Deferred Leasing Costs and Acquisition-related Intangible Assets and Liabilities, net (Details 1) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016		Mar. 31, 2015	Dec. 31, 2015
Amortization for the period related to deferred leasing costs and acquisition-related intangibles
Amortization of intangible assets		$ 8,045		$ 9,092
Estimated annual amortization related to acquisition-related intangibles
Finite-lived intangible assets, net		186,271			$ 176,683
Acquisition-related Intangible Liabilities, net	[1]	(30,303)			(32,324)
Deferred Leasing Costs [Member]
Amortization for the period related to deferred leasing costs and acquisition-related intangibles
Amortization of intangible assets	[2]	6,783		6,822
Estimated annual amortization related to acquisition-related intangibles
Remaining 2016		20,497
2017		24,704
2018		21,490
2019		17,492
2020		13,515
Thereafter		48,315
Finite-lived intangible assets, net		146,013			133,143
Above-Market Leases [Member]
Amortization for the period related to deferred leasing costs and acquisition-related intangibles
Amortization of intangible assets	[3]	392		911
Estimated annual amortization related to acquisition-related intangibles
Remaining 2016	[4]	1,109
2017	[4]	1,241
2018	[4]	831
2019	[4]	643
2020	[4]	16
Thereafter	[4]	18
Finite-lived intangible assets, net		3,858	[4]		4,250
In-Place Leases [Member]
Amortization for the period related to deferred leasing costs and acquisition-related intangibles
Amortization of intangible assets	[2]	2,888		4,221
Estimated annual amortization related to acquisition-related intangibles
Remaining 2016		7,725
2017		9,036
2018		6,296
2019		4,637
2020		2,789
Thereafter		5,458
Finite-lived intangible assets, net		35,941			38,829
Below Market Ground Lease Obligation [Member]
Amortization for the period related to deferred leasing costs and acquisition-related intangibles
Amortization of intangible assets	[5]	2		2
Estimated annual amortization related to acquisition-related intangibles
Remaining 2016	[6]	6
2017	[6]	8
2018	[6]	8
2019	[6]	8
2020	[6]	8
Thereafter	[6]	421
Finite-lived intangible assets, net		459	[6]		461
Below Market Leases [Member]
Amortization for the period related to deferred leasing costs and acquisition-related intangibles
Amortization of intangible liabilities	[7]	(1,995)		(2,839)
Estimated annual amortization related to acquisition-related intangibles
Remaining 2016	[8]	(5,689)
2017	[8]	(6,997)
2018	[8]	(5,713)
2019	[8]	(3,574)
2020	[8]	(2,035)
Thereafter	[8]	(425)
Acquisition-related Intangible Liabilities, net	[1]	(24,433)	[8]		(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	[9]	(25)		$ (25)
Estimated annual amortization related to acquisition-related intangibles
Remaining 2016	[10]	(75)
2017	[10]	(101)
2018	[10]	(101)
2019	[10]	(101)
2020	[10]	(101)
Thereafter	[10]	(5,391)
Acquisition-related Intangible Liabilities, net	[1]	$ (5,870)	[10]		$ (5,896)

[1] Included in deferred revenue and acquisition-related intangible liabilities, net in the consolidated balance sheets.

[2] The amortization of deferred leasing costs and in-place leases is recorded to depreciation and amortization expense in the consolidated statements of operations for the periods presented.

[3] The amortization of above-market operating leases is recorded as a decrease to rental income in the consolidated statements of operations for the periods presented.

[4] Represents estimated annual amortization related to above-market operating leases. Amounts will be recorded as a decrease to rental income in the consolidated statements of operations.

[5] The amortization of the below-market ground lease obligation is recorded as an increase to ground lease expense in the consolidated statements of operations for the periods presented.

[6] Represents estimated annual amortization related to below-market ground lease obligations. Amounts will be recorded as an increase to ground lease expense in the consolidated statements of operations.

[7] The amortization of below-market operating leases is recorded as an increase to rental income in the consolidated statements of operations for the periods presented.

[8] Represents estimated annual amortization related to below-market operating leases. Amounts will be recorded as an increase to rental income in the consolidated statements of operations.

[9] The amortization of the above-market ground lease obligation is recorded as a decrease to ground lease expense in the consolidated statements of operations for the periods presented.

[10] Represents estimated annual amortization related to above-market ground lease obligations. Amounts will be recorded as a decrease to ground lease expense in the consolidated statements of operations.