Deferred fee plan (Details) (Deferred Fee Plan [Member], USD $)	12 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2012
Deferred Fee Plan [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Trustee fee expense	$ 1,204,000	$ 1,101,000	$ 1,045,000
Deferred trustee fees	5,163,000	4,703,000
Deferred accrued interest	$ 3,854,000	$ 3,110,000
Interest rate on any deferred fee	9.00%
Basis spread on any deferred fee (percentage)	1.50%
Term of distribution to participants	10 years