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Number of Real Estate Properties Disposed.

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Number of Wholly Owned Subsidiaries

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Proceeds from Sale of Real Estate, Net of Concessions and Credits

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Shares Outstanding, Percent

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Amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation.

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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The net gain (loss) resulting from sales and other disposals of real estate owned for investment purposes.

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Line items represent financial 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.

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

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Cash received for the sale of real estate that is not part of an investing activity during the current period.

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Carrying amount as of the balance sheet date of investments in land and buildings held for sale, excluding real estate considered to be inventory of the entity.

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The cumulative amount of depreciation for real estate property held for investment purposes.

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REAL ESTATE DISPOSITIONS (Narrative) (Details) $ in Thousands										12 Months Ended
	Nov. 01, 2019 USD ($) property shares	Oct. 29, 2019 USD ($) shares	Jul. 19, 2019 USD ($)	Jan. 11, 2019 USD ($)	Nov. 30, 2018 USD ($) property	Nov. 26, 2018 USD ($) shares	Jul. 17, 2018 USD ($)	Nov. 08, 2017 USD ($) property shares	May 15, 2017 USD ($)	Dec. 31, 2019 USD ($) property	Dec. 31, 2018 USD ($) property	Dec. 31, 2017 USD ($) property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of real estate, net										$ 34,077	$ 80,594	$ 255,935
Real estate held for sale										0	128,146
Accumulated depreciation and amortization										65,381	38,052
Loss on extinguishment of debt										1,106	493	478
Real estate held for investment, net										759,479	552,974
Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Closing costs										$ 12,667	$ 36,736	$ 104,589
Disposed of by Sale \| SREIT
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Issuance of common stock (in shares) \| shares	56,979,352					186,236,224
Common stock, shares acquired (in shares) \| shares		7,186,000
Common stock, shares acquired		$ 5,200
Disposed of by Sale \| SREIT
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership interest	6.89%	6.89%				7.00%
Common stock, shares acquired (in shares) \| shares						12,979,852
Common stock, shares acquired						$ 6,500
Disposed of by Sale \| 125 John Carpenter
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration	$ 99,800
Closing costs	200
Gain on sale of real estate, net		$ 16,000
Real estate held for sale	82,400
Accumulated depreciation and amortization	$ 9,100
Disposed of by Sale \| Burbank Collection
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration			$ 25,900
Gain on sale of real estate, net			10,500
Real estate held for sale			14,700
Accumulated depreciation and amortization			$ 2,600
Disposed of by Sale \| 424 Bedford
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration				$ 43,800
Gain on sale of real estate, net				7,600
Real estate held for sale				34,000
Accumulated depreciation and amortization				$ 5,300
Disposed of by Sale \| Westpark Portfolio
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration					$ 166,400
Closing costs					3,200
Gain on sale of real estate, net					$ 32,500
Disposed of by Sale \| Central Building
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration							$ 67,500
Gain on sale of real estate, net							32,100
Real estate held for sale							32,600
Accumulated depreciation and amortization							$ 5,600
Disposed of by Sale \| Singapore Portfolio
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties disposed \| property								11
Consideration								$ 804,000
Closing costs								7,700
Gain on sale of real estate, net								236,900
Real estate held for sale								543,200
Accumulated depreciation and amortization								$ 103,000
Number of wholly owned subsidiaries \| property								11
Deferred gains on sale								$ 17,100
Loss on extinguishment of debt								$ 500
Disposed of by Sale \| Singapore Portfolio \| SREIT
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Shares received as part of consideration \| shares								44,000,000
Shares outstanding, percent								7.00%
Disposed of by Sale \| 50 Congress Street
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of real estate, net									$ 29,400
Accumulated depreciation and amortization									5,900
Proceeds from Sale of Real Estate									79,000
Proceeds from sales of real estate, net of concessions and credits									78,800
Real estate held for investment, net									$ 47,700
Office Properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties \| property										6
Office Properties \| Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties disposed \| property										1	1	12
Office Properties \| Disposed of by Sale \| 125 John Carpenter
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties disposed \| property	2
Retail Property \| Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties disposed \| property										1
Apartment Building \| Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties disposed \| property										1
Office/Flex/Industrial Portfolio \| Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties disposed \| property											1
Office/Flex/Industrial Buildings \| Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties disposed \| property											21
Office/Flex/Industrial Buildings \| Disposed of by Sale \| Westpark Portfolio
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties disposed \| property					21