MORTGAGE LOAN RECEIVABLES (Details)	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2016 USD ($) loan servicing_asset	Sep. 30, 2016 USD ($) loan	Dec. 31, 2015 USD ($) loan
Mortgage Loans on Real Estate [Line Items]
Number of assets transferred accounted for as secured borrowings \| servicing_asset	3
Loans receivable with fixed rates of interest	$ 207,600,000	$ 207,600,000	$ 343,200,000
Percentage of loans receivable with fixed rates of interest	12.60%	12.60%	19.70%
Unamortized discounts included in mortgage loan receivables held for investment, at amortized cost	$ 600,000	$ 600,000	$ 700,000
Number of mortgage loans impaired \| loan	0	0	0
Accrued and unpaid interest receivable	$ 23,794,000	$ 23,794,000	$ 22,776,000
Mortgage loan financing
Mortgage Loans on Real Estate [Line Items]
Transfers of assets accounted for as secured borrowings, carrying amount	137,600,000	137,600,000
Transfers of assets accounted for as secured borrowings, non-nontrolling pari passu interests	61,600,000	61,600,000
Proceeds from transfers of assets accounted for as sales	63,200,000
Mortgage loan receivables held for investment, at amortized cost
Mortgage Loans on Real Estate [Line Items]
Transfer of financial assets (loans) treated as sales	324,400,000	324,400,000
Loans receivable with fixed rates of interest	$ 1,400,000,000	$ 1,400,000,000	$ 1,400,000,000
Percentage of loans receivable with fixed rates of interest	87.40%	87.40%	80.30%
Number or loans in default \| loan		2
Loans in default, carrying value	$ 26,900,000	$ 26,900,000
Impairment recorded on defaulted loans		0
Accrued and unpaid interest receivable	2,291,000	2,291,000
Default interest included in accrued and unpaid interest receivable	1,538,000	1,538,000
Mortgage loan receivables held for sale
Mortgage Loans on Real Estate [Line Items]
Loans receivable with fixed rates of interest	$ 784,200,000	$ 784,200,000	$ 571,800,000
Percentage of loans receivable with fixed rates of interest	100.00%	100.00%	100.00%
Loan on non-accrual status
Mortgage Loans on Real Estate [Line Items]
Number of loans on non-accrual status \| loan		0	0

Financing Receivable Recorded Investment 90 Days Past Due And Still Accruing Number of Contracts

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- Definition

Interest Receivable, Loans Past Due over 90 Days and Still Accruing

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Loans Receivable with Fixed Rates of Interest, Percentage

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- Definition

Represents the number of mortgage loans individually impaired.

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Transfers Accounted for as Secured Borrowings, Assets, Non-Controlling Pari Passu Interests

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No definition available.

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Transfers Accounted for as Secured Borrowings, Assets, Number

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Cash Flows between a transferor and a transferee attributable to newly transferred assets related to either a securitization, asset-backed financing arrangement, or similar transfer in which the transferor has continuing involvement with the transferred financial assets underlying the transaction (including, but not limited to, servicing, recourse, and restrictions on transferor's interests in the transferred financial assets).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (d)(1)
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Principal amount of transferred financial assets in which the transferor has continuing involvement with the assets underlying the transaction. Continuing involvement includes, but is not limited to, servicing, recourse, and restrictions on transferor's interests in transferred financial assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Recorded investment in financing receivables that are 90 days or more past due and still accruing.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reflects the amount of additional interest income that would have been recorded if impaired or nonperforming loans were instead current, in compliance with their original terms, and outstanding throughout the reporting period or since origination (if held for part of the period).

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Amount of loan with fixed rate of interest.

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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.

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No definition available.

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- Definition

Indicates the number of mortgages under each classification.

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-Publisher FASB
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-Topic 948
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Amount of derecognized financial assets from transactions which comprise an initial transfer and an agreement entered into in contemplation of the initial transfer resulting in retention of substantially all of the exposure to the economic return throughout the term of the transaction, at the date of derecognition.

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-SubTopic 20
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Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.

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