Intangible Assets and Below Market Lease Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Assets:
Deferred leasing costs (including lease incentives and above market lease and in-place lease acquisition-related intangible assets)	$ 344,067		$ 344,067		$ 344,548
Deferred leasing costs, accumulated amortization	(148,019)		(148,019)		(149,275)
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	196,048		196,048		195,273
Liabilities (in accounts payable, accrued expenses and other liabilities):
Acquisition-related below market lease liabilities, gross	53,861		53,861		57,955
Acquisition-related below market lease liabilities, accumulated amortization	(33,285)		(33,285)		(32,307)
Acquisition-related below market lease liabilities, net	20,576		20,576		$ 25,648
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	181,470		181,470
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	9,003	$ 8,969	28,077	$ 27,671
Lease Incentives (in Rental and Other Revenues) [Member]
Assets:
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	10,214		10,214
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	540	452	3,848	1,357
Acquisition-Related Intangible Assets (in Rental and Other Revenues) [Member]
Assets:
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	3,713		3,713
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	305	415	1,005	1,292
Acquisition-Related Intangible Assets (in Rental Property and Other Expenses) [Member]
Assets:
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	651		651
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	140	140	416	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	20,576		20,576
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of acquisition-related below market lease liabilities	$ (1,656)	$ (1,535)	$ (5,072)	$ (4,553)