Debt (Details) (USD $)	3 Months Ended		6 Months Ended						0 Months Ended					6 Months Ended				0 Months Ended			0 Months Ended												3 Months Ended
	Jan. 26, 2013	Jan. 28, 2012	Jan. 26, 2013	Jan. 28, 2012	Jul. 28, 2012	Jan. 26, 2013 Senior Loans Credit Agreement, December 3, 2012, Maturing December 2017	Dec. 03, 2012 Senior Loans Credit Agreement, December 3, 2012, Maturing December 2017	Jul. 28, 2012 Senior Loans Credit Agreement, December 3, 2012, Maturing December 2017	Dec. 12, 2012 Senior Subordinated Notes 7.125% Senior Subordinated Notes Due 2021	Jan. 26, 2013 Senior Subordinated Notes 7.125% Senior Subordinated Notes Due 2021	Jul. 28, 2012 Senior Subordinated Notes 7.125% Senior Subordinated Notes Due 2021	Jan. 26, 2013 Capital Leases	Jul. 28, 2012 Capital Leases	Jan. 26, 2013 Revolving Credit Facility Prior Credit Agreement Which Has Been Terminated or Replaced	Dec. 03, 2012 Revolving Credit Facility Prior Credit Agreement Which Has Been Terminated or Replaced	Jul. 28, 2012 Revolving Credit Facility Prior Credit Agreement Which Has Been Terminated or Replaced	Jul. 28, 2012 Revolving Credit Facility Prior Credit Agreement Which Has Been Terminated or Replaced Standby Letters of Credit	Jan. 26, 2013 Revolving Credit Facility Credit Agreement, December 3, 2012, Maturing December 2017	Dec. 03, 2012 Revolving Credit Facility Credit Agreement, December 3, 2012, Maturing December 2017	Jul. 28, 2012 Revolving Credit Facility Credit Agreement, December 3, 2012, Maturing December 2017	Dec. 03, 2012 Revolving Credit Facility Credit Agreement, December 3, 2012, Maturing December 2017 Minimum	Dec. 03, 2012 Revolving Credit Facility Credit Agreement, December 3, 2012, Maturing December 2017 Maximum	Dec. 03, 2012 Revolving Credit Facility Credit Agreement, December 3, 2012, Maturing December 2017 Commercial Letters of Credit Minimum	Dec. 03, 2012 Revolving Credit Facility Credit Agreement, December 3, 2012, Maturing December 2017 Commercial Letters of Credit Maximum	Dec. 03, 2012 Revolving Credit Facility Credit Agreement, December 3, 2012, Maturing December 2017 Swingline Loans Minimum	Dec. 03, 2012 Revolving Credit Facility Credit Agreement, December 3, 2012, Maturing December 2017 Swingline Loans Maximum	Jan. 26, 2013 Revolving Credit Facility Credit Agreement, December 3, 2012, Maturing December 2017 Standby Letters of Credit	Dec. 03, 2012 Revolving Credit Facility Credit Agreement, December 3, 2012, Maturing December 2017 Standby Letters of Credit	Dec. 03, 2012 Revolving Credit Facility Credit Agreement, December 3, 2012, Maturing December 2017 Federal Fund Rate	Dec. 03, 2012 Revolving Credit Facility Credit Agreement, December 3, 2012, Maturing December 2017 Administrative Agent Base Rate Swingline Loans	Dec. 03, 2012 Revolving Credit Facility Credit Agreement, December 3, 2012, Maturing December 2017 Eurodollar Rate Swingline Loans	Dec. 03, 2012 Revolving Credit Facility Credit Agreement, December 3, 2012, Maturing December 2017 One Month LIBOR Rate	Oct. 27, 2012 Fiscal Quarters Ending January 26, 2013 Through April 26, 2014 Credit Agreement, December 3, 2012, Maturing December 2017	Oct. 27, 2012 Fiscal Quarters Ending July 26, 2014 Through April 25, 2015 Credit Agreement, December 3, 2012, Maturing December 2017	Oct. 27, 2012 Fiscal Quarters Ending July 25, 2015 And Thereafter On A Trailing Four Quarter Basis Credit Agreement, December 3, 2012, Maturing December 2017	Oct. 27, 2012 Fiscal Quarters After July 25, 2015 Credit Agreement, December 3, 2012, Maturing December 2017	Jan. 26, 2013 Debt Premium 7.125% Senior Subordinated Notes Due 2021
Debt Instrument [Line Items]
Debt and capital lease obligations	$ 426,283,000		$ 426,283,000		$ 187,574,000	$ 125,000,000		$ 0		$ 277,500,000	$ 187,500,000	$ 0	$ 74,000					$ 20,000,000		$ 0																	$ 281,283,000
Proceeds from issuance of long-term debt									90,000,000
Senior subordinated notes issued under the indenture (in percent)									104.25%
Debt premium	3,800,000		3,800,000							3,783,000	0
Long-term debt, fair value										299,900,000	192,000,000
Revolving Credit Facility
Credit facility amount							125,000,000
Line of credit current borrowing capacity																			275,000,000									150,000,000
Line of credit incremental additional facilities option																			100,000,000
Line of credit, amount outstanding															0
Write-off of deferred financing costs	321,000	0	321,000	0										321,000
Debt, highest referenced basis spread on variable rate, referenced rate (in percent)																													0.50%			1.00%
Debt instrument basis spread on variable rate (in percent)																														1.00%	2.00%
Unutilized Commitment fee (in percent)																		0.35%			0.25%	0.40%	0.75%	1.125%	1.50%	2.25%	2.00%
Debt Iinterest rate at period end (in percent)																		2.21%
Debt periodic payment - year one (in percent)						5.00%
Debt periodic payment - year one						6,300,000
Debt periodic payment - year two (in percent)						7.50%
Debt periodic payment - year two						9,400,000
Debt periodic payment - year three (in percent)						10.00%
Debt periodic payment - year three						12,500,000
Debt periodic payment - year four (in percent)						12.50%
Debt periodic payment - year four						15,600,000
Debt periodic payment - year five (in percent)						11.30%
Debt periodic payment - year five						14,100,000
Debt covenant compliance, consolidated leverage maximum (ratio)																																	3.50	3.25	3.00	3.00
Letters of credit outstanding amount																	38,500,000										44,100,000
Additional borrowing availability																$ 186,500,000		$ 210,900,000
Debt, interest rate (in percent)										7.125%	7.125%