INVESTMENTS IN REAL ESTATE SECURITIES - Summary of Changes in Accretable Yield for Securities (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Certain Loans Acquired in Transfer Accounted for as Available-for-sale Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance, beginning	$ 143,067	$ 90,077
Additions	189,252	155,854
Accretion	(14,035)	(19,939)
Reclassifications from non-accretable difference	20,385	40,785
Disposals	(156,998)	(123,710)
Balance, ending	$ 181,671	$ 143,067

The aggregate excess of a loan's cash flows expected to be collected over the investor's initial investment in the loan. This relates to loans accounted for as available-for-sale debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 30

-Section 15

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=27045933&loc=d3e13503-111538

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

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- Definition

Current period recognition of the accretion of the excess of a loan's cash flows expected to be collected over the investor's initial investment in the loan. This element relates to loans accounted for as available-for-sale debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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- Definition

Increases in the aggregate excess of a loan's cash flows expected to be collected over the investor's initial investment in the loan. This relates to loans accounted for as available-for-sale debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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- Definition

Sale or transfer of a loan during the period resulting in a reduction in the excess of a loan's cash flows expected to be collected over the investor's initial investment. This relates to a loan accounted for as an available-for-sale debt security, with evidence of deterioration of credit quality since origination that was acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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- Definition

Change in the estimate of cash flows expected to be collected, which results in an increase in accretable yield. This relates to a loan accounted for as an available-for-sale debt security, with evidence of deterioration of credit quality since origination that was acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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