Intangible assets (Detail) - USD ($) $ in Thousands	Jan. 31, 2018	Oct. 31, 2017
Intangible Assets [Line Items]
Amortizable intangible assets, net	$ 2,891	$ 3,030
Non-amortizable intangible assets, trade marks	1,237	1,237
Non-compete agreements (estimated lives 3 - 5 years)
Intangible Assets [Line Items]
Amortizable intangible assets, accumulated amortization	(2,323)	(2,186)
Customer relationships (estimated lives 7 - 15 years)
Intangible Assets [Line Items]
Amortizable intangible assets, gross	5,099	5,099
Amortizable intangible assets, accumulated amortization	(27)	(25)
Amortizable intangible assets, net	2,776	2,913
Patents (estimated life 14 years)
Intangible Assets [Line Items]
Amortizable intangible assets, gross	142	142
Amortizable intangible assets, net	$ 116	$ 117