MORTGAGE NOTES AND LOANS PAYABLE (Details Narrative)			12 Months Ended
	Nov. 15, 2019 USD ($)	Mar. 31, 2019	Sep. 30, 2019 USD ($) Properties	Sep. 30, 2018 USD ($) Properties	Sep. 30, 2017 USD ($)
Obligation with Joint and Several Liability Arrangement [Line Items]
Number of properties owned | Properties			114	111
Fixed Rate Mortgage Notes Payable, net of Unamortized Debt Issuance Costs			$ 752,900,000
Mortgage loans on real estate, weighted average interest rate			4.03%	4.07%
Weighted average loan maturity of mortgage notes payable			11.3 years	11.7 years
Loans payable			$ 95,000,000	$ 186,609,000
Interest expense			1,300,000	1,200,000	$ 1,200,000
Subsequent Event [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Unsecured term loan	$ 75,000,000.0
Line of credit, unsecured term loan maximum borrowing capacity	$ 300,000,000.0
Line of credit facility, description	Availability under the New Facility is limited to 60% of the value of the borrowing base properties. The value of the borrowing base properties is determined by applying a capitalization rate to the NOI generated by our unencumbered, wholly-owned industrial properties. Under the New Facility the capitalization rate applied to our NOI generated by our unencumbered, wholly-owned industrial properties was lowered from 6.5% under the Old Facility to 6.25% under the New Facility, thus increasing the value of the borrowing base properties under the terms of the New Facility.
Unsecured revolving line of credit, interest rate description	LIBOR plus 135 basis points to 205 basis points
Unsecured revolving line of credit, BMO interest rate description	BMO’s prime lending rate plus 35 basis points to 105 basis points
Unsecured revolving line of credit, interest rate description on current leverage ratio	LIBOR plus 145 basis points
Loan maturity, term loan	January 2025
Debt instrument interest rate description	The interest rate for borrowings under the Term Loan, at our election, either i) bear interest at LIBOR plus 130 basis points to 200 basis points, depending on our leverage ratio, or ii) bear interest at BMO’s prime lending rate plus 30 basis points to 100 basis points, depending on our leverage ratio.
New Facility [Member] | Subsequent Event [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Line of credit current borrowing capacity	$ 225,000,000.0
Total amount available including the accordion on the line of credit facility	$ 400,000,000.0
Line of credit facility, description	Availability under the New Facility is limited to 60% of the value of the borrowing base properties. The value of the borrowing base properties is determined by applying a capitalization rate to the NOI generated by our unencumbered, wholly-owned industrial properties.
New Revolver [Member] | Subsequent Event [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Loans payable	$ 10,000,000.0
Line of credit facility, description	January 2024 with two options to extend for additional six-month periods, at our option.
Interest rate	3.21%
BMO Capital Markets [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Total amount available including the accordion on the line of credit facility			325,000,000.0
BMO Capital Markets [Member] | Subsequent Event [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Unsecured term loan	$ 75,000,000.0
BMO Capital Markets [Member] | Subsequent Event [Member] | B M O R B C And J P Morgan [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Line of credit current borrowing capacity	$ 225,000,000.0
Line of credit facility, description	January 2024, with two options to extend for additional six-month periods, at our option
BMO Capital Markets [Member] | Old Facility [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Loans payable			95,000,000.0
Line of credit current borrowing capacity			$ 200,000,000.0
Line of credit facility, description			The Old Facility was originally set to mature in September 2020 with a one-year extension at our option
Repayments of lines of credit			$ 65,000,000.0
Line of credit			100,000,000.0
BMO Capital Markets [Member] | New Facility [Member] | Subsequent Event [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Line of credit current borrowing capacity	$ 225,000,000.0
Total amount available including the accordion on the line of credit facility	400,000,000.0
BMO Capital Markets [Member] | Revolving Credit Facility [Member] | Subsequent Event [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Line of credit, unsecured term loan maximum borrowing capacity	300,000,000.0
Old Facility [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Total amount available including the accordion on the line of credit facility			$ 300,000,000.0
Line of credit facility, description			Availability under the Old Facility was limited to 60% of the value of the borrowing base properties. The value of the borrowing base properties was determined by applying a capitalization rate to the NOI generated by our unencumbered, wholly-owned industrial properties. Effective in March 2018, the capitalization rate applied to our NOI generated by our unencumbered, wholly-owned industrial properties was lowered from 7.0% to 6.5%, thus increasing the value of the borrowing base properties under the terms of the Old Facility. Borrowings under the Old Facility, at our election, either i) bore interest at LIBOR plus 140 basis points to 220 basis points, depending on our leverage ratio, or ii) bore interest at Bank of Montreal’s (BMO’s) prime lending rate plus 40 basis points to 120 basis points, depending on our leverage ratio. Our borrowings as of September 30, 2019, based on our leverage ratio as of September 30, 2019, bore interest at LIBOR plus 170 basis points, which was at an interest rate of 3.74% as of September 30, 2019.
Unsecured revolving line of credit, interest rate description			LIBOR plus 140 basis points to 220 basis points
Unsecured revolving line of credit, BMO interest rate description			Bank of Montreal’s (BMO’s) prime lending rate plus 40 basis points to 120 basis points
Unsecured revolving line of credit, interest rate description on current leverage ratio			LIBOR plus 170 basis points
Unsecured line of credit, interest rate			3.74%
RepaidLoans [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Amount repaid on mortgage loans			$ 12,500,000	12,500,000
Term Loan [Member] | Subsequent Event [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Unsecured term loan	$ 75,000,000.0
Term loan, interest rate	2.92%
Term loan, amount outstanding	$ 75,000,000.0
Margin Loans [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Loans payable			$ 0	$ 26,600,000
Percentage of amount available to borrow on margin			50.00%
Percentage of amount available to borrow on margin, interest rate			2.50%	2.75%
Percentage of amount available to borrow on margin, current interest rate			2.25%
Three Mortgages Loans One [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Amortizing mortgage loan period			15 years
Three Mortgages Loans Two [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Amortizing mortgage loan period			15 years
Three Mortgages Loans Three [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Amortizing mortgage loan period			15 years
Three Mortgages Loans [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Mortgage loans on real estate, weighted average interest rate			4.21%
Amount repaid on mortgage loans			$ 89,500,000
Weighted average loan maturity of mortgage notes payable			15 years
Minimum [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Mortgage loans on real estate, weighted average interest rate			3.45%
Minimum [Member] | BMO Capital Markets [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Percentage of capitalization rate		6.50%
Maximum [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Mortgage loans on real estate, weighted average interest rate			6.875%
Maximum [Member] | BMO Capital Markets [Member]
Obligation with Joint and Several Liability Arrangement [Line Items]
Percentage of capitalization rate		7.00%