Common Stock Stock Split (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Apr. 30, 2017	Apr. 30, 2016
Class of Stock [Line Items]
Adjustments to Additional Paid in Capital, Stock Split	$ 0
Common stock, par value	$ 0.15
Common stock, Class A, voting [Member]
Class of Stock [Line Items]
Common stock, shares authorized	170,000,000	85,000,000
Common stock, shares issued	170,000,000	85,000,000
Common stock, par value	$ 0.15	$ 0.15
Common Stock, Class B, nonvoting [Member]
Class of Stock [Line Items]
Common stock, shares authorized	400,000,000
Common stock, shares issued	284,626,000	142,313,000
Common stock, par value	$ 0.15	$ 0.15
Additional Paid-in Capital [Member]
Class of Stock [Line Items]
Adjustments to Additional Paid in Capital, Stock Split	$ 34