Deferred fee plan (Details) - USD ($)	12 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2015
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Dividends payable		$ 2,022,000	$ 2,018,000
Deferred Fee Plan [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Trustee fee expense	802,800	683,100
Deferred trustee fees	5,224,000	5,224,000
Deferred accrued interest	$ 3,854,000	$ 3,854,000
Interest rate on any deferred fee	9.00%
Basis spread on any deferred fee (percentage)	1.50%
Term of distribution to participants	10 years
Shares issued	44,548	38,194
Dividends payable	$ 13,000	$ 76,000