Reconciliation of Basic and Diluted Income (Loss) Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Jan. 25, 2014	Jan. 26, 2013	Jan. 25, 2014	Jan. 26, 2013
Numerator for basic income (loss) per share:
Net income (loss)	$ 63,230	$ (3,683)	$ (10,564)	$ (43,010)
Allocation of earnings and dividends to participating securities	(2,604)
Net income (loss) available to common shareholders	56,368	(8,364)	(23,336)	(56,343)
Numerator for diluted income (loss) per share:
Net income (loss) available to common shareholders	56,368	(8,364)	(23,336)	(56,343)
Allocation of earnings and dividends to participating securities	2,604
Less diluted allocation of earnings and dividends to participating securities	(2,338)
Effect of dilutive options
Net income (loss) available to common shareholders	60,892	(8,364)	(23,336)	(56,343)
Denominator for basic income (loss) per share:
Basic weighted average common shares	59,033	58,316	58,919	58,168
Denominator for diluted income (loss) per share:
Basic weighted average common shares	59,033	58,316	58,919	58,168
Preferred shares	12,000
Diluted weighted average common shares	71,033	58,316	58,919	58,168
Income (loss) per common share
Basic	$ 0.95	$ (0.14)	$ (0.40)	$ (0.97)
Diluted	$ 0.86	$ (0.14)	$ (0.40)	$ (0.97)
Basic Earnings Per Share
Numerator for basic income (loss) per share:
Preferred stock dividends	(3,942)	(3,942)	(11,825)	(11,825)
Accretion of dividends on preferred stock	(316)	(739)	(947)	(1,508)
Numerator for diluted income (loss) per share:
Preferred stock dividends	3,942	3,942	11,825	11,825
Accretion of dividends on preferred stock	(316)	(739)	(947)	(1,508)
Diluted Earnings Per Share
Numerator for basic income (loss) per share:
Preferred stock dividends	(3,942)
Accretion of dividends on preferred stock	316
Numerator for diluted income (loss) per share:
Preferred stock dividends	3,942
Accretion of dividends on preferred stock	$ 316