Identified Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Finite-Lived Intangible Assets and Liabilities
Gross amount	$ 387,791		$ 387,791		$ 400,061
Accumulated amortization	(211,285)		(211,285)		(207,330)
Net	176,506		176,506		192,731
Gross amount	581,471		581,471		586,969
Accumulated amortization	(340,131)		(340,131)		(323,183)
Net	241,340		241,340		$ 263,786
Below Market Leases Net Of Above Market Leases
Finite-Lived Intangible Assets and Liabilities
Amortization of Intangible Assets	12,932	$ 12,301	24,391	$ 29,808
2018	44,474		44,474
2019	32,297		32,297
2020	23,472		23,472
2021	18,646		18,646
2022	15,530		15,530
Other Identified Intangible Assets
Finite-Lived Intangible Assets and Liabilities
Amortization of Intangible Assets	6,971	8,066	14,079	15,859
2018	20,073		20,073
2019	15,737		15,737
2020	12,291		12,291
2021	11,288		11,288
2022	9,532		9,532
Tenant Under Ground Leases
Finite-Lived Intangible Assets and Liabilities
Amortization of Intangible Assets	458	$ 458	916	$ 916
2018	1,832		1,832
2019	1,832		1,832
2020	1,832		1,832
2021	1,832		1,832
2022	$ 1,832		$ 1,832