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Segment Information - Unconsolidated Real Estate Ventures of Company's Reportable Segments (Additional Information) (Details)	Sep. 30, 2019 ft² property	Dec. 11, 2018 ft² property
Segment Reporting Information [Line Items]
Number of properties | property	95
Net rentable area (in square feet) | ft²	16,711,387
DRA Austin Venture
Segment Reporting Information [Line Items]
Equity method investment, ownership percentage		50.00%
Number of properties | property		12
Net rentable area (in square feet) | ft²		1,570,123

X

- Definition

Area of a real estate property.

+ References

No definition available.

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X

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

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- Definition

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

+ References

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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.

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