Intangible Assets and Below Market Lease Liabilities - Scheduled Future Amortization (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Scheduled future amortization of intangible assets [Abstract]
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 195,863	$ 195,273
Scheduled future amortization of below market lease liabilities [Abstract]
Total scheduled future amortization of acquisition-related below market lease liabilities	(22,231)	$ (25,648)
Deferred Leasing Costs and Acquisition-Related Intangible Assets (in Depreciation and Amortization) [Member]
Scheduled future amortization of intangible assets [Abstract]
July 1 through December 31, 2019	19,120
2020	34,072
2021	29,482
2022	25,090
2023	21,630
Thereafter	53,368
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 182,762
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 2 months 12 days
Lease Incentives (in Rental and Other Revenues) [Member]
Scheduled future amortization of intangible assets [Abstract]
July 1 through December 31, 2019	$ 779
2020	1,318
2021	1,071
2022	840
2023	763
Thereafter	3,521
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 8,292
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 1 month 6 days
Acquisition-Related Intangible Assets (in Rental and Other Revenues) [Member]
Scheduled future amortization of intangible assets [Abstract]
July 1 through December 31, 2019	$ 560
2020	957
2021	631
2022	462
2023	308
Thereafter	1,100
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 4,018
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]
July 1 through December 31, 2019	$ 277
2020	514
2021	0
2022	0
2023	0
Thereafter	0
Deferred leasing costs, net/Total scheduled future amortization of intangible assets	$ 791
Weighted average remaining amortization periods for intangible assets and below market lease liabilities [Abstract]
Finite-lived intangible assets, average useful life (in years)	1 year 6 months
Acquisition-Related Below Market Lease Liabilities (in Rental and Other Revenues) [Member]
Scheduled future amortization of below market lease liabilities [Abstract]
July 1 through December 31, 2019	$ (2,885)
2020	(5,005)
2021	(4,204)
2022	(3,133)
2023	(2,753)
Thereafter	(4,251)
Total scheduled future amortization of acquisition-related below market lease liabilities	$ (22,231)
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)	5 years 4 months 24 days