DEBT - Schedule of Debt (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Short Term Debt [LineItems]
Total mortgage notes payable	$ 116,815,505
Less unamortized deferred financing costs	(1,990,507)
Net principal	$ 114,824,998
Loan to value ratio (as a percent)	60.00%
Accredo/Walgreen properties
Short Term Debt [LineItems]
Total mortgage notes payable	$ 6,889,730	$ 6,996,469
Contractual interest rate, stated (as a percent)	3.95%
Effective interest rate	3.95%
Dana property
Short Term Debt [LineItems]
Total mortgage notes payable	$ 4,572,030	4,632,398
Contractual interest rate, stated (as a percent)	4.56%
Effective interest rate	4.56%
Six Dollar General properties
Short Term Debt [LineItems]
Total mortgage notes payable	$ 3,834,828	3,885,334
Contractual interest rate, stated (as a percent)	4.69%
Effective interest rate	4.69%
Wyndham property
Short Term Debt [LineItems]
Total mortgage notes payable	$ 5,742,900	5,820,600
Effective interest rate	4.34%
Williams Sonoma property
Short Term Debt [LineItems]
Total mortgage notes payable	$ 4,551,900	4,615,800
Effective interest rate	4.05%
Omnicare property
Short Term Debt [LineItems]
Total mortgage notes payable	$ 4,293,753	4,349,963
Contractual interest rate, stated (as a percent)	4.36%
Effective interest rate	4.36%
Harley property
Short Term Debt [LineItems]
Total mortgage notes payable	$ 6,778,769	6,868,254
Contractual interest rate, stated (as a percent)	4.25%
Effective interest rate	4.25%
Northrop Grumman property
Short Term Debt [LineItems]
Total mortgage notes payable	$ 5,703,258	5,809,367
Contractual interest rate, stated (as a percent)	4.40%
Effective interest rate	4.40%
EMCOR property
Short Term Debt [LineItems]
Total mortgage notes payable	$ 2,875,046	2,911,577
Contractual interest rate, stated (as a percent)	4.35%
Effective interest rate	4.35%
exp US Services property
Short Term Debt [LineItems]
Total mortgage notes payable	$ 3,400,983	3,446,493
Effective interest rate	4.25%
Husqvarna property
Short Term Debt [LineItems]
Total mortgage notes payable	$ 6,379,182	6,379,182
Effective interest rate	4.60%
AvAir property
Short Term Debt [LineItems]
Total mortgage notes payable	$ 14,575,000	14,575,000
Effective interest rate	4.84%
3M property
Short Term Debt [LineItems]
Total mortgage notes payable	$ 8,320,000	8,360,000
Effective interest rate	5.09%
Cummins property
Short Term Debt [LineItems]
Total mortgage notes payable	$ 8,489,200	8,530,000
Effective interest rate	5.16%
24 Hour Fitness
Short Term Debt [LineItems]
Total mortgage notes payable	$ 6,308,926	8,900,000
Contractual interest rate, stated (as a percent)	4.64%
Effective interest rate	4.64%
Texas Health property
Short Term Debt [LineItems]
Total mortgage notes payable	$ 0	4,842,500
Effective interest rate	6.56%
Bon Secours
Short Term Debt [LineItems]
Total mortgage notes payable	$ 5,250,000	5,250,000
Contractual interest rate, stated (as a percent)	5.41%
Effective interest rate	5.41%
Costco
Short Term Debt [LineItems]
Total mortgage notes payable	$ 18,850,000	18,850,000
Contractual interest rate, stated (as a percent)	4.85%
Effective interest rate	4.85%
Husqvarna
Short Term Debt [LineItems]
Contractual interest rate, stated (as a percent)	4.60%
AvAir
Short Term Debt [LineItems]
Contractual interest rate, stated (as a percent)	4.84%
LIBOR | Wyndham property
Short Term Debt [LineItems]
Contractual interest rate, variable (as a percent)	2.05%
LIBOR | Williams Sonoma property
Short Term Debt [LineItems]
Contractual interest rate, variable (as a percent)	2.05%
LIBOR | 3M property
Short Term Debt [LineItems]
Contractual interest rate, variable (as a percent)	2.25%
LIBOR | Cummins property
Short Term Debt [LineItems]
Contractual interest rate, variable (as a percent)	2.25%
LIBOR | Texas Health property
Short Term Debt [LineItems]
Contractual interest rate, variable (as a percent)	4.30%
Treasury Bill Index | exp US Services property
Short Term Debt [LineItems]
Contractual interest rate, stated (as a percent)	3.25%
Minimum | Treasury Bill Index | AvAir
Short Term Debt [LineItems]
Contractual interest rate, stated (as a percent)	4.60%
Maximum | Treasury Bill Index | Husqvarna
Short Term Debt [LineItems]
Contractual interest rate, stated (as a percent)	2.45%
Maximum | Treasury Bill Index | AvAir
Short Term Debt [LineItems]
Contractual interest rate, stated (as a percent)	2.45%
Mortgages
Short Term Debt [LineItems]
Total mortgage notes payable	$ 116,815,505	125,022,937
Less unamortized deferred financing costs	(1,990,507)	(2,313,629)
Net principal	$ 114,824,998	$ 122,709,308
Initial Contractual Interest One | exp US Services property
Short Term Debt [LineItems]
Credit facility interest rate, period start (as a percent)	4.25%