Intangible Assets and Below Market Lease Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Intangible assets and below market lease liabilities, net [Abstract]
Deferred leasing costs (including lease incentives and above market lease and in-place lease acquisition-related intangible assets)	$ 346,294		$ 346,294		$ 346,937
Deferred leasing costs, accumulated amortization	(129,252)		(129,252)		(115,172)
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	217,042		217,042		231,765
Acquisition-related below market lease liabilities, gross	63,400		63,400		63,830
Acquisition-related below market lease liabilities, accumulated amortization	(22,057)		(22,057)		(17,927)
Acquisition-related below market lease liabilities, net	41,343		41,343		$ 45,903
Deferred Leasing Costs and Acquisition-Related Intangible Assets [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	196,408		196,408
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	11,731	$ 9,888	23,066	$ 19,889
Lease Incentives [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	7,131		7,131
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	390	412	1,101	763
Acquisition-Related Intangible Assets (in Rental and Other Revenues) [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	11,043		11,043
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	972	1,189	2,003	2,355
Acquisition-Related Intangible Assets (in Rental Property and Other Expenses) [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	2,460		2,460
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	139	139	277	276
Acquisition-Related Below Market Lease Liabilities [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Acquisition-related below market lease liabilities, net	41,343		41,343
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of acquisition-related below market lease liabilities	$ (2,788)	$ (1,674)	$ (4,560)	$ (3,406)