INTANGIBLE ASSETS AND LIABILITIES - Activity (Details)	9 Months Ended
	Sep. 30, 2020 USD ($) property	Mar. 31, 2020 property	Dec. 31, 2019 USD ($)
Intangible Assets And Liabilities
Number of real estate properties | property	1
Net amortization increase (decrease)	$ 788,000
Net increase in intangible assets and liabilities	5,000,000.0
Below market lease value	$ 24,910,921		$ 26,198,248
Single-tenant
Intangible Assets And Liabilities
Number of real estate properties | property	2
2018 acquisitions of income property subject to a lease | Single-tenant
Intangible Assets And Liabilities
Number of real estate properties | property	4
2018 acquisitions of income property subject to a lease | Multi-tenant
Intangible Assets And Liabilities
Number of real estate properties | property	1	2
Wells Fargo property | Raleigh, NC
Intangible Assets And Liabilities
Below market lease value	$ 20,400,000		$ 22,200,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Single-tenant
Intangible Assets And Liabilities
Number of real estate properties | property	3
Value of In-Place Leases
Intangible Assets And Liabilities
Increase from acquisitions	$ 2,200,000
Value of Above Market In-Place Leases
Intangible Assets And Liabilities
Increase from acquisitions	3,500,000
Value of Intangible Leasing Costs
Intangible Assets And Liabilities
Decrease from acquisitions	(1,200,000)
Value of Below Market In-Place Leases
Intangible Assets And Liabilities
Decrease in below-market in-place leases from acquisitions	$ 300,000