Property, Plant and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Jul. 31, 2014	Oct. 31, 2013	Jul. 31, 2013	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2013
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 273,501			$ 348,868	$ 273,501
Accumulated depreciation	103,639			114,823	103,639
Net cash proceeds from land and buildings and improvements	7,352			381	8,699	$ 361
Gain on the sale of land and buildings and improvements	$ 1,888			91	1,897	47
Non-cash impairment charge		$ 710	$ 2,000		$ 710	$ 2,000
Assets Held under Capital Leases
Property, Plant and Equipment [Line Items]
Property, plant and equipment				6,527
Accumulated depreciation				$ 136