Real Estate Activities - Impairments (Details) - USD ($)	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Real Estate Properties [Line Items]
Impairment of asset	$ 9,938,000	$ 0
Gains (losses) on sales of investment real estate	(1,180,000)	$ 11,444,000
Exton Square Mall
Real Estate Properties [Line Items]
Impairment of asset	$ 8,374,000

The net gain (loss) resulting from sales and other disposals of real estate owned for investment purposes.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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+ Details