Summary of Significant Accounting Policies - Additional Information (Detail)		12 Months Ended
	Oct. 01, 2021 USD ($)	Dec. 31, 2021 USD ($) Segment Lease	Dec. 31, 2020 USD ($) Lease
Summary of Significant Accounting Policies [Line Items]
Net impact to rental revenues due to the amortization of above market and below market leases		$ 400,000	$ 700,000
Amortization to below market leases		2,524,000	3,247,000
Assets		504,397,000	512,093,000
Liabilities		428,193,000	427,796,000
Revenues		62,181,000	58,355,000
Expenses		35,621,000	32,932,000
Impairment related to long-lived assets		$ 0	0
Number of reportable segments | Segment		1
Aggregate future lease obligations		$ 3,818,000
Incremental borrowing rate	3.86%
Right-of-use asset - operating lease, net	$ 3,104,000	3,042,000	0
Right-of-use liability - operating lease	$ 3,104,000	$ 3,134,000	0
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesMember
Income Tax Holiday, Description		The Company is organized and conducts its operations to qualify as a REIT for Federal income tax purposes. Accordingly, the Company is generally not subject to Federal income taxation on the portion of its distributable income that qualifies as REIT taxable income, to the extent that it distributes at least 90% of its REIT taxable income to its stockholders and complies with certain other requirements as defined in the Code.
Unrecognized tax positions		$ 0	0
Standard maximum deposit insurance amount		250,000
Annual rental lease rent		$ 62,181,000	$ 58,355,000
Customer Concentration Risk [Member] | Sales Revenue Net [Member] | Federal Express [Member]
Summary of Significant Accounting Policies [Line Items]
Number of operating leases | Lease		4	3
Annual rental lease rent		$ 8,600,000	$ 6,500,000
Percentage of rental income		14.00%	11.00%
Customer Concentration Risk [Member] | Sales Revenue Net [Member] | New York [Member]
Summary of Significant Accounting Policies [Line Items]
Number of operating leases | Lease		5	5
Annual rental lease rent		$ 9,600,000	$ 9,500,000
Percentage of rental income		15.00%	16.00%
Accounting Standards Update 2016-02 [Member]
Summary of Significant Accounting Policies [Line Items]
Monthly operating lease cost	$ 27,000
Lease term of contract	10 years
Aggregate future lease obligations		$ 3,800,000
Minimum [Member]
Summary of Significant Accounting Policies [Line Items]
Proportion Of Taxable Income Distributed to stockholders		90.00%	90.00%
Minimum [Member] | Properties and Property Improvements [Member]
Summary of Significant Accounting Policies [Line Items]
Estimated useful life		5 years
Minimum [Member] | Furniture, Fixtures and Equipment [Member]
Summary of Significant Accounting Policies [Line Items]
Estimated useful life		5 years
Maximum [Member] | Properties and Property Improvements [Member]
Summary of Significant Accounting Policies [Line Items]
Estimated useful life		40 years
Maximum [Member] | Furniture, Fixtures and Equipment [Member]
Summary of Significant Accounting Policies [Line Items]
Estimated useful life		10 years
Above Market Lease [Member]
Summary of Significant Accounting Policies [Line Items]
Acquired lease intangible assets, net		$ 300,000	$ 600,000
In-place Lease [Member]
Summary of Significant Accounting Policies [Line Items]
Acquired lease intangible assets, net		5,835,000	7,300,000
Buildings and Improvements [Member]
Summary of Significant Accounting Policies [Line Items]
Real estate under development		0	0
Investments in Unconsolidated Affiliates [Member]
Summary of Significant Accounting Policies [Line Items]
Assets		17,400,000	17,900,000
Liabilities		9,800,000	10,000,000.0
Revenues		1,600,000	1,500,000
Expenses		1,300,000	1,300,000
Other Assets [Member]
Summary of Significant Accounting Policies [Line Items]
Tenant receivables		$ 1,400,000	$ 1,000,000.0