Stockholders' Equity - Additional Information (Detail) (USD $)	12 Months Ended				12 Months Ended								12 Months Ended
	Apr. 28, 2012 Hour	Apr. 30, 2011	Mar. 31, 2011	Dec. 31, 2007	Apr. 28, 2012 Minimum Year	Apr. 28, 2012 Maximum Year	Apr. 28, 2012 Thompson	Apr. 30, 2011 Thompson	Apr. 24, 2010 Thompson	Apr. 28, 2012 1990 Note	Apr. 30, 2011 1990 Note	Apr. 24, 2010 1990 Note	Apr. 28, 2012 2006 Notes	Apr. 30, 2011 2006 Notes
Shareholders Equity [Line Items]
Common stock repurchased and retired, shares	11,954,257	3,257,374
Common stock repurchased and retired, value	$ 361,047,000	$ 98,960,000
Average cost of common shares repurchased and retired	$ 30.20	$ 30.38
Shares authorized for repurchase under share repurchase program				25,000,000
Number of shares repurchased to date			20,500,000
Additional shares authorized for repurchase under repurchase program			25,000,000
Remaining shares available under repurchase program	11,136,742
Stock repurchase program, expiration date	Mar. 15, 2016
ESOP company loan										22,000,000			105,000,000
Hours of service completed in order to be allocated shares of stock acquired by plan	1,000
Shares secured with an aggregate cost							298,000	81,000	111,000		1,635,000	1,615,000	458,000	397,000
Additional loan to ESOP							12,612,000
ESOP acquiring shares during acquisition							665,978						3,159,645
Interest due from ESOP							200,000
Total shares allocated to ESOP							97,810
Remaining shares in ESOP							568,168
Number of shares allocated to ESOP	14,432,446
Number of shares allocated to ESOP, fair value	490,600,000
Committed-to-be-released shares							9,569						14,730
Suspense shares							473,669						3,131,694
Unearned shares held by ESOP to occur over a period (in years)					10	15
Fair value of unearned shares by ESOP	$ 122,500,000