FAIR VALUE MEASUREMENTS - Long-Lived Assets Measured at Fair Value (Details)	1 Months Ended				3 Months Ended			12 Months Ended
	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Jan. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) community_center	Dec. 31, 2018 USD ($)	Jun. 30, 2018 USD ($)	Dec. 31, 2019 USD ($) mall community_center	Dec. 31, 2018 USD ($) mall	Dec. 31, 2017 USD ($) mall outparcel	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Jun. 30, 2017 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on impairment								$ 239,521,000	$ 174,529,000	$ 71,401,000
Number of malls with impairment \| mall								6	5	2
Number of community center with impairment \| community_center					1			1
Long-lived assets	$ 91,841,000				$ 199,740,000	$ 91,841,000		$ 199,740,000	$ 91,841,000	$ 81,350,000
Number of stores with Impairment (outparcel) \| outparcel										1
Loss on Impairment										$ 71,285,000
Greenbrier Mall \| Malls
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on impairment								22,770,000
Long-lived assets					56,300,000			56,300,000
Honey Creek Mall
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on impairment						48,640,000
Honey Creek Mall \| Malls
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on impairment	48,640,000							2,045,000
Long-lived assets	16,400,000					16,400,000			16,400,000			$ 14,360,000
Investment in consolidated joint venture, fair value	$ 16,400,000					$ 16,400,000			$ 16,400,000
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)	0.180					0.180			0.180
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)	0.200					0.200			0.200
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
The Forumat Grandview \| All Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on impairment								8,582,000
Long-lived assets											$ 31,559,000
Eastgate Mall \| Malls
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on impairment								33,265,000
Long-lived assets					$ 25,100,000			$ 25,100,000
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)					0.145			0.145
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)					0.150			0.150
Eastgate 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
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on impairment								$ 83,621,000
Long-lived assets					$ 53,340,000			$ 53,340,000
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)					0.125			0.125
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)					0.1325			0.1325
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
Laurel Park Place \| Malls
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on impairment								$ 52,067,000
Long-lived assets					$ 26,000,000			$ 26,000,000
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)					0.135			0.135
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)					0.140			0.140
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
Park Plaza Mall
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on impairment					$ 37,400,000
Park Plaza Mall \| Malls
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on impairment								$ 37,400,000
Long-lived assets					$ 39,000,000			$ 39,000,000
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)					0.130			0.130
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)					0.140			0.140
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
Prior Sales Adjustment \| Malls
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on impairment								$ (229,000)
Prior Sales Adjustment \| Malls And All Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on Impairment										606,000
Greenbrier Mall \| Measurement Input, Expected Term
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Holding period					10 years
Greenbrier Mall \| Malls
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-lived assets					$ 56,300,000			$ 56,300,000
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)					11.5			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)					11.5			11.5
Janesville Mall \| Malls
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on impairment				$ 18,061,000
Investment in consolidated joint venture, fair value			$ 17,640,000				$ 17,640,000
Cary Towne Center
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on impairment						$ 2,693,000	$ 51,983,000
Cary Towne Center \| 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)			0.13				0.13
Cary Towne Center \| 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
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on impairment			$ 54,678,000
Long-lived assets	$ 30,971,000		$ 30,971,000			30,971,000	$ 30,971,000		$ 30,971,000
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)			0.120				0.120
D'Ibervilee, MS - Land \| Malls And All Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on impairment		$ 14,598,000
Long-lived assets		$ 8,100,000
Investment in consolidated joint venture, fair value					$ 8,100,000			$ 8,100,000
Acadania Mall - Macy's & Land \| Malls
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on impairment	1,593,000
Long-lived assets	3,920,000					3,920,000			3,920,000
Eastland Mall
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on impairment						36,525,000
Eastland Mall \| Malls
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on impairment	36,525,000
Long-lived assets	26,450,000					26,450,000			26,450,000
Investment in consolidated joint venture, fair value	26,450,000					26,450,000			$ 26,450,000
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)			0.150				0.150
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)			0.170				0.170
Eastland Mall \| Malls \| Measurement Input, Expected Term
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Holding period									10 years
Pavilion at Port Orange - Land \| Malls And All Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss on impairment	434,000
Long-lived assets	6,000,000					6,000,000			$ 6,000,000
Acadiana Mall \| Malls
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-lived assets	3,920,000					3,920,000			3,920,000	67,300,000			$ 67,300,000
Investment in consolidated joint venture, fair value	$ 3,920,000					$ 3,920,000			$ 3,920,000				$ 67,300,000
Loss on Impairment										$ 43,007,000
Acadiana 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)										0.155
Acadiana 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)										0.1575
Acadiana Mall \| Malls \| Measurement Input, Expected Term
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Holding period										10 years
Woodstock, GA - Land \| Malls
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in consolidated joint venture, fair value										$ 1,000,000
Loss on Impairment										3,147,000
Hickory Point Mall \| Malls
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-lived assets										14,050,000
Loss on Impairment										$ 24,525,000
Hickory Point 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
Hickory Point 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)										19.0
Hickory Point Mall \| Malls \| Measurement Input, Expected Term
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Holding period										10 years
Outparcel Sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-cash impairment of long-lived asset										$ 116,000
Number of properties disposed of (property) \| outparcel										1