Valuation (Schedule Of Financial Instruments) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended		12 Months Ended
	Sep. 30, 2013		Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives-assets at fair value-	$ 43,567		$ 48,504
Fair value	40,994	[1]	13,650	[1]
Investments sold short at fair value-	(860,128)		(622,301)
Financial derivatives-liabilities at fair value-	(33,457)		(15,212)
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	186,737		59,084
Total investments, financial derivatives-assets at fair value, and repurchase agreements	976		0
Total investments sold short, financial derivatives-liabilities at fair value, and securitized debt	(1)		(70)
Level 1 [Member] | Investments Sold Short [Member] | U.S. Treasury And 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] | Financial Derivatives - Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives-liabilities at fair value-	(1)		(70)
Level 1 [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Corporate 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 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] | 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-	(1)		(70)
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] | U.S. Treasury And 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] | 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] | 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] | Financial Derivatives - Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives-assets at fair value-	976		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] | 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] | 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-	976
Level 1 [Member] | Repurchase Agreements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	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, financial derivatives-assets at fair value, and repurchase agreements	1,135,244		837,356
Total investments sold short, financial derivatives-liabilities at fair value, and securitized debt	(893,265)		(637,442)
Level 2 [Member] | Investments Sold Short [Member] | U.S. Treasury And 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-	(860,128)		(622,301)
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-	(33,137)		(15,141)
Level 2 [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Corporate Indices [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives-liabilities at fair value-	(9,679)		(484)
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-	(19,310)		(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] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives-liabilities at fair value-	(4,122)		(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-	(22)		(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-	(4)
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] | 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-	1,069,274		811,233
Level 2 [Member] | Investments [Member] | U.S. Treasury And Agency Residential Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value-	1,069,274		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] | 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] | Financial Derivatives - Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives-assets at fair value-	24,976		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-	9,184		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] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives-assets at fair value-	15,773		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-	15
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-	4
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] | Repurchase Agreements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	40,994		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, financial derivatives-assets at fair value, and repurchase agreements	800,092		599,914
Total investments sold short, financial derivatives-liabilities at fair value, and securitized debt	(1,357)		(1,336)
Level 3 [Member] | Investments Sold Short [Member] | U.S. Treasury And 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] | Financial Derivatives - Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives-liabilities at fair value-	(319)		(1)
Level 3 [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Corporate 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 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-	(319)		(1)
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] | Securitized Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securitized debt	(1,038)		(1,335)
Level 3 [Member] | Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value-	782,477		563,883
Level 3 [Member] | Investments [Member] | U.S. Treasury And Agency Residential Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value-	37,033		6,644
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-	651,982		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-	33,271		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-	14,936		9,546
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-	45,255
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-	17,615		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-	17,615		36,031
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] | 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] | Repurchase Agreements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	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	186,737		59,084
Total investments, financial derivatives-assets at fair value, and repurchase agreements	1,936,312		1,437,270
Total investments sold short, financial derivatives-liabilities at fair value, and securitized debt	(894,623)		(638,848)
Estimate of Fair Value, Fair Value Disclosure [Member] | Investments Sold Short [Member] | U.S. Treasury And 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-	(860,128)		(622,301)
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-	(33,457)		(15,212)
Estimate of Fair Value, Fair Value Disclosure [Member] | Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Corporate Indices [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial derivatives-liabilities at fair value-	(9,679)		(484)
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-	(19,310)		(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-	(319)		(1)
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-	(4,122)		(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-	(22)		(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-	(4)
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-	(1)		(70)
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	(1,038)		(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-	1,851,751		1,375,116
Estimate of Fair Value, Fair Value Disclosure [Member] | Investments [Member] | U.S. Treasury And Agency Residential Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments at fair value-	1,106,307		817,877
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-	651,982		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-	33,271		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-	14,936		9,546
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-	45,255
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-	43,567		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-	9,184		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-	17,615		36,031
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-	15,773		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-	15
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-	4
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-	976
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	40,994		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 the repurchase agreements, reverse repurchase agreements, and derivatives transactions are presented on a gross basis.