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Summary of Significant Accounting Policies - Basis of Presentation and Real Estate Properties (Details) $ in Thousands | 1 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2017 building property | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($)
Basis of Presentation |  |  |  |
Ownership interest in subsidiaries (as a percent) |  | 100.00% |  |
Number of properties included in joint venture agreement | property | 1 |  |  |
Number of buildings included in joint venture agreement | building | 2 |  |  |
Variable interest entity, consolidated, carrying amount of assets |  | $ 1,102,986 |  |
Variable interest entity, consolidated, carrying amount of liabilities |  | 720,678 |  |
Increase in capitalized above and below market leases rental income |  | 5,349 | $ 4,941 | $ 4,060
Amortization of acquired real estate leases and other intangible assets |  | $ 72,035 | $ 92,818 | $ 80,040
Land and Building | Real Estate Investment | Maximum |  |  |  |
Basis of Presentation |  |  |  |
Estimated useful lives |  | 40 years |  |

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- Definition The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) and liabilities in a systematic and rational manner to the periods expected to be impacted from such assets and liabilities. As a noncash expense/ income, this element is added back to/deducted from net income when calculating cash provided by (used in) operations using the indirect method. + References No definition available. + Details
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- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
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