Intangible Assets and Below Market Lease Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Assets:
Deferred leasing costs (including lease incentives and above market lease and in-place lease acquisition-related intangible assets)	$ 369,374		$ 369,374		$ 377,472
Deferred leasing costs, accumulated amortization	(153,045)		(153,045)		(146,125)
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	216,329		216,329		231,347
Liabilities (in accounts payable, accrued expenses and other liabilities):
Acquisition-related below market lease liabilities, gross	64,569		64,569		65,971
Acquisition-related below market lease liabilities, accumulated amortization	(37,173)		(37,173)		(34,014)
Acquisition-related below market lease liabilities, net	27,396		27,396		$ 31,957
Deferred Leasing Costs and Acquisition-Related Intangible Assets (in Depreciation and Amortization) [Member]
Assets:
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	200,123		200,123
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	8,466	$ 9,003	25,830	$ 28,077
Lease Incentives (in Rental and Other Revenues) [Member]
Assets:
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	11,569		11,569
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	477	540	1,396	3,848
Acquisition-Related Intangible Assets (in Rental and Other Revenues) [Member]
Assets:
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	4,544		4,544
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	273	305	882	1,005
Acquisition-Related Intangible Assets (in Rental Property and Other Expenses) [Member]
Assets:
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	93		93
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	140	140	417	416
Acquisition-Related Below Market Lease Liabilities (in Rental and Other Revenues) [Member]
Liabilities (in accounts payable, accrued expenses and other liabilities):
Acquisition-related below market lease liabilities, net	27,396		27,396
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of acquisition-related below market lease liabilities	$ (1,479)	$ (1,656)	$ (4,562)	$ (5,072)