Real Estate Amortization of finite lived intangible assets (Details) - 103 Carnegie Center [Member] $ in Thousands	May 15, 2017 USD ($)
Business Acquisition [Line Items]
Land	$ 2,890
Building and improvements	11,229
Tenant improvements	871
In-place lease intangibles	2,389
Below-market lease intangible	(1,426)
Acquired In-Place Lease Intangibles
Business Acquisition [Line Items]
Period from May 15, 2017 through December 31, 2017	660
2018	590
2019	367
2020	243
2021	96
Acquired Below- Market Lease Intangibles
Business Acquisition [Line Items]
Period from May 15, 2017 through December 31, 2017	(248)
2018	(363)
2019	(337)
2020	(308)
2021	$ (105)

Amount of tenant improvements acquired at the acquistion date

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Business Combination Recognized Identifiable Liabilities Assumed Intangibles Finite Lived Assets

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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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Amount of facility held for productive use including, but not limited to, office, production, storage and distribution facilities, acquired at the acquisition date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
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The amount of identifiable intangible assets recognized as of the acquisition date.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 55
-Paragraph 37
-URI http://asc.fasb.org/extlink&oid=73531372&loc=d3e2207-128464

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Amount of real estate acquired, at the acquisition date.

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- Definition

Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized in the remainder of the fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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