Summary of Significant Accounting Policies (Narrative) (Details)		12 Months Ended
	Nov. 25, 2020	Dec. 31, 2022 USD ($) Segment	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2017 shares	Jun. 28, 2022	May 01, 2019 shares	Apr. 30, 2019 shares
Summary Of Significant Accounting Policies [Line Items]
VIE real estate owned carrying value		$ 364,110,000	$ 369,827,000
Mortgage loan payable		131,462,000	156,821,000
Depreciation expense, net of discontinued operations		8,500,000	11,100,000	$ 15,200,000
Cash at consolidated joint ventures		0.0	200,000
Uncollectible lease rental revenue		0	200,000	4,100,000
Deferred rent receivables written-off		(300,000)	0	700,000
Allowance for doubtful accounts receivable		2,000,000.0	1,000,000.0
Provision for doubtful accounts included in operating, maintenance and management expenses		$ (300,000)	(600,000)	$ (3,900,000)
Number of reportable segment | Segment		1
Property One [Member]
Summary Of Significant Accounting Policies [Line Items]
Sales revenue percentage		15.80%
2017 Stock Incentive Plan [Member]
Summary Of Significant Accounting Policies [Line Items]
Maximum number of shares may be issued under the plan | shares							909,000	303,000
Maximum number of shares to be granted per year to a participant | shares					76,000
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Real estate investments useful life		3 years
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Real estate investments useful life		40 years
Crossroads II [Member]
Summary Of Significant Accounting Policies [Line Items]
Minority ownership interest percentage						40.00%
Variable Interest Entity, Primary Beneficiary [Member] | Other Ownership Interest [Member]
Summary Of Significant Accounting Policies [Line Items]
VIE real estate owned carrying value			36,200,000
Mortgage loan payable			$ 0
Crossroads II [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Other Ownership Interest [Member]
Summary Of Significant Accounting Policies [Line Items]
Ownership percentage		60.00%
Common Stock [Member]
Summary Of Significant Accounting Policies [Line Items]
Stockholders' equity, reverse stock split, conversion ratio	0.15
Stockholders' equity, reverse stock split		Each 6.6 shares of the Company's issued and outstanding common stock were combined into one share of the Company's common stock.