Commitments and Contingencies (Details) $ in Thousands		9 Months Ended
	Sep. 30, 2020 USD ($) property	Sep. 30, 2020 USD ($) property	Sep. 30, 2019 USD ($)
Commitments and Contingencies [Line Items]
Amount of letters of credit outstanding	$ 291	$ 291
Number of properties with letters of credit | property	1	1
Aggregate proceeds, net		$ 11,369	$ 44,656
Circle East
Commitments and Contingencies [Line Items]
Redevelopment costs incurred	$ 24,915	24,915
Circle East | Minimum
Commitments and Contingencies [Line Items]
Net estimated redevelopment costs	42,000	42,000
Circle East | Maximum
Commitments and Contingencies [Line Items]
Net estimated redevelopment costs	44,000	44,000
One Loudoun Downtown - Pads G & H
Commitments and Contingencies [Line Items]
Redevelopment costs incurred	53,441	53,441
One Loudoun Downtown - Pads G & H | Minimum
Commitments and Contingencies [Line Items]
Net estimated redevelopment costs	125,000	125,000
One Loudoun Downtown - Pads G & H | Maximum
Commitments and Contingencies [Line Items]
Net estimated redevelopment costs	135,000	135,000
The Shoppes at Quarterfield
Commitments and Contingencies [Line Items]
Redevelopment costs incurred	2,003	2,003
The Shoppes at Quarterfield | Minimum
Commitments and Contingencies [Line Items]
Net estimated redevelopment costs	9,000	9,000
The Shoppes at Quarterfield | Maximum
Commitments and Contingencies [Line Items]
Net estimated redevelopment costs	10,000	10,000
Southlake Town Square - Pad
Commitments and Contingencies [Line Items]
Redevelopment costs incurred	952	952
Southlake Town Square - Pad | Minimum
Commitments and Contingencies [Line Items]
Net estimated redevelopment costs	2,000	2,000
Southlake Town Square - Pad | Maximum
Commitments and Contingencies [Line Items]
Net estimated redevelopment costs	2,500	$ 2,500
Circle East, air rights
Commitments and Contingencies [Line Items]
Aggregate proceeds, net	$ 11,820