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SIGNIFICANT ACCOUNTING POLICIES - Principles of Consolidation (Details) | 12 Months Ended
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Dec. 31, 2017 USD ($) item | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($)
Investment in Joint Ventures and Variable Interest Entities |  |  |
Number of Unconsolidated Joint Venture VIEs | item | 0 |  |
Recourse debt of joint venture | $ 0 |  |
Impairment charge relating to investments in unconsolidated joint ventures | 0 |  |
Revenue Recognition |  |  |
Additional rental income for the reimbursement of expenses | $ 7,672,000 | $ 6,424,000 | $ 3,852,000
Purchase Accounting for Acquisition of Real Estate |  |  |
Estimated useful lives of intangible assets, minimum | 1 year |  |
Estimated useful lives of building and intangible assets, maximum | 38 years |  |
Escrow, Deposits and Other Assets and Receivables |  |  |
Real estate taxes, insurance and other escrows | $ 460,000 | $ 387,000 |

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- Definition The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 35 -Paragraph 34 -URI http://asc.fasb.org/extlink&oid=27723805&loc=d3e25351-111560 + Details
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- Definition In accordance with the provisions of their lease agreement, this element represents allowable charges due a landlord from its tenant. In retail store and office building leases, for example, tenant reimbursements may cover items such as taxes, utilities, and common area expenses. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1(e)) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
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