Aggregate gross sales price of a joint venture.

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- Definition

Gross proceeds from sale of property, plant and equipment.

+ References

No definition available.

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- Definition

Lease agreement term.

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- Definition

Number of properties contributed to joint venture.

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No definition available.

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- Definition

Amount relates to closings costs paid in connection with a disposition of a wholly owned asset.

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No definition available.

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- Definition

Working capital contribution.

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No definition available.

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- Definition

Area of land held.

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No definition available.

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- Definition

Area of a real estate property.

+ References

No definition available.

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- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

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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-Publisher FASB
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- Definition

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

+ References

No definition available.

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- Definition

The cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale.

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- Definition

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.

+ References

No definition available.

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Segment Information - Real Estate Investments, at Cost of Company's Reportable Segments (Parenthetical) (Details) $ in Thousands			12 Months Ended
	Dec. 20, 2018 USD ($) ft² property	Dec. 11, 2018 USD ($) ft² property	Dec. 31, 2018 USD ($) ft² a property	Dec. 31, 2017 USD ($) a	Dec. 31, 2016 USD ($) property	Mar. 31, 2017 property	Dec. 31, 2016 Office	Mar. 31, 2016 property
Segment Reporting Information [Line Items]
Area of Real Estate Property \| ft²			16,777,249
Proceeds from the sale of properties			$ 324,090	$ 171,860	$ 784,331
Number of Properties \| property			97
Assets Held-for-sale [Member]
Segment Reporting Information [Line Items]
Acreage of land \| a				13.1
Assets Held-for-sale [Member] \| Land Held For Development [Member]
Segment Reporting Information [Line Items]
Acreage of land \| a			37.9
Metropolitan DC [Member]
Segment Reporting Information [Line Items]
Number of Properties							3	2
Other [Member]
Segment Reporting Information [Line Items]
Number of Properties			1		3	4	2
Other [Member] \| Assets Held-for-sale [Member] \| Land Held For Development [Member]
Segment Reporting Information [Line Items]
Acreage of land \| a			35.2	13.1
Pennsylvania Suburbs [Member] \| Assets Held-for-sale [Member] \| Land Held For Development [Member]
Segment Reporting Information [Line Items]
Acreage of land \| a			2.7
DRA Austin Venture [Member]
Segment Reporting Information [Line Items]
Area of Real Estate Property \| ft²		1,570,123
Ownership percentage		50.00%
Number of Properties \| property		12
Aggregate purchase price		$ 535,100
3001-3003 and 3025 JFK Boulevard [Member]
Segment Reporting Information [Line Items]
Lease agreement term			99 years
Herndon Innovation Center Metro Portfolio Venture, LLC [Member] \| Metropolitan Washington, D.C. - Office [Member]
Segment Reporting Information [Line Items]
Number of properties contributed to a joint venture \| property	8
Area of Real Estate Property \| ft²	1,293,197
Aggregate gross sales price of a joint venture	$ 312,000
Ownership percentage	15.00%
Cash proceeds received from sale of properties	$ 265,200
Closing costs	2,200
Working capital contribution	600
Proceeds from the sale of properties	$ 262,400
Herndon Innovation Center Metro Portfolio Venture, LLC [Member] \| Metropolitan Washington, D.C. - Office [Member] \| Rockpoint [Member]
Segment Reporting Information [Line Items]
Ownership percentage	85.00%