Deferred fee plan (Details) - USD ($)	12 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2018	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	21,000	214,000	$ 365,000
Deferred Fee Plan [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Trustee fee expense	526,000	986,000
Deferred trustee fees	526,000	879,800
Deferred accrued interest	$ 1,091,000	$ 3,188,000
Basis spread on any deferred fee (percentage)	1.50%
Shares issued	29,134	60,148
Dividends payable	$ 0	$ 106,200
Cumulative fees	$ 1,542,000	$ 4,422,000
Deferred Fee Plan [Member] | Robert S. Hekemian [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