Real Estate Investments - Textual (Details) $ in Thousands		3 Months Ended		9 Months Ended
	Feb. 02, 2021 USD ($)	Sep. 30, 2021 USD ($) a parcel	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) a parcel	Sep. 30, 2020 USD ($)	Feb. 02, 2021 ft²	Feb. 02, 2021 a	Dec. 31, 2020 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Investment in real estate ventures		$ 427,411		$ 427,411				$ 389,811
Net gain on sale of undepreciated real estate		910	$ 0	2,903	$ 201
Assets held for sale, net		562		562				$ 7,349
Held-for-sale | Other - Land
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale, net		$ 600		$ 600
Held-for-sale | Other - Land | Other
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of land (in acres) | a		10.0		10.0
Number of parcels of land | parcel		2		2
3025 JFK Venture
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Lease agreement term	99 years
Area of land (in acres)						1	1
Investment in real estate ventures	$ 34,800
Net gain on sale of undepreciated real estate	$ 2,000