Fair Value Measurements - Long-Lived Assets Measured at Fair Value (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($) mall	Jun. 30, 2021 USD ($) mall	Jun. 30, 2020 USD ($) mall
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-lived assets	$ 38,500,000	$ 166,900,000	$ 38,500,000	$ 166,900,000
Loss on impairment	0	13,274,000	$ 57,182,000	$ 146,918,000
Number of malls with impairment \| mall			3	3
Malls
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-lived assets	38,500,000	166,900,000	$ 38,500,000	$ 166,900,000
Loss on impairment		$ 13,274,000	$ 57,182,000	$ 146,918,000
Number of malls with impairment \| mall		1	3	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
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
Significant Unobservable Inputs (Level 3)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-lived assets	$ 38,500,000	$ 166,900,000	$ 38,500,000	$ 166,900,000