

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-

(1,264,854,000)

(839,245,000)

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-

(1,209,539,000)

(811,957,000)

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-

(55,315,000)

(27,288,000)

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

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-

(65,796,000)

(42,068,000)

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-

(4,410,000)

(11,866,000)

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-

(28,588,000)

(24,949,000)

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-

(2,953,000)

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-

(29,405,000)

(5,064,000)

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-

(21,000)

(67,000)

Level 2 [Member] | Financial Derivatives - Liabilities [Member] | Swaption [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial derivatives–liabilities, at fair value-

(137,000)

Level 2 [Member] | Financial Derivatives - Liabilities [Member] | Options [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial derivatives–liabilities, at fair value-

(146,000)

(84,000)

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-

(136,000)

(38,000)

Level 2 [Member] | Securitized Debt [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Securitized debt(1)

0

^[2]

0

^[3]

Level 2 [Member] | Investments [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Investments, at fair value-

1,545,083,000

989,842,000

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-

1,258,699,000

989,842,000

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-

1,636,000

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-

284,748,000

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

0

Level 2 [Member] | Investments [Member] | Other 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] | Other asset-backed securities and 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] | Corporate Debt [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Investments, at fair value-

0

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

Level 2 [Member] | Investments [Member] | Private Corporate Investments [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Investments, at fair value-

0

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-

68,281,000

43,018,000

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-

1,881,000

4,937,000

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-

35,865,000

14,273,000

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-

28,654,000

23,553,000

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-

8,000

4,000

Level 2 [Member] | Financial Derivatives - Assets [Member] | Swaption [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial derivatives–assets, at fair value-

344,000

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-

645,000

251,000

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

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-

884,000

Level 2 [Member] | Financial Derivatives - Assets [Member] | Warrant [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial derivatives–assets, at fair value-

0

Level 2 [Member] | Repurchase Agreements [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Fair value repurchase agreements

172,001,000

27,962,000

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

638,486,000

756,934,000

Total investments sold short, financial derivatives–liabilities, and securitized debt, at fair value

(1,013,000)

(1,333,000)

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

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

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

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

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-

(239,000)

(350,000)

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-

(239,000)

(350,000)

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] | 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

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] | Swaption [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] | Options [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] | 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

0

Level 3 [Member] | Securitized Debt [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Securitized debt(1)

(774,000)

^[2]

(983,000)

^[3]

Level 3 [Member] | Investments [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Investments, at fair value-

626,999,000

740,288,000

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-

31,385,000

40,504,000

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

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-

274,369,000

580,772,000

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-

53,311,000

32,994,000

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-

28,309,000

23,887,000

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-

27,482,000

24,062,000

Level 3 [Member] | Investments [Member] | Other Asset-backed Securities [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Investments, at fair value-

38,069,000

Level 3 [Member] | Investments [Member] | Other asset-backed securities and loans [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Investments, at fair value-

146,288,000

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-

42,708,000

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-

8,635,000

Level 3 [Member] | Investments [Member] | Private Corporate Investments [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Investments, at fair value-

14,512,000

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-

11,487,000

16,646,000

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-

11,387,000

16,646,000

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

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

0

Level 3 [Member] | Financial Derivatives - Assets [Member] | Swaption [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] | Options [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] | Futures [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] | Forwards [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] | Warrant [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial derivatives–assets, at fair value-

100,000

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

114,140,000

183,489,000

Total investments and financial derivatives–assets, at fair value and repurchase agreements

2,424,112,000

1,817,756,000

Total investments sold short, financial derivatives–liabilities, and securitized debt, at fair value

(1,358,260,000)

(891,388,000)

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-

(1,291,370,000)

(845,614,000)

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-

(1,209,539,000)

(811,957,000)

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-

(55,315,000)

(27,288,000)

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-

(26,516,000)

(6,369,000)

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-

(66,116,000)

(44,791,000)

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-

(4,410,000)

(11,866,000)

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-

(239,000)

(350,000)

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-

(28,588,000)

(24,949,000)

Estimate of Fair Value, Fair Value Disclosure [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-

(2,953,000)

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-

(29,405,000)

(5,064,000)

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-

(21,000)

(67,000)

Estimate of Fair Value, Fair Value Disclosure [Member] | Financial Derivatives - Liabilities [Member] | Swaption [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial derivatives–liabilities, at fair value-

(137,000)

Estimate of Fair Value, Fair Value Disclosure [Member] | Financial Derivatives - Liabilities [Member] | Options [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial derivatives–liabilities, at fair value-

(146,000)

(84,000)

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-

(81,000)

(2,373,000)

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-

(136,000)

(38,000)

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(1)

(774,000)

^[2]

(983,000)

^[3]

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-

2,172,082,000

1,730,130,000

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-

1,290,084,000

1,030,346,000

Estimate of Fair Value, Fair Value Disclosure [Member] | Investments [Member] | US Treasury Securities [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Investments, at fair value-

1,636,000

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-

559,117,000

580,772,000

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-

53,311,000

32,994,000

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-

28,309,000

23,887,000

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-

27,482,000

24,062,000

Estimate of Fair Value, Fair Value Disclosure [Member] | Investments [Member] | Other Asset-backed Securities [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Investments, at fair value-

38,069,000

Estimate of Fair Value, Fair Value Disclosure [Member] | Investments [Member] | Other asset-backed securities and loans [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Investments, at fair value-

146,288,000

Estimate of Fair Value, Fair Value Disclosure [Member] | Investments [Member] | Corporate Debt [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Investments, at fair value-

42,708,000

Estimate of Fair Value, Fair Value Disclosure [Member] | Investments [Member] | Real Estate Owned [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Investments, at fair value-

8,635,000

Estimate of Fair Value, Fair Value Disclosure [Member] | Investments [Member] | Private Corporate Investments [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Investments, at fair value-

14,512,000

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-

80,029,000

59,664,000

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-

1,881,000

4,937,000

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-

11,387,000

16,646,000

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-

35,865,000

14,273,000

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-

28,654,000

23,553,000

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-

8,000

4,000

Estimate of Fair Value, Fair Value Disclosure [Member] | Financial Derivatives - Assets [Member] | Swaption [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial derivatives–assets, at fair value-

344,000

Estimate of Fair Value, Fair Value Disclosure [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-

645,000

251,000

Estimate of Fair Value, Fair Value Disclosure [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-

261,000

Estimate of Fair Value, Fair Value Disclosure [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-

884,000

Estimate of Fair Value, Fair Value Disclosure [Member] | Financial Derivatives - Assets [Member] | Warrant [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Financial derivatives–assets, at fair value-

100,000

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

172,001,000

27,962,000

Fair Value, Measurements, Recurring [Member]

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Fair Value, Level 1 To Level 2 To Level 3 Transfers Amount

0

Fair Value, Transfers between Level 1 and Level 2

$ 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.
[2]	The asset subject to the resecuritization had a fair value of $2.2 million as of December 31, 2014, which is included on the Consolidated Schedule of Investments under Principal and Interest – Private Label Securities.
[3]	The asset subject to the resecuritization had a fair value of $2.3 million as of December 31, 2013, which is included on the Consolidated Schedule of Investments under Principal and Interest – Private Label Securities.