Deferred Leasing Costs and Acquisition-Related Intangible Assets and Liabilities, net - Deferred Leasing Costs and Acquisition-related Intangible Assets and Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred Leasing Costs and Acquisition-related Intangible Assets and Liabilities, Net
Total deferred leasing costs and acquisition-related intangible assets, net	$ 212,805	$ 197,574
Acquisition-related Intangible Liabilities, Net [Abstract]
Total acquisitions-related intangible liabilities, net	24,092	29,138
Deferred leasing costs [Member]
Deferred Leasing Costs and Acquisition-related Intangible Assets and Liabilities, Net
Finite-lived intangible assets/liabilities, gross	286,026	266,905
Accumulated amortization	(100,145)	(100,805)
Finite-lived intangible assets	185,881	166,100
Above market leases [Member]
Deferred Leasing Costs and Acquisition-related Intangible Assets and Liabilities, Net
Finite-lived intangible assets/liabilities, gross	611	2,836
Accumulated amortization	(116)	(2,150)
Finite-lived intangible assets	495	686
In-place leases [Member]
Deferred Leasing Costs and Acquisition-related Intangible Assets and Liabilities, Net
Finite-lived intangible assets/liabilities, gross	58,076	66,526
Accumulated amortization	(31,647)	(36,174)
Finite-lived intangible assets	26,429	30,352
Below-market ground lease obligation, net [Member]
Deferred Leasing Costs and Acquisition-related Intangible Assets and Liabilities, Net
Finite-lived intangible assets/liabilities, gross	0	490
Accumulated amortization	0	(54)
Finite-lived intangible assets	0	436
Below-market operating leases [Member]
Acquisition-related Intangible Liabilities, Net [Abstract]
Acquisition-related intangible liabilities, gross	51,263	53,523
Accumulated amortization	(27,171)	(29,978)
Acquisition-related intangible liabilities, net	24,092	23,545
Above-market ground lease obligation [Member]
Acquisition-related Intangible Liabilities, Net [Abstract]
Acquisition-related intangible liabilities, gross	0	6,320
Accumulated amortization	0	(727)
Acquisition-related intangible liabilities, net	$ 0	$ 5,593