Intangible Assets and Below Market Lease Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Assets:
Deferred leasing costs (including lease incentives and above market lease and in-place lease acquisition-related intangible assets)	$ 343,211		$ 344,191
Deferred leasing costs, accumulated amortization	(146,909)		(143,512)
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	196,302		200,679
Liabilities (in accounts payable, accrued expenses and other liabilities):
Acquisition-related below market lease liabilities, gross	59,646		59,947
Acquisition-related below market lease liabilities, accumulated amortization	(29,436)		(28,214)
Acquisition-related below market lease liabilities, net	30,210		$ 31,733
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	178,871
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	9,495	$ 10,619
Lease Incentives (in Rental and Other Revenues) [Member]
Assets:
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	9,997
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	429	397
Acquisition-Related Intangible Assets (in Rental and Other Revenues) [Member]
Assets:
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	5,947
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of intangible assets	448	1,036
Acquisition-Related Intangible Assets (in Rental Property and Other Expenses) [Member]
Assets:
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	1,487
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	30,210
Amortization of intangible assets and below market lease liabilities [Abstract]
Amortization of acquisition-related below market lease liabilities	$ (1,523)	$ (1,580)