Stock option plan (Schedule of Stock Option Activity) (Details) - Employee Stock Option [Member] - USD ($)			3 Months Ended
	Nov. 10, 2016	Sep. 04, 2014	Jan. 31, 2018
No. of Options Outstanding
Options outstanding beginning of period			$ 267,780
Options granted during period	38,000	246,000
Options forfeited/cancelled during period
Options outstanding end of period			267,780
Options vested and expected to vest			262,280
Options exercisable at end of period			140,260
Weighted Average Exercise Price
Options outstanding beginning of period			$ 18.81
Options granted during period	$ 21.00	$ 18.45
Options forfeited/cancelled during period
Options outstanding end of period			$ 18.81