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Real Estate Investments - Gross Carrying Value of Operating Properties (Details) - USD ($) $ in Thousands | Sep. 30, 2019 | Dec. 31, 2018
--- | --- | ---
Real Estate [Line Items] |  |
Building and improvements | $ 3,995,228 | $ 3,951,719
Total | 3,995,228 | 3,951,719
Land |  |
Real Estate [Line Items] |  |
Land | 489,744 | 487,301
Building and Building Improvements |  |
Real Estate [Line Items] |  |
Building and improvements | 3,049,606 | 3,048,889
Tenant Improvements |  |
Real Estate [Line Items] |  |
Tenant improvements | $ 455,878 | $ 415,529

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- Definition Aggregate of the carrying amounts as of the balance sheet date of investments in building and building improvements. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1(d)) -URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910 + Details
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- Definition Carrying amount as of the balance sheet date of improvements having a life longer than one year that were made for the benefit of one or more tenants. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1(f)) -URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910 + Details
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