Intangible Assets and Below Market Lease Liabilities - Scheduled Future Amortization (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Scheduled future amortization of intangible assets [Abstract]
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 196,302	$ 200,679
Scheduled future amortization of below market lease liabilities [Abstract]
Total scheduled future amortization of acquisition-related below market lease liabilities	(30,210)	$ (31,733)
Deferred Leasing Costs and Acquisition-Related Intangible Assets (in Depreciation and Amortization) [Member]
Scheduled future amortization of intangible assets [Abstract]
April 1 through December 31, 2018	27,309
2019	31,646
2020	27,150
2021	22,748
2022	18,565
Thereafter	51,453
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 178,871
Weighted average remaining amortization periods for intangible assets and below market lease liabilities [Abstract]
Finite-lived intangible assets, average useful life (in years)	7 years 7 months 7 days
Lease Incentives (in Rental and Other Revenues) [Member]
Scheduled future amortization of intangible assets [Abstract]
April 1 through December 31, 2018	$ 1,218
2019	1,503
2020	1,227
2021	1,002
2022	788
Thereafter	4,259
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 9,997
Weighted average remaining amortization periods for intangible assets and below market lease liabilities [Abstract]
Finite-lived intangible assets, average useful life (in years)	9 years 9 months 20 days
Acquisition-Related Intangible Assets (in Rental and Other Revenues) [Member]
Scheduled future amortization of intangible assets [Abstract]
April 1 through December 31, 2018	$ 1,213
2019	1,273
2020	959
2021	632
2022	462
Thereafter	1,408
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 5,947
Weighted average remaining amortization periods for intangible assets and below market lease liabilities [Abstract]
Finite-lived intangible assets, average useful life (in years)	6 years 6 months
Acquisition-Related Intangible Assets (in Rental Property and Other Expenses) [Member]
Scheduled future amortization of intangible assets [Abstract]
April 1 through December 31, 2018	$ 416
2019	553
2020	518
2021	0
2022	0
Thereafter	0
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 1,487
Weighted average remaining amortization periods for intangible assets and below market lease liabilities [Abstract]
Finite-lived intangible assets, average useful life (in years)	2 years 8 months 15 days
Acquisition-Related Below Market Lease Liabilities (in Rental and Other Revenues) [Member]
Scheduled future amortization of below market lease liabilities [Abstract]
April 1 through December 31, 2018	$ (4,414)
2019	(5,446)
2020	(5,186)
2021	(4,377)
2022	(3,264)
Thereafter	(7,523)
Total scheduled future amortization of acquisition-related below market lease liabilities	$ (30,210)
Weighted average remaining amortization periods for intangible assets and below market lease liabilities [Abstract]
Finite-lived below market lease liabilities, average useful life (in years)	6 years 4 months 25 days