Variable Interest Entities (Details) - USD ($) $ in Thousands		Jun. 30, 2018	Sep. 30, 2017	Jun. 30, 2017	Sep. 30, 2016
Variable Interest Entity [Line Items]
Real estate properties, net		$ 1,054,484	$ 902,281
Cash and cash equivalents		25,061	12,383	$ 9,795	$ 27,399
Deposits and escrows		23,265	27,839
Other assets		8,573	9,359
Real estate property held for sale		0	8,969
Total Assets	[1]	1,144,605	993,897
Mortgages payable		783,532	697,826
Accounts payable and accrued liabilities		22,554	22,348
Total Liabilities	[1]	843,119	757,192
Real estate properties, net of accumulated depreciation		77,692	64,290
Deferred mortgage costs		7,040	6,727
Variable interest entity
Variable Interest Entity [Line Items]
Real estate properties, net		655,889	707,546
Cash and cash equivalents		7,041	8,626
Deposits and escrows		9,916	13,873
Other assets		6,629	8,148
Real estate property held for sale		0	8,969
Total Assets		679,475	747,162
Mortgages payable		500,912	558,568
Accounts payable and accrued liabilities		10,893	14,419
Total Liabilities		511,805	572,987
Real estate properties, net of accumulated depreciation		53,918	52,873
Mortgages
Variable Interest Entity [Line Items]
Deferred mortgage costs		6,673	6,345
Mortgages | Variable interest entity
Variable Interest Entity [Line Items]
Deferred mortgage costs		$ 4,200	$ 5,170

[1] The Company's consolidated balance sheets include the assets and liabilities of consolidated variable interest entities (VIEs). See note 6. The consolidated balance sheets include the following amounts related to the Company's VIEs as of June 30, 2018 and September 30, 2017, respectively: $655,889 and $707,546 of real estate properties, $7,041 and $8,626 of cash and cash equivalents, $9,916 and $13,873 of deposits and escrows, $6,629 and $8,148 of other assets, $0 and $8,969 of real estate properties held for sale, $500,912 and $558,568 of mortgages payable and $10,893 and $14,419 of accounts payable and accrued liabilities.