FAIR VALUE MEASUREMENT - Schedule of Financial Instruments Measured at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets:
Derivative financial instruments	$ 1,509	$ 0
Purchase options related to real estate loans	6,078	0
Liabilities:
Derivative financial instruments	190	1,118
Recurring basis
Assets:
Purchase options related to real estate loans	6,078
Recurring basis \| Interest rate swaps
Assets:
Derivative financial instruments	1,509
Liabilities:
Derivative financial instruments	190	1,118
Recurring basis \| Level 1
Assets:
Purchase options related to real estate loans	0
Recurring basis \| Level 1 \| Interest rate swaps
Assets:
Derivative financial instruments	0
Liabilities:
Derivative financial instruments	0	0
Recurring basis \| Level 2
Assets:
Purchase options related to real estate loans	0
Recurring basis \| Level 2 \| Interest rate swaps
Assets:
Derivative financial instruments	1,509
Liabilities:
Derivative financial instruments	190	1,118
Recurring basis \| Level 3
Assets:
Purchase options related to real estate loans	6,078
Recurring basis \| Level 3 \| Interest rate swaps
Assets:
Derivative financial instruments	0
Liabilities:
Derivative financial instruments	$ 0	$ 0

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.

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
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13433-108611

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13495-108611

Reference 6: 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

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant