Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Jul. 31, 2016	Jul. 31, 2015
Property, Plant and Equipment [Abstract]
Equipment	$ 74,030	$ 77,126
Land and buildings	61,407	60,703
Computer software	67,651	59,839
Leasehold improvements	1,745	1,739
Furniture and fixtures	1,473	3,869
Property, plant and equipment, gross	206,306	203,276
Less accumulated depreciation and amortization	(118,932)	(111,960)
Property, plant and equipment, net	$ 87,374	$ 91,316