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Real Estate and Intangible Assets - Carrying Value of Intangible Assets and Accumulated Amortization (Detail) - USD ($) $ in Thousands | Jun. 30, 2018 | Dec. 31, 2017
--- | --- | ---
Finite-Lived Intangible Assets [Line Items] |  |
Below market leases and deferred revenue, gross | $ (26,752) | $ (26,725)
Below market leases and deferred revenue, accumulated amortization | 11,474 | 10,475
Lease Intangibles |  |
Finite-Lived Intangible Assets [Line Items] |  |
Lease Intangibles | 196,061 | 194,942
Intangibles, accumulated amortization | (84,083) | (76,015)
In-place leases |  |
Finite-Lived Intangible Assets [Line Items] |  |
Lease Intangibles | 80,638 | 80,355
Intangibles, accumulated amortization | (36,834) | (33,201)
Leasing costs |  |
Finite-Lived Intangible Assets [Line Items] |  |
Lease Intangibles | 56,147 | 55,695
Intangibles, accumulated amortization | (25,458) | (23,016)
Customer relationships |  |
Finite-Lived Intangible Assets [Line Items] |  |
Lease Intangibles | 59,276 | 58,892
Intangibles, accumulated amortization | (21,791) | (19,798)
Above market leases and below market leases and deferred revenue |  |
Finite-Lived Intangible Assets [Line Items] |  |
Finite-lived intangible assets (liabilities), gross | (12,241) | (12,300)
Finite-lived intangible assets (liabilities), accumulated amortization | 3,035 | 2,513
Above market leases |  |
Finite-Lived Intangible Assets [Line Items] |  |
Lease Intangibles | 14,511 | 14,425
Intangibles, accumulated amortization | $ (8,439) | $ (7,962)

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- Definition Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References 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)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
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