DEBT OBLIGATIONS - Mortgage Payable (Details)	12 Months Ended
	Sep. 30, 2018 USD ($) property	Sep. 30, 2017 USD ($)
Debt Instrument [Line Items]
Deferred mortgage costs	$ (6,735,000)	$ (6,727,000)
Total debt obligations	$ 829,470,000	734,844,000
Number of Properties at September 30, 2018 | property	36
Mortgages
Debt Instrument [Line Items]
Debt, long-term and short-term debt, combined amount	$ 798,805,000	704,171,000
Debt face amount	164,310,000	159,559,000
Mortgages | Additional mortgages obtained
Debt Instrument [Line Items]
Debt face amount		7,202,000
Mortgages | Madison, AL | Mortgages Maturing In January 2028
Debt Instrument [Line Items]
Debt face amount	$ 15,000,000
Interest rate (as a percent)	4.08%
Average maturity	60 months
Mortgages | Boerne, TX | Mortgages Maturing In January 2028
Debt Instrument [Line Items]
Debt face amount	$ 9,200,000
Interest rate (as a percent)	2.39%
Average maturity	36 months
Debt interest rate cap (as a percentage)	386.00%
Mortgages | Ocoee, FL | Mortgages Maturing In January 2028
Debt Instrument [Line Items]
Debt face amount	$ 53,060,000
Interest rate (as a percent)	3.90%
Average maturity	84 months
Mortgages | Lawrenceville, GA | Mortgages Maturing In March 2028
Debt Instrument [Line Items]
Debt face amount	$ 54,447,000
Interest rate (as a percent)	3.97%
Average maturity	120 months
Mortgages | Daytona Beach, FL | Mortgages Maturing In May 2025
Debt Instrument [Line Items]
Debt face amount	$ 13,608,000
Interest rate (as a percent)	3.94%
Average maturity	24 months
Mortgages | Grand Prairie, TX | Mortgages Maturing In June 2028
Debt Instrument [Line Items]
Debt face amount	$ 18,995,000
Interest rate (as a percent)	4.37%
Average maturity	60 months
Mortgages | Fredricksburg, VA | Mortgages Maturing in February 2027
Debt Instrument [Line Items]
Debt face amount		$ 27,638,000
Interest rate (as a percent)		3.68%
Mortgages | St. Louis, MO (Tower at OPOP) | Mortgages Maturing in March 2027
Debt Instrument [Line Items]
Debt face amount		$ 20,000,000
Interest rate (as a percent)		4.79%
Average maturity		72 months
Mortgages | St. Louis, MO (Lofts at OPOP) | Mortgages Maturing in March 2027
Debt Instrument [Line Items]
Debt face amount		$ 6,197,000
Interest rate (as a percent)		4.84%
Average maturity		72 months
Mortgages | Creve Coeur, MO | Mortgages Maturing In July 2019
Debt Instrument [Line Items]
Debt face amount		$ 29,000,000
Interest rate (as a percent)		2.50%
Mortgages | Farmers Branch, TX | Mortgages Maturing in July 2028
Debt Instrument [Line Items]
Debt face amount		$ 55,200,000
Interest rate (as a percent)		4.22%
Average maturity		60 months
Mortgages | Tallahassee, FL | Mortgages Maturing in September 2027
Debt Instrument [Line Items]
Debt face amount		$ 21,524,000
Interest rate (as a percent)		4.19%
Average maturity		60 months
Mortgages | Decatur, GA | Mortgages Maturing in December 2022
Debt Instrument [Line Items]
Debt face amount		$ 4,941,000
Interest rate (as a percent)		5.32%
Mortgages | Fredricksburg, VA (Location 2) | Mortgages Maturing in February 2027
Debt Instrument [Line Items]
Debt face amount		$ 2,261,000
Interest rate (as a percent)		4.84%
Junior subordinated notes
Debt Instrument [Line Items]
Debt, long-term and short-term debt, combined amount	$ 37,400,000	$ 37,400,000
Multi-family residential | Mortgages
Debt Instrument [Line Items]
Mortgage debt outstanding	$ 798,805,000
Number of Properties at September 30, 2018 | property	36
Debt, weighted average interest rate (as a percentage)	4.18%
Average maturity	6 years 10 months 24 days