SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Investments and Reclassifications) (Details) $ in Thousands	Jun. 30, 2018 USD ($) property	Dec. 31, 2017 USD ($)
Investment [Line Items]
Investments in unconsolidated joint ventures \| $	$ 50,986	$ 55,577
Office Properties
Investment [Line Items]
Number of real estate properties	6
Held-for-sale
Investment [Line Items]
Number of real estate properties	1
Held-for-sale \| Office Properties
Investment [Line Items]
Number of real estate properties	1
NIP Joint Venture
Investment [Line Items]
Investments in unconsolidated joint ventures \| $	$ 2,514	$ 3,674
Number of real estate properties	4

Line items represent reporting 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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 12
-Sentence Column A

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- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

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- Definition

The carrying amount of investments in unconsolidated real estate and other joint ventures not separately presented. This includes direct and indirect investments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.1(d))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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