Intangible Assets and Below Market Lease Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Intangible assets and below market lease liabilities, net [Abstract]
Deferred leasing costs, accumulated amortization	$ (140,081)	$ (115,172)
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	213,500	231,765
Acquired intangible assets (amortized in rental and other revenue)	122
Acquired intangible assets (amortized in depreciation and amortization)	5,008
Assumed below market lease liabilities (amortized in rental and other revenue)	(428)
Deferred Leasing Costs [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred leasing costs, gross	353,581	346,937
Deferred leasing costs, accumulated amortization	(140,081)	(115,172)
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	194,032
Amortization of intangible assets and below market lease liabilities
Amortization of intangible assets	44,968	43,332	$ 38,144
Lease Incentives [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	7,968
Amortization of intangible assets and below market lease liabilities
Amortization of intangible assets	1,779	1,493	1,419
Acquisition-Related Intangible Assets (in Rental and Other Revenue) [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	9,316
Amortization of intangible assets and below market lease liabilities
Amortization of intangible assets	3,851	5,062	4,549
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	2,184
Amortization of intangible assets and below market lease liabilities
Amortization of intangible assets	557	557	557
Acquisition-Related Below Market Lease Liabilities [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Acquisition-related below market lease liabilities, gross	61,221	63,830
Acquisition-related below market lease liabilities, accumulated amortization	(23,074)	(17,927)
Acquisition-related below market lease liabilities, net	38,147	45,903
Amortization of intangible assets and below market lease liabilities
Amortization of acquisition-related below market lease liabilities	$ (8,183)	$ (7,065)	$ (6,129)