Intangible Assets and Below Market Lease Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 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)	$ 347,089		$ 346,937
Deferred leasing costs, accumulated amortization	(122,630)		(115,172)
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	224,459		231,765
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	202,648
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	11,335	$ 10,001
Lease Incentives [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	7,199
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	711	351
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	12,013
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	1,031	1,166
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	2,599
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	138	137
Acquisition-Related Below Market Lease Liabilities [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Acquisition-related below market lease liabilities, gross	63,628		63,830
Acquisition-related below market lease liabilities, accumulated amortization	(19,497)		(17,927)
Acquisition-related below market lease liabilities, net	44,131		$ 45,903
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of acquisition-related below market lease liabilities	$ (1,772)	$ (1,732)