Debt (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	0 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended
	Jan. 02, 2014	Jan. 23, 2015	Jan. 24, 2014	Jan. 23, 2015	Jan. 24, 2014	Jul. 25, 2014	Apr. 25, 2014	Jul. 23, 2014	Apr. 24, 2015
Line of Credit Facility [Line Items]
Long-term Debt		$ 447,991		$ 447,991			$ 459,733
Revolving Credit Facility, Maximum Borrowing Capacity	750,000
Revolving Credit Facility	750,000
Line of Credit Facility, Amount Outstanding	50,000	444,409		444,409
Accordion Option	1,050,000
Credit Facility Unused Capacity Commitment Fee Percentage Low End Of Range	0.15%
Credit Facility Unused Capacity Commitment Fee Percentage High End Of Range	0.25%
Financing costs	2,064
Unamortized debt financing cost	760
Debt financing cost amortization period	5 years
Effective interest rate		2.31%	1.57%	2.00%	1.50%
Impact of change in effective interest rate		4,506		4,506
Standby Letters of Credit
Line of Credit Facility [Line Items]
Revolving Credit Facility		12,424		12,424
LIBOR
Line of Credit Facility [Line Items]
Credit Facility Variable Rate Low End	0.00%
Credit Facility Variable Rate High End	2.75%
Debt Instrument, Basis Spread on Variable Rate	1.00%
Base Rate
Line of Credit Facility [Line Items]
Credit Facility Variable Rate Low End	0.00%
Credit Facility Variable Rate High End	1.75%
Federal Funds Rate
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.50%
First Amendment to the Credit Agreement | Credit facility borrowings
Line of Credit Facility [Line Items]
Unamortized debt financing cost								1,279
Coverage ratio requirement		3.00		3.00
Leverage ratio requirement		4.25		4.25
Current coverage ratio		12.81		12.81
Current leverage ratio		3.69		3.69
Credit Agreement, Additional Indebtedness								300,000
Credit Agreement, Sale Leaseback Capacity								100,000
Credit Agreement, Additional Capacity, Mortgage Indebtedness								50,000
R&D Loan
Line of Credit Facility [Line Items]
Loans Payable						3,000
Interest-free-loan period						7 years
R&D Loan | Minimum
Line of Credit Facility [Line Items]
Variable interest rate						2.00%
Scenario, Forecast | First Amendment to the Credit Agreement | Credit facility borrowings
Line of Credit Facility [Line Items]
Leverage ratio requirement									4.00
Interest-free loan
Line of Credit Facility [Line Items]
Long-term Debt		850		850			835
R&D Loan
Line of Credit Facility [Line Items]
Long-term Debt		2,732		2,732			0
Loans Payable						1,000
Credit facility borrowings
Line of Credit Facility [Line Items]
Long-term Debt		444,409		444,409			458,898
OHIO | R&D Loan
Line of Credit Facility [Line Items]
Long-term Debt		$ 2,323		$ 2,323