INCOME PROPERTIES AND LEASES - General Information (Details)		3 Months Ended		6 Months Ended
	Nov. 26, 2019 shares	Jun. 30, 2020 USD ($) ft² property	Jun. 30, 2019 USD ($) ft² property	Jun. 30, 2020 USD ($) ft² property	Jun. 30, 2019 USD ($) ft² property	Mar. 31, 2020 property
Acquisitions of Income Properties
Payments to Acquire Commercial Real Estate				$ 137,235,000	$ 40,559,000
Stock Issuance		$ 109,789	$ 91,115	$ 350,930	$ 363,246
Area of real estate property | ft²		522,681	139,514	522,681	139,514
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate		$ 18,488,912	$ 34,625,173	$ 18,488,912	$ 34,625,173
Aggregate outstanding principal balance		$ 18,320,000	34,570,000	$ 18,320,000	34,570,000
Single-tenant
Acquisitions of Income Properties
Number of real estate properties | property		2		2
2020 dispositions | Single-tenant
Acquisitions of Income Properties
Number of real estate properties		4		4
2020 dispositions | Multi-tenant
Acquisitions of Income Properties
Number of real estate properties		1		1
Ground Lease | 2020 dispositions
Acquisitions of Income Properties
Number of real estate properties		3		3
Carpenter Hotel-400 Josephine Street, Austin, TX
Acquisitions of Income Properties
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate		$ 16,635,073		$ 16,635,073
Aggregate outstanding principal balance		16,250,000		16,250,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations
Acquisitions of Income Properties
Sales price		$ 39,339,138	$ 79,870,000	39,339,138	79,870,000
Gain on Sale				7,428,817	18,681,864
2020 acquisitions of income property subject to lease
Acquisitions of Income Properties
Payments to Acquire Commercial Real Estate				137,200,000
Aggregate acquisition cost including capitalized acquisition costs				$ 137,700,000
2020 acquisitions of income property subject to lease | Multi-tenant
Acquisitions of Income Properties
Number of real estate properties | property		2		2
2020 acquisitions of income property subject to lease | Nonrecurring basis
Acquisitions of Income Properties
Land		$ 46,700,000		$ 46,700,000
Buildings and improvements		74,000,000.0		74,000,000.0
Intangible assets pertaining to the in-place lease value, leasing fees and above market lease value		18,800,000		18,800,000
Intangible liabilities for below market lease value		$ 1,800,000		$ 1,800,000
Alpine
Acquisitions of Income Properties
Units issued | shares	2,040,000.00
Percentage of investment in PINE	23.50%	23.50%		23.50%
Alpine | OP Units
Acquisitions of Income Properties
Units issued | shares	1,223,854
2019 acquisitions of income property subject to lease
Acquisitions of Income Properties
Payments to Acquire Commercial Real Estate					40,600,000
Aggregate acquisition cost including capitalized acquisition costs					$ 40,900,000
Amount allocated of total acquisition cost
Weighted average amortization period of intangible assets					9 years 6 months
2019 acquisitions of income property subject to lease | Single-tenant
Acquisitions of Income Properties
Number of real estate properties | property			5		5
2019 acquisitions of income property subject to lease | Nonrecurring basis
Acquisitions of Income Properties
Land			$ 16,300,000		$ 16,300,000
Buildings and improvements			20,500,000		20,500,000
Intangible assets pertaining to the in-place lease value, leasing fees and above market lease value			4,400,000		4,400,000
Intangible liabilities for below market lease value			$ 300,000		$ 300,000
2018 acquisitions of income property subject to a lease | Single-tenant
Acquisitions of Income Properties
Number of real estate properties | property		4		4
2018 acquisitions of income property subject to a lease | Multi-tenant
Acquisitions of Income Properties
Number of real estate properties | property		1		1		2