COMMITMENTS AND CONTINGENCIES (Details) ft² in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($) property	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($) property	Nov. 03, 2020	Sep. 10, 2020 ft²	Jun. 15, 2020 ft²	Dec. 31, 2019 USD ($) property	Jun. 13, 2018	Sep. 20, 2017 property
Loss Contingencies [Line Items]
Real estate redevelopment in process		$ 132,400,000		$ 132,400,000
Estimated cost to complete development and redevelopment projects		91,300,000		91,300,000
Insurance coverage, general liability insurance, limit per occurrence		200,000,000		200,000,000
Insurance coverage, rental value insurance, limit per occurrence		500,000,000		500,000,000
Insurance coverage, pollution insurance, limit per occurence		50,000,000		50,000,000
Rental revenue deemed uncollectible				21,464,000	$ 1,107,000
Deferred lease expense		$ 1,000,000.0		$ 1,000,000.0					$ 2,700,000
Puerto Rico
Loss Contingencies [Line Items]
Number of real estate properties		2		2
Puerto Rico | Mall
Loss Contingencies [Line Items]
Number of real estate properties | property			2		2				2		2
Puerto Rico | Hurricane Maria
Loss Contingencies [Line Items]
Insurance coverage, rental value insurance, limit per occurrence		$ 147,000,000		$ 147,000,000
Shopping Center Wilkes-Barre, PA | Tornado | Hurricane Maria
Loss Contingencies [Line Items]
Casualty Gains (Losses)			$ 4,800,000
Gain on Business Interruption Insurance Recovery					$ 300,000
Percentage of Rentable Area Damaged										13.00%
Proceeds from Insurance Settlement, Operating Activities			5,500,000
COVID-19
Loss Contingencies [Line Items]
Rental revenue deemed uncollectible		$ 8,400,000		21,500,000
Rents received, percent		83.00%
Rent deferrals granted, amount		$ 2,600,000		2,600,000
Abatements granted, aggregate amount		800,000		800,000
Allowance for credit loss, writeoff		4,700,000		10,700,000
COVID-19 | Paramus, NJ | Century 21
Loss Contingencies [Line Items]
Rental revenue deemed uncollectible		900,000		2,100,000
Area of real estate property (in sq ft) | ft²							157
Annual rental revenue				4,400,000
Allowance for credit loss, writeoff		2,500,000		2,500,000
COVID-19 | Paramus, NJ | 24 Hour Fitness
Loss Contingencies [Line Items]
Rental revenue deemed uncollectible		500,000		1,300,000
Area of real estate property (in sq ft) | ft²								54
Annual rental revenue				3,100,000
Allowance for credit loss, writeoff		$ 3,500,000		$ 3,500,000
COVID-19 | Subsequent Event
Loss Contingencies [Line Items]
Leasable area, gross, percent						98.00%
Rents received, percent	86.00%
Business Interruption | Hurricane | Puerto Rico | Hurricane Maria
Loss Contingencies [Line Items]
Insurance Settlements Receivable			14,300,000		14,300,000
Loss Contingency, Receivable, Proceeds					3,300,000
Loss Contingency, Insurance Deductible					$ 2,300,000
Gains (Losses) on Business Interruption			$ 8,700,000