Acquisitions - Estimated Fair Values of Assets and Liabilities Assumed (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) acquisition
Assets
Land and improvements	$ 150,561	$ 80,269
Buildings and improvements	30,932	172,059
Deferred leasing costs and acquisition-related intangible assets	12,063	13,593
Right of use ground lease asset	13,334
Total assets acquired	206,890	265,921
Liabilities
Acquisition-related intangible liabilities	9,950	8,921
Ground lease liability	10,940
Total liabilities assumed	20,890	8,921
Net assets and liabilities acquired	$ 186,000	$ 257,000
Number of acquisitions | acquisition		2
Discount rate	4.79%
Below-market leases acquired	$ 10,000	$ 8,900
Weighted average amortization period of below-market leases	3 years 6 months	9 years 9 months 18 days
In-place leases [Member]
Assets
Deferred leasing costs and acquisition-related intangible assets	$ 9,200	$ 11,800
Liabilities
Weighted average amortization period of above-market leases in years	3 years 3 months 18 days	1 year 3 months 18 days
Deferred leasing costs [Member]
Assets
Deferred leasing costs and acquisition-related intangible assets	$ 2,900	$ 1,800
Liabilities
Weighted average amortization period of above-market leases in years	3 years 6 months	6 years 7 months 6 days