Identified Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross amount	$ 402,614		$ 402,614		$ 415,261
Accumulated amortization	(201,164)		(201,164)		(187,360)
Net	201,450		201,450		227,901
Gross amount	587,157		587,157		643,488
Accumulated amortization	(310,685)		(310,685)		(325,340)
Net	276,472		276,472		$ 318,148
Below Market Leases Net Of Above Market Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	11,868	$ 19,786	41,676	$ 45,614
2017	45,591		45,591
2018	44,331		44,331
2019	32,168		32,168
2020	23,342		23,342
2021	18,159		18,159
Other Identified Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	6,918	12,908	22,777	24,402
2017	24,502		24,502
2018	20,251		20,251
2019	15,912		15,912
2020	12,441		12,441
2021	11,209		11,209
Tenant Under Ground Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	458	$ 458	1,374	$ 1,374
2017	1,832		1,832
2018	1,832		1,832
2019	1,832		1,832
2020	1,832		1,832
2021	$ 1,832		$ 1,832