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Management agreement, fees and transactions with related party (Details) - USD ($)	1 Months Ended	3 Months Ended			9 Months Ended		12 Months Ended
	Feb. 28, 2018	Jul. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018	Oct. 30, 2013
Related Party Transaction [Line Items]
Asset management fees		$ 655,000		$ 633,000	$ 1,940,000	$ 1,893,000
Consulting fees		15,000		15,000	45,000	19,200
Secured loans receivable		4,000,000	$ 4,000,000		$ 4,000,000
Minimum [Member]
Related Party Transaction [Line Items]
Asset management fees percentage rate					4.00%
Maximum [Member]
Related Party Transaction [Line Items]
Asset management fees percentage rate					5.00%
Damascus 100 members [Member]
Related Party Transaction [Line Items]
Secured notes paid off			1,870,000
Principal amount on notes paid off			1,451,000
Accrued interest payable paid off			419,000
Rotunda 100 members [Member]
Related Party Transaction [Line Items]
Secured loans receivable		4,000,000	4,000,000		$ 4,000,000
Unpaid accrued interest		$ 1,007,000	862,000		$ 1,007,000
Grande Rotunda, LLC [Member]
Related Party Transaction [Line Items]
Ownership by noncontrolling owners (percentage)		40.00%			40.00%
Ownership by parent (percentage)		60.00%			60.00%
Due to affiliate		$ 5,600,000	$ 5,400,000		$ 5,600,000
Damascus Centre, LLC [Member]
Related Party Transaction [Line Items]
Ownership by noncontrolling owners (percentage)		30.00%			30.00%
Ownership by parent (percentage)		70.00%			70.00%
Managing Agent Hekemian & Co [Member]
Related Party Transaction [Line Items]
Asset management fees		$ 643,000		612,000	$ 1,898,000	1,806,000
Leasing commissions and reimbursement of operating expenses		136,000		321,000	447,000	591,000
Sales commissions						522,500
Insurance commissions		80,000		112,000	129,000	161,000
Additional services		0		0	131,250	1,195,000
Grande Rotunda LLC [Member]
Related Party Transaction [Line Items]
Fee amount	$ 900,000					945,000	$ 500,000
Affiliated Entity 1 [Member]
Related Party Transaction [Line Items]
Development fees included in accounts payable	900,000
Hekemian and Resources [Member]
Related Party Transaction [Line Items]
Fee amount	$ 900,000
Robert S. Hekemian [Member]
Related Party Transaction [Line Items]
Trustee fees and related interest payable in stock units		51,000		54,000	164,000	309,000
Consulting fee per month					5,000
Consulting fee quarterly installments					15,000
Robert S. Hekemian, Jr. [Member]
Related Party Transaction [Line Items]
Trustee fees and related interest payable in stock units		93,000		54,000	286,000	96,000
Allan Tubin [Member]
Related Party Transaction [Line Items]
Trustee fees and related interest payable in stock units		8,000		0	14,000	0
David Hekemian [Member]
Related Party Transaction [Line Items]
Trustee fees and related interest payable in stock units		$ 14,000		$ 13,000	$ 41,000	16,000
Grande Rotunda LLC Loan [Member]
Related Party Transaction [Line Items]
Brokerage fee commissions						400,000
Pierre Towers, LLC [Member]
Related Party Transaction [Line Items]
Brokerage fee commissions						240,000
Line of Credit [Member]
Related Party Transaction [Line Items]
Brokerage fee commissions						$ 32,500