INCOME PROPERTIES - Properties Acquired (Details)	12 Months Ended
	Dec. 31, 2018 USD ($) a ft²	Dec. 31, 2017 USD ($)
Real Estate Operations
Description of properties acquired
Square-Feet | ft²	281,700
Purchase price	$ 106,636,566
Remaining Lease Term	14 years 4 months 24 days
Aspen, Colorado | Single-tenant
Description of properties acquired
Purchase price	$ 28,000,000
2017 acquisitions of income property subject to a lease | Real Estate Operations
Description of properties acquired
Purchase price		$ 79,800,000
2017 acquisitions of income property subject to a lease | Brandon, FL | Single-tenant
Description of properties acquired
Square-Feet | ft²	4,512
2018 acquisitions of income property subject to lease - Master Tenant for Commercial Building | Aspen, Colorado | Single-tenant
Description of properties acquired
Square-Feet | ft²	19,596
Acres | a	0.18
Purchase price	$ 28,000,000
Percentage Leased	100.00%
Remaining Lease Term	20 years
2018 acquisitions of income property subject to lease - Fidelity Investments | Albuquerque, NM | Single-tenant
Description of properties acquired
Square-Feet | ft²	210,067
Acres | a	26.25
Purchase price	$ 44,000,000
Percentage Leased	100.00%
Remaining Lease Term	10 years 2 months 12 days
2018 acquisitions of income property subject to lease - Chase Bank | Jacksonville, FL | Single-tenant
Description of properties acquired
Square-Feet | ft²	3,614
Acres | a	0.73
Purchase price	$ 5,432,500
Percentage Leased	100.00%
Remaining Lease Term	19 years
2018 acquisitions of income property subject to lease - Cheddar's Scratch Kitchen | Jacksonville, FL | Single-tenant
Description of properties acquired
Square-Feet | ft²	8,146
Acres | a	1.05
Purchase price	$ 2,608,017
Percentage Leased	100.00%
Remaining Lease Term	9 years
2018 acquisitions of income property subject to lease - Chuy's | Jacksonville, FL | Single-tenant
Description of properties acquired
Square-Feet | ft²	7,950
Acres | a	1.24
Purchase price	$ 6,086,957
Percentage Leased	100.00%
Remaining Lease Term	13 years 10 months 24 days
2018 acquisitions of income property subject to lease - Firebirds Wood Fired Grill | Jacksonville, FL | Single-tenant
Description of properties acquired
Square-Feet | ft²	6,948
Acres | a	1.03
Purchase price	$ 4,441,080
Percentage Leased	100.00%
Remaining Lease Term	9 years 1 month 6 days
2018 acquisitions of income property subject to lease - Moe's Southwest Grill | Jacksonville, FL | Single-tenant
Description of properties acquired
Square-Feet | ft²	3,111
Acres | a	0.98
Purchase price	$ 2,309,958
Percentage Leased	100.00%
Remaining Lease Term	19 years 2 months 12 days
2018 acquisitions of income property subject to lease - PDQ | Jacksonville, FL | Single-tenant
Description of properties acquired
Square-Feet | ft²	3,366
Acres | a	1.64
Purchase price	$ 2,309,958
Percentage Leased	100.00%
Remaining Lease Term	8 years 9 months 18 days
2018 acquisitions of income property subject to lease - Scrubbles Car Wash | Jacksonville, FL | Single-tenant
Description of properties acquired
Square-Feet | ft²	4,512
Acres | a	1.62
Purchase price	$ 2,491,429
Percentage Leased	100.00%
Remaining Lease Term	19 years 1 month 6 days
2018 acquisitions of income property subject to lease - Wawa | Jacksonville, FL | Single-tenant
Description of properties acquired
Square-Feet | ft²	6,267
Acres | a	2.16
Purchase price	$ 6,666,667
Percentage Leased	100.00%
Remaining Lease Term	19 years 3 months 18 days
2018 acquisitions of income property subject to lease - Macaroni Grill | Arlington, TX | Single-tenant
Description of properties acquired
Square-Feet | ft²	8,123
Acres | a	1.70
Purchase price	$ 2,290,000
Percentage Leased	100.00%
Remaining Lease Term	15 years