Intangible Assets and Below Market Lease Liabilities (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Intangible assets and below market lease liabilities, net [Abstract]
Deferred financing and leasing costs, accumulated amortization	$ (90,241)		$ (90,241)		$ (75,863)
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	227,826		227,826		166,009
Acquired above market lease intangible assets	17,201		17,201
Acquired in-place lease intangible assets	58,422		58,422
Assumed below market lease liabilities	(19,124)		(19,124)
Deferred Financing Costs [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred financing and leasing costs, gross	19,506		19,506		21,759
Deferred financing and leasing costs, accumulated amortization	(8,632)		(8,632)		(7,862)
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	10,874		10,874		13,897
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	963	907	2,860	2,709
Deferred Leasing Costs [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred financing and leasing costs, gross	298,561		298,561		220,113
Deferred financing and leasing costs, accumulated amortization	(81,609)		(81,609)		(68,001)
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	216,952		216,952		152,112
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	186,988		186,988
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	10,751	6,667	26,962	19,930
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	6,566		6,566
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	347	386	1,061	1,037
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	19,406		19,406
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	1,548	433	2,499	1,027
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	3,992		3,992
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	140	46	416	46
Acquisition-Related Below Market Lease Liabilities [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Acquisition-related below market lease liabilities, gross	55,323		55,323		37,019
Acquisition-related below market lease liabilities, accumulated amortization	(6,900)		(6,900)		(3,383)
Acquisition-related below market lease liabilities, net	48,423		48,423		33,636
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of acquisition-related below market lease liabilities	$ (1,584)	$ (647)	$ (3,737)	$ (1,744)