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Real Estate and Intangible Assets - Carrying Value of Intangible Assets and Accumulated Amortization (Detail) - USD ($) $ in Thousands | Sep. 30, 2017 | Dec. 31, 2016
--- | --- | ---
Finite-Lived Intangible Assets [Line Items] |  |
Below market leases and deferred revenue, gross | $ (25,576) | $ (21,606)
Below market leases and deferred revenue, accumulated amortization | 10,022 | 8,959
Lease Intangibles |  |
Finite-Lived Intangible Assets [Line Items] |  |
Lease Intangibles | 188,528 | 169,734
Intangibles, accumulated amortization | (73,318) | (64,181)
In-place leases |  |
Finite-Lived Intangible Assets [Line Items] |  |
Lease Intangibles | 78,975 | 71,482
Intangibles, accumulated amortization | (32,140) | (28,182)
Leasing costs |  |
Finite-Lived Intangible Assets [Line Items] |  |
Lease Intangibles | 53,706 | 48,000
Intangibles, accumulated amortization | (21,889) | (18,599)
Customer relationships |  |
Finite-Lived Intangible Assets [Line Items] |  |
Lease Intangibles | 55,847 | 50,252
Intangibles, accumulated amortization | (19,289) | (17,400)
Above market leases and below market leases and deferred revenue |  |
Finite-Lived Intangible Assets [Line Items] |  |
Finite-lived intangible assets (liabilities), gross | (13,059) | (11,127)
Finite-lived intangible assets (liabilities), accumulated amortization | 2,296 | 1,663
Above market leases |  |
Finite-Lived Intangible Assets [Line Items] |  |
Lease Intangibles | 12,517 | 10,479
Intangibles, accumulated amortization | $ (7,726) | $ (7,296)

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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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