Identified Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Finite-Lived Intangible Assets and Liabilities
Gross amount	$ 310,881		$ 310,881		$ 384,090
Accumulated amortization	(144,683)		(144,683)		(194,422)
Total, net	166,198		166,198		189,668
Gross amount	544,956		544,956		550,454
Accumulated amortization	(326,661)		(326,661)		(298,238)
Total, net	218,295		218,295		$ 252,216
Below Market Leases Net Of Above Market Leases
Finite-Lived Intangible Assets and Liabilities
Amortization of Intangible Assets	11,054	$ 11,529	34,758	$ 40,664
2018	42,556		42,556
2019	30,820		30,820
2020	22,185		22,185
2021	17,370		17,370
2022	14,271		14,271
Other Identified Intangible Assets
Finite-Lived Intangible Assets and Liabilities
Amortization of Intangible Assets	6,069	6,646	19,896	22,319
2018	19,510		19,510
2019	15,229		15,229
2020	12,020		12,020
2021	11,041		11,041
2022	9,433		9,433
Tenant Under Ground Leases
Finite-Lived Intangible Assets and Liabilities
Amortization of Intangible Assets	437	$ 437	1,310	$ 1,310
2018	1,747		1,747
2019	1,747		1,747
2020	1,747		1,747
2021	1,747		1,747
2022	$ 1,747		$ 1,747