The interest rate for investments that have an interest rate. For fixed rate investments, this indicates the fixed interest rate. If the investment has a variable interest rate, the rate stated here may be the rate that is currently relevant. In this case the "Investment, Interest Rate is Current Rate for Variable Rate Investment Flag", "Investment, Interest Rate is Discount Rate at Purchase Flag", "Investment, Interest Rate Reflects Current Yield Flag" should be used. If one of these flags are not appropriate to explain the interest rate that is indicated, then a new flag should be added or an explanation should be included in "Investment, Additional Information".

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

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- Definition

Represents the interest expense on mortgage backed securities in linked transactions (MBS purchase and repurchase financing) accounted for as derivative forward contracts.

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- Definition

Represents the amortized cost of mortgage backed securities in linked transactions (MBS purchase and repurchase financing) accounted for as derivative forward contracts.

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- Definition

Represents the fair value of mortgage backed securities in linked transactions (MBS purchase and repurchase financing) accounted for as derivative forward contracts.

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- Definition

Represents the principal balance of mortgage backed securities in linked transactions (MBS purchase and repurchase financing) accounted for as derivative forward contracts.

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- Definition

Represents the carrying value as of the balance sheet date of repurchase financing agreements related to MBS purchases, which are accounted for as forward purchase agreements and are netted against the carrying value of the associated MBS.

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- Definition

Represents unrealized net (losses)/gains and net interest income from linked transactions of the entity.

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- Definition

The interest rate associated with the repurchase agreements. This is also known as the repo rate.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 4

-Section 08

-Paragraph m

-Subparagraph 1

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(m)(1)(i)(A)(ii))

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- Definition

Represents interest income, including any amortization and accretion (as applicable) of discounts and premiums, derived from securities backed by a pool of mortgages or trust deeds. Mortgage-backed securities might represent mortgage pass-through securities, collateralized mortgage obligations (CMO), real estate mortgage investment conduits (REMICs), CMO and REMIC residuals, and stripped mortgage-backed securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 65

-Paragraph 34

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 2

-Article 9

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-04.2)

-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Mortgage-Backed Securities

-URI http://asc.fasb.org/extlink&oid=6517959

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- Definition

The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 28

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

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Derivatives (Details 2) (Linked Transactions, USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Linked Repurchase Agreements
Balance	$ 192,960		$ 192,960		$ 567,287
Weighted Average Interest Rate (as a percent)	1.63%		1.63%		1.62%
Linked MBS
Fair Value	256,369		256,369		744,369
Amortized Cost	260,927		260,927		718,734
Par/Current Face	321,779		321,779		863,280
Weighted Average Coupon Rate			5.09%		4.56%
Components of the gain on Linked Transactions
Interest income attributable to MBS underlying Linked Transactions	4,631	9,520	21,475	24,748
Interest expense attributable to linked repurchase agreement borrowings underlying Linked Transactions	(864)	(1,722)	(3,938)	(4,392)
Change in fair value of Linked Transactions included in earnings	(3,034)	13,509	(7,567)	20,948
Unrealized net (losses)/gains and net interest income from Linked Transactions	733	21,307	9,970	41,304
Within 30 days
Linked Repurchase Agreements
Balance	113,013		113,013		289,522
Weighted Average Interest Rate (as a percent)	1.67%		1.67%		1.62%
Over 30 days to 90 days
Linked Repurchase Agreements
Balance	64,647		64,647		277,765
Weighted Average Interest Rate (as a percent)	1.64%		1.64%		1.62%
90 days to 180 days
Linked Repurchase Agreements
Balance	15,300		15,300
Weighted Average Interest Rate (as a percent)	1.35%		1.35%
Rated AAA
Linked MBS
Fair Value	30,553		30,553		46,710
Amortized Cost	30,682		30,682		46,367
Par/Current Face	31,507		31,507		47,151
Weighted Average Coupon Rate			3.32%		4.13%
Rated AA
Linked MBS
Fair Value	19,193		19,193		57,634
Amortized Cost	18,361		18,361		54,176
Par/Current Face	18,816		18,816		61,389
Weighted Average Coupon Rate			5.00%		3.51%
Rated A
Linked MBS
Fair Value					36,440
Amortized Cost					34,620
Par/Current Face					41,984
Weighted Average Coupon Rate					2.53%
Rated BBB
Linked MBS
Fair Value	27,141		27,141		69,397
Amortized Cost	26,602		26,602		66,848
Par/Current Face	30,795		30,795		78,741
Weighted Average Coupon Rate			3.07%		3.38%
Rated BB
Linked MBS
Fair Value					14,536
Amortized Cost					14,456
Par/Current Face					17,513
Weighted Average Coupon Rate					2.51%
Rated B
Linked MBS
Fair Value					129,962
Amortized Cost					121,198
Par/Current Face					139,763
Weighted Average Coupon Rate					4.28%
Rated CCC
Linked MBS
Fair Value	32,509		32,509		216,398
Amortized Cost	33,075		33,075		211,302
Par/Current Face	41,841		41,841		255,667
Weighted Average Coupon Rate			4.51%		4.98%
Rated CC
Linked MBS
Fair Value	79,891		79,891		89,833
Amortized Cost	82,143		82,143		86,509
Par/Current Face	107,837		107,837		110,518
Weighted Average Coupon Rate			5.89%		5.45%
Rated C
Linked MBS
Fair Value	35,912		35,912		78,181
Amortized Cost	38,739		38,739		78,038
Par/Current Face	49,970		49,970		100,204
Weighted Average Coupon Rate			5.97%		5.77%
D-rated
Linked MBS
Fair Value	31,170		31,170
Amortized Cost	31,325		31,325
Par/Current Face	41,013		41,013
Weighted Average Coupon Rate			5.44%
Not Rated
Linked MBS
Fair Value					5,278
Amortized Cost					5,220
Par/Current Face					$ 10,350
Weighted Average Coupon Rate					6.00%