Legal Proceedings (Details) (USD $)	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Dec. 29, 2005	Jul. 28, 2012	Jul. 30, 2011	Jul. 28, 2012	Jul. 30, 2011	Feb. 02, 2008	Jan. 28, 2012	Apr. 30, 2011	Dec. 10, 2010	Dec. 14, 2007
Legal Proceedings (Textual) [Abstract]
Minimum estimated undiscounted costs of preparing RIFS for remedial alternatives		$ 0
Maximum estimated undiscounted costs of preparing RIFS for remedial alternatives		24,000,000
Present worth for remedy of a combination of groundwater extraction and treatment and in-site chemical oxidation		10,700,000		10,700,000
Minimum historical cost associated with enhanced treatment required by the impact of groundwater plume		1,800,000
Maximum historical cost associated with enhanced treatment required by the impact of groundwater plume		2,500,000
Future operation and maintenance costs		126,400
Minimum amount of complaint under number of state law theories										41,000,000
Period of complaint under number of state law theories						70
Company's maximum share in cost sharing agreements and consent decrees	250,000
Amount related to outstanding environmental contingencies		12,300,000		12,300,000			13,000,000	14,200,000
Pretax accruals for environmental contingencies included in provision for discontinued operations		100,000	1,200,000	400,000	1,600,000
Approximate claims asserted against the company's acquiring bank									$ 15,400,000