Intangible Assets and Below Market Lease Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Intangible assets and below market lease liabilities, net [Abstract]
Deferred financing and leasing costs, accumulated amortization	$ (123,723)	$ (108,122)
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	241,663	222,448
Acquired intangible assets (amortized in rental and other revenue)	3,051
Acquired intangible assets (amortized in depreciation and amortization)	35,534
Assumed below market lease liabilities (amortized in rental and other revenue)	(10,733)
Deferred Financing Costs [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred financing and leasing costs, gross	18,449	19,478
Deferred financing and leasing costs, accumulated amortization	(8,551)	(7,953)
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	9,898	11,525
Amortization of intangible assets and below market lease liabilities
Amortization of intangible assets	3,645	3,082	$ 3,802
Deferred Leasing Costs [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred financing and leasing costs, gross	346,937	311,092
Deferred financing and leasing costs, accumulated amortization	(115,172)	(100,169)
Deferred financing and leasing costs, net/Total scheduled future amortization of intangible assets	231,765	210,923
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	209,063
Amortization of intangible assets and below market lease liabilities
Amortization of intangible assets	43,332	38,144	35,941
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	6,920
Amortization of intangible assets and below market lease liabilities
Amortization of intangible assets	1,493	1,419	1,361
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	13,045
Amortization of intangible assets and below market lease liabilities
Amortization of intangible assets	5,062	4,549	3,676
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	2,737
Amortization of intangible assets and below market lease liabilities
Amortization of intangible assets	557	557	556
Acquisition-Related Below Market Lease Liabilities [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Acquisition-related below market lease liabilities, gross	63,830	55,783
Acquisition-related below market lease liabilities, accumulated amortization	(17,927)	(13,548)
Acquisition-related below market lease liabilities, net	45,903	42,235
Amortization of intangible assets and below market lease liabilities
Amortization of acquisition-related below market lease liabilities	$ (7,065)	$ (6,129)	$ (5,316)