Revolving Credit Facility (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
	Jul. 27, 2012	Oct. 26, 2012
Line of Credit Facility [Abstract]
Revolving Credit Facility, Maximum Borrowing Capacity	$ 300,000
Line of Credit Facility, Amount Outstanding		99,759
Letters of Credit Outstanding, Amount		12,849
Revolving Credit Facility Term	five
Credit Facility Unused Capacity Commitment Fee Percentage Low End Of Range	0.15%
Credit Facility Unused Capacity Commitment Fee Percentage High End Of Range	0.275%
Revolving Credit Facility, Commitment Fee Amount	1,000
Loans Payable		$ 1,000
Loan Issueance Date		Aug. 28, 2012
Loan Interest Rate		0.00%
Loan Due Date		Aug. 28, 2022
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Effective Percentage		1.20%
Federal Funds Rate [Member]
Line of Credit Facility [Line Items]
Interest Added To Base Rate (As A Percent)	0.50%
Libor [Member]
Line of Credit Facility [Line Items]
Credit Facility Variable Rate Low End	0.75%
Credit Facility Variable Rate High End	2.00%
Interest Added To Base Rate (As A Percent)	1.00%
Base Rate [Member]
Line of Credit Facility [Line Items]
Interest Added To Base Rate (As A Percent)	1.00%