Intangible Assets and Below Market Lease Liabilities - Scheduled Future Amortization (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Scheduled future amortization of intangible assets [Abstract]
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 202,814	$ 213,500
Scheduled future amortization of below market lease liabilities [Abstract]
Total scheduled future amortization of acquisition-related below market lease liabilities	(33,399)	$ (38,147)
Deferred Leasing Costs and Acquisition-Related Intangible Assets (in Depreciation and Amortization) [Member]
Scheduled future amortization of intangible assets [Abstract]
October 1 through December 31, 2017	10,019
2018	35,970
2019	30,311
2020	25,589
2021	21,254
Thereafter	61,333
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 184,476
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 12 days
Lease Incentives (in Rental and Other Revenues) [Member]
Scheduled future amortization of intangible assets [Abstract]
October 1 through December 31, 2017	$ 427
2018	1,599
2019	1,377
2020	1,101
2021	886
Thereafter	4,249
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 9,639
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 6 months
Acquisition-Related Intangible Assets (in Rental and Other Revenues) [Member]
Scheduled future amortization of intangible assets [Abstract]
October 1 through December 31, 2017	$ 469
2018	1,680
2019	1,286
2020	967
2021	647
Thereafter	1,885
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 6,934
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]
October 1 through December 31, 2017	$ 134
2018	553
2019	553
2020	525
2021	0
Thereafter	0
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 1,765
Weighted average remaining amortization periods for intangible assets and below market lease liabilities [Abstract]
Finite-lived intangible assets, average useful life (in years)	3 years 2 months 15 days
Acquisition-Related Below Market Lease Liabilities (in Rental and Other Revenues) [Member]
Scheduled future amortization of below market lease liabilities [Abstract]
October 1 through December 31, 2017	$ (1,497)
2018	(5,962)
2019	(5,492)
2020	(5,180)
2021	(4,409)
Thereafter	(10,859)
Total scheduled future amortization of acquisition-related below market lease liabilities	$ (33,399)
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 9 months 20 days