Identified Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross amount	$ 406,482		$ 415,261
Accumulated amortization	(188,094)		(187,360)
Net	218,388		227,901
Gross amount	607,241		643,488
Accumulated amortization	(307,858)		(325,340)
Net	299,383		$ 318,148
Below Market Leases Net Of Above Market Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	17,507	$ 12,450
2017	44,463
2018	42,991
2019	30,973
2020	23,320
2021	18,263
Other Identified Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	7,793	6,185
2017	24,427
2018	20,063
2019	15,779
2020	12,345
2021	10,957
Tenant Under Ground Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	458	$ 458
2017	1,832
2018	1,832
2019	1,832
2020	1,832
2021	$ 1,832