Real Estate Properties - Summary of Acquisition Activities (Details) - Manassas, VA $ in Thousands	12 Months Ended
Dec. 31, 2017 USD ($) ft² property	Dec. 31, 2017 USD ($) ft²	Dec. 31, 2017 USD ($) ft²
Real Estate Properties [Line Items]
Square feet (in square feet) \| ft²	69,374	69,374	69,374
Purchase price		$ 12,657
Land	$ 1,562	1,562	$ 1,562
Building and Improvements	8,253	8,253	8,253
Other Assumed Assets	$ 2,842	$ 2,842	$ 2,842
Office Property
Real Estate Properties [Line Items]
Number of properties	1		1

Number Of Properties Acquired

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- Definition

Represents the amount of purchase price allocated to building and building improvements.

+ References

No definition available.

+ Details

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- Definition

Represent the value of other assumed assets.

+ References

No definition available.

+ Details

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- Definition

Area of a real estate property.

+ References

No definition available.

+ Details

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- Definition

Amount of real estate acquired, at the acquisition date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=116869197&loc=d3e4845-128472

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- Definition

The cash outflow from the acquisition of a piece of land and anything permanently fixed to it, including buildings, structures on it and so forth, and payments to develop real estate assets by adding improvements on or to a parcel of land. Such improvements may include drainage, utilities, subdividing, access, buildings, and any combination of these elements. Including real estate intended to generate income for the owner; excluding real estate acquired for use by the owner.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3213-108585

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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.

+ Details

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- Details

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