Intangible Assets and Below Market Lease Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Intangible assets and below market lease liabilities, net [Abstract]
Deferred financing and leasing costs, accumulated amortization	$ (119,396)		$ (119,396)		$ (112,804)
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	223,380		223,380		228,768
Acquired intangible assets (amortized in rental and other revenue)	498		498
Acquired intangible assets (amortized in depreciation and amortization)	1,671		1,671
Assumed below market lease liabilities (amortized in rental and other revenue)	(37)		(37)
Deferred Financing Costs [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred financing and leasing costs, gross	19,508		19,508		19,478
Deferred financing and leasing costs, accumulated amortization	(8,093)		(8,093)		(7,953)
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	11,415		11,415		11,525
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	828	$ 799	1,628	$ 1,451
Deferred Leasing Costs [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred financing and leasing costs, gross	323,268		323,268		322,094
Deferred financing and leasing costs, accumulated amortization	(111,303)		(111,303)		(104,851)
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	211,965		211,965		217,243
Deferred Leasing Costs and Acquisition-Related Intangible Assets [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	188,264		188,264
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	10,169	10,050	20,462	19,978
Lease Incentives [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	7,484		7,484
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	422	399	784	750
Acquisition-Related Intangible Assets (in Rental and Other Revenues) [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	13,199		13,199
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	1,189	1,114	2,355	2,230
Acquisition-Related Intangible Assets (in Rental Property and Other Expenses) [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	3,018		3,018
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	139	139	276	276
Acquisition-Related Below Market Lease Liabilities [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Acquisition-related below market lease liabilities, gross	55,166		55,166		55,783
Acquisition-related below market lease liabilities, accumulated amortization	(16,300)		(16,300)		(13,548)
Acquisition-related below market lease liabilities, net	38,866		38,866		$ 42,235
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of acquisition-related below market lease liabilities	$ (1,674)	$ (1,500)	$ (3,406)	$ (3,022)