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, 2012	Jan. 31, 2011	Jan. 31, 2012	Jan. 31, 2011
Loss Per Share And Stockholders' Equity [Abstract]
Net loss from continuing operations attributable to shareholders	$ (3,567)	$ (11,034)	$ (245,735)	$ (250,286)
Amounts allocated to participating securities (nonvested shares)	24	(148)	(152)	(142)
Net loss from continuing operations attributable to common shareholders	$ (3,543)	$ (11,182)	$ (245,887)	$ (250,428)
Basic weighted average common shares	292,963	305,144	299,450	310,546
Potential dilutive shares
Dilutive weighted average common shares	292,963	305,144	299,450	310,546
Loss per share from continuing operations:
Basic	$ (0.01)	$ (0.04)	$ (0.82)	$ (0.80)
Diluted	$ (0.01)	$ (0.04)	$ (0.82)	$ (0.80)