DISCLOSURES REGARDING FAIR VALUES OF FINANCIAL INSTRUMENTS, Balance Sheet Location (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2016	Dec. 31, 2015
Financial assets [Abstract]
Residential mortgage loans	$ 13,582,323	$ 14,154,737
Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Repurchase arrangements, initial term	120 days
Carrying Amount [Member]
Financial assets [Abstract]
Residential mortgage loans	$ 2,674	3,817
Lending counterparty investments	15,002	65,002
Financial liabilities [Abstract]
Secured borrowings with initial terms of greater than 120 days	839,101	3,246,177
Unsecured borrowings	98,065	97,986
Carrying Amount [Member] \| Interest Rate Swap Agreements [Member] \| Portfolio-Related [Member]
Financial assets [Abstract]
Portfolio-related interest rate swap agreements	2,501	7,720
Financial liabilities [Abstract]
Interest rate swap agreements	5,981	1,051
Carrying Amount [Member] \| Interest Rate Swap Agreements [Member] \| Unsecured Borrowings-Related [Member]
Financial liabilities [Abstract]
Interest rate swap agreements	40,973	25,010
Fair Value [Member]
Financial assets [Abstract]
Residential mortgage loans	2,700	3,900
Lending counterparty investments	15,002	65,002
Financial liabilities [Abstract]
Secured borrowings with initial terms of greater than 120 days	839,300	3,245,000
Unsecured borrowings	59,100	77,200
Fair Value [Member] \| Interest Rate Swap Agreements [Member] \| Portfolio-Related [Member]
Financial assets [Abstract]
Portfolio-related interest rate swap agreements	2,501	7,720
Financial liabilities [Abstract]
Interest rate swap agreements	5,981	1,051
Fair Value [Member] \| Interest Rate Swap Agreements [Member] \| Unsecured Borrowings-Related [Member]
Financial liabilities [Abstract]
Interest rate swap agreements	$ 40,973	$ 25,010

Investments in FHLB stock and other junior notes receivable with lending counterparties.

No definition available.

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- Definition

Refers to the initial term of investment repurchase agreement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

Fair value portion of FHLB advances and securities that an entity sells and agrees to repurchase at a specified date for a specified price.

+ References

No definition available.

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- Definition

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
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- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=51825145&loc=SL20226008-175313

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-Topic 825
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-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13495-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

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-Publisher FASB
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-Topic 825
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-Section 50
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- References

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- Definition

The fair value as of the balance sheet date of firm holdings in mortgages, mortgage backed securities (investment instruments that represent ownership of an undivided interest in a group of mortgages, where principal and interest from the individual mortgages are used to pay investors' principal and interest on the mortgage backed security) and asset-backed securities that are primarily paid from the cash flows of a discrete pool of receivables or other financial assets (such as credit-card receivables), either fixed or revolving, that by their terms convert into cash within a finite time period. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 940
-SubTopic 320
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-Paragraph 2
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- References

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- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

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