Net proceeds received from real estate venture transactions.

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- Definition

Number of real estate properties to be sold.

+ References

No definition available.

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- Definition

Number of real estate property to be acquired.

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- Definition

Percentage of ownership interest to be acquired.

+ References

No definition available.

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- Definition

Area of a real estate property.

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No definition available.

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- Definition

Amount of long-term debt due after one year or the normal operating cycle, if longer, assumed at the acquisition date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
-Section 50
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- Definition

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

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No definition available.

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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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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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- Definition

The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale.

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-Publisher FASB
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- Definition

The cash outflow for acquisition of buildings (properties) whether for investment or use.

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-Name Accounting Standards Codification
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- Definition

The book value of investments in real estate joint ventures including direct and indirect investments.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
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- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

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Subsequent Events (Textual) (Details) $ in Millions			3 Months Ended	9 Months Ended
Subsequent Events (Textual) (Details) $ in Millions	Oct. 17, 2018 USD ($) ft² property	Oct. 16, 2018 USD ($) ft² property	Sep. 30, 2018 USD ($) ft²	Sep. 30, 2018 USD ($) ft²	Sep. 30, 2017
Subsequent Event [Line Items]
Net Rentable Square Feet \| ft²			16,462,764	16,462,764
DRA Austin Venture [Member]
Subsequent Event [Line Items]
Equity method investment, ownership percentage			50.00%	50.00%	50.00%
Investment in real estate venture			$ 14.4	$ 14.4
Held for Sale Properties Included in Continuing Operations [Member] \| Metropolitan Washington, D.C. - Office [Member]
Subsequent Event [Line Items]
Impairment on assets held for sale			$ 56.9
Subsequent Event [Member] \| DRA Austin Venture [Member]
Subsequent Event [Line Items]
Net Rentable Square Feet \| ft²	1,570,123
Percentage of ownership interest to be acquired	50.00%
Number of real estate property to be acquired \| property	12
Purchase price to be transferred to acquire real estate properties	$ 537.0
Mortgage debt to be assumed in connection with acquisition of real estate properties	$ 245.8
Subsequent Event [Member] \| Held for Sale Properties Included in Continuing Operations [Member] \| Metropolitan Washington, D.C. - Office [Member]
Subsequent Event [Line Items]
Number of properties to be sold \| property		8
Net Rentable Square Feet \| ft²		1,293,197
Sales Price		$ 312.0
Equity method investment, ownership percentage		15.00%
Net proceeds received from real estate venture transactions		$ 292.0
Impairment on assets held for sale				$ 56.9