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		6 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
Earnings Per Share [Abstract]
Net loss from continuing operations attributable to shareholders	$ (170,937)	$ (148,312)	$ (319,734)	$ (276,130)
Amounts allocated to participating securities	(144)	(161)	(286)	(321)
Net loss from continuing operations attributable to common shareholders	$ (171,081)	$ (148,473)	$ (320,020)	$ (276,451)
Basic weighted average common shares (in shares)	205,520	209,065	206,596	208,500
Potential dilutive shares (in shares)	0	0	0	0
Dilutive weighted average common shares (in shares)	205,520	209,065	206,596	208,500
Basic (in usd per share)	$ (0.83)	$ (0.71)	$ (1.55)	$ (1.33)
Diluted (in usd per share)	$ (0.83)	$ (0.71)	$ (1.55)	$ (1.33)