Deferred fee plan (Details) - USD ($)	12 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017	Dec. 31, 2019
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Dividends payable	$ 1,357,000	$ 338,000
Robert S. Hekemian [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Trustee fee expense	214,000	365,000	$ 538,000
Deferred Fee Plan [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Trustee fee expense	986,000	805,800
Deferred trustee fees	879,800	784,000
Deferred accrued interest	$ 3,188,000	$ 3,576,000
Basis spread on any deferred fee (percentage)	1.50%
Shares issued	60,148	51,109
Dividends payable	$ 106,200	$ 21,800
Cumulative fees	$ 4,422,000	$ 4,881,000
Deferred Fee Plan [Member] | Robert S. Hekemian [Member] | Subsequent Event [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Lump sum accrued plan benefits payable related party				$ 4,800,000