Cash dividend and declared dividends - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2014	Jul. 31, 2015	Jul. 31, 2014
Dividends Payable [Line Items]
Dividends paid, per share	$ 0.07			$ 0.07
Dividends paid		$ 1,800	$ 1,800		$ 1,700	$ 1,700	$ 1,773	$ 1,723