Real Estate - Acquisitions (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2020 USD ($) a	Dec. 31, 2020 USD ($) a	Dec. 31, 2019 USD ($)
The RailYard
Business Acquisition [Line Items]
Payments to acquire businesses, gross		$ 201,300
Tangible assets:
Operating properties		201,153
Tangible assets		201,153
Intangible assets:
Total intangible assets		9,289
Intangible liabilities:
Total intangible liabilities		(9,129)
Total net assets acquired		201,313
The RailYard | In-place leases
Intangible assets:
Total intangible assets		8,850
Intangible liabilities:
Total intangible liabilities		(9,129)
The RailYard | Above market leases
Intangible assets:
Total intangible assets		439
Parking Garage In Charlotte, North Carolina
Business Acquisition [Line Items]
Payments to acquire businesses, gross		$ 85,300
Area of property | a	1,550	1,550
South End Submarket Of Charlotte Land Purchase, 3.4 Acres
Business Acquisition [Line Items]
Payments to acquire businesses, gross	$ 28,100
Area of property | a	3.4	3.4
South End Submarket Of Charlotte Land Purchase, 2.4 Acres
Business Acquisition [Line Items]
Payments to acquire businesses, gross	$ 18,800
Area of property | a	2.4	2.4
1200 Peachtree
Tangible assets:
Building and improvements			$ 62,836
Land and improvements			19,495
Tangible assets			82,331
Intangible assets:
Total intangible assets			9,969
Intangible liabilities:
Total intangible liabilities			0
Total net assets acquired			92,300
1200 Peachtree | In-place leases
Intangible assets:
Total intangible assets			9,969
Intangible liabilities:
Total intangible liabilities			0
1200 Peachtree | Above market leases
Intangible assets:
Total intangible assets			0
Terminus
Tangible assets:
Building and improvements			410,826
Land and improvements			49,345
Tangible assets			460,171
Intangible assets:
Total intangible assets			31,867
Intangible liabilities:
Total intangible liabilities			(4,745)
Total net assets acquired			487,293
Terminus | In-place leases
Intangible assets:
Total intangible assets			24,674
Intangible liabilities:
Total intangible liabilities			(4,745)
Terminus | Above market leases
Intangible assets:
Total intangible assets			$ 7,193