Reconciliation of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Jul. 27, 2013	Jul. 28, 2012
Numerator for basic income (loss) per share:
Net loss	$ (87,022)	$ (39,828)
Preferred stock dividends	(3,942)	(3,942)
Accretion of dividends on preferred stock	(758)	(316)
Net loss available to common shareholders	(91,722)	(44,086)
Numerator for diluted income (loss) per share:
Net loss available to common shareholders	$ (91,722)	$ (44,086)
Denominator for basic and diluted loss per share:
Basic weighted average common shares	58,768	58,021
Loss per common share:
Basic	$ (1.56)	$ (0.76)
Diluted	$ (1.56)	$ (0.76)