Financial Instruments (Details 2) (Level 2, USD $) In Millions, unless otherwise specified	9 Months Ended
Sep. 30, 2012
Agency mortgage-backed securities
Financial Instrument Characteristics
Weighted average loan size	$ 0.2
Interest rate (as a percent)	4.70%
Weighted average annualized constant prepayment rate (as a percent)	22.90%
Weighted average FICO score	743
Weighted average coupon rate (as a percent)	4.00%
Federal agency obligations
Financial Instrument Characteristics
Weighted average coupon rate (as a percent)	1.80%
Weighted Average Maturity	2019
Non-agency residential mortgage backed securities
Financial Instrument Characteristics
Weighted Average Credit Rating	DDD
Weighted Average Issuance Year	2005
Loans
Financial Instrument Characteristics
Weighted average loan size	0.2
Unrealized losses arising from fair value changes	0.4
Weighted average coupon rate (as a percent)	3.70%
Unpaid principal	$ 77.6
Corporate debt securities
Financial Instrument Characteristics
Weighted Average Maturity	2027
Weighted Average Credit Rating	BBB
Weighted Average Issuance Year	2007

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Represents weighted average prepayment rate of the underlying financial instruments.

+ References

No definition available.

+ Details

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- Definition

Represents weighted average coupon rate of underlying financial instruments.

+ References

No definition available.

+ Details

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- Definition

Represents the weighted average credit rating of the underlying financial instruments.

+ References

No definition available.

+ Details

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- Definition

Represents weighted average FICO score of the underlying financial instruments.

+ References

No definition available.

+ Details

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- Definition

Represents the weighted average maturity of the underlying financial instruments.

+ References

No definition available.

+ Details

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- Definition

Represents the weighted average loan size of the securities.

+ References

No definition available.

+ Details

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- Definition

Represents the weighted average maturity of the underlying financial instruments.

+ References

No definition available.

+ Details

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- Definition

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".

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 12

-Sentence Column A

+ Details

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- Definition

For each line item in the statement of financial position, the amounts of gains and losses from fair value changes included in earnings.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 30

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14172-108612

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Balance Type:	credit
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- Definition

This is the result of the principal amount outstanding of total loans managed or securitized less securitized loans and loans that are in the process of being securitized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=13989330&loc=d3e107314-111719

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS140-4 and FIN46(R)-8

-Paragraph B11

-Subparagraph b

-Clause 6

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 140

-Paragraph 17

-Subparagraph i

-Subclause a

-Clause 4

-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.

+ Details

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