Acquired Intangible Assets and Liabilities - Summary of Acquired Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Acquired in-place lease value
Finite-Lived Intangible Assets [Line Items]
Gross amount	$ 1,382,563	$ 1,357,190
Accumulated amortization	(1,004,421)	(899,071)
Total	378,142	458,119
Customer Relationship Value
Finite-Lived Intangible Assets [Line Items]
Gross amount	2,993,093	1,845,949
Accumulated amortization	(570,886)	(400,570)
Total	2,422,207	1,445,379
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Gross amount	57,370
Accumulated amortization	(7,107)
Total	50,263
Acquired above-market leases
Finite-Lived Intangible Assets [Line Items]
Gross amount	280,216	279,048
Accumulated amortization	(236,922)	(204,233)
Total	43,294	74,815
Below-Market Leases
Finite-Lived Intangible Assets [Line Items]
Gross amount	401,539	396,509
Accumulated amortization	(270,649)	(247,735)
Total	$ 130,890	$ 148,774