Significant Accounting Policies - Narrative - Property, Plant and Equipment (Details)	12 Months Ended
	Apr. 30, 2016
Buildings and improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives of property, plant and equipment	5 years
Buildings and improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives of property, plant and equipment	40 years
Machinery and equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives of property, plant and equipment	3 years
Machinery and equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives of property, plant and equipment	15 years