Number of real estate properties sold.

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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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No definition available.

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The cash inflow from the sale of formerly productive land held for sale, anything permanently fixed to it, including buildings, structures on it, and so forth.

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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 value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

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Real Estate Activities - Dispositions (Details) $ in Thousands		1 Months Ended						3 Months Ended		9 Months Ended		12 Months Ended
	Aug. 17, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Jan. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Nov. 30, 2019 USD ($) Property	Mar. 31, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Mortgage loans payable, net					$ 899,753			$ 890,848		$ 890,848		$ 899,753
Gain on debt extinguishment, net								0	$ 29,600	0	$ 24,832
Number of real estate properties sold \| Property						14
Sale of properties						$ 29,900
Gains (losses) on sales of investment real estate								(94)	$ 1,171	11,169	$ 2,684
Mortgage Loan
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Mortgage loans payable, net								890,800		890,800
Capital City Mall Camp Hill Pennsylvania \| Mortgage Loan
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Mortgage loans payable, net								$ 27,200		$ 27,200
Gain on debt extinguishment, net	$ 7,000
Woodland Mall
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of properties				$ 5,100
Magnolia Mall
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of properties			$ 2,900
Capital City Mall and Magnolia Mall
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal group, consideration					5,200							5,200
Gains (losses) on sales of investment real estate												$ 2,700
Woodland Mall and Magnolia Mall
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gains (losses) on sales of investment real estate			$ 1,900
Magnolia Mall, Valley Mall and Jacksonville Mall
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal group, consideration		$ 14,400
Gains (losses) on sales of investment real estate		$ 9,300
Undeveloped Land Parcel Gainesville Florida
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal group, consideration							$ 15,000
Gains (losses) on sales of investment real estate							(1,500)
Proceeds from sale of real estate					$ 10,000		$ 5,000