Reconciliation of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Oct. 26, 2013		Oct. 27, 2012		Oct. 26, 2013		Oct. 27, 2012
Numerator for basic income (loss) per share:
Net income (loss)	$ 13,229		$ 501		$ (73,793)		$ (39,327)
Less allocation of earnings and dividends to participating securities	(363)
Net income (loss) available to common shareholders	8,608		(3,894)		(82,308)		(47,980)
Net income (loss) available to common shareholders	8,608		(3,894)		(82,308)		(47,980)
Effect of dilutive options
Net income (loss) available to common shareholders	8,608		(3,894)		(82,308)		(47,980)
Denominator for basic income (loss) per share:
Basic weighted average common shares	58,956		58,168		58,862		58,094
Denominator for diluted income (loss) per share:
Basic weighted average common shares	58,956		58,168		58,862		58,094
Preferred shares	0	[1]			0	[1]
Diluted weighted average common shares	58,956		58,168		58,862		58,094
Income (loss) per common share
Basic	$ 0.15		$ (0.07)		$ (1.40)		$ (0.83)
Diluted	$ 0.15		$ (0.07)		$ (1.40)		$ (0.83)
Basic Earnings Per Share
Numerator for basic income (loss) per share:
Preferred stock dividends	(3,942)		(3,942)		(7,884)		(7,884)
Accretion of dividends on preferred stock	(316)		(453)		(631)		(769)
Preferred stock dividends	(3,942)		(3,942)		(7,884)		(7,884)
Accretion of dividends on preferred stock	(316)		(453)		(631)		(769)
Diluted Earnings Per Share
Numerator for basic income (loss) per share:
Preferred stock dividends		[1]		[1]		[1]		[1]
Accretion of dividends on preferred stock		[1]		[1]		[1]		[1]
Preferred stock dividends		[1]		[1]		[1]		[1]
Accretion of dividends on preferred stock		[1]		[1]		[1]		[1]

[1] Although the Company was in a net income position during the 13 weeks ended October 26, 2013, the dilutive effect of the Company's convertible preferred shares were excluded from the calculation of income per share using the two-class method because the effect would be antidilutive.