Unconsolidated Affiliates and Noncontrolling Interests - Narrative (Details)	1 Months Ended			2 Months Ended	9 Months Ended
	Oct. 31, 2021	Jul. 31, 2021 USD ($)	Mar. 31, 2021	Nov. 15, 2021	Sep. 30, 2021 USD ($) entity	Sep. 30, 2020 USD ($)
Schedule Of Equity Method Investments [Line Items]
Number of entities - equity method of accounting (entity) | entity					31
Number of 50/50 joint ventures | entity					17
Long-lived assets					$ 99,390,000	$ 166,900,000
Gain on deconsolidation					55,131,000
Loans in default, aggregate outstanding balance					727,603,000
Extended Maturity
Schedule Of Equity Method Investments [Line Items]
Debt instrument, maturity date		Dec. 31, 2021
Net proceeds from increase in principal amount of loan		$ 4,349,000
Extended Maturity | Subsequent Event
Schedule Of Equity Method Investments [Line Items]
Debt instrument, maturity date	Oct. 31, 2022
Extended Maturity | LIBOR
Schedule Of Equity Method Investments [Line Items]
Basis spread on variable rate (as a percent)		2.00%
Asheville Mall and Park Plaza
Schedule Of Equity Method Investments [Line Items]
Long-lived assets					0
Gain on deconsolidation					$ 55,131,000
Ambassador Infrastructure, LLC
Schedule Of Equity Method Investments [Line Items]
Loan maturity date					Mar. 31, 2025
Loan agreement term					4 years
Line of credit fixed interest rate					3.00%
Loan outstanding balance					$ 8,250,000
Amount paid in conjunction with modification					$ 1,110,000
Debtors emerged from bankruptcy date					Nov. 01, 2021
Port Orange I, LLC
Schedule Of Equity Method Investments [Line Items]
Loan maturity date			Feb. 28, 2026
Loan agreement term			4 years
Loan outstanding balance					$ 51,998,000
Debtors emerged from bankruptcy date			Nov. 01, 2021
Loan term of extension option			1 year
Shoppes at Eagle Point, LLC | Subsequent Event
Schedule Of Equity Method Investments [Line Items]
Loan maturity date				Oct. 31, 2022
Loan agreement term				1 year
West Melbourne I, LLC
Schedule Of Equity Method Investments [Line Items]
Loan maturity date			Feb. 28, 2026
Loan agreement term			4 years
Loan outstanding balance					53,360,000
Debtors emerged from bankruptcy date			Nov. 01, 2021
Loan term of extension option			1 year
Loans in default, aggregate outstanding balance					$ 622,959,000
Minimum
Schedule Of Equity Method Investments [Line Items]
Ownership interest in joint venture (as a percent)					20.00%
Ownership in variable interest entity (as a percent)					50.00%
Minimum | Extended Maturity
Schedule Of Equity Method Investments [Line Items]
Aggregate principal amount of senior unsecured notes		$ 19,314,000
Maximum
Schedule Of Equity Method Investments [Line Items]
Ownership interest in joint venture (as a percent)					100.00%
Ownership in variable interest entity (as a percent)					92.00%
Maximum | Extended Maturity
Schedule Of Equity Method Investments [Line Items]
Aggregate principal amount of senior unsecured notes		$ 44,400,000