Intangible Assets and Liabilities - Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Intangible Assets [Line Items]
Intangible assets, total cost	$ 90,169	$ 94,173
Intangible assets, accumulated amortization	(46,286)	(45,603)
Intangible assets, net	43,883	48,570
Intangible liabilities, total cost	30,736	31,263
Intangible liabilities, accumulated amortization	(13,663)	(12,815)
Intangible liabilities, net	17,073	18,448
In-place lease value
Intangible Assets [Line Items]
Intangible assets, total cost	87,946	91,552
Intangible assets, accumulated amortization	(44,427)	(43,400)
Intangible assets, net	43,519	48,152
Tenant relationship value
Intangible Assets [Line Items]
Intangible assets, total cost	1,737	2,091
Intangible assets, accumulated amortization	(1,615)	(1,938)
Intangible assets, net	122	153
Above market leases acquired
Intangible Assets [Line Items]
Intangible assets, total cost	486	530
Intangible assets, accumulated amortization	(244)	(265)
Intangible assets, net	$ 242	$ 265