Summary of Significant Accounting Policies - Future Amortization Expense Related to Deferred Leasing Intangibles (Details) $ in Thousands	Dec. 31, 2017 USD ($)
In-Place Leases and Tenant Relationships
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
2018	$ 5,648
2019	4,753
2020	3,982
2021	2,590
2022	2,339
Above and Below Market Leases
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
2018	1,009
2019	1,019
2020	914
2021	845
2022	$ 833

Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the next 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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

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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.

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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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