Deferred Leasing Costs and Acquisition-Related Intangible Assets and Liabilities, net - Amortization of Deferred Leasing Costs and Acquisition-related Intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Amortization for the period related to deferred leasing costs and acquisition-related intangibles
Amortization for the period related to deferred leasing costs and acquisition-related intangibles	$ 45,188	$ 40,415	$ 41,704
Deferred leasing costs [Member]
Amortization for the period related to deferred leasing costs and acquisition-related intangibles
Amortization for the period related to deferred leasing costs and acquisition-related intangibles	35,779	34,341	31,675
Estimated annual amortization related to acquisition-related intangible assets
Finite-lived intangible assets, 2020	30,897
Finite-lived intangible assets, 2021	27,043
Finite-lived intangible assets, 2022	23,642
Finite-lived intangible assets, 2023	19,904
Finite-lived intangible assets, 2024	16,976
Finite-lived intangible assets, thereafter	67,419
Finite-lived intangible assets	185,881	166,100
Above market leases [Member]
Amortization for the period related to deferred leasing costs and acquisition-related intangibles
Amortization for the period related to deferred leasing costs and acquisition-related intangibles	192	444	2,240
Estimated annual amortization related to acquisition-related intangible assets
Finite-lived intangible assets, 2020	38
Finite-lived intangible assets, 2021	38
Finite-lived intangible assets, 2022	38
Finite-lived intangible assets, 2023	38
Finite-lived intangible assets, 2024	38
Finite-lived intangible assets, thereafter	305
Finite-lived intangible assets	495	686
In-place leases [Member]
Amortization for the period related to deferred leasing costs and acquisition-related intangibles
Amortization for the period related to deferred leasing costs and acquisition-related intangibles	18,615	15,915	18,650
Estimated annual amortization related to acquisition-related intangible assets
Finite-lived intangible assets, 2020	11,379
Finite-lived intangible assets, 2021	6,668
Finite-lived intangible assets, 2022	4,001
Finite-lived intangible assets, 2023	1,641
Finite-lived intangible assets, 2024	602
Finite-lived intangible assets, thereafter	2,138
Finite-lived intangible assets	26,429	30,352
Below-market ground lease obligation [Member]
Amortization for the period related to deferred leasing costs and acquisition-related intangibles
Amortization for the period related to deferred leasing costs and acquisition-related intangibles	0	8	8
Estimated annual amortization related to acquisition-related intangible assets
Finite-lived intangible assets	0	436
Below-market operating leases [Member]
Amortization for the period related to deferred leasing costs and acquisition-related intangibles
Amortization of intangible liabilities	(9,398)	(10,192)	(10,768)
Estimated annual amortization related to acquisition-related intangible liabilities
Acquisition-related intangible liabilities, 2020	(7,258)
Acquisition-related intangible liabilities, 2021	(4,543)
Acquisition-related intangible liabilities, 2022	(3,553)
Acquisition-related intangible liabilities, 2023	(1,866)
Acquisition-related intangible liabilities, 2024	(1,090)
Acquisition-related intangible liabilities, thereafter	(5,782)
Acquisition-related intangible liabilities	(24,092)	(23,545)
Above-market ground lease obligation [Member]
Amortization for the period related to deferred leasing costs and acquisition-related intangibles
Amortization of intangible liabilities	0	(101)	$ (101)
Estimated annual amortization related to acquisition-related intangible liabilities
Acquisition-related intangible liabilities	$ 0	$ (5,593)