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Schedule III - Real Estate and Accumulated Depreciation and Amortization (Details Textual) - USD ($) $ in Millions |  |  |  | 12 Months Ended
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Feb. 19, 2021 | Feb. 09, 2021 | Jan. 28, 2021 | Dec. 31, 2020
Subsequent Event [Member] | Waterman Plaza [Member] |  |  |  |
Proceeds from Sale of Real Estate, Total |  |  | $ 3.5 |
Subsequent Event [Member] | Garden Gateway [Member] |  |  |  |
Proceeds from Sale of Real Estate, Total | $ 11.2 | $ 11.2 |  |
Building and Building Improvements [Member] |  |  |  |
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation, Life Used for Depreciation (Year) |  |  |  | 39 years

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- Definition Cash received for the sale of real estate that is not part of an investing activity during the current period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3179-108585 + Details
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- Definition Useful life on which depreciation was computed for entities with a substantial portion of business acquiring and holding investment real estate, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 970 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28(Column I)) -URI http://asc.fasb.org/extlink&oid=120402810&loc=d3e638233-123024 + Details
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