INCOME PROPERTIES - General Information (Details)				12 Months Ended
	Nov. 26, 2019 USD ($) tenant property shares	Jul. 16, 2019 USD ($) Options	Mar. 23, 2019 USD ($) ft²	Dec. 31, 2019 USD ($) ft² Options property shares	Dec. 31, 2018 USD ($) ft² building property	Dec. 31, 2017 USD ($) property	Aug. 07, 2019 USD ($) a	Jun. 24, 2019 USD ($) ft²	Feb. 21, 2019 USD ($) ft²	Mar. 26, 2018 USD ($)	Dec. 31, 2016 USD ($)
Acquisitions of Income Properties
Number of real estate properties | property				34
Payments to Acquire Commercial Real Estate				$ 164,670,000
Number of properties in the disposal group | property					4
Stock Issuance				531,914	$ 238,712	$ 103,136
Gain on sale of properties (in dollars per share)				$ 20.60		3.51
Area of real estate property | ft²				502,626
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate				$ 34,625,173		11,925,699					$ 23,960,467
Aggregate outstanding principal balance				$ 34,570,000
Amount allocated of total acquisition cost
Weighted average amortization period of intangible assets				13 years
Weighted average amortization period of intangible liabilities				13 years
Real Estate Operations
Acquisitions of Income Properties
Payments to Acquire Commercial Real Estate					$ 106,600,000
2019 dispositions
Acquisitions of Income Properties
Number of properties disposed for cash | property	15
Number of properties disposed for units | property	5
Gain on sale of properties (in dollars per share)	$ 0.16
Gain on Sale	$ 1,000,000
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				$ 16,443,942
Aggregate outstanding principal balance				$ 16,250,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | 2019 dispositions | Single-tenant
Acquisitions of Income Properties
Number of properties sold | property				21
Disposal Group, Disposed of by Sale, Not Discontinued Operations | 2019 dispositions | Multi-tenant
Acquisitions of Income Properties
Number of properties sold | property					3
Daytona Beach, FL
Acquisitions of Income Properties
Sales price										$ 11,400,000
Aspen, Colorado
Acquisitions of Income Properties
Payments to Acquire Commercial Real Estate					$ 28,000,000
Alpine
Acquisitions of Income Properties
Units issued | shares	2,040,000
Percentage of investment in PINE	22.30%			22.30%
Alpine | 2019 dispositions
Acquisitions of Income Properties
Units issued | shares	2,040,000
Alpine | 2019 dispositions | Single-tenant
Acquisitions of Income Properties
Number of properties in the disposal group | tenant	20
Alpine | OP Units
Acquisitions of Income Properties
Sales price	$ 125,900,000
Units issued | shares	1,223,854			1,223,854
Stock Issuance	$ 23,300,000			$ 23,300,000
Alpine | OP Units | 2019 dispositions
Acquisitions of Income Properties
Stock Issuance	$ 15,500,000
Alpine | Common Stock | 2019 dispositions
Acquisitions of Income Properties
Units issued | shares	815,790
Percentage of investment in PINE	22.30%
2019 acquisitions of income property subject to lease
Acquisitions of Income Properties
Aggregate acquisition cost including capitalized acquisition costs				$ 165,700,000
Amount allocated of total acquisition cost
Weighted average amortization period of intangible assets				9 years 8 months 12 days
Weighted average amortization period of intangible liabilities				9 years 8 months 12 days
2019 acquisitions of income property subject to lease | Single-tenant
Acquisitions of Income Properties
Number of real estate properties | property				10
2019 acquisitions of income property subject to lease | Multi-tenant
Acquisitions of Income Properties
Number of real estate properties | property				1
2019 acquisitions of income property subject to lease | Nonrecurring basis
Acquisitions of Income Properties
Land				$ 45,600,000
Buildings and improvements				83,500,000
Intangible assets pertaining to the in-place lease value, leasing fees and above market lease value				23,400,000
Intangible liabilities for below market lease value				$ 3,100,000
2017 acquisitions of income property subject to a lease
Acquisitions of Income Properties
Payments to Acquire Commercial Real Estate						79,800,000
Aggregate acquisition cost including capitalized acquisition costs						$ 80,600,000
Amount allocated of total acquisition cost
Weighted average amortization period of intangible assets						8 years 10 months 24 days
Weighted average amortization period of intangible liabilities						8 years 10 months 24 days
2017 acquisitions of income property subject to a lease | Single-tenant
Acquisitions of Income Properties
Number of real estate properties | property						4
2017 acquisitions of income property subject to a lease | Multi-tenant
Acquisitions of Income Properties
Number of real estate properties | property						2
2017 acquisitions of income property subject to a lease | Nonrecurring basis
Acquisitions of Income Properties
Land						$ 28,000,000
Buildings and improvements						45,200,000
Intangible assets pertaining to the in-place lease value, leasing fees and above market lease value						9,300,000
Intangible liabilities for below market lease value						$ 1,900,000
2018 acquisitions of income property subject to a lease | Real Estate Operations
Acquisitions of Income Properties
Aggregate acquisition cost including capitalized acquisition costs					$ 107,800,000
Amount allocated of total acquisition cost
Weighted average amortization period of intangible assets					13 years 2 months 12 days
Weighted average amortization period of intangible liabilities					13 years 2 months 12 days
2018 acquisitions of income property subject to a lease | Single-tenant
Acquisitions of Income Properties
Number of real estate properties | property				10	11
2018 acquisitions of income property subject to a lease | Multi-tenant
Acquisitions of Income Properties
Number of real estate properties | property				1
2018 acquisitions of income property subject to a lease | Nonrecurring basis | Real Estate Operations
Acquisitions of Income Properties
Land					$ 47,900,000
Buildings and improvements					45,600,000
Intangible assets pertaining to the in-place lease value, leasing fees and above market lease value					15,600,000
Intangible liabilities for below market lease value					$ 1,300,000
Concierge Office Building
Acquisitions of Income Properties
Area of real estate property | ft²					22,012
Williamson Business Park office building
Acquisitions of Income Properties
Gain on sale of properties (in dollars per share)					$ 0.49
Area of real estate property | ft²					15,360
Gain on Sale					$ 3,700,000
Area of real estate property leased | ft²					7,600
Lease term					5 years
Mason Commerce Center
Acquisitions of Income Properties
Area of real estate property | ft²					30,720
Number of office building | building					2
Whole Foods | Sarasota, FL | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Acquisitions of Income Properties
Sales price									$ 24,600,000
Gain on sale of properties (in dollars per share)				$ 0.96
Area of real estate property | ft²									59,000
Gain on Sale				6,900,000
3600 Peterson | Santa Clara, CA | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Acquisitions of Income Properties
Sales price								$ 37,000,000
Gain on sale of properties (in dollars per share)				1.36
Area of real estate property | ft²								76,000
Gain on Sale				9,000,000
The Grove | Winter Park, FL | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Acquisitions of Income Properties
Sales price			$ 18,300,000
Gain on sale of properties (in dollars per share)				0.42
Gain on Sale				2,800,000
Area of real estate property leased | ft²			112,000
Wawa Sale | Winter Park, FL | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Acquisitions of Income Properties
Sales price							$ 2,800,000
Gain on sale of properties (in dollars per share)				0.33
Area of real estate property | a							1.56
Gain on Sale				2,100,000
Beachfront restaurant properties | Daytona Beach, FL | Cocina 214
Acquisitions of Income Properties
Amount funded to tenants		$ 1,000,000
Collection of lease rent		300,000
Payments for Tenant Improvements		$ 693,000
Beachfront restaurant properties | Daytona Beach, FL | Broken Hook LLC
Acquisitions of Income Properties
Lease term		10 years
Option to extend		true
Number of renewal options | Options		4
Renewal term		5 years
2019 acquisitions of income property subject to lease - Carpenter Hotel
Acquisitions of Income Properties
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate				$ 16,250,000
Number Of Tenant Repurchase Options | Options				2