Other Assets and Deferred Charges, Net (Components of Other Assets and Deferred Charges, Net) (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Deferred Costs And Other Assets [Line Items]
Lease origination costs	$ 4,747,000	$ 4,710,000
Right-of-use assets	$ 2,062,000	$ 9,861,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Total other assets and deferred charges, net	Total other assets and deferred charges, net
Prepaid expenses	$ 1,029,000	$ 7,255,000
Investments related to share-based compensation		955,000
Unsecured revolving credit facility financing costs	3,538,000	3,129,000
Leasehold improvements, furniture and fixtures		50,000
Other	86,000	(188,000)
Total other assets and deferred charges, net	7,924,000	23,777,000
Accumulated amortization of intangible lease assets	10,600,000
Intangible Lease Assets [Member]
Deferred Costs And Other Assets [Line Items]
Deferred charges, net	100,000	100,000
Cost of intangible lease assets	1,800,000	3,100,000
Accumulated amortization of intangible lease assets	$ 1,700,000	3,000,000.0
Unsecured Revolving Credit Facility [Member]
Deferred Costs And Other Assets [Line Items]
Unsecured revolving credit facility financing costs		$ 1,134,000