Collateral Positions (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Collateral Positions
Assets Pledged	$ 8,473,834	$ 10,620,406
Collateral Held	507,318	510,767
Derivative Hedging Instruments
Collateral Positions
Assets Pledged	29,721	86,317
Derivative Hedging Instruments \| Agency MBS
Collateral Positions
Assets Pledged	23,197	32,468
Derivative Hedging Instruments \| Cash
Collateral Positions
Assets Pledged	6,524	53,849
Repurchase Agreement Borrowings
Collateral Positions
Assets Pledged	8,444,113	10,306,845
Repurchase Agreement Borrowings \| Agency MBS
Collateral Positions
Assets Pledged	2,888,156	3,280,689
Repurchase Agreement Borrowings \| Legacy Non-Agency MBS
Collateral Positions
Assets Pledged	1,848,134	2,317,708
Non-Agency MBS acquired from consolidated VIEs		172,400
Non-Agency MBS pledged as collateral in connection with contemporaneous repurchase and reverse repurchase agreements entered into with a single counterparty	689,300	688,200
Repurchase Agreement Borrowings \| RPL/NPL MBS
Collateral Positions
Assets Pledged	1,005,757	2,433,711
Repurchase Agreement Borrowings \| U.S. Treasury securities
Collateral Positions
Assets Pledged	475,688	510,767
Repurchase Agreement Borrowings \| CRT securities
Collateral Positions
Assets Pledged	530,833	357,488
Repurchase Agreement Borrowings \| MSR related assets
Collateral Positions
Assets Pledged	412,674	226,780
Repurchase Agreement Borrowings \| Residential whole loans
Collateral Positions
Assets Pledged	1,273,955	1,175,088
Repurchase Agreement Borrowings \| Cash
Collateral Positions
Assets Pledged	8,916	4,614
FHLB Advances
Collateral Positions
Assets Pledged	0	227,244
FHLB Advances \| Agency MBS
Collateral Positions
Assets Pledged	0	227,244
Reverse Repurchase Agreements
Collateral Positions
Collateral Held	507,318	510,767
Reverse Repurchase Agreements \| U.S. Treasury securities
Collateral Positions
Collateral Held	$ 507,318	$ 510,767

-- None. No documentation exists for this element. --

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- Definition

For an unclassified balance sheet, represents investments in debt and equity securities, categorized neither as held-to-maturity nor trading, which are acquired from a consolidated variable interest entity and eliminated on the entity's consolidated balance sheet.

+ References

No definition available.

+ Details

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- Definition

Represents the non-agency MBS pledged as collateral in connection with contemporaneous repurchase and reverse repurchase agreements entered into with a single counterparty.

+ References

No definition available.

+ Details

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- Definition

The carrying amount, as of the date of the latest financial statement presented, of all assets that are pledged as collateral for the payment of the related debt obligation primarily arising from secured borrowings, repurchase agreements or other current or potential obligations, where the secured party does not have the right by contract or custom to sell or re-pledge the collateral and therefore are not reclassified and separately reported in the statement of financial position.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (b)(1)(i)
-URI http://asc.fasb.org/extlink&oid=64858031&loc=SL6224234-111729

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- Definition

Fair value of the securities pledged as collateral against securities loaned.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=82849420&loc=SL20226013-175313

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