Deferred fee plan (Details) - USD ($)	3 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Oct. 31, 2018
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Dividends payable	$ 1,014,000		$ 338,000
Deferred Fee Plan [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Trustee fee expense	238,200	201,000
Deferred trustee fees	$ 212,600	$ 201,000
Basis spread on any deferred fee (percentage)	1.50%
Term of distribution to participants	10 years
Shares issued	15,204	13,289
Dividends payable	$ 25,600	$ 0