Stock option plan (Schedule of Stock Option Activity) (Details) - Employee Stock Option [Member] - USD ($)			9 Months Ended
	Nov. 10, 2016	Sep. 04, 2014	Jul. 31, 2017
No. of Options Outstanding
Options outstanding beginning of period			$ 229,880
Options granted during period	38,000	246,000	38,000
Options forfeited/cancelled during period			(60)
Options outstanding end of period			267,820
Options vested and expected to vest			262,280
Options exercisable at end of period			84,080
Weighted Average Exercise Price
Options outstanding beginning of period			$ 18.45
Options granted during period	$ 21.00	$ 18.45	21.00
Options forfeited/cancelled during period			18.45
Options outstanding end of period			$ 18.81