Capitalized interest (Details) - USD ($)	3 Months Ended		9 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2016	Jul. 31, 2015
Capitalized interest [Abstract]
Interest capitalized	$ 916,000	$ 667,000	$ 2,611,000	$ 1,600,000