Intangible Assets and Liabilities - Summary of Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Assets
Gross	$ 667,257	$ 665,679
Accumulated amortization	(416,501)	(387,827)
Total	$ 250,756	$ 277,852
Weighted Average Remaining Amortization in Years	9 years 4 months 24 days	9 years 4 months 24 days
Liabilities
Accumulated amortization	$ (31,523)	$ (27,187)
Total	$ 35,076	$ 38,779
Weighted Average Remaining Amortization in Years	14 years 4 months 24 days	13 years 10 months 24 days
Below market leases
Liabilities
Gross	$ 66,599	$ 65,966
Weighted Average Remaining Amortization in Years	14 years 4 months 24 days	13 years 10 months 24 days
In place leases
Assets
Gross	$ 483,001	$ 481,173
Weighted Average Remaining Amortization in Years	9 years 7 months 6 days	9 years 6 months
Tenant relationships
Assets
Gross	$ 146,477	$ 146,893
Weighted Average Remaining Amortization in Years	9 years 9 months 18 days	9 years 8 months 12 days
Above market leases
Assets
Gross	$ 37,779	$ 37,613
Weighted Average Remaining Amortization in Years	6 years	6 years 2 months 12 days