Impairments (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) ft²	Jun. 30, 2019 USD ($) ft²	Jun. 30, 2020 USD ($) ft²	Jun. 30, 2019 USD ($) ft²
Real Estate Properties [Line Items]
GLA | ft²	200,237	321,382	251,147	479,947
Impairment Charge | $	$ 5,962	$ 6,186	$ 10,560	$ 9,298
30th Street Plaza
Real Estate Properties [Line Items]
GLA | ft²	145,935		145,935
Impairment Charge | $	$ 4,449		$ 4,449
Chamberlain Plaza
Real Estate Properties [Line Items]
GLA | ft²	54,302		54,302
Impairment Charge | $	$ 1,513		$ 1,513
Spring Mall
Real Estate Properties [Line Items]
GLA | ft²			45,920
Impairment Charge | $			$ 4,584
Parcel at Lakes Crossing
Real Estate Properties [Line Items]
GLA | ft²			4,990
Impairment Charge | $			$ 14
Westview Center
Real Estate Properties [Line Items]
GLA | ft²		321,382		321,382
Impairment Charge | $		$ 6,186		$ 6,186
Brice Park
Real Estate Properties [Line Items]
GLA | ft²				158,565
Impairment Charge | $				$ 3,112