Loss Per Share and Stockholders' Equity (Computations Of Basic And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Jul. 31, 2019	Jul. 31, 2018
Earnings Per Share [Abstract]
Net loss from continuing operations attributable to shareholders	$ (145,724)	$ (148,797)
Amounts allocated to participating securities	(149)	(142)
Net loss from continuing operations attributable to common shareholders	$ (145,873)	$ (148,939)
Basic weighted average common shares (in shares)	202,037	207,673
Potential dilutive shares (in shares)	0	0
Dilutive weighted average common shares (in shares)	202,037	207,673
Basic (in usd per share)	$ (0.72)	$ (0.72)
Diluted (in usd per share)	$ (0.72)	$ (0.72)