Intangible Assets and Below Market Lease Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Intangible assets and below market lease liabilities, net [Abstract]
Deferred leasing costs, gross	$ 361,027	$ 377,472
Deferred leasing costs, accumulated amortization	(151,698)	(146,125)
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	209,329	231,347
Acquisition-related below market lease liabilities, gross	63,748	65,971
Acquisition-related below market lease liabilities, accumulated amortization	(37,838)	(34,014)
Acquisition-related below market lease liabilities, net	25,910	31,957
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	194,121
Amortization of intangible assets and below market lease liabilities
Amortization of intangible assets	34,401	37,386	$ 36,486
Lease Incentives [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	10,915
Amortization of intangible assets and below market lease liabilities
Amortization of intangible assets	1,847	4,281	1,908
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	4,293
Amortization of intangible assets and below market lease liabilities
Amortization of intangible assets	1,137	1,290	1,677
Acquisition-Related Intangible Assets (in Rental Property and Other Expenses) [Member]
Amortization of intangible assets and below market lease liabilities
Amortization of intangible assets	510	557	557
Acquisition-Related Below Market Lease Liabilities [Member]
Intangible assets and below market lease liabilities, net [Abstract]
Acquisition-related below market lease liabilities, net	25,910
Amortization of intangible assets and below market lease liabilities
Amortization of acquisition-related below market lease liabilities	$ (6,031)	$ (6,633)	$ (6,085)