Acquired Intangible Assets and Liabilities - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Below-Market Leases, Net of Above-Market Leases
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired leases	$ (1.4)	$ (3.3)
Customer Relationship Value, Acquired In-Place Lease Value and Other Intangibles
Finite-Lived Intangible Assets [Line Items]
Amortization of customer relationship value, acquired in-place lease value and deferred leasing costs	$ 67.7	$ 56.3

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
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-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
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-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274

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