1. Summary of Accounting Policies (Details)	12 Months Ended
	Apr. 30, 2017
Certification Marks [Member]
1. Summary of Accounting Policies (Details) [Line Items]
Finite-Lived Intangible Asset, Useful Life	3 years
Building [Member]
1. Summary of Accounting Policies (Details) [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Other Depreciable Assets [Member] | Minimum [Member]
1. Summary of Accounting Policies (Details) [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Other Depreciable Assets [Member] | Maximum [Member]
1. Summary of Accounting Policies (Details) [Line Items]
Property, Plant and Equipment, Useful Life	10 years