Fair Value Measurements - Long-Lived Assets Measured at Fair Value (Details)	1 Months Ended	3 Months Ended		9 Months Ended
	Jul. 31, 2021 USD ($)	Sep. 30, 2021 USD ($) mall	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) mall outparcel	Sep. 30, 2020 USD ($) mall vacantlandparcel
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-lived assets		$ 99,390,000	$ 166,900,000	$ 99,390,000	$ 166,900,000
Loss on impairment		63,160,000	46,000	$ 120,342,000	$ 146,964,000
Number of malls with impairment \| mall				5	3
Number of stores sold (outparcel) \| outparcel				1
Number of vacant land parcel \| vacantlandparcel					1
Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment		$ 63,160,000	0	$ 120,342,000	$ 146,964,000
Number of malls with impairment \| mall		2		5	3
Eastland Mall \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-lived assets		$ 10,700,000		$ 10,700,000
Loss on impairment				$ 13,243,000
Eastland Mall \| Malls \| Measurement Input, Expected Term
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Holding period				9 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)		14.0		14.0
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)		15.0		15.0
Old Hickory Mall \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-lived assets		$ 12,400,000		$ 12,400,000
Loss on impairment				$ 20,149,000
Old Hickory Mall \| Malls \| Measurement Input, Expected Term
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Holding period				9 years
Old Hickory 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		13.0
Old Hickory 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		14.0
Stroud Mall \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-lived assets		$ 15,400,000		$ 15,400,000
Loss on impairment				$ 23,790,000
Stroud Mall \| Malls \| Measurement Input, Expected Term
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Holding period				9 years
Stroud 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)		11.75		11.75
Stroud 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)		12.5		12.5
The Landing at Arbor Place - Outparcel
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Proceeds from sale of real estate	$ 590,000
The Landing at Arbor Place - Outparcel \| All Other
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-lived assets		$ 590,000		$ 590,000
Loss on impairment				1,682,000
Laurel Park Place \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-lived assets		$ 9,800,000		9,800,000
Loss on impairment				$ 14,267,000
Laurel Park Place \| Malls \| Measurement Input, Expected Term
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Holding period				9 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)		11.5		11.5
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)		13.0		13.0
Parkdale Mall and Crossing \| Malls All Other
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-lived assets		$ 50,500,000		$ 50,500,000
Loss on impairment				47,211,000
Parkdale Mall Parkdale Crossing and Parkdale Anchor \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-lived assets		$ 50,500,000		$ 50,500,000
Parkdale Mall Parkdale Crossing and Parkdale Anchor \| Malls \| Measurement Input, Expected Term
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Holding period				10 years
Parkdale Mall Parkdale Crossing and Parkdale Anchor \| 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)		12.3		12.3
Parkdale Mall Parkdale Crossing and Parkdale Anchor \| 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)		14.2		14.2
Asheville Mall and Park Plaza
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-lived assets		$ 0		$ 0
Burnsville Center \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-lived assets			$ 47,300,000		$ 47,300,000
Loss on impairment					$ 26,562,000
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		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		15.5
Monroeville Mall \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-lived assets			$ 67,000,000		$ 67,000,000
Loss on impairment					$ 107,082,000
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		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		14.5
Asheville Mall \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-lived assets			$ 52,600,000		$ 52,600,000
Loss on impairment					$ 13,274,000
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		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		14.0
Vacant Land \| Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loss on impairment					$ 46,000
Significant Unobservable Inputs (Level 3)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-lived assets		$ 99,390,000	$ 166,900,000	$ 99,390,000	$ 166,900,000