Other Assets and Deferred Charges, Net (Components of Other Assets and Deferred Charges, Net) (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020	Jan. 01, 2019
Deferred Costs And Other Assets [Line Items]
Lease origination costs	$ 15,233,000	$ 22,331,000
Right-of-use assets	9,861,000	13,828,000	$ 14,600,000
Prepaid expenses	7,255,000	6,906,000
Investments related to share-based compensation	955,000	948,000
Unsecured revolving credit facility financing costs	3,129,000	2,002,000
Leasehold improvements, furniture and fixtures	50,000	85,000
Other	582,000	534,000
Total other assets and deferred charges, net	35,070,000	45,255,000
Intangible Lease Assets [Member]
Deferred Costs And Other Assets [Line Items]
Deferred charges, net	4,500,000	5,500,000
Cost of intangible lease assets	17,800,000	19,400,000
Accumulated amortization of intangible lease assets	13,300,000	13,900,000
Unsecured Revolving Credit Facility [Member]
Deferred Costs And Other Assets [Line Items]
Unsecured revolving credit facility financing costs	1,134,000	$ 623,000
Accumulated amortization of intangible lease assets	$ 36,300,000