Intangible Assets and Below Market Lease Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Intangible assets and below market lease liabilities, net [Abstract]
Deferred leasing costs (including lease incentives and above market lease and in-place lease acquisition-related intangible assets)	$ 355,268		$ 355,268		$ 346,937
Deferred leasing costs, accumulated amortization	(136,292)		(136,292)		(115,172)
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	218,976		218,976		231,765
Acquisition-related below market lease liabilities, gross	63,712		63,712		63,830
Acquisition-related below market lease liabilities, accumulated amortization	(23,675)		(23,675)		(17,927)
Acquisition-related below market lease liabilities, net	40,037		40,037		$ 45,903
Amortization of intangible assets and below market lease liabilities [Abstract]
Acquired intangible assets (amortized in rental and other revenues)	122		122
Acquired intangible assets (amortized in depreciation and amortization)	5,008		5,008
Assumed below market lease liabilities (amortized in rental and other revenues)	(428)		(428)
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	198,911		198,911
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	10,111	$ 10,858	33,177	$ 30,747
Lease Incentives [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	7,480		7,480
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	273	368	1,374	1,131
Acquisition-Related Intangible Assets (in Rental and Other Revenues) [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	10,264		10,264
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	901	1,414	2,904	3,769
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	2,321		2,321
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	140	140	417	416
Acquisition-Related Below Market Lease Liabilities [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Acquisition-related below market lease liabilities, net	40,037		40,037
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of acquisition-related below market lease liabilities	$ (1,734)	$ (1,727)	$ (6,294)	$ (5,133)