Deferred Leasing Costs and Acquisition-related Intangible Assets and Liabilities, net (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
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	$ 33,057	$ 33,947	$ 41,155
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	28,639	27,866	27,555
Estimated annual amortization related to acquisition-related intangibles
Finite-lived intangible assets, remainder of 2017	29,190
Finite-lived intangible assets, 2018	25,761
Finite-lived intangible assets, 2019	21,397
Finite-lived intangible assets, 2020	16,703
Finite-lived intangible assets, 2021	12,590
Finite-lived intangible assets, thereafter	44,684
Finite-lived intangible assets	150,325	133,143
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	1,509	2,532	5,303
Estimated annual amortization related to acquisition-related intangibles
Finite-lived intangible assets, remainder of 2017	1,298
Finite-lived intangible assets, 2018	869
Finite-lived intangible assets, 2019	681
Finite-lived intangible assets, 2020	53
Finite-lived intangible assets, 2021	53
Finite-lived intangible assets, thereafter	417
Finite-lived intangible assets	3,371	4,250
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	11,676	14,622	21,628
Estimated annual amortization related to acquisition-related intangibles
Finite-lived intangible assets, remainder of 2017	18,366
Finite-lived intangible assets, 2018	13,556
Finite-lived intangible assets, 2019	8,856
Finite-lived intangible assets, 2020	5,739
Finite-lived intangible assets, 2021	2,505
Finite-lived intangible assets, thereafter	5,198
Finite-lived intangible assets	54,220	38,829
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	8	8	8
Estimated annual amortization related to acquisition-related intangibles
Finite-lived intangible assets, remainder of 2017	8
Finite-lived intangible assets, 2018	8
Finite-lived intangible assets, 2019	8
Finite-lived intangible assets, 2020	8
Finite-lived intangible assets, 2021	8
Finite-lived intangible assets, thereafter	412
Finite-lived intangible assets	452	461
Below Market Operating Lease [Member]
Amortization for the period related to deferred leasing costs and acquisition-related intangibles
Amortization Of Intangible Liabilities	(8,674)	(10,980)	(13,238)
Estimated annual amortization related to acquisition-related intangibles
Acquisition-related intangible liabilities, remainder of 2017	(10,633)
Acquisition-related intangible liabilities, 2018	(9,116)
Acquisition-related intangible liabilities, 2019	6,519
Acquisition-related intangible liabilities, 2020	3,676
Acquisition-related intangible liabilities, 2021	(1,031)
Acquisition-related intangible liabilities, thereafter	(4,808)
Acquisition-related intangible liabilities	(35,783)	(26,428)
Above-Market Ground Lease Obligation [Member]
Amortization for the period related to deferred leasing costs and acquisition-related intangibles
Amortization Of Intangible Liabilities	(101)	(101)	$ (101)
Estimated annual amortization related to acquisition-related intangibles
Acquisition-related intangible liabilities, remainder of 2017	(101)
Acquisition-related intangible liabilities, 2018	(101)
Acquisition-related intangible liabilities, 2019	101
Acquisition-related intangible liabilities, 2020	101
Acquisition-related intangible liabilities, 2021	(101)
Acquisition-related intangible liabilities, thereafter	(5,290)
Acquisition-related intangible liabilities	$ (5,795)	$ (5,896)