Loss Per Share And Stockholders' Equity (Computation Of Basic And Diluted Loss Per Share From Continuing Operations) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2013	Jan. 31, 2012
Loss Per Share And Stockholders' Equity [Abstract]
Net loss from continuing operations attributable to shareholders	$ (16,915)	$ (3,567)	$ (223,764)	$ (245,735)
Income (loss) allocated to participating securities (nonvested shares)	62	(24)	199	152
Net loss from continuing operations attributable to common shareholders	$ (16,977)	$ (3,543)	$ (223,963)	$ (245,887)
Basic weighted average common shares	271,542	292,963	273,281	299,450
Potential dilutive shares
Dilutive weighted average common shares	271,542	292,963	273,281	299,450
Basic	$ (0.06)	$ (0.01)	$ (0.82)	$ (0.82)
Diluted	$ (0.06)	$ (0.01)	$ (0.82)	$ (0.82)