Basis of Presentation and Significant Accounting Policies - Additional Information (Details)	3 Months Ended	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2023 USD ($) Segment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Investment in joint venture	$ 393,503,000	$ 132,239,000	$ 393,503,000
Minimum percentage of taxable income distributed to shareholders		90.00%
Income tax expense		$ 1,426,000	3,265,000	$ 3,643,000
Number of reportable segments | Segment		2
111 Sutter Street [Member]
Proportionate share of impairment losses	$ 31,685,000		31,685,000
Taxable REIT Subsidiaries [Member]
Income tax expense		$ 484,000	1,942,000	2,024,000
Deferred income tax expense (benefit)		$ 181,000	$ 101,000	$ 703,000
Minimum [Member]
Estimated useful lives of the assets, years		5 years
Lease term		5 years
Maximum [Member]
Estimated useful lives of the assets, years		40 years
Lease term		15 years