Financing Activity - Mortgage Loan Activity (Details) - USD ($)				1 Months Ended	9 Months Ended
	Oct. 26, 2023	Aug. 25, 2023	May 01, 2023	Jun. 30, 2023	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Debt Instrument [Line Items]
Mortgage loans, carrying value					$ 669,781,000		$ 749,396,000
Cash proceeds from sales of real estate					$ 29,713,000	$ 39,515,000
Cherry Hill Mall
Debt Instrument [Line Items]
Debt instrument, maturity date			Dec. 01, 2023		May 01, 2024
Debt instrument extended maturity period description					This agreement extended the maturity date to December 1, 2023 with a $5.0 million principal paydown at time of execution, and requires the borrower to continue making scheduled monthly debt service payments. The agreement also includes an option to extend the maturity to May 1, 2024 with an additional $5.0 million principal payment.
Principal payment					$ 5,000,000
Cherry Hill Mall | Mortgage Loan | Commercial Real Estate
Debt Instrument [Line Items]
Mortgage loans, carrying value					$ 228,200,000
Required principal paydown			$ 5,000,000
Woodland Mall
Debt Instrument [Line Items]
Debt instrument, maturity date					Oct. 05, 2023
Sale price				$ 4,800,000
Cash proceeds from sales of real estate				$ 3,400,000
Woodland Mall | Subsequent Event [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Nov. 10, 2023
Woodland Mall | Mortgage Loan | Commercial Real Estate
Debt Instrument [Line Items]
Debt instrument, maturity date					Oct. 05, 2023
Mortgage loans, carrying value					$ 100,700,000
Sale price					4,800,000
Cash proceeds from sales of real estate					$ 3,400,000
Dartmouth Mall | Mortgage Loan | Commercial Real Estate
Debt Instrument [Line Items]
Debt instrument, maturity date		Nov. 27, 2023			Apr. 01, 2023
Mortgage loans, carrying value					$ 0
Principal payment		$ 500,000