FAIR VALUE MEASUREMENTS - Long-Lived Assets Measured at Fair Value (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) mall vacantlandparcel	Dec. 31, 2019 USD ($) mall community_center	Dec. 31, 2018 USD ($) mall
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment	$ 213,358	$ 239,521	$ 174,529
Number of malls with impairment \| mall	6	6	5
Number of vacant land parcel \| vacantlandparcel	1
Long-lived assets	$ 268,830	$ 199,740	$ 91,841
Number of community center with impairment \| community_center		1
Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment	$ 213,358
Number of malls with impairment \| mall	6
Long-lived assets	$ 268,830
Burnsville Center \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment	26,562
Long-lived assets	$ 47,300
Burnsville Center \| Malls \| Measurement Input, Expected Term
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Holding period	10 years
Burnsville Center \| Malls \| Cap Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)	14.5
Burnsville Center \| Malls \| Discount Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)	15.5
Monroeville Mall \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment	$ 107,082
Long-lived assets	$ 67,000
Monroeville Mall \| Malls \| Measurement Input, Expected Term
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Holding period	10 years
Monroeville Mall \| Malls \| Cap Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)	14.0
Monroeville Mall \| Malls \| Discount Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)	14.5
Asheville Mall \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment	$ 13,274
Long-lived assets	$ 52,600
Asheville Mall \| Malls \| Measurement Input, Expected Term
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Holding period	10 years
Asheville Mall \| Malls \| Cap Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)	13.25
Asheville Mall \| Malls \| Discount Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)	14.0
Vacant Land \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment	$ 46
EastGate Mall \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment	5,980	$ 33,265
Long-lived assets	$ 16,530	$ 25,100
EastGate Mall \| Malls \| Measurement Input, Expected Term
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Holding period	10 years	10 years
EastGate Mall \| Malls \| Cap Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)	17.0	14.5
EastGate Mall \| Malls \| Discount Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)	18.0	15.0
Greenbrier Mall \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment	$ 8,923	$ 22,770
Long-lived assets	$ 42,500	$ 56,300
Greenbrier Mall \| Malls \| Measurement Input, Expected Term
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Holding period	10 years	10 years
Greenbrier Mall \| Malls \| Cap Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)	12.5	11.5
Greenbrier Mall \| Malls \| Discount Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)	13.0	11.5
The Outlet Shoppes at Laredo \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment	$ 51,491
Long-lived assets	$ 42,900
The Outlet Shoppes at Laredo \| Malls \| Measurement Input, Expected Term
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Holding period	10 years
The Outlet Shoppes at Laredo \| Malls \| Cap Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)	8.5
The Outlet Shoppes at Laredo \| Malls \| Discount Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)	9.0
Honey Creek Mall \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment		$ 2,045	48,640
Long-lived assets			$ 16,400
Assets book value		14,360
Honey Creek Mall \| Malls \| Measurement Input, Expected Term
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Holding period			10 years
Honey Creek Mall \| Malls \| Cap Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)			18.0
Honey Creek Mall \| Malls \| Discount Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)			20.0
The Forum at Grandview \| All Other
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment		8,582
Assets book value		31,559
Mid Rivers Mall \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment		83,621
Long-lived assets		$ 53,340
Mid Rivers Mall \| Malls \| Measurement Input, Expected Term
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Holding period		10 years
Mid Rivers Mall \| Malls \| Cap Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)		12.5
Mid Rivers Mall \| Malls \| Discount Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)		13.25
Laurel Park Place \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment		$ 52,067
Long-lived assets		$ 26,000
Laurel Park Place \| Malls \| Measurement Input, Expected Term
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Holding period		10 years
Laurel Park Place \| Malls \| Cap Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)		13.5
Laurel Park Place \| Malls \| Discount Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)		14.0
Park Plaza Mall \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment		$ 37,400
Long-lived assets		$ 39,000
Park Plaza Mall \| Malls \| Measurement Input, Expected Term
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Holding period		10 years
Park Plaza Mall \| Malls \| Cap Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)		13.0
Park Plaza Mall \| Malls \| Discount Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)		14.0
Prior Sales Adjustment \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment		$ (229)
Janesville Mall \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment			$ 18,061
Assets book value			17,640
Cary Towne Center \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment			54,678
Long-lived assets			$ 30,971
Cary Towne Center \| Malls \| Measurement Input, Expected Term
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Holding period			10 years
Cary Towne Center \| Malls \| Cap Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)			12.0
Cary Towne Center \| Malls \| Discount Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)			13
D'Ibervilee, MS - Land \| All Other
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment			$ 14,598
Long-lived assets			8,100
Assets book value			8,100
Acadania Mall - Macy's & Land \| Malls And All Other
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment			1,593
Long-lived assets			3,920
Assets book value			3,920
Eastland Mall \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment			36,525
Long-lived assets			$ 26,450
Eastland Mall \| Malls \| Measurement Input, Expected Term
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Holding period			10 years
Eastland Mall \| Malls \| Cap Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)			15.0
Eastland Mall \| Malls \| Discount Rate (as a percent)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value measurement input (as a percent)			17.0
Pavilion at Port Orange - Land \| All Other
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment			$ 434
Long-lived assets			$ 6,000