Intangible Assets and Below Market Lease Liabilities (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Intangible assets and below market lease liabilities, net [Abstract]
Deferred financing and leasing costs, accumulated amortization	$ (92,220)	$ (75,008)
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	222,211	163,964
Acquired intangible assets (amortized in rental and other revenue)	17,201
Acquired intangible assets (amortized in depreciation and amortization)	58,422
Assumed below market lease liabilities (amortized in rental and other revenue)	(19,124)
Deferred Financing Costs [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred financing and leasing costs, gross	17,363	21,759
Deferred financing and leasing costs, accumulated amortization	(5,204)	(7,862)
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	12,159	13,897
Amortization of intangible assets and below market lease liabilities
Amortization of intangible assets	3,802	3,685	3,312
Deferred Leasing Costs [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred financing and leasing costs, gross	297,068	217,213
Deferred financing and leasing costs, accumulated amortization	(87,016)	(67,146)
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	210,052	150,067
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	181,304
Amortization of intangible assets and below market lease liabilities
Amortization of intangible assets	37,094	26,509	19,562
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	6,668
Amortization of intangible assets and below market lease liabilities
Amortization of intangible assets	1,409	1,389	1,302
Acquisition-Related Intangible Assets (in Rental and Other Revenue) [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	18,229
Amortization of intangible assets and below market lease liabilities
Amortization of intangible assets	3,676	1,357	915
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	3,851
Amortization of intangible assets and below market lease liabilities
Amortization of intangible assets	556	186	0
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	37,019
Acquisition-related below market lease liabilities, accumulated amortization	(8,478)	(3,383)
Acquisition-related below market lease liabilities, net	46,845	33,636
Amortization of intangible assets and below market lease liabilities
Amortization of acquisition-related below market lease liabilities	$ (5,316)	$ (2,627)	$ (840)