REAL ESTATE INVESTMENTS - Held for Use Impairment and Sale (Narrative) (Details)	12 Months Ended
	Dec. 31, 2021 USD ($) a parcel	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jan. 20, 2022 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of properties held for use	$ 0	$ 0	$ 0
Assets held for sale, net	562,000	$ 7,349,000
Held for Sale Properties Included in Continuing Operations | Other Land
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale, net	$ 600,000
Held for Sale Properties Included in Continuing Operations | Other Land | Subsequent Event
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Aggregate sales price				$ 1,600,000
Held for Sale Properties Included in Continuing Operations | Other Land | Other
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of land parcels | parcel	2
Land area | a	10.0