BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Investments in Real Estate (Details) - USD ($)	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Investments in Real Estate
Impairment of long-lived assets	$ 0	$ 0
Buildings and improvements \| Minimum
Investments in Real Estate
Estimated useful lives	15 years
Buildings and improvements \| Maximum
Investments in Real Estate
Estimated useful lives	40 years
Furniture, fixtures, and equipment \| Minimum
Investments in Real Estate
Estimated useful lives	3 years
Furniture, fixtures, and equipment \| Maximum
Investments in Real Estate
Estimated useful lives	5 years

The charge against earnings in the period to reduce the carrying amount of real property to fair value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84176398&loc=d3e2921-110230

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

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