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Number of Joint Venture Interests

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Area of land held.

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Value of property contributed in noncash investing and financing activities.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Cap rate on an interest rate derivative such as an interest rate cap or collar. If market rates exceed the cap rate, a payment or receipt is triggered on the contract.

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Period the derivative contract is outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

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Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee.

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Period between issuance and maturity of long-term debt, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of debt for which creditor does not have general recourse to the debtor but rather has recourse only to the property used for collateral in the transaction or other specific property.

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The cash outflow associated with the investment in or advances to an entity in which the reporting entity shares control of the entity with another party or group.

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- Definition

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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Amount of real estate investment property which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

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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 fair value of transfer of mortgage payable in noncash investing or financing activities.

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Investments in Non-Consolidated Entities - Schedule of Investments in and Non-consolidated Entities (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2018 USD ($) a term property	Dec. 31, 2019 USD ($) a office_asset partnership	Dec. 31, 2018 USD ($) a building term	Dec. 31, 2017 USD ($) a
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 66,183	$ 57,168	$ 66,183
Proceeds from sale of property		504,118	898,514	$ 223,853
Real estate, at cost	3,090,134	$ 3,320,574	3,090,134
Mortgages \| NNN Office Joint Venture
Schedule of Equity Method Investments [Line Items]
Non-recourse debt	$ 362,800		$ 362,800
Long-term debt, term	3 years		3 years
Number of additional extensions available \| term	2		2
Term of additional extensions			1 year
Term of contract			2 years
Mortgages \| NNN Office Joint Venture \| London Interbank Offered Rate (LIBOR)
Schedule of Equity Method Investments [Line Items]
Basis spread on variable rate			200.00%
Basis spread rate increase per extension			15.00%
Cap interest rate	4.00%		4.00%
Office Building
Schedule of Equity Method Investments [Line Items]
Number of properties sold \| property	6
NNN Office Joint Venture Properties \| Office Building \| Transferred Property
Schedule of Equity Method Investments [Line Items]
Number of properties sold \| building			21
Proceeds from sale of property			$ 725,800
Minimum
Schedule of Equity Method Investments [Line Items]
Ownership percentage		15.00%
Maximum
Schedule of Equity Method Investments [Line Items]
Ownership percentage		25.00%
NNN Office Joint Venture
Schedule of Equity Method Investments [Line Items]
Ownership percentage	20.00%	20.00%	20.00%
Etna Park 70
Schedule of Equity Method Investments [Line Items]
Ownership percentage		90.00%
Etna Park 70 East LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage		90.00%
Etna Park 70
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 4,774	$ 8,352	$ 4,774
Etna Park 70 East LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	0	4,310	0
Other Joint Ventures
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 8,265	$ 5,218	$ 8,265
Number of joint venture interests \| partnership		1
Etna GL 66 LLC
Schedule of Equity Method Investments [Line Items]
Area of land (in acres) \| a	57	129.6	57	151
Real estate, at cost	$ 3,008		$ 3,008
NNN Office Joint Venture
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 53,144	$ 39,288	53,144
NNN Office Joint Venture \| NNN Office Joint Venture Properties
Schedule of Equity Method Investments [Line Items]
Number of properties sold \| office_asset		4
NNN Office Joint Venture \| 2 of 21 Transferred Properties
Schedule of Equity Method Investments [Line Items]
Contribution of property			45,653
Payments to acquire interest in joint venture			8,053
Gain (loss) on disposition of assets			14,645
Transfer mortgage payable			$ 103,400