REAL ESTATE SALES - Additional Information (Details) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) property	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Real Estate Properties [Line Items]
Gain on sale	$ 0	$ 50,938	$ 20,459	$ 50,938
Disposed of by Sale
Real Estate Properties [Line Items]
Cost and expenses	0	$ 3,295	$ 262	$ 7,399
Anchor Centre | Disposed of by Sale
Real Estate Properties [Line Items]
Number of real estate properties disposed | property			1
Disposal group, consideration	103,500		$ 103,500
Consideration, net of credits	$ 100,500		100,500
Cost and expenses			1,100
Gain on sale			$ 20,500
Hardware Village
Real Estate Properties [Line Items]
Gain on sale					$ 49,500
Hardware Village | Disposed of by Sale
Real Estate Properties [Line Items]
Disposal group, consideration					$ 178,000