Real Estate and Intangible Assets - Weighted Average Amortization Period for Intangible Assets Acquired and Liabilities Assumed (Detail)  | 
3 Months Ended | 
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Mar. 31, 2018  | |
| Acquired Finite-Lived Intangible Assets [Line Items] | |
| Weighted-Average Amortization Period | 9 years 7 months 6 days | 
| In-place leases | |
| Acquired Finite-Lived Intangible Assets [Line Items] | |
| Weighted-Average Amortization Period | 9 years 7 months 6 days | 
| Leasing costs | |
| Acquired Finite-Lived Intangible Assets [Line Items] | |
| Weighted-Average Amortization Period | 9 years 7 months 6 days | 
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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. No definition available. 
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- Definition Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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