Intangible Assets and Below Market Lease Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Assets:
Deferred leasing costs (including lease incentives and above market lease and in-place lease acquisition-related intangible assets)	$ 344,711		$ 344,548
Deferred leasing costs, accumulated amortization	(149,863)		(149,275)
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	194,848		195,273
Liabilities (in accounts payable, accrued expenses and other liabilities):
Acquisition-related below market lease liabilities, gross	56,865		57,955
Acquisition-related below market lease liabilities, accumulated amortization	(32,870)		(32,307)
Acquisition-related below market lease liabilities, net	23,995		$ 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	180,855
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	10,315	$ 9,495
Lease Incentives (in Rental and Other Revenues) [Member]
Assets:
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	8,702
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	2,848	429
Acquisition-Related Intangible Assets (in Rental and Other Revenues) [Member]
Assets:
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	4,361
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	357	448
Acquisition-Related Intangible Assets (in Rental Property and Other Expenses) [Member]
Assets:
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	930
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	137	137
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	23,995
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of acquisition-related below market lease liabilities	$ (1,653)	$ (1,523)